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-   -   Short Top Tube & Reach for Singletrack? (https://www.bikeforums.net/showthread.php?t=1222004)

Moisture 01-20-21 07:12 PM

Short Top Tube & Reach for Singletrack?
 
I'm looking to either use my current road bike or buy something else specifically for singletrack use this upcoming spring.

I get good comfort and performance on a road bike with a short reach/top tube (390mm reach, 580mm top tube) converted to flat bar using a tall 40mm stem. I want my handlebars slightly above or nearly level with my seat.

I feel like I can rip singletrack on this bike, but tire clearance is lacking in the rear dropouts and the bottom bracket is too low to do anything serious.

I'm thinking that some sort of flat bar gravel bike with extra tire clearance might work best.

Do you think that the short top tube and reach which I prefer isn't ideal for singletrack?

Kapusta 01-21-21 07:24 AM

MTBs tend to have longer top tubes and frame reach numbers than road/gravel bikes.

This has been true for many years but in recent years the difference has become even greater.

Go to any bike company's website and look at the top tube and frame reach numbers of drop bar road/gravel bikes compared to MTBs for a given recommended rider height

Several reasons for this:

1- Drop bars add a lot more reach than flat bars, so the frame reach needs to be shorter.

2- A longer reach frame with a short stem puts the front wheel farther out in front of you, which make the bike less endo-prone.

Of course, if you WANT an extraordinarily short reach.... then a drop bar frame with a flat bar will get that for you. But there are reasons that MTB designers and riders have long moved away from that.

OTOH, the fact that you feel like you can really rip single-track on your road bike (along with other comments you have make about suspension and single-track) makes me think that what you are calling single-track is not what most people mean by it.

Moisture 01-21-21 07:44 AM


Originally Posted by Kapusta (Post 21887590)
MTBs tend to have longer top tubes and frame reach numbers than road/gravel bikes.

This has been true for many years but in recent years the difference has become even greater.

Go to any bike company's website and look at the top tube and frame reach numbers of drop bar road/gravel bikes compared to MTBs for a given recommended rider height

Several reasons for this:

1- Drop bars add a lot more reach than flat bars, so the frame reach needs to be shorter.

2- A longer reach frame with a short stem puts the front wheel farther out in front of you, which make the bike less endo-prone.

Of course, if you WANT an extraordinarily short reach.... then a drop bar frame with a flat bar will get that for you. But there are reasons that MTB designers and riders have long moved away from that.

OTOH, the fact that you feel like you can really rip single-track on your road bike (along with other comments you have make about suspension and single-track) makes me think that what you are calling single-track is not what most people mean by it.

Yes I know, the top tube and reach figures tend to be significantly longer on the trail bikes. But are there any issues with forgoing the norm like I wish to?

Kapusta 01-21-21 08:30 AM


Originally Posted by Moisture (Post 21887618)
Yes I know, the top tube and reach figures tend to be significantly longer on the trail bikes. But are there any issues with forgoing the norm like I wish to?

Well I just outlined one issue in my first reply (see point #2, and consider the opposite situation).

Also, are you going to run a longer stem to compensate for the reduction in reach moving from the drop bar to the flat bar? If so, you are again making the bike more endo-prone. If not, you are going to have a fairly cramped cockpit that does not allow you to practice what is now widely accepted as good bike handling technique. I am not going to try to fully explain this, as you can learn this yourself with some Googling, but what is mostly comes down to is a super short reach it makes it hard (if not impossible) to achieve a good, balanced "attack" position. When you try to get low, you also end up having to get far back, which is not great for maintaining a good fore-aft balance. Yes, you don't want the reach so long that you can't move fore/aft, but making too short prevents you from getting low in an effective manor, and leaves you very cramped while trying to do so.

One other issue not related to the reach is the fact that gravel and road bikes have steeper head tube angles, which not only decreases stability at high speeds in the rough (an issue that is real, though I think it often gets a bit overblown), but also pulls the front wheel closer in, thus increasing the tendency to endo.

prj71 01-21-21 09:47 AM

It comes down to having the right tool for the job.

Would you buy a mountain bike and expect it to be a great performer as a road bike?

If you are riding true single track then get yourself a mountain bike.

Moisture 01-21-21 09:57 AM


Originally Posted by Kapusta (Post 21887673)
Well I just outlined one issue in my first reply (see point #2, and consider the opposite situation).

