Gear ratios for Hills
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[QUOTE=fietsbob;21546291]The Basics: little in the front Big in the back .. a 56 or 54 BCD Granny on a triple can have a 20t..
[Brompton 16" wheel 2 speed geared crank ,in low range, the pedals turn 2.5X faster than the chainring,
QUOTE]
I don't mean to contradict you, but my pedals turn at the same rotation as the chain ring, unless it's broken...
Edit: I did the research as instructed and learned about Schlump drives. They are amazing---and very expensive! Thank you,
[Brompton 16" wheel 2 speed geared crank ,in low range, the pedals turn 2.5X faster than the chainring,
QUOTE]
I don't mean to contradict you, but my pedals turn at the same rotation as the chain ring, unless it's broken...
Edit: I did the research as instructed and learned about Schlump drives. They are amazing---and very expensive! Thank you,
Last edited by Bigbus; 06-22-20 at 10:09 AM.
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There's a limit to how slow a rider can climb, without losing steering control or balance. For me, it's near 3 mph. So that limits the max grade I can climb. Even with extremely low gearing like touring bikes have (24 front, 36 rear for example) I don't know if I'd have enough power to keep moving all the way to the top.
I'm not doing as much cargo hauling as I had been doing earlier, but I had thought the next logical step would be a trike, and perhaps 5th wheel for traction. Idler pully system for lower gearing?
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I borrowed the photo from another thread and it shows the type of vicinity where I work every once in a while. For this, I built up really low gears and the lowest one now gives 1.06m of development. It is useful for transient periods such as steep turns. My guess is that your 33% is just such a transient. For prolonged rides straight up such a gear is not really useful, as you begin to roll back during the half-turn of pedals, before you manage to complete that very half-turn. My next lowest gear yields 1.30m and, in my memory, is already useful for prolonged straight rides up. When you enter the hiccups, it takes less effort to walk and you are faster walking. I hope this helps in providing you with a boundary.
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I don't mean to contradict you, but my pedals turn at the same rotation as the chain ring, unless it's broken...
Schlumpf drives are commonly used on Bromptons because of their small diameter wheels. His fietsbob is probably the High-Speed drive @ 2.5:1 ratio...or equivalent to a 30-75 crankset. (Assuming a 30 tooth chainring, of course) Mountain drives are 2.5:1 reduction ratio.
The regular 1.62:1 "speed drives" are commonly used on recumbants because they offer an equivalent range to a triple crankset with all the simplicity and chain wrap considerations as 1x gearing. Indeed thats why I have one on my mountain bike. It looks like a 1x but mated to an 11 speed XTR 11-46 cassette my mountain bike has ~680% range...The same as a 22 cog, 10-68 cassette if anyone in the 1x world would invent such a thing. *cough, SRAM, cough, cough* (lol)
Mine in a "Type -08" model. The standard models with a 5x110bcd can take multiple chainrings to expand the range even further. Look 'em up. They are made by Haberstock Mobility. Cool. Rare.
Last edited by base2; 06-22-20 at 01:28 AM.
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I don't know the numbers for gradient, speed, power etc. But i know i can climb any hill with any of my bikes unloaded or loaded. Get 18 gear inch and below.
Trailer + 3 kids no problem.
Trailer + 3 kids no problem.
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There's close to a dozen 18-22% block-long grades in the neighborhoods near my house. I've climbed most of them with ~20 gear inch low gear, usually while cursing the idiots who laid out streets like that. Because the city decided to build them out of concrete, which has pitted (and now gives motorized vehicles a little more traction when wet), they're miserable AND scary coming down, and only miserable going up them.
Now-a-days I tend to avoid those for the most part. If I can't, it's easier to walk. MTB pedals and shoes help.
Now-a-days I tend to avoid those for the most part. If I can't, it's easier to walk. MTB pedals and shoes help.
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#33
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I would just like to say that as someone from Illinois who has never gone up anything more than a short bump at more than a couple %, this thread is making me very uncomfortable. I'm used to 10' a mile, 15 is hilly...
Best of luck to you on this insanity!
Best of luck to you on this insanity!
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#34
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[QUOTE=Bigbus;21546491]
Au Contraire, mate.. your exposure to things mechanical may be limited..
Florian Schlumpf , an engineer in Switzerland, created an internal , with a planetary/epicyclic * gear crankset many years ago..
the BB shaft, that holds the arms has the 'sun' gear , (like an AW3 has one on the axle) the chain ring spider is attached to the annular gear ring,
and there are 4 planet gears between them .. so the rate of rotation can differ..
https://en.wikipedia.org/wiki/Epicyclic_gearing ..
