Picked up a 63.5cm Vintage Norco Road Bike..
#51
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
Yes I meant 26" on the back and 700c on the front, the idea being to to slacken the seat-tube angle. But yes it's true it will lower the BB and it sounds like that's a problem.
It will slacken the head angle by the same amount which is a pretty big difference-- 5 degrees on the head angle could increase the trail by 15cm which is a lot. Really you would need more fork offset. If I was building a frame like this I think I would go slack on the HT in order to bring the handlebar back towards the seat. And then use fork offset to get the trail back to a reasonable value. But if trying to life-hack with existing parts you'd want to start with a frame with a steep HT to start with, like 74 degrees. The problem is that means a road bike and the BB will be quite low.
You're thinking about frame flex or aerodynamics? Neither should be a huge problem. Long chainstays may also add a bit of suspension. But going as slack as 65 degrees on the seat-tube would necessitate chainstays longer than are supplied by the regular bicycle tubing manufacturers. I did once see an interesting bike that had sort of wishbone chainstays. I can't remember exactly how they'd done it but there was some kind of tube going back from the BB to what may have been another BB shell and then the regular chainstays started there. I think it had sort of laid-back semi-recumbent geometry.
It will slacken the head angle by the same amount which is a pretty big difference-- 5 degrees on the head angle could increase the trail by 15cm which is a lot. Really you would need more fork offset. If I was building a frame like this I think I would go slack on the HT in order to bring the handlebar back towards the seat. And then use fork offset to get the trail back to a reasonable value. But if trying to life-hack with existing parts you'd want to start with a frame with a steep HT to start with, like 74 degrees. The problem is that means a road bike and the BB will be quite low.
You're thinking about frame flex or aerodynamics? Neither should be a huge problem. Long chainstays may also add a bit of suspension. But going as slack as 65 degrees on the seat-tube would necessitate chainstays longer than are supplied by the regular bicycle tubing manufacturers. I did once see an interesting bike that had sort of wishbone chainstays. I can't remember exactly how they'd done it but there was some kind of tube going back from the BB to what may have been another BB shell and then the regular chainstays started there. I think it had sort of laid-back semi-recumbent geometry.
you could make it work, but I think with the extra increase in wheelbase using the longer chainstays and fork rake, it would become sort of a cargo bike freight train
I definetly agree on having the seat tube pretty slack, but from the perspective of balancing performance with stability at the sort of lower speeds I typically ride at, I would want a head tube angle sufficiently steep enough to lower trail figures slightly, with less rake taken in consideration.
my idea is to subtly lower the wheelbase front and rear in order to increase low speed agility without making such a big difference that high speed handling would suffer. This was my idea for shortening the chain stays - purely based on the "liveliness" and the way the bike pivots/manveures when asked to perform a technical corner.
As it is right now, the current combination of slack head tube with aggressive fork rake is designed to achieve the best balance possible between low speed response with high speed stability- with a light load in mind, particularly in the front. For a lighter rider, or even for someone like me at 200lb riding mostly unloaded, you'd want slightly less fork rake but a somewhat more significant increase in headtube angle to make up for it. While leaving the seat tube angle roughly the same as before.
As it is right now, the front end of the bike feels extremely stable, particularly when riding with up to roughly 35lb of load evenly distributed front and rear. Without a load, the front end is tuned to grip in a way which allows the rear axle to come around in a graceful manner, which i wouldn't expect with a slack seat tube. So there are obviously other factors at play here which concern handling and stability toward the rear of the bike.
#52
Senior Member
Join Date: Dec 2019
Posts: 956
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 321 Post(s)
Liked 263 Times
in
212 Posts
The difference between achieving a given trail with slack + rake rather than steeper with less rake is that the former has more wheel flop. This is why touring bikes sometimes use steeper and less rake because if you're carrying bags on the fork they exaggerate the wheel flop. So yes with 5kg on the front probably don't want too much flop, so less slack is better.
If you use long CS because of a slack ST you aren't actually making the wheelbase longer. The CS just have to become longer because the BB is further forward.
Does anyone know what the actual geometry of a traditional "roadster" was/is? I'm guessing about 68 degree seat tube, and possibly parallel head-tube. People are still riding probably huge distances on these bikes in China, India and other places.
If you use long CS because of a slack ST you aren't actually making the wheelbase longer. The CS just have to become longer because the BB is further forward.
Does anyone know what the actual geometry of a traditional "roadster" was/is? I'm guessing about 68 degree seat tube, and possibly parallel head-tube. People are still riding probably huge distances on these bikes in China, India and other places.
#53
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
The difference between achieving a given trail with slack + rake rather than steeper with less rake is that the former has more wheel flop. This is why touring bikes sometimes use steeper and less rake because if you're carrying bags on the fork they exaggerate the wheel flop. So yes with 5kg on the front probably don't want too much flop, so less slack is better.
If you use long CS because of a slack ST you aren't actually making the wheelbase longer. The CS just have to become longer because the BB is further forward.
Does anyone know what the actual geometry of a traditional "roadster" was/is? I'm guessing about 68 degree seat tube, and possibly parallel head-tube. People are still riding probably huge distances on these bikes in China, India and other places.
If you use long CS because of a slack ST you aren't actually making the wheelbase longer. The CS just have to become longer because the BB is further forward.
Does anyone know what the actual geometry of a traditional "roadster" was/is? I'm guessing about 68 degree seat tube, and possibly parallel head-tube. People are still riding probably huge distances on these bikes in China, India and other places.
What about the other end of the spectrum? A steep head tube angle with relatively little fork rake? If you play around with the parameters to achieve similar trail figures, what would be the main differences in handling?