Also, are you going to run a longer stem to compensate for the reduction in reach moving from the drop bar to the flat bar? If so, you are again making the bike more endo-prone. If not, you are going to have a fairly cramped cockpit that does not allow you to practice what is now widely accepted as good bike handling technique. I am not going to try to fully explain this, as you can learn this yourself with some Googling, but what is mostly comes down to is a super short reach it makes it hard (if not impossible) to achieve a good, balanced "attack" position. When you try to get low, you also end up having to get far back, which is not great for maintaining a good fore-aft balance. Yes, you don't want the reach so long that you can't move fore/aft, but making too short prevents you from getting low in an effective manor, and leaves you very cramped while trying to do so.

One other issue not related to the reach is the fact that gravel and road bikes have steeper head tube angles, which not only decreases stability at high speeds in the rough (an issue that is real, though I think it often gets a bit overblown), but also pulls the front wheel closer in, thus increasing the tendency to endo.

May you please elaborate what you mean by endo prone?,

Kapusta 01-21-21 10:02 AM


Originally Posted by Moisture (Post 21887808)
May you please elaborate what you mean by endo prone?,

Come on, man. Just Google "Mountain Bike Endo" maybe add "crash" to the search.

Moisture 01-21-21 10:18 AM


Originally Posted by Kapusta (Post 21887818)
Come on, man. Just Google "Mountain Bike Endo" maybe add "crash" to the search.

I did try searching up bike endo first, didn't find much.. I understand now.

Well, from the perspective of how poised and balanced I feel on the bike currently, I wouldn't want my setup to be any different unless we are talking about more technical singletrack with rocky and rooty stuff. If were talking about quick flowy more XC related stuff, I dont think I'd be able to do any better than what I have now. With the addition of my 40mm stem, down from 60mm, I was able to slide my seat back roughly 8mm, so that I am still in a slightly leaning forward position without sacrificing that rear weight biased feeling I have been longing for.

If we are talking about something more technical which requires you to be frequently out of the saddle to navigate, I think I would need a combination of just a slightly longer stem paired with a slightly longer top tube so that I can slide my seat a bit more rear wards to get that stretched out position necessary for such terrain.

So until I experiment with some legitimate trail bikes, I think I'd be better off sticking to with some more mild trails...

because if I do simply opt for a longer stem, like 60mm or longer, I feel a bit too endo prone.

Kapusta 01-21-21 10:48 AM


Originally Posted by Moisture (Post 21887848)
I did try searching up bike endo first, didn't find much.. I understand now.

Well, from the perspective of how poised and balanced I feel on the bike currently, I wouldn't want my setup to be any different unless we are talking about more technical singletrack with rocky and rooty stuff. If were talking about quick flowy more XC related stuff, I dont think I'd be able to do any better than what I have now. With the addition of my 40mm stem, down from 60mm, I was able to slide my seat back roughly 8mm, so that I am still in a slightly leaning forward position without sacrificing that rear weight biased feeling I have been longing for.

If we are talking about something more technical which requires you to be frequently out of the saddle to navigate, I think I would need a combination of just a slightly longer stem paired with a slightly longer top tube so that I can slide my seat a bit more rear wards to get that stretched out position necessary for such terrain.

So until I experiment with some legitimate trail bikes, I think I'd be better off sticking to with some more mild trails...

because if I do simply opt for a longer stem, like 60mm or longer, I feel a bit too endo prone.

Well it is certainly cheaper to play around with what you already have.

But if you can try out a dedicated MTB, you should consider doing so, so that you have something to compare your current setup against.

HD3andMe 01-21-21 12:36 PM

What, the account that has claimed to own the best mtb ever(Zaskar) is now trolling the MTB forum with different bait?

Color my unsurprised.

You've been warned.

https://www.bikeforums.net/general-c...-geometry.html

Moisture 01-21-21 01:11 PM


Originally Posted by Cabbage Man (Post 21887889)
Well it is certainly cheaper to play around with what you already have.

But if you can try out a dedicated MTB, you should consider doing so, so that you have something to compare your current setup against.

I still have my Zaskar laying around in the garage, which is in the process of finding a new home. The geomtery of this bike is more or less the same as other XL hardtails I've found online - that is to say, long and low, the exact opposite of what I find comfortable, or, at the very least effective. I'm not so interested in going down that route once more.

Darth Lefty 01-21-21 01:21 PM

If you never get off the seat I'm sure it will be fine.

DMC707 01-21-21 03:17 PM


Originally Posted by Darth Lefty (Post 21888163)
If you never get off the seat I'm sure it will be fine.