He has, it seems, gone on to do other things of late..
The Basics: little in the front Big in the back .. a 56 or 54 BCD Granny on a triple can have a 20t..
[Brompton 16" wheel 2 speed geared crank ,in low range, the pedals turn 2.5X faster than the chainring,
QUOTE]
I don't mean to contradict you, but my pedals turn at the same rotation as the chain ring, unless it's broken...
[Brompton 16" wheel 2 speed geared crank ,in low range, the pedals turn 2.5X faster than the chainring,
QUOTE]
I don't mean to contradict you, but my pedals turn at the same rotation as the chain ring, unless it's broken...
Florian Schlumpf , an engineer in Switzerland, created an internal , with a planetary/epicyclic * gear crankset many years ago..
the BB shaft, that holds the arms has the 'sun' gear , (like an AW3 has one on the axle) the chain ring spider is attached to the annular gear ring,
and there are 4 planet gears between them .. so the rate of rotation can differ..
https://en.wikipedia.org/wiki/Epicyclic_gearing ..
He has, it seems, gone on to do other things of late..
Last edited by fietsbob; 06-22-20 at 10:56 AM.
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#35
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AW3 15t, Mountain Drive 54t ('21.6t' low),
torque transfer is via a lever with a knob on it.
the knob sits atop the frame part that contains the rear fold pivot axis.
3 top, of low, to 4, bottom of high range is a quick double shift.. both can shift at any speed... even stopped..
Yes, there are 2 overdrive versions, the 1.6 mentioned above and one that is the inverse of the reduction 2.5:1.. a 2.5x overdreve
/...
torque transfer is via a lever with a knob on it.
the knob sits atop the frame part that contains the rear fold pivot axis.
3 top, of low, to 4, bottom of high range is a quick double shift.. both can shift at any speed... even stopped..
Yes, there are 2 overdrive versions, the 1.6 mentioned above and one that is the inverse of the reduction 2.5:1.. a 2.5x overdreve
/...
Last edited by fietsbob; 06-22-20 at 10:58 AM.
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#37
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Thanks for the note back - yes I know the hills are surprisingly steep aren't they, they are all paved and used by cars. I live in the hilliest part of England, if you search 'top hill climbs lake district' you'll see the top 8 hills all of which are within 1-15 miles from where I live. I even got it wrong, the steepest is actually 33% not 30. These are the stats for Hardknott pass:Distance: 2.2km
Height gain 298m
Average gradient: 13%
Max gradient: 33%
I hope you can now see the reason behind the question, the hills are monsters around here.
Cheers
Height gain 298m
Average gradient: 13%
Max gradient: 33%
I hope you can now see the reason behind the question, the hills are monsters around here.
Cheers
Last edited by AlgarveCycling; 06-22-20 at 10:44 AM.
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#38
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I think your gearing is fine. I went up one of my local steeper ones last week on the way up to Foia, Monchique our highest point. It's 2.36km, average 10% and max gradient on the switchbacks hits above 30% but they are brief so not all that different. My time was 13:26 and I have a compact 50/34 and 11/28 set up on my bike. It was just one hill on a 2552m, 136km ride. I'm a similar weight to you, 64kg. My bike is 5.8kg...
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#39
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Yes.
I grew up on the Jersey Shore, this is very flat. I moved to NE PA a while back 16 years ago. Right after moving I tried to ride my road bike in my neighborhood, just a few miles turned out to be an epic fail. So the extremely small amount of bicycle riding I did going forward was on the flat trails.
Got back into riding a year and a half ago, did a little bit of riding then thought what the heck and went on an organized 35 mile road ride. Three times I had to get off the bike and walk. This was June 2019. I then went back to riding flats.
Over the winter I started using a fluid trainer and a VR program. After about 3 weeks into this I started doing VR hills. Each week more and more. I was worried how that would translate into riding outside and was very concerned during my first ride in the spring. I'm doing 8-10% grades with a triple CR 52-42-30 and 11-26 freehub. I can do the 8-9% and even a bit harder using my 42-26 which is great because that gives me a 30 chain ring in reserve. For me at 62 it is heart pounding but quite satisfying. When I'm on a local hill and recall that just a year ago I would have never even tried to ride it it is a great feeling of accomplishment.
One thing I haven't figured out is going from my 42 chain ring to the 30 gracefully.
Last edited by Thomas15; 06-22-20 at 02:50 PM.
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This is a wonderful clip from a few years ago. 7.5 inch gears.
