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Shorter Cranks for Climbing

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Shorter Cranks for Climbing

Old 12-11-20, 03:26 AM
  #51  
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Originally Posted by Wilmingtech View Post
Mentioning Cranks on BF is like mentioning oil on any number of automobile forums.

Anyways I was listening to this Podcast from Trainer Road "Ask a Cycling Coach" Episode 287 and starting @ 01:36:00 They have a great discussion with quite a few examples and research on crank length -
Here is the excerpt from that episode - Trainer Road "Ask A Cycling Coach Episode 287

Overall it seems that you will be better off with shorter cranks than long ones. Most of the reasoning seems to be around the ability to have a faster cadence with shorter cranks with less effort.

-Sean
I have used both correct crank size 170mm and 150mm (too short) crank lenth few months each.

I'm simply faster with the short crank. It's not just easier for me to spin at higher cadence with the short crank but A LOT easier so I end up being more efficient with 150mm. I change gear less often too. Just leave it at lower gears and spin like crazy to get faster without worry of blowing up. Great for rolling hills. Much harder to do with longer cranks, especially spinning at very high cadence.

I only found one advantage with longer cranks being faster in climbs - if you're going to spend considerable time pedaling out of the saddle. But if you're going to pedal out of the saddle only for short periods of time in climbs, the short crank still wins in climbing performance, providing you have smaller (easier) gears to drive with short cranks.
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Old 12-13-20, 09:00 AM
  #52  
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Originally Posted by Wilmingtech View Post
I am 5'11 and a 185 lbs and am typically more comfortable on a 53.5-54cm (within certain geometries). I currently own a Ridley Helium in a medium which is like a 56.

I have the bike setup to fit me and it's not uncomfortable on long rides. My question is...

I have a long ride tomorrow that is mostly climbing (15 miles up 4000' and another 7 up 2000'). Would it benefit to slide the seat up a half cm and throw a 172.5 crank on there? (I typically ride with a 175)

I've got the crankset here in the garage and it would take me all of maybe 30 min to set it up. Just not sure how much the shorter crankset would help, if at all.

Thanks!

-Sean
IMO as a somewhat taller person, the longer crank arms should work well for you. If you can handle longer crank arms, logic dictates you can apply greater torque with the proper gearing.
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Old 07-29-21, 11:36 AM
  #53  
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It has been over a year now and I wanted to follow up on this post. I have made quite a few changes to the bike that was initially mentioned that I switched out to the shorter cranks.


Changes made to the bike -

Ridley Helium:

2020 - 175mm cranks, 11-28 Cassette, SMP Avant Saddle

2021 - 170mm cranks, 11-30 Cassette, Specialized Power Saddle


My build and strength is more of a sprinter than a climber. I weigh in at around 180lbs (175 when in good shape and 185 when I am taking extra helpings of dinner and dessert) and I have a pretty good sprint (1100w for 15 sec) for my age (50) considering I only put in about 3000 miles a year and don't race or train other than for personal improvement and friendly competition against the other guys that I regularly ride with and improving my Strava segment times.

Most of the riding I do where I live is more Ardennes style short punchy 1-3 mile climbs with lots of rollers. But we are surrounded by mountains and there are a few rides that do have climbs in the 10+ mile range. In 2020 the notable climbs were the ride up to Johnston Ridge on the Spirit Lake Hwy (504 up to Mt. St. Helens) and then we have a loop that we do a couple times a year from Ashford, Wa up to Paradise (Mt. Rainier) and then around to Packwood and back to Ashford on Skate Creek Rd.


Here are the Profiles for those 2 rides to give you an idea -


These routes are quite different from the short punchy climbs and as such I figured I would try swapping to the shorter cranks for the long climbs to see what kind of difference it would make and how it would affect my rides.

One thing to note is that I was in much better cycling shape in 2021 than I was through 2020.

The difference between the 175mm cranks and 170mm cranks is quite noticeable. The 170mm cranks feel like a department store bike with the shorter turns and after using the 175s for a while I feel like I am spinning at a higher cadence to keep the same power in the same gear. This is not a bad thing it's just a different feel for the shorter cranks. I do notice I naturally ride in a slightly higher cadence in the shorter cranks (slightly above 90rpm vs 85-90 on average). I do not feel like I can kick up a sprint on the shorter cranks like I can on the 175s. For the same cadence (I can spin the 175s up as fast as I can the 170s) there is more power output on the 175s.