YEs - it would be foolhardy to get off the seat for mountain bicycling

DMC707 01-21-21 03:20 PM


Originally Posted by Moisture (Post 21887135)
I'm looking to either use my current road bike or buy something else specifically for singletrack use this upcoming spring.

I get good comfort and performance on a road bike with a short reach/top tube (390mm reach, 580mm top tube) converted to flat bar using a tall 40mm stem. I want my handlebars slightly above or nearly level with my seat.

I feel like I can rip singletrack on this bike, but tire clearance is lacking in the rear dropouts and the bottom bracket is too low to do anything serious.

I'm thinking that some sort of flat bar gravel bike with extra tire clearance might work best.

Do you think that the short top tube and reach which I prefer isn't ideal for singletrack?




What manner of road bike is this? Does it have cantilever brakes at least so you can fit say, a 32c cyclocross tire even?

ITs been a long long time ago, but i picked up some aggressive "Rain tread" tires for my bike and thought they would be the ticket for light duty trail use ---- so i hit it on some dry days -- Was unique and fun for a ride or two. Then i realized my real mountain bike was more fun

Moisture 01-21-21 06:20 PM


Originally Posted by Darth Lefty (Post 21888163)
If you never get off the seat I'm sure it will be fine.

The long reach makes me feel like a 9 year old riding his first supercycle. Im like leaning way over the front axle and it feels ridiculous. With my road bike,.pedalling out of the saddle my butt is hovering over the saddle placing my weight rearward for stability and excellent power transfer. It could work well on singletrack.. mostly.


Originally Posted by DMC707 (Post 21888375)
What manner of road bike is this? Does it have cantilever brakes at least so you can fit say, a 32c cyclocross tire even?

ITs been a long long time ago, but i picked up some aggressive "Rain tread" tires for my bike and thought they would be the ticket for light duty trail use ---- so i hit it on some dry days -- Was unique and fun for a ride or two. Then i realized my real mountain bike was more fun

I got some Dia compe side pull brakes. I can fit up to 45 in the front and maybe 32 or 34 max in the rear.

Rage 01-21-21 09:59 PM

Iím still kicking myself in the head now for having sold my Zaskar twenty years ago.
You really should give that bike a shot on the singletrack.

Moisture 01-22-21 10:39 AM


Originally Posted by Rage (Post 21888872)
Iím still kicking myself in the head now for having sold my Zaskar twenty years ago.
You really should give that bike a shot on the singletrack.

I did... but with my seat set all the way up to baseline, even if I use a 32mm stem the stack is much too low and the reach/top tube length much too high.

I was using a ridiculous stem riser with backwards 32mm stem setup along with a 100mm fork which was way too long for that frame and bent, despite all this, the bike actually performed relatively well over some fairly tough rocky/rooty stuff. Its definetely a fantastic bike and very capable, but not for me.

mack_turtle 01-22-21 11:14 AM

I am so confused by this thread. it's all over the place. can you tell us the following:
  • how tall are you?
  • what frame(s) are you starting with for this project?
handlebar/ saddle difference is only one part of the equation because it does not take into account BB drop, not to mention ETT and reach/ stack differences.

Moisture 01-22-21 12:16 PM


Originally Posted by mack_turtle (Post 21889454)
I am so confused by this thread. it's all over the place. can you tell us the following:
  • how tall are you?
  • what frame(s) are you starting with for this project?
handlebar/ saddle difference is only one part of the equation because it does not take into account BB drop, not to mention ETT and reach/ stack differences.

I'm about 6ft3.

No frame in mind just yet. The used market is very slow right now.

Looking for a slightly shorter chainstay length at 425mm, slightly longer top tube and reach at 590mm and 400mm respectively, obviously will need sufficient BB clearance as I wish to use 180mm crank arms, and slightly less fork rake. Sounds to me like I'll need a gravel bike with extra tire clearance .

mack_turtle 01-22-21 12:32 PM

590 ETT and 400 reach is about what I would expect for a bike that would fit you with a drop bar. if you put a flat bar on a bike with dimensions like that, you're either going to end up with a cramped, upright position, or you'll need to put a longer stem on it to compensate.you can do whatever you want, but there are good reasons why no one makes a bike that short with a flat bar in mind.