If you increase bottom bracket height to compensate for longer crank arms, would thst neutralize any penalty with a higher centre of gravity?
#54
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
Just bought this on ebay for the GT:
https://www.ebay.com/p/1201571143
Super excited to install and try it out on singletrack this season.
https://www.ebay.com/p/1201571143
Super excited to install and try it out on singletrack this season.
#55
Senior Member
Join Date: Dec 2019
Posts: 956
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 321 Post(s)
Liked 263 Times
in
212 Posts
Very good points you bring up. Seems you know quite a bit about bike fit. What sort of frames do you typically build? Opinion on materials other than steel? Any benefits with using steeper seat tubes?
What about the other end of the spectrum? A steep head tube angle with relatively little fork rake? If you play around with the parameters to achieve similar trail figures, what would be the main differences in handling?
If you increase bottom bracket height to compensate for longer crank arms, would thst neutralize any penalty with a higher centre of gravity?
What about the other end of the spectrum? A steep head tube angle with relatively little fork rake? If you play around with the parameters to achieve similar trail figures, what would be the main differences in handling?
If you increase bottom bracket height to compensate for longer crank arms, would thst neutralize any penalty with a higher centre of gravity?
A steeper ST is better if you want to lean forward over the handlebar more, which is more aero and faster. They knew this in 1945 and the "Club" and "Sports" models had more upright STs and lower handlebars (sometimes the same handlebar only turned upside down). It's perfectly comfortable when you're used to it.
But it feels sometimes like we keep going in circles perhaps trying to recreate the roadsters of the 1930s but not wanting to admit it because they aren't cool. In the 80s everyone was sold a drop handlebar 10 speed. Many flipped the bars upside down for more stack height. Then in the 90s we all rode rigid fork MTBs on the road which were more upright and had softer tyres. Then we had "hybrids". Now we're making "gravel" bikes with fat tyres and a taller stack. It might be interesting to make something with roadster geometry but with modern tubing and drivetrain.
I've built various frames but mostly fairly conventional geometry, especially the ones for my own use because I'm used to that kind of bike. The homemade frame I ride the most is 73 parallel, 555mm square with a 1" horizontal TT and pretty short CS, 70mm BB drop. Very traditional road bike design from the 70s or 80s and extremely comfortable for me.
The 29er hardtail I made was a bit different from "standard" because I went longer CS, lower BB and lighter than what you would normally buy. Because I knew that the guy I was making it for wasn't going to be sending massive jumps or anything so didn't need such an overbuilt frame (or high BB) as what you would buy. The longer CS was to balance out the slack front end and stop the front wheel popping up as much on climbs. Another road bike I made I went 5mm lower on the BB because I knew the person it was for wanted 165mm cranks. So it's quite fun to be able to tweak details on custom builds like this.
Carbon fibre is ultimately the best material for a bike because it has the best strength-to-weight ratio. But it doesn't have the aesthetic appeal of steel and is not as much fun to work with. Titanium is probably very good but harder to work with and more expensive so not really worth getting involved with at my level.
Steeper HT and less rake can give you the same trail with less flop. But idk what this would actually feel like in practice. Most sources say you want a bit of wheel flop or it feels weird.
I tend to think you want the BB low but this isn't based on any good science. Unless it's a fixed gear pedal strike is unlikely to be a problem as you can just lift the inside crank on fast downhill corners.
#56
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
I don't know much about bike fit but I'm also quite skeptical that anyone does. It's quite a difficult subject to be objective about because people get used to different things. It also seems to be driven by fashion quite a bit.
A steeper ST is better if you want to lean forward over the handlebar more, which is more aero and faster. They knew this in 1945 and the "Club" and "Sports" models had more upright STs and lower handlebars (sometimes the same handlebar only turned upside down). It's perfectly comfortable when you're used to it.
But it feels sometimes like we keep going in circles perhaps trying to recreate the roadsters of the 1930s but not wanting to admit it because they aren't cool. In the 80s everyone was sold a drop handlebar 10 speed. Many flipped the bars upside down for more stack height. Then in the 90s we all rode rigid fork MTBs on the road which were more upright and had softer tyres. Then we had "hybrids". Now we're making "gravel" bikes with fat tyres and a taller stack. It might be interesting to make something with roadster geometry but with modern tubing and drivetrain.
I've built various frames but mostly fairly conventional geometry, especially the ones for my own use because I'm used to that kind of bike. The homemade frame I ride the most is 73 parallel, 555mm square with a 1" horizontal TT and pretty short CS, 70mm BB drop. Very traditional road bike design from the 70s or 80s and extremely comfortable for me.
The 29er hardtail I made was a bit different from "standard" because I went longer CS, lower BB and lighter than what you would normally buy. Because I knew that the guy I was making it for wasn't going to be sending massive jumps or anything so didn't need such an overbuilt frame (or high BB) as what you would buy. The longer CS was to balance out the slack front end and stop the front wheel popping up as much on climbs. Another road bike I made I went 5mm lower on the BB because I knew the person it was for wanted 165mm cranks. So it's quite fun to be able to tweak details on custom builds like this.
Carbon fibre is ultimately the best material for a bike because it has the best strength-to-weight ratio. But it doesn't have the aesthetic appeal of steel and is not as much fun to work with. Titanium is probably very good but harder to work with and more expensive so not really worth getting involved with at my level.
Steeper HT and less rake can give you the same trail with less flop. But idk what this would actually feel like in practice. Most sources say you want a bit of wheel flop or it feels weird.