Where I did notice the difference when switching to the 170s is that on these long hauls I was able to keep a more consistent power output over the length of the climbs. Unscientifically (as I have not done these climbs twice on the same day with the same bike with different cranks) I noticed that I was able to push closer to 220w and keep it there much later in the climb on the 170s where as the 175s I would keep up with the guys in the bottom half of the climb but as it got later into the climb I would start to fall off and struggle to keep up with them.

Don't get me wrong the 170's didn't allow me to stay with the guys on the climb the entire way (As I climb like a sprinter) but they did allow me to hang a bit longer with them feeling less leg fatigue than on previous rides up these climbs.

One other thing that was overwhelmingly welcome with the 170's is that I did not get the leg cramps going over the top of the Paradise climb. The previous 3 times I have done this route I would always cramp up toward the top and have to shovel bananas and quite a bit of electrolytes to manage as well as stopping to stretch a bit at the top of the climb and even then would still feel some cramping start to creep back up on the descent and later into the second climb as well. Some of this may be that I was in better shape for the climb this time around but I also noticed strain on different muscles as well.

The Sartorius and Vastus Medialis (Inside of my thigh) were where the noticeable leg cramps were on previous climbs on the 175's where as this time I felt a little more strain on the Vastus Lateralis and Rectus Femoris (Top and outside of my thigh) than in past climbs. This may have been due to a bit of seat adjustment when I swapped out the cranks. With the shorter cranks being, well, shorter, the bottom of the pedal stroke is slightly higher from the ground and the spindle on the pedal is now closer to the bottom bracket. Taking these adjustments into consideration, I pushed the seat up a 1/2cm and also revisited the KOPS and adjusted the seat back when I went to the Specialized Power Saddle. I do think there is a better average over the muscle groups now with the shorter cranks.

I do have a 2nd bike that I built over the winter (Another Ridley - Noah SL) that is more for my regular rides with 172.5 cranks. This bike is more aero and fun to sprint and descend on. The Helium project over the winter this coming year will be to see if I can shed more weight from it and keep it as my all day climbing bike. Its already pretty light weighing in at around 7kg but I am certain I can find a few more grams to drop.

-Sean


PS - Some gratuitous pics from the Paradise ride this past week


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Old 07-29-21, 01:19 PM
  #54  
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Thanks for the update!

I also made the 175 -> 170 switch about six months go based on a bike fitter recommendation. I confess I paid no attention to it after the first 5 minutes on the new cranks.

But, in looking at my cadence numbers I have gone from 80-85 to 90 on average. It took awhile to get there but my body slowly adapted to the new cranks. I'm standing less as well, not sure why but less force in the seated cadence means I don't need so much relief perhaps.
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Old 09-29-21, 10:18 PM
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Im 5'7" but with a short 28" inseam. I recently moved down to 165mm cranks and got quite a bit of relief in my old knees. I see everyone here posting height but not inseam- seems like thats what matters. My torso is a couple inches too tall or legs are too short for my height.
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Old 09-30-21, 04:31 PM
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Originally Posted by Crang View Post
Im 5'7" but with a short 28" inseam. I recently moved down to 165mm cranks and got quite a bit of relief in my old knees. I see everyone here posting height but not inseam- seems like thats what matters. My torso is a couple inches too tall or legs are too short for my height.
Am 5'9" but with the same essential dimensions. Long-waisted, and shorter legs. Add to that an old injury in one leg/hip, power's down significantly there, and so I find 160-165mm cranks much more tolerable. I've altered the gearing way down from typical, to accommodate. Works best with the shorter cranks. Might not work for everyone, but it seems to work for you (knee joint relief) and me (easier pedaling, better cadence, more tolerant of injury area).
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Old 10-06-21, 03:25 PM
  #57  
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Originally Posted by Crang View Post
Im 5'7" but with a short 28" inseam. I recently moved down to 165mm cranks and got quite a bit of relief in my old knees. I see everyone here posting height but not inseam- seems like thats what matters. My torso is a couple inches too tall or legs are too short for my height.
My wife has a 27" inseam and rides 151mm cranks. In the universe where we all ride cranks according to leg length, you'd be on 155mm.
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Old 10-06-21, 05:02 PM
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Originally Posted by Carbonfiberboy View Post
My wife has a 27" inseam and rides 151mm cranks. In the universe where we all ride cranks according to leg length, you'd be on 155mm.