All City is making the Super Professional with dimensions like that in the 61cm size and building it with a flat bar. it looks like they are using a mtb-style wide handlebar and a pretty long stem to make that work. it might not be the bike for you, but the geometry and build could be a good starting point for inspiration.

you have to ask yourself: do you want something that fits and handles like a road bike with a flat bar, or do you want something that fits and handles like a mountain bike? there's a difference.

prj71 01-22-21 01:33 PM


Originally Posted by Moisture (Post 21889595)
I'm about 6ft3.

No frame in mind just yet. The used market is very slow right now.
.

Used bikes all over pinkbike.com

DMC707 01-22-21 01:38 PM


Originally Posted by Moisture (Post 21889390)

I was using a ridiculous stem riser with backwards 32mm stem me.


Do you have a much shorter torso than leg length? With your height, there are not many bikes out there that are too big for you unless there are unique body dimensions to consider, or if you have a medical condition that dictates you ride completely upright

Moisture 01-22-21 02:01 PM


Originally Posted by mack_turtle (Post 21889623)
590 ETT and 400 reach is about what I would expect for a bike that would fit you with a drop bar. if you put a flat bar on a bike with dimensions like that, you're either going to end up with a cramped, upright position, or you'll need to put a longer stem on it to compensate.you can do whatever you want, but there are good reasons why no one makes a bike that short with a flat bar in mind.

All City is making the Super Professional with dimensions like that in the 61cm size and building it with a flat bar. it looks like they are using a mtb-style wide handlebar and a pretty long stem to make that work. it might not be the bike for you, but the geometry and build could be a good starting point for inspiration.

you have to ask yourself: do you want something that fits and handles like a road bike with a flat bar, or do you want something that fits and handles like a mountain bike? there's a difference.

my current bike has a 580 ett and 390mm reach. Im using a 40mm stem. I don't feel cramped on it at all. It works perfectly for me with the seat slid almost all the way back.

Originally Posted by DMC707 (Post 21889723)
Do you have a much shorter torso than leg length? With your height, there are not many bikes out there that are too big for you unless there are unique body dimensions to consider, or if you have a medical condition that dictates you ride completely upright

Well, im somewhere between 6ft2 and 6ft3, and my inseam is almost 35" so I think I do have a fairly short torso, although that seems to be about average for my height.

I am basing my preference for such a set up based not just on how comfortable I feel, but in terms of power trasnfer and overall rider balance while cornering and maneuvering.

mack_turtle 01-22-21 02:19 PM


Originally Posted by Moisture (Post 21889766)
my current bike has a 580 ett and 390mm reach. Im using a 40mm stem. I don't feel cramped on it at all. It works perfectly for me with the seat slid almost all the way back..

with a flat bar? if that works for you, that's fine. almost every other person in the world would find that incredibly uncomfortable, which is why you're on your own for making this work. a fit that compact sounds like a Dutch commuter bike to me, which would not handle well on "singletrack."

Moisture 01-22-21 03:06 PM


Originally Posted by mack_turtle (Post 21889795)
with a flat bar? if that works for you, that's fine. almost every other person in the world would find that incredibly uncomfortable, which is why you're on your own for making this work. a fit that compact sounds like a Dutch commuter bike to me, which would not handle well on "singletrack."

Yes, flat bar, with a very tall 220mm stem:


https://cimg3.ibsrv.net/gimg/bikefor...13200f2fb2.jpg

It works absolutely brilliant for me. As long as the handlebars are level or just above the seat, im happy.

When I am maneuvering obstacles with loose pebbles strewn about, or muddy turns, slippery snow etc, I feel so bang on centre, its usually the front end which hooks and the rear end comes sliding about extremely gracefully. I literally feel like I can control the slide and keep the rear tire in check by steering with my butt. I also really like the reach, because when navigating sketchy terrain, i can keep my weight centered into the pedals although my butt is still hovering just over the saddle. It is an incredibly stable feeling - one which I've been longing to achieve for a very long time.

I'm well aware that on serious singeltrack, this cockpit is simply too cramped. Other than going for a slightly longer top tube, I'm not sure what else I can do which still always me to achieve this sort of balance.

when im riding a bike with a certain length top tube, I feel like I am hanging over the front of the bike and it totally ruins the handling response for me. I have to enter corners gently and gingerly to avoid front tire skidding. With this current setup, I can downright thrash the bike through any turn I like, whether the surface is smooth or rough, and I am always rewarded with superb balance and a very commendable response/agility for a 200lb rider.

However, as you can see, I need a very tall stem. This limits my options to frames with a threaded fork and quill stem.


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