I tend to think you want the BB low but this isn't based on any good science. Unless it's a fixed gear pedal strike is unlikely to be a problem as you can just lift the inside crank on fast downhill corners.
A steeper ST is better if you want to lean forward over the handlebar more, which is more aero and faster. They knew this in 1945 and the "Club" and "Sports" models had more upright STs and lower handlebars (sometimes the same handlebar only turned upside down). It's perfectly comfortable when you're used to it.
But it feels sometimes like we keep going in circles perhaps trying to recreate the roadsters of the 1930s but not wanting to admit it because they aren't cool. In the 80s everyone was sold a drop handlebar 10 speed. Many flipped the bars upside down for more stack height. Then in the 90s we all rode rigid fork MTBs on the road which were more upright and had softer tyres. Then we had "hybrids". Now we're making "gravel" bikes with fat tyres and a taller stack. It might be interesting to make something with roadster geometry but with modern tubing and drivetrain.
I've built various frames but mostly fairly conventional geometry, especially the ones for my own use because I'm used to that kind of bike. The homemade frame I ride the most is 73 parallel, 555mm square with a 1" horizontal TT and pretty short CS, 70mm BB drop. Very traditional road bike design from the 70s or 80s and extremely comfortable for me.
The 29er hardtail I made was a bit different from "standard" because I went longer CS, lower BB and lighter than what you would normally buy. Because I knew that the guy I was making it for wasn't going to be sending massive jumps or anything so didn't need such an overbuilt frame (or high BB) as what you would buy. The longer CS was to balance out the slack front end and stop the front wheel popping up as much on climbs. Another road bike I made I went 5mm lower on the BB because I knew the person it was for wanted 165mm cranks. So it's quite fun to be able to tweak details on custom builds like this.
Carbon fibre is ultimately the best material for a bike because it has the best strength-to-weight ratio. But it doesn't have the aesthetic appeal of steel and is not as much fun to work with. Titanium is probably very good but harder to work with and more expensive so not really worth getting involved with at my level.
Steeper HT and less rake can give you the same trail with less flop. But idk what this would actually feel like in practice. Most sources say you want a bit of wheel flop or it feels weird.
I tend to think you want the BB low but this isn't based on any good science. Unless it's a fixed gear pedal strike is unlikely to be a problem as you can just lift the inside crank on fast downhill corners.
regarding frame fit - for the average person it shouldn't be such a difficult ordeal. But then there are outliers. Since everyone is proportioned differently nonetheless, one person's ideas will not coincide with another. Starts a whole bunch of commotion like you've seen. With bike fit, you find what works for you and hope you come across someone else with a similar idea. Otherwise internet frame fitting is pretty pointless.
Another thing I've noticed about slacker head tube angles is that they can help set your weight rearwards for climbing. My GT zaskar when equipped with a 100mm fork which was wayyy too long for the geomtery it was designed for.. Zero dork rake, super slack head tube angle, super slack seat tube.. on a super stiff and lightweight racing aluminum frame. It was such a disaster. I find that the slack seat tube made climbing easier. Changing to a shorter fork with more releastic angles for that frame made climbing slightly more difficult perhaps, but easily offset with the more aggressive angles and lighter weight by being significantly faster up the hill.
I realized that due to my upright riding position, id probably need longer chainstays if anything . When accelerating hard from a stop or grinding up a hill, I need to pull firmly at the bars to try and keep the front end from getting all light on me. On the plus side, I'm able to pop a perfectly balanced wheelie for the first time ever on my road bike
Whats your opinion on having steeper head tube angles and some fork rake, (rigid fork) on singletrack or xc bikes?
#57
Senior Member
Join Date: Dec 2019
Posts: 956
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 321 Post(s)
Liked 263 Times
in
212 Posts
The trend for MTBs now is very slack at the front, like 65 degrees or even less. Gravel bikes are also going slack. I think this makes for a lot of stability downhill. Climbing off-road is often quite hard because the front wheel pops up into the air. This is why I think making the CS a bit longer is a good idea. I've ready conflicting schience/marketing about the effect of that on downhill handling. Some people reckon a short CS is more "nimble". Others say a long one is actually totally fine...
I don't think the length of the front makes much difference to wheelies unless you put heavy bags on there. It's more about where the rear is compared to the CoG. Just as the position of the rear doesn't make much difference to whether you endo on braking. That's all about where the front is compared to the CoG. So I think the slack front end works very well but you need a long rear as well. This means your bike might not fit in your car any more The one I made has a wheelbase of 1218mm, probably 200mm longer or so than an MTB from the 90s which would also have had smaller diameter wheels.
Climbing is a very different consideration for MTBs because the hills are that much steeper. There are very few surfaced roads where there's a risk of popping the front wheel.
On a road bike with a slack ST you can get away with a more rear biased weight distribution. But it's true that since you are pushing the weight back there will come a point where you really want to make the rear longer and the front shorter. An HT that's steeper than the ST might be interesting. Normally you have a slack HT with a slack ST partly perhaps because parallel frames were easier to mass produce but also because you do need to pull the handlebar back towards the seat. This can however be achieved with a short stem and swept back bar.
One thing about ST angle that's very important is what happens when you stand on the pedals. At some point if you make the ST too slack you can't stand up without hitting your legs on the handlebar. I guess this marks the point where you've crossed over into a full recumbent.