yeah my wife is 3.5" shorter than me and our seat positions on the same bike are identical. My reach is significantly longer though.
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Old 10-15-21, 12:06 PM
  #59  
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I just wanted to bump this thread and see if any shorter riders (5"8" and under) actually go with longer cranks? I find 170mm to work well on my road bike to give me better sprints on the flats and climbs and I like 165mm on my gravel bike where I can do seated climbs at higher cadence. I was thinking of trying 172.5mm or 175mm to get additional torque on my road bike or would I risk more toe strike by doing so? Curious to hear opinions, thanks!
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Old 10-15-21, 12:19 PM
  #60  
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Originally Posted by jonathanf2 View Post
I just wanted to bump this thread and see if any shorter riders (5"8" and under) actually go with longer cranks? I find 170mm to work well on my road bike to give me better sprints on the flats and climbs and I like 165mm on my gravel bike where I can do seated climbs at higher cadence. I was thinking of trying 172.5mm or 175mm to get additional torque on my road bike or would I risk more toe strike by doing so? Curious to hear opinions, thanks!
Have you measured your cycling inseam? You can probably go up to 172.5, although I would stick to 165-170.
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Old 10-15-21, 05:20 PM
  #61  
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Originally Posted by jonathanf2 View Post
I just wanted to bump this thread and see if any shorter riders (5"8" and under) actually go with longer cranks? I find 170mm to work well on my road bike to give me better sprints on the flats and climbs and I like 165mm on my gravel bike where I can do seated climbs at higher cadence. I was thinking of trying 172.5mm or 175mm to get additional torque on my road bike or would I risk more toe strike by doing so? Curious to hear opinions, thanks!
The problem with the notion that longer cranks give you more torque is that our legs need to travel through a 360 degree motion of muscle and joint movements, and while you may get more torque at the 9-3 position you also get less torque at the 12-6 position. Shorter cranks smooth out the torque delivery rather than reducing it.
When moving from longer cranks to shorter cranks its quite important to move your saddle BACK, as well as up in order to maximise the torque from the shorter cranks.
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Old 10-15-21, 05:52 PM
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Originally Posted by AnthonyG View Post
The problem with the notion that longer cranks give you more torque is that our legs need to travel through a 360 degree motion of muscle and joint movements, and while you may get more torque at the 9-3 position you also get less torque at the 12-6 position. Shorter cranks smooth out the torque delivery rather than reducing it.
When moving from longer cranks to shorter cranks its quite important to move your saddle BACK, as well as up in order to maximise the torque from the shorter cranks.
Its all true, only question is what's considered too short versus too long.

Longer crank arms can and often will help with better power output at more specific cadences.
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Old 10-16-21, 12:34 AM
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Originally Posted by jonathanf2 View Post
I just wanted to bump this thread and see if any shorter riders (5"8" and under) actually go with longer cranks? I find 170mm to work well on my road bike to give me better sprints on the flats and climbs and I like 165mm on my gravel bike where I can do seated climbs at higher cadence. I was thinking of trying 172.5mm or 175mm to get additional torque on my road bike or would I risk more toe strike by doing so? Curious to hear opinions, thanks!
I'm 5'6" and ride 170 on my road bike, 175 on our tandem. Pantani rode 180 in the mountains. He liked to climb OOS so the long cranks gave him more power. It's hard to argue with yellow. I ride 175 on the tandem. If I had shorter cranks, our gear ratio would have to be stupid low. We're riding 24/40 now, team age 148. We spin 90 just fine.
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Old 10-16-21, 09:56 AM
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Originally Posted by Carbonfiberboy View Post
I'm 5'6" and ride 170 on my road bike, 175 on our tandem. Pantani rode 180 in the mountains. He liked to climb OOS so the long cranks gave him more power. It's hard to argue with yellow. I ride 175 on the tandem. If I had shorter cranks, our gear ratio would have to be stupid low. We're riding 24/40 now, team age 148. We spin 90 just fine.
Yeah I was thinking about Patani when going longer cranks! I'm about 5'7" myself. The reason I'm fine with shorter 165mm cranks on my gravel bike is that due to the trail terrain I ride, I can't climb OOS (or I loose traction) and the shorter cranks reduce toe overlap on the technical sections. On my road bike I have the traction to ride OOS and I don't need to worry so much about toe overlap since my turning is more dependent on leaning into a curve or making sure I follow the correct line. Would 175mm be too extreme though? Honestly I don't do long rides (mostly around 30 miles per session), so I'm not too concerned about long range riding comfort and I mostly focus on hard hill climbing and fast descents.