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When it comes to touring bikes, 18 gear inches is considered a good granny gear. Gear inches is how many inches you travel forward for one complete pedal revolution. Even with a 10/36 and 30/43 setup, your lowest gear would afford you 22 gear inches given a 700c/32 wheel/tire combo. You should go lower. Aim for that 18 gear-inch number with your lowest ratio..
Think back to the high wheeler days. A bigger wheel meant you could go faster assuming your legs were long enough to turn the pedals. When chain drive "safety bicycles" were invented sellers needed a way to compare the gear ratio with the high wheelers that people were used to.
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#42
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That YouTube was amazing. Yes I need 7.5 inch gears haha. He was certainly 'Spinning to Win' rather than 'Grinding for the money'.
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Converting my meter development numbers to gear inches, I get 1.06m=13" and 1.30m=16". I find 16" still usable when you actually need it, and 13" just for short periods, when 16" is not enough. As to the 7.5" above, I reckon that hill could be ridden straight up on a higher gear without getting out of the saddle. You can use 7.5" at the cost of maintaining a rather high cadence. At the point where you would actually need to resort to 7.5", because higher gears were not enough, I claim you would not be able to use it and need to retreat to walking. On the side, the general problem with extremely low gears is that is very hard to shift between them when you are ridding uphill at a highly tensioned chain. With this,sometimes you may end up shifting preventively to the very low gear before the slope gets steep and continue for a while at an unreasonably high cadence.
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You already have a 1:1 gear, just suck it up and power through. Those really steep ramps can't be more than what, 50m at a time? You can do it.
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#45
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Looks like keeping what I have and just putting more training in will be the major winner. I've seen that many road bikes run 36 front and 28 back - with that ratio I'd need to be a Tour rider.
Sadly most of the good rides do involve one or more of the steep hills, the Lake District is quite small and I live in the middle (big mistake 😂🤣😂.
Cheers.
Sadly most of the good rides do involve one or more of the steep hills, the Lake District is quite small and I live in the middle (big mistake 😂🤣😂.
Cheers.
I'd say, if it was me, stick with the gears you've got. The trouble is that everyone is different so what works for one won't for another. My feeling is, thought, since you are clearly very fit that it shouldn't take you long before you're finding those hills relatively easy. Not that they're ever going to be a breeze, but that's my three ha'pence worth.
I know what you mean about every ride involving a climb. I live in the Surrey hills and you can't go out of my front door without hitting a hill. Only the hills here are on quite a different scale. I have 52/36 front and 11-26 rear and I can just manage the worst hills around here which, I'm told, briefly ramp up to 20%. The dilemma you have is that if you gear your bike totally towards the hills you're going to compromise for other parts of your ride. I put that 11-26 cassette on my bike because for most of my riding I like the ratios to be fairly close so I compromised for the hills. You'll have to decide what compromise works best for you but until you've started to get used to the hills you won't really know. That's why I'd hold off on spending a shed load of money at this stage - as long as the challenge isn't putting you off, of course.
Are you planning to do the Fred Whitton Challenge any time soon? A third of an Everest in a single day.
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#46
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First of all, lucky you living in such a stunningly beautiful part of the country. My daughter lives in an area of Scotland that certainly rivals the Lake District but is far less accessible (for me, at least).
I'd say, if it was me, stick with the gears you've got. The trouble is that everyone is different so what works for one won't for another. My feeling is, thought, since you are clearly very fit that it shouldn't take you long before you're finding those hills relatively easy. Not that they're ever going to be a breeze, but that's my three ha'pence worth.
I know what you mean about every ride involving a climb. I live in the Surrey hills and you can't go out of my front door without hitting a hill. Only the hills here are on quite a different scale. I have 52/36 front and 11-26 rear and I can just manage the worst hills around here which, I'm told, briefly ramp up to 20%. The dilemma you have is that if you gear your bike totally towards the hills you're going to compromise for other parts of your ride. I put that 11-26 cassette on my bike because for most of my riding I like the ratios to be fairly close so I compromised for the hills. You'll have to decide what compromise works best for you but until you've started to get used to the hills you won't really know. That's why I'd hold off on spending a shed load of money at this stage - as long as the challenge isn't putting you off, of course.
Are you planning to do the Fred Whitton Challenge any time soon? A third of an Everest in a single day.
I'd say, if it was me, stick with the gears you've got. The trouble is that everyone is different so what works for one won't for another. My feeling is, thought, since you are clearly very fit that it shouldn't take you long before you're finding those hills relatively easy. Not that they're ever going to be a breeze, but that's my three ha'pence worth.