I wonder if the "roadster" position is easier for people who've never ridden a bike before and this is why it was so popular at a time when many people were getting on a bike for the first time. It may be that the position and muscles used are closer to walking. People also tended to pedal with much lower cadence than now. There was none of this spinning. The part I don't buy into though is that it's necessarily uncomfortable over long distances. The Dutch do of course still ride these kinds of bikes but apart from the super traditional "omafiets" and "opafiets" the more modern takes on them look like they do have slightly steeper seat angles. The handlebar is still high though and the seat squishy. These days a battery is often added and quite often clip-on TT bars (NL is as flat as a pancake nearly everywhere but subject to very strong winds). Interestingly when you see "roadies" in the Netherlands they more often ride on the tops than I've seen in the UK. These are people who are used to the traditional style of bike from an early age.
I don't think the length of the front makes much difference to wheelies unless you put heavy bags on there. It's more about where the rear is compared to the CoG. Just as the position of the rear doesn't make much difference to whether you endo on braking. That's all about where the front is compared to the CoG. So I think the slack front end works very well but you need a long rear as well. This means your bike might not fit in your car any more The one I made has a wheelbase of 1218mm, probably 200mm longer or so than an MTB from the 90s which would also have had smaller diameter wheels.
Climbing is a very different consideration for MTBs because the hills are that much steeper. There are very few surfaced roads where there's a risk of popping the front wheel.
On a road bike with a slack ST you can get away with a more rear biased weight distribution. But it's true that since you are pushing the weight back there will come a point where you really want to make the rear longer and the front shorter. An HT that's steeper than the ST might be interesting. Normally you have a slack HT with a slack ST partly perhaps because parallel frames were easier to mass produce but also because you do need to pull the handlebar back towards the seat. This can however be achieved with a short stem and swept back bar.
One thing about ST angle that's very important is what happens when you stand on the pedals. At some point if you make the ST too slack you can't stand up without hitting your legs on the handlebar. I guess this marks the point where you've crossed over into a full recumbent.
I wonder if the "roadster" position is easier for people who've never ridden a bike before and this is why it was so popular at a time when many people were getting on a bike for the first time. It may be that the position and muscles used are closer to walking. People also tended to pedal with much lower cadence than now. There was none of this spinning. The part I don't buy into though is that it's necessarily uncomfortable over long distances. The Dutch do of course still ride these kinds of bikes but apart from the super traditional "omafiets" and "opafiets" the more modern takes on them look like they do have slightly steeper seat angles. The handlebar is still high though and the seat squishy. These days a battery is often added and quite often clip-on TT bars (NL is as flat as a pancake nearly everywhere but subject to very strong winds). Interestingly when you see "roadies" in the Netherlands they more often ride on the tops than I've seen in the UK. These are people who are used to the traditional style of bike from an early age.
Last edited by guy153; 02-06-21 at 03:49 AM.
#58
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
The trend for MTBs now is very slack at the front, like 65 degrees or even less. Gravel bikes are also going slack. I think this makes for a lot of stability downhill. Climbing off-road is often quite hard because the front wheel pops up into the air. This is why I think making the CS a bit longer is a good idea. I've ready conflicting schience/marketing about the effect of that on downhill handling. Some people reckon a short CS is more "nimble". Others say a long one is actually totally fine...
I don't think the length of the front makes much difference to wheelies unless you put heavy bags on there. It's more about where the rear is compared to the CoG. Just as the position of the rear doesn't make much difference to whether you endo on braking. That's all about where the front is compared to the CoG. So I think the slack front end works very well but you need a long rear as well. This means your bike might not fit in your car any more The one I made has a wheelbase of 1218mm, probably 200mm longer or so than an MTB from the 90s which would also have had smaller diameter wheels.
Climbing is a very different consideration for MTBs because the hills are that much steeper. There are very few surfaced roads where there's a risk of popping the front wheel.
On a road bike with a slack ST you can get away with a more rear biased weight distribution. But it's true that since you are pushing the weight back there will come a point where you really want to make the rear longer and the front shorter. An HT that's steeper than the ST might be interesting. Normally you have a slack HT with a slack ST partly perhaps because parallel frames were easier to mass produce but also because you do need to pull the handlebar back towards the seat. This can however be achieved with a short stem and swept back bar.
One thing about ST angle that's very important is what happens when you stand on the pedals. At some point if you make the ST too slack you can't stand up without hitting your legs on the handlebar. I guess this marks the point where you've crossed over into a full recumbent.
I wonder if the "roadster" position is easier for people who've never ridden a bike before and this is why it was so popular at a time when many people were getting on a bike for the first time. It may be that the position and muscles used are closer to walking. People also tended to pedal with much lower cadence than now. There was none of this spinning. The part I don't buy into though is that it's necessarily uncomfortable over long distances. The Dutch do of course still ride these kinds of bikes but apart from the super traditional "omafiets" and "opafiets" the more modern takes on them look like they do have slightly steeper seat angles. The handlebar is still high though and the seat squishy. These days a battery is often added and quite often clip-on TT bars (NL is as flat as a pancake nearly everywhere but subject to very strong winds). Interestingly when you see "roadies" in the Netherlands they more often ride on the tops than I've seen in the UK. These are people who are used to the traditional style of bike from an early age.
I don't think the length of the front makes much difference to wheelies unless you put heavy bags on there. It's more about where the rear is compared to the CoG. Just as the position of the rear doesn't make much difference to whether you endo on braking. That's all about where the front is compared to the CoG. So I think the slack front end works very well but you need a long rear as well. This means your bike might not fit in your car any more The one I made has a wheelbase of 1218mm, probably 200mm longer or so than an MTB from the 90s which would also have had smaller diameter wheels.
Climbing is a very different consideration for MTBs because the hills are that much steeper. There are very few surfaced roads where there's a risk of popping the front wheel.