Would 172.5mm make a big difference over 170mm though? I figure if I go long, 175mm would be the way to go for maximum torque.
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Old 10-16-21, 12:14 PM
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Originally Posted by jonathanf2 View Post
Yeah I was thinking about Patani when going longer cranks! I'm about 5'7" myself. The reason I'm fine with shorter 165mm cranks on my gravel bike is that due to the trail terrain I ride, I can't climb OOS (or I loose traction) and the shorter cranks reduce toe overlap on the technical sections. On my road bike I have the traction to ride OOS and I don't need to worry so much about toe overlap since my turning is more dependent on leaning into a curve or making sure I follow the correct line. Would 175mm be too extreme though? Honestly I don't do long rides (mostly around 30 miles per session), so I'm not too concerned about long range riding comfort and I mostly focus on hard hill climbing and fast descents.

Would 172.5mm make a big difference over 170mm though? I figure if I go long, 175mm would be the way to go for maximum torque.
I think there are so many opinions on best crank length because . . . everyone's different, sorta like saddles. IOW experiment, realizing that changing any aspect of fit requires a period of adaptation during which the feeling of "weird" becomes a feeling of "good" . . . or not. Personally, I don't think I'd climb better on shorter cranks.

OTOH, my wife was riding much too long cranks on our tandem and kept getting leg cramps, not good. I put on a set that was the correct length for her and which she really likes, but our climbing is worse now. Tandems fit is often a compromise. She can run those longer cranks on her trainer bike just fine, but the hard effort of long steep climbs is another story. Neither of us has every had knee issues like folks complain of when they talk about crank length.

IMO knee issues are a function of inadequate physical development. I think one hears so much about knee issues in runners because exact running form and conditioning to enable that exact form is so important. Similar idea. We had a couple our age (76&72) to dinner yesterday. The guy was telling me it was a bad idea to go to the gym because I was going to injure myself. Uh-huh. He has bilateral detached upper biceps because he never worked out. /rant

I know what you're talking about re gravel. Gotta keep that max torque down and cadence up.
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Old 10-16-21, 03:52 PM
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Originally Posted by Carbonfiberboy View Post
I think there are so many opinions on best crank length because . . . everyone's different, sorta like saddles. IOW experiment, realizing that changing any aspect of fit requires a period of adaptation during which the feeling of "weird" becomes a feeling of "good" . . . or not. Personally, I don't think I'd climb better on shorter cranks.

OTOH, my wife was riding much too long cranks on our tandem and kept getting leg cramps, not good. I put on a set that was the correct length for her and which she really likes, but our climbing is worse now. Tandems fit is often a compromise. She can run those longer cranks on her trainer bike just fine, but the hard effort of long steep climbs is another story. Neither of us has every had knee issues like folks complain of when they talk about crank length.

IMO knee issues are a function of inadequate physical development. I think one hears so much about knee issues in runners because exact running form and conditioning to enable that exact form is so important. Similar idea. We had a couple our age (76&72) to dinner yesterday. The guy was telling me it was a bad idea to go to the gym because I was going to injure myself. Uh-huh. He has bilateral detached upper biceps because he never worked out. /rant