I know what you mean about every ride involving a climb. I live in the Surrey hills and you can't go out of my front door without hitting a hill. Only the hills here are on quite a different scale. I have 52/36 front and 11-26 rear and I can just manage the worst hills around here which, I'm told, briefly ramp up to 20%. The dilemma you have is that if you gear your bike totally towards the hills you're going to compromise for other parts of your ride. I put that 11-26 cassette on my bike because for most of my riding I like the ratios to be fairly close so I compromised for the hills. You'll have to decide what compromise works best for you but until you've started to get used to the hills you won't really know. That's why I'd hold off on spending a shed load of money at this stage - as long as the challenge isn't putting you off, of course.
Are you planning to do the Fred Whitton Challenge any time soon? A third of an Everest in a single day.
Yes the Fred Whitten is an objective, I doubt I'll do it on the charity day with the other 2,000 cyclists (a bit too busy for a relative newby like me) and ask the family to help out with a few food and drink stations. I think if it can do it in 8-9 hours I'll be chuffed. A friend did it in 6:40 (he came 49th) but he is fit and very strong. 112miles and 4000m of ascent will be tough.
Cheers again.
#47
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Great thanks for the detailed note back. I think you are right, stick with what I have which is already quite conservative versus most road bikes. And just get stronger and fitter.
Yes the Fred Whitten is an objective, I doubt I'll do it on the charity day with the other 2,000 cyclists (a bit too busy for a relative newby like me) and ask the family to help out with a few food and drink stations. I think if it can do it in 8-9 hours I'll be chuffed. A friend did it in 6:40 (he came 49th) but he is fit and very strong. 112miles and 4000m of ascent will be tough.
Cheers again.
Yes the Fred Whitten is an objective, I doubt I'll do it on the charity day with the other 2,000 cyclists (a bit too busy for a relative newby like me) and ask the family to help out with a few food and drink stations. I think if it can do it in 8-9 hours I'll be chuffed. A friend did it in 6:40 (he came 49th) but he is fit and very strong. 112miles and 4000m of ascent will be tough.
Cheers again.
By the way, I read a discussion once on bike weights. They came to the conclusion that the cheapest way to shave half a kilo off your bike was to pay someone to carry your water bottle so getting friends and family to help out with food and drink stations sounds like a good plan.
#48
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For me 112 miles is a challenge on ordinary roads! I have a work colleague who's done it three times. The third time he was in the process of moving his family to Northern Ireland and bare got to do any training - to the extent that he considered pulling out. He came back into work the next week and announced 'It turns out training's overrated.' Apparently he'd decided to take it really easy but still managed a personal best.
By the way, I read a discussion once on bike weights. They came to the conclusion that the cheapest way to shave half a kilo off your bike was to pay someone to carry your water bottle so getting friends and family to help out with food and drink stations sounds like a good plan.
By the way, I read a discussion once on bike weights. They came to the conclusion that the cheapest way to shave half a kilo off your bike was to pay someone to carry your water bottle so getting friends and family to help out with food and drink stations sounds like a good plan.
Great tip about the water and makes perfect sense, you could easily save close to 1kg. Bit the previous posters sub 6 kilo bike does sound nice. Lucky chap!
#49
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If your crank will take a 30t chainring, problem solved and shouldn't be a lot of money. That's if your RD can take up the slack. I swapped out RD and cassette this year to get close to where you are now, low gear at 1.12:1. It's perfect for the hilly area I live. I couldn't put a much smaller chainring on, as I have a 39t on 130bcd crank.
Mg gravel bike has low gear of 0.84 (30F/34R) and that's good for remaining seated for traction on loose sand and gravel slopes.
If standing up and grinding up the hills is too much, try the 30t chainring. There's no such thing as a gear too low when you are fatigued, the hills are long and steep, the temperature and humidity are high, etc. A gear low enough to allow you to remain seated will keep you from passing out when your not up to standing on the pedals.
Mg gravel bike has low gear of 0.84 (30F/34R) and that's good for remaining seated for traction on loose sand and gravel slopes.
If standing up and grinding up the hills is too much, try the 30t chainring. There's no such thing as a gear too low when you are fatigued, the hills are long and steep, the temperature and humidity are high, etc. A gear low enough to allow you to remain seated will keep you from passing out when your not up to standing on the pedals.
Last edited by Chuckles1; 06-23-20 at 09:32 AM.
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1:1 with decent fitness should get you through those climbs, on pavement at least where you can stand through the short steep sections. If it's loose, like gravel, then I'd want more gear so I could still spin while seated.