On a road bike with a slack ST you can get away with a more rear biased weight distribution. But it's true that since you are pushing the weight back there will come a point where you really want to make the rear longer and the front shorter. An HT that's steeper than the ST might be interesting. Normally you have a slack HT with a slack ST partly perhaps because parallel frames were easier to mass produce but also because you do need to pull the handlebar back towards the seat. This can however be achieved with a short stem and swept back bar.
One thing about ST angle that's very important is what happens when you stand on the pedals. At some point if you make the ST too slack you can't stand up without hitting your legs on the handlebar. I guess this marks the point where you've crossed over into a full recumbent.
I wonder if the "roadster" position is easier for people who've never ridden a bike before and this is why it was so popular at a time when many people were getting on a bike for the first time. It may be that the position and muscles used are closer to walking. People also tended to pedal with much lower cadence than now. There was none of this spinning. The part I don't buy into though is that it's necessarily uncomfortable over long distances. The Dutch do of course still ride these kinds of bikes but apart from the super traditional "omafiets" and "opafiets" the more modern takes on them look like they do have slightly steeper seat angles. The handlebar is still high though and the seat squishy. These days a battery is often added and quite often clip-on TT bars (NL is as flat as a pancake nearly everywhere but subject to very strong winds). Interestingly when you see "roadies" in the Netherlands they more often ride on the tops than I've seen in the UK. These are people who are used to the traditional style of bike from an early age.
What do you think of optimizing frame geomtery on 60+cm frames for 26" wheels? Or would you stick to 700c? 650b?
#59
Senior Member
Join Date: Dec 2019
Posts: 956
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 321 Post(s)
Liked 263 Times
in
212 Posts
I actually just came across this 1953 Claude Butler, which looks like it has a steeper head angle than seat angle:
https://www.bikeforums.net/classic-v...-colson-2.html
This is a fillet-brazed frame so they weren't restricted by what lugs (or "brackets") were available or in use. It looks like it means you can make the whole frame a bit shorter. Quite a nice compact design.
26" wheels may be coming back into style because you can run tyres with taller sidewalls. https://www.renehersecycles.com/why-...t-roll-faster/
My opinion is that on a big frame for road use wheel size doesn't matter a whole lot especially in the range 26" thru 700c. The main reason for smaller wheels is for a small frame-- anyone not much taller than 5 ft may be better off with a front wheel smaller than 700c. And then you may as well make the back wheel smaller too so you don't have to carry two spare tubes everywhere.
26" wheels on larger bikes might be a nicer way to get the tyre clearance for the fat tyres people like to run these days. You see all kinds of hacks^H^H^H^H^H solutions to squeeze the tyre and the crank in like dropped chainstays, yokes. They probably don't do any harm but I don't like them aesthetically. If the diameter is smaller then there's much more space for the tyre for a given CS length as the CS get further apart the further back you go.
https://www.bikeforums.net/classic-v...-colson-2.html
This is a fillet-brazed frame so they weren't restricted by what lugs (or "brackets") were available or in use. It looks like it means you can make the whole frame a bit shorter. Quite a nice compact design.
26" wheels may be coming back into style because you can run tyres with taller sidewalls. https://www.renehersecycles.com/why-...t-roll-faster/
My opinion is that on a big frame for road use wheel size doesn't matter a whole lot especially in the range 26" thru 700c. The main reason for smaller wheels is for a small frame-- anyone not much taller than 5 ft may be better off with a front wheel smaller than 700c. And then you may as well make the back wheel smaller too so you don't have to carry two spare tubes everywhere.
26" wheels on larger bikes might be a nicer way to get the tyre clearance for the fat tyres people like to run these days. You see all kinds of hacks^H^H^H^H^H solutions to squeeze the tyre and the crank in like dropped chainstays, yokes. They probably don't do any harm but I don't like them aesthetically. If the diameter is smaller then there's much more space for the tyre for a given CS length as the CS get further apart the further back you go.
#60
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
I actually just came across this 1953 Claude Butler, which looks like it has a steeper head angle than seat angle:
https://www.bikeforums.net/classic-v...-colson-2.html
This is a fillet-brazed frame so they weren't restricted by what lugs (or "brackets") were available or in use. It looks like it means you can make the whole frame a bit shorter. Quite a nice compact design.
26" wheels may be coming back into style because you can run tyres with taller sidewalls. https://www.renehersecycles.com/why-...t-roll-faster/
My opinion is that on a big frame for road use wheel size doesn't matter a whole lot especially in the range 26" thru 700c. The main reason for smaller wheels is for a small frame-- anyone not much taller than 5 ft may be better off with a front wheel smaller than 700c. And then you may as well make the back wheel smaller too so you don't have to carry two spare tubes everywhere.
26" wheels on larger bikes might be a nicer way to get the tyre clearance for the fat tyres people like to run these days. You see all kinds of hacks^H^H^H^H^H solutions to squeeze the tyre and the crank in like dropped chainstays, yokes. They probably don't do any harm but I don't like them aesthetically. If the diameter is smaller then there's much more space for the tyre for a given CS length as the CS get further apart the further back you go.
https://www.bikeforums.net/classic-v...-colson-2.html
This is a fillet-brazed frame so they weren't restricted by what lugs (or "brackets") were available or in use. It looks like it means you can make the whole frame a bit shorter. Quite a nice compact design.
26" wheels may be coming back into style because you can run tyres with taller sidewalls. https://www.renehersecycles.com/why-...t-roll-faster/
My opinion is that on a big frame for road use wheel size doesn't matter a whole lot especially in the range 26" thru 700c. The main reason for smaller wheels is for a small frame-- anyone not much taller than 5 ft may be better off with a front wheel smaller than 700c. And then you may as well make the back wheel smaller too so you don't have to carry two spare tubes everywhere.