I know what you're talking about re gravel. Gotta keep that max torque down and cadence up.
I'm a gym regular and on my non-bike days I do strength training. I've come to the conclusion if I want to be healthy into old age (I'm in my early 40s), exercise either on a bike or in the gym is a lifetime endeavor. I do quite a bit of stretching as well and my core is quite strong since I do focus on back and leg work quite a bit. My goal is to be one of those ultra fit grandpas! That's why I think I can handle the longer cranks with minimal risk of injury. It's funny, amongst my biking buddies we live and breath bicycling, we wake up thinking about bikes first thing!
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Old 10-16-21, 07:32 PM
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IME you are absolutely correct. Future: I didn't hit a steep drop-off until 63, another at ~70. But one just has to never quit, never give up. I haven't done a 400k since my mid-60s, but my wife and I rode our tandem on a 154 mile, 9500' event ride in our late 60s. We just came back from a very nice 23 mile tandem toot, legs feel great. Did a lot of 95 cadence on the flat, get a little more power out of those short stoker cranks!
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Old 10-17-21, 06:35 AM
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Originally Posted by Moisture View Post
Its all true, only question is what's considered too short versus too long.

Longer crank arms can and often will help with better power output at more specific cadences.
My calculated crank length is 170 mm but I have consistently higher average speed on 150 mm crank and signficantly higher average speeds on segments. I did have to spin higher cadence on short crank BUT it's so much easier to spin high cadence on short crank.

Scientific studies also gave favorable results towards short cranks. Popular info suggests best usage on TT bikes to maximize threshold power output (same thing you need on long climbs) I don't see why not road bikes too.
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Old 10-17-21, 05:09 PM
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Originally Posted by cubewheels View Post
My calculated crank length is 170 mm but I have consistently higher average speed on 150 mm crank and signficantly higher average speeds on segments. I did have to spin higher cadence on short crank BUT it's so much easier to spin high cadence on short crank.

Scientific studies also gave favorable results towards short cranks. Popular info suggests best usage on TT bikes to maximize threshold power output (same thing you need on long climbs) I don't see why not road bikes too.
Calculated based on what? For me, something between 20.5% - 21.2% of my cycling inseam seems to work best in terms of balancing an ideal cadence with good power output.

for me, it's mainly the change in gear inches which i look for.
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Old 10-17-21, 11:11 PM
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Originally Posted by Moisture View Post
Calculated based on what? For me, something between 20.5% - 21.2% of my cycling inseam seems to work best in terms of balancing an ideal cadence with good power output.

for me, it's mainly the change in gear inches which i look for.
I used a calculator based on inseam. After I tried 150mm, I started hating 170mm.

The only advantage I see with longer cranks is enabling lower cadence when pedaling out of the saddle (OOS). Lower cadence is an advantage in OOS to avoid lactic acid build up (high cadence is not advisable for OOS unless you have incredible aerobic performance).

Workout buffs would also appreciate longer cranks as it can better emulate some leg gym workouts, better workout for more muscle groups like if you're wanting to have a bigger butt.
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Old 10-19-21, 03:01 AM
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Originally Posted by cubewheels View Post
I used a calculator based on inseam. After I tried 150mm, I started hating 170mm.

The only advantage I see with longer cranks is enabling lower cadence when pedaling out of the saddle (OOS). Lower cadence is an advantage in OOS to avoid lactic acid build up (high cadence is not advisable for OOS unless you have incredible aerobic performance).

Workout buffs would also appreciate longer cranks as it can better emulate some leg gym workouts, better workout for more muscle groups like if you're wanting to have a bigger butt.
I'm just curious what percentage of your cycling inseam 150mm would be.

you might be more happy with some 160mm cranks give or take.
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Old 10-19-21, 09:50 AM
  #72  
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Originally Posted by cubewheels View Post
I used a calculator based on inseam. After I tried 150mm, I started hating 170mm.

The only advantage I see with longer cranks is enabling lower cadence when pedaling out of the saddle (OOS). Lower cadence is an advantage in OOS to avoid lactic acid build up (high cadence is not advisable for OOS unless you have incredible aerobic performance).