26" wheels on larger bikes might be a nicer way to get the tyre clearance for the fat tyres people like to run these days. You see all kinds of hacks^H^H^H^H^H solutions to squeeze the tyre and the crank in like dropped chainstays, yokes. They probably don't do any harm but I don't like them aesthetically. If the diameter is smaller then there's much more space for the tyre for a given CS length as the CS get further apart the further back you go.
As for the whole rim and tire ordeal, seems like the general consensus is that the casing and design of the tire itself would offer the best balance between handling, stability, ride comfort, etc. Each bike is designed around a specific diameter wheel which can be compensated with different diameter rims, tires, etc. Personally I think the biggest advantage from a performance perspective with thinner tires would be aerodynamics, that's about it. Because a wider tire will offer the same contact patch as something more narrow if PSI is the same. So id rather go for a wider tire and simply play around with PSI figures depending on terrain.
Obviously, the tread pattern of the tire would probably be the most important thing to consider here. You don't want knobby trail tires for pavement and vice versa. With a carefully designed tire tread and compound, you can certainly achieve a balance where one tire will perform most tasks rather well.
The other thing would be the width of the rim versus the tire. The tighter the tire bead fits, the better the performance will be. You don't want to use a 45mm wide tire on a rim designed for 28mm road tires. Itll fit, but you'll get a balloon effect because the tire won't be as tight on there as it should. For example, im using a 26x1.75 (45mm wide tire) on a 22mm wide rim, but according to my caliper measuring tool, the tire only fits to be 40mm wide.
26" rims tend to look small on XXL frames, but i do really like the notable difference in handling response when running smaller diameter rims and tires. However, you'd probably need tires which are simply too tall and wide to work properly with the geomtery. I think 650x45 would be the best balance.
Its okay to play around with different diameter rims and tires on a frame to experiment, but from personal experience, I would suggest not differentiating diameters front versus rear more than 10mm or so. Even if you are trying to change angles on a frame with different size rims front or rear, it just doesn't work as well as you might have hoped for.
The last thing to note, is that these road frames are clearly designed around thin tires. I wonder what youd have to change, according to frame geomtery, material, tube butting/diameter etc to account for wider or narrower tires.
#61
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
guy153
Another thing to note, is that you can really take advantage of a tubeless setup with wider tires. The smoother ride should be very helpful with rolling resistance.
The link you've posted proves that super high psi is not necessarily doing to reduce rolling resistsnce. You want to find the right balance between the casing of the tire compressing and retaining its circular shape with each revolution, I suppose.
Another thing to note, is that you can really take advantage of a tubeless setup with wider tires. The smoother ride should be very helpful with rolling resistance.
The link you've posted proves that super high psi is not necessarily doing to reduce rolling resistsnce. You want to find the right balance between the casing of the tire compressing and retaining its circular shape with each revolution, I suppose.
#62
Senior Member
Join Date: Jun 2013
Location: Yolo County, West Sacramento CA
Posts: 517
Bikes: Modified 26 inch frame Schwinn Varsity with 700c wheels and 10 speed cassette hub. Ryan Vanguard recumbent. 67cm 27"x1 1/4" Schwinn Sports Tourer from the 1980's. 1980's 68cm Nishiki Sebring with 700c aero wheels, 30 speeds, flat bar bicycle.
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 131 Post(s)
Liked 141 Times
in
102 Posts
Tektro 559
I own a pair of Tektro 559's that are mounted on my Schwinn Chicago Varsity. A couple of pictures of the bicycle with the 559's mounted. This bike came with 27"x1 1/4" wheels but now sports Velocity Chukkar 700c rims on Velo Orange hubs. The brakes are actuated by Tektro MTB short pull levers. The brakes work fine in this application. I have run one of these frames and forks with double 26" x 1 3/4" wheels and tires for off roading. The bottom bracket was a little lower but never caused me issues while mountain biking. This bike is running a 10 speed cassette on the rear and is a 1x10 setup with Shimano Shadow MTB rear derailleur shifted by a Microshift indexed thumb shifter. This bike is a real pleasure to ride. The tires are 700c x 40mm Schwalbe Marathon Plus and are super durable and pretty fast. This bike excels at gravel and dirt roads. Because of its slack head tube and seatpost tube it handles very nicely and is my favorite bicycle for handling. The seat is soon to be changed to a Spiderflex noseless saddle. I'll post my thoughts on the Spiderflex saddle soon.
#63
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
guy153 - your "effective" seat tube angle changes according to saddle angle. The more the nose of the saddle is angled up, the slacker the seat tube will "feel"
Road bikes most likely have more fork rake because this prevents the bike from leaning too much side to side as you ride. You can get away with a lower bottom bracket height.
Road bikes most likely have more fork rake because this prevents the bike from leaning too much side to side as you ride. You can get away with a lower bottom bracket height.
#64
Senior Member
Join Date: Dec 2019
Posts: 956
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 321 Post(s)
Liked 263 Times
in
212 Posts
guy153 - your "effective" seat tube angle changes according to saddle angle. The more the nose of the saddle is angled up, the slacker the seat tube will "feel"
Road bikes most likely have more fork rake because this prevents the bike from leaning too much side to side as you ride. You can get away with a lower bottom bracket height.
Road bikes most likely have more fork rake because this prevents the bike from leaning too much side to side as you ride. You can get away with a lower bottom bracket height.
Most bikes have pretty standard fork rakes (an offset of I think 45mm) but road bikes tend to have slightly steeper HTs meaning less trail and handling that is more "nimble" and less "stable".
Trail is the most important factor but a given trail can be achieved with a range of different fork rake and head angle combinations. These differ in the amount of wheel flop. But most bikes nowadays use standard forks anyway.
I have now finished my "fitting bike" (pictures in the framebuilders forum) and am designing a frame with a slack 67.5° seat tube angle, long head tube, and a high and swept-back handlebar for a rider who doesn't like putting so much weight on her hands. So we'll see how it turns out! It's going to be a kind of mini-opafiets but made of modern lightweight Reynolds tubing.
#65
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
The lean is a direct function of cornering acceleration and is the same on any bike taking a given corner at a given speed. Otherwise it would fall over.
Most bikes have pretty standard fork rakes (an offset of I think 45mm) but road bikes tend to have slightly steeper HTs meaning less trail and handling that is more "nimble" and less "stable".
Trail is the most important factor but a given trail can be achieved with a range of different fork rake and head angle combinations. These differ in the amount of wheel flop. But most bikes nowadays use standard forks anyway.
I have now finished my "fitting bike" (pictures in the framebuilders forum) and am designing a frame with a slack 67.5° seat tube angle, long head tube, and a high and swept-back handlebar for a rider who doesn't like putting so much weight on her hands. So we'll see how it turns out! It's going to be a kind of mini-opafiets but made of modern lightweight Reynolds tubing.
Most bikes have pretty standard fork rakes (an offset of I think 45mm) but road bikes tend to have slightly steeper HTs meaning less trail and handling that is more "nimble" and less "stable".
Trail is the most important factor but a given trail can be achieved with a range of different fork rake and head angle combinations. These differ in the amount of wheel flop. But most bikes nowadays use standard forks anyway.
I have now finished my "fitting bike" (pictures in the framebuilders forum) and am designing a frame with a slack 67.5° seat tube angle, long head tube, and a high and swept-back handlebar for a rider who doesn't like putting so much weight on her hands. So we'll see how it turns out! It's going to be a kind of mini-opafiets but made of modern lightweight Reynolds tubing.
What would be the primary design factors to consider between a bike designed for low speed versus high speed handling?
I've heard that large frames, like 62cm or more tend to have a death wobble at high speed. Is it because the tubing and design of the frame is more biased toward smaller sizes? Do frames this large need to be designed differently?
Is it true that you can adjust the "effective" seat tube angle by adjusting the saddle angle?
What about the rims? This is also an important factor to be considering for comfort reasons.
All in all, I like your approach for making frames comfortable, because blending in some of these characteristics into an otherwise sporty performance bike can really help further increase its performance by factoring in some compliance and stability over rough road surfaces etc.
What do you think about those road bikes with a curved seat tube such as this?
You can achieve that rearwards balance you were talking about while simultaneously speeding up handling and agility with the shorter wheelbase. Id like a shorter wheelbase to help with the mostly low speed riding I tend to do. But how can you do so without really paying any penalties in stability when you do end up going fast?
#66
Senior Member
Join Date: Dec 2019
Posts: 956
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 321 Post(s)
Liked 263 Times
in
212 Posts
This guy has some interesting thoughts about it:
Dave Moulton's Blog - Dave Moulton's Bike Blog - A Different Thought on Frame Sizing
All in all, I like your approach for making frames comfortable, because blending in some of these characteristics into an otherwise sporty performance bike can really help further increase its performance by factoring in some compliance and stability over rough road surfaces etc.
What do you think about those road bikes with a curved seat tube such as this?
You can achieve that rearwards balance you were talking about while simultaneously speeding up handling and agility with the shorter wheelbase. Id like a shorter wheelbase to help with the mostly low speed riding I tend to do. But how can you do so without really paying any penalties in stability when you do end up going fast?
You can achieve that rearwards balance you were talking about while simultaneously speeding up handling and agility with the shorter wheelbase. Id like a shorter wheelbase to help with the mostly low speed riding I tend to do. But how can you do so without really paying any penalties in stability when you do end up going fast?
#67
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
tallbikeman hows it going man? What have you been working on? Going for any fun rides? Have you resolved your issue with hand soreness?
- 190mm crank arms with integrated spindle outboard bearing bottom bracket -
Better power output, much smoother spin, improved fit and range of motion, much better gear spacing... im now much less specific about maintaining a particular cadence. Can mash a high gear or spin quickly depending on terrain and energy levels etc.
- Going down to 190lb from 220lb made quite a huge difference with my fit. I am now using a 120mm stem. My balance on the bike is the same as before, now with a lower centre of gravity
- freewheel versus freehub...
- Freehub feels more stable and planted over rough surfaces. Much stiffer design when riding loaded. Responds better to hard cornering. The freewheel design seems prone to flexing slightly under load due to the way the bearings are oriented.
- drop bar versus flat...
Drop bars were definetly out of the question for me when i had excess weight in my abdomen area. I loved them alot for the way they weigh the front axle. Really adds to the stability and power trasnfer of the bike during hard acceleration. Unfortunately they had to go because the bars were too narrow for me and I didn't like the way the brake levers felt when braking in the hoods. Im using a pair of ergonomic 50cm flat bars now which are conveniently my shoulder width. I wouldn't want to go narrower than this, but a bit wider is fine. Unfortunately my ergo grips don't fit onto the bar with the brake levers in place.
-tires... im running 700cx28. Would prefer something wider but not a larger diameter. Maybe a frame designed around 650b x 1.75 would be nice.