Workout buffs would also appreciate longer cranks as it can better emulate some leg gym workouts, better workout for more muscle groups like if you're wanting to have a bigger butt.
I tried 160mm and did not like it on my road bike even after fit adjustments. With 170mm OOS, it's true I can really feel the muscle groups I use from gym training. I do squats regularly and usually go OOS once I get close to a hill climb checkpoint allowing me to sprint to the top.
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Old 10-19-21, 10:04 AM
  #73  
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Longer cranks getting more muscles involved yes, but obviously the way you are positioned over the bottom bracket matters.
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Old 10-21-21, 06:28 AM
  #74  
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Originally Posted by Moisture View Post
I'm just curious what percentage of your cycling inseam 150mm would be.

you might be more happy with some 160mm cranks give or take.
With such big difference I had going to 150mm from 170mm, I doubt 160mm would be any better, given the smaller difference from 170mm.
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Old 10-25-21, 12:53 AM
  #75  
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The thread bump gave me the (sad) opportunity to read this missed thread in its entirety. Holy Moly what a cluster____ of speculation, misinformation, misperception and all manner of illogic. Carbonfiberboy is about the only poster making consistent sense. I'm sure he isn't the only one, but cripes. Listen. the percent change in ANYTHING between 170 and 175 is less than 3%! 2.94 if we want to get exact about it. Not perceptible. When you are talking about as gross an anatomical usage as an 80rpm cadence ... 3% gets quickly lost in the white noise of lactic acid overload. I don't doubt that for the first few tentative strokes with the new setup a person might think they have made a significant change, but once they start hammering it all just goes away. It really does.

A 10% change ... now you're talking. Why anyone would want 10% LESS torque to work with, I don't know, but if you are going to make changes, 10% is about the minimum that actually makes any real difference. For a 175mm crank that would be a 160mm crank. If you are doing it right you will also lower your gears 10%. Practically speaking you wouldn't try to lower each and every cog and chainring, just at the ends. Or you could drop down a gear (~13%) whenever you think about it. Chances are you'll do that automatically when you start to fatigue from having 10% less torque to work with.

As I have said before, the cranks we have are a compromise. Ideally they would be longer! All human powered endeavor is a need for speed. Our bicycles are descended from UCI sanctioned racing steeds that sought to allow constant high cadence pedaling for as long as possible. This meant keeping cadence constant through left and right hand turns at high speed. Much longer than 170mm and there is a real possibility of pedal strike in a corner and ... nobody wants that. Hybrids can run 175 because they run slower in the corners. But you are unlikely to see much below 160 or much more than 175 in regular production. Mainly because it makes little sense to have shorter cranks and 170/5 is the practical upper limit for longer ones without a frame redesign. Simplistic but true.

So why are there 155 ... 140. 100! Cranks? Because people want them. Misguided people, but they are a market. Fair game. Don't be that cyclist. Hold on to your money for something better than a crankset you don't need. The recumbent market is especially susceptible to the short crank thing. For 99% of recumbents standard cranks are just fine. The exceptions are those that enclose the riders feet as many only provide minimal clearance around the pedal circle. American feet just don't fit inside the toe boxes of European velomobiles with sporting pretensions. Sometimes cranks as short as 130mm need to be used but when you have the kind of drag coefficient the average velomobile does, what are a few (dozen) newton-meters of torque lost?

Look. I'm all for people doing what makes them happy. I just am dismayed that the reboot of this thread is just carrying the same old misinformation forward. At least know why you are doing something. Longer cranks are not the devil. Shorter cranks do not make you faster, or give you more endurance. At least not in the way most of you use them! Shorter cranks do not even really help your knees. Lower gears are a much better way of saving your knees than trying to limit the effective range of your knee flexion. TL;DR: unless you have a real good reason, and that is unlikely, the crankset sold with your bike, at least with respect to length, probably suffices. Piffling changes of 2.5mm and 5mm are just a colossal waste of time and money. Unless you are buying cheap crap cranksets and why would you do that?

I've yet to meet the production bike that wasn't grossly overgeared out of the box. If you are still using the 30/42/52 triple that came with your hybrid, or the 50/39 that came with your road racer you are not having a quality experience. The 30 (front) x 32 (rear) combination commonly found on most hybrids as the "granny" gear is about 27" which is also about the "gear'" that humans walk in. The low gear on my bike is 22 x 36. About 18". I don't expect a road racer to have an 18" low gear but if you guessed that the 39 (front) x 27(rear) low gear on many road bikes is too high, you'd be right. And you need LONGER cranks to wrestle that smb into submission, NOT shorter.
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