All in all, my new nishiki feels stiffer and a lot more performance oriented than my old norco. Still very smooth and balanced. Fantastic blend between stability and agile handling. If I were to find drop bars which were 50cm at the hoods than this is what id use. Otherwise I would prefer geomtery more oriented towards flat bar. I'd want a longer top tube so that I can use a shorter stem and probably longer chainstays as the front end feels light when accelerating hard from a low speed.
otherwise, I've been biking quite a lot, on a near daily basis and have since developed some mild pain in my right knee from hard acceleration, or climbing hills when riding loaded. I'll probably have to take a break from cycling as a result.
- 190mm crank arms with integrated spindle outboard bearing bottom bracket -
Better power output, much smoother spin, improved fit and range of motion, much better gear spacing... im now much less specific about maintaining a particular cadence. Can mash a high gear or spin quickly depending on terrain and energy levels etc.
- Going down to 190lb from 220lb made quite a huge difference with my fit. I am now using a 120mm stem. My balance on the bike is the same as before, now with a lower centre of gravity
- freewheel versus freehub...
- Freehub feels more stable and planted over rough surfaces. Much stiffer design when riding loaded. Responds better to hard cornering. The freewheel design seems prone to flexing slightly under load due to the way the bearings are oriented.
- drop bar versus flat...
Drop bars were definetly out of the question for me when i had excess weight in my abdomen area. I loved them alot for the way they weigh the front axle. Really adds to the stability and power trasnfer of the bike during hard acceleration. Unfortunately they had to go because the bars were too narrow for me and I didn't like the way the brake levers felt when braking in the hoods. Im using a pair of ergonomic 50cm flat bars now which are conveniently my shoulder width. I wouldn't want to go narrower than this, but a bit wider is fine. Unfortunately my ergo grips don't fit onto the bar with the brake levers in place.
-tires... im running 700cx28. Would prefer something wider but not a larger diameter. Maybe a frame designed around 650b x 1.75 would be nice.
All in all, my new nishiki feels stiffer and a lot more performance oriented than my old norco. Still very smooth and balanced. Fantastic blend between stability and agile handling. If I were to find drop bars which were 50cm at the hoods than this is what id use. Otherwise I would prefer geomtery more oriented towards flat bar. I'd want a longer top tube so that I can use a shorter stem and probably longer chainstays as the front end feels light when accelerating hard from a low speed.
otherwise, I've been biking quite a lot, on a near daily basis and have since developed some mild pain in my right knee from hard acceleration, or climbing hills when riding loaded. I'll probably have to take a break from cycling as a result.
#68
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
guy153 how does geometry differ between a design based around flat bar versus drop bars? Longer chainstay and top tube, longer reach for the flat bar oriented setup? Drop bar designs seem to be more biased toward high speed stability with the longer stems.
Since losing weight ive been wanting to stretch out more with a longer stem and getting used to a more leaning position. Still some sort of mix between upright and leaning. The geomtery of the bike seems to be very adaptable according to how I want to ride the bike.
Since losing weight ive been wanting to stretch out more with a longer stem and getting used to a more leaning position. Still some sort of mix between upright and leaning. The geomtery of the bike seems to be very adaptable according to how I want to ride the bike.
#69
Senior Member
Join Date: Dec 2019
Posts: 956
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 321 Post(s)
Liked 263 Times
in
212 Posts
guy153 how does geometry differ between a design based around flat bar versus drop bars? Longer chainstay and top tube, longer reach for the flat bar oriented setup? Drop bar designs seem to be more biased toward high speed stability with the longer stems.
#70
Drip, Drip.
Thread Starter
Join Date: Oct 2020
Location: Southern Ontario
Posts: 1,575
Bikes: Trek Verve E bike, Felt Doctrine 4 XC, Opus Horizon Apex 1
Mentioned: 8 Post(s)
Tagged: 0 Thread(s)
Quoted: 1034 Post(s)
Liked 193 Times
in
163 Posts
Good question, I'm not sure. I think if you have a wider handlebar (the ones currently used on MTBs are ridiculously wide) you probably want longer trail. Increasing the trail kind of gears up the steering (smaller movements, heavier feel) and a wide bar does the opposite. And obviously you need to design the frame properly around fit.
When compared to a typical road bike frame, the top tube length and the reach is the same. The FX, has slightly more slack angles and longer chainstays to adapt to a somewhat more upright riding position.
The angles are slack and the chainstays might be fairly long, but the handling is insanely linear and sharp. With some mindful weight transferring and careful steering inputs, the bike response is quite sufficient for sporty cornering.
The longer chainstays feel tremendous. I have much better stability and climbing ability
The aluminum frame is not so good with road buzz. And smaller bumps compared to steel, but rides more fluidly on smooth surfaces and feels the same over larger bumps. With that being said, there is far more stiffness and very little torsional flexing when cornering and/or pedalling hard.
The bike came with a rack. I've hauled up to about 28kg on this bike. I weigh about 190lb. 20kg extra weight is the most id want to haul on this thing, but for a bike clearly not designed for touring, I think it performed great.
Now I am wondering how much better I can do with a higher end and sportier frame..
#71
Expired Member
Join Date: Jun 2007
Location: TN
Posts: 11,546
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 3674 Post(s)
Liked 5,435 Times
in
2,761 Posts
Welcome back! Some strong competition has emerged in your absence.
#73
Expired Member
Join Date: Jun 2007
Location: TN
Posts: 11,546
Mentioned: 37 Post(s)
Tagged: 0 Thread(s)
Quoted: 3674 Post(s)
Liked 5,435 Times
in
2,761 Posts
Check threads by Alo. Also Cheez and Larry Sellerz.