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  #31  
Old 09-18-2024, 05:27 PM
tv_vt tv_vt is offline
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Just get the 172.5 cranks and be done. Totally fine for you. (Been there, done that…)
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  #32  
Old 09-18-2024, 05:52 PM
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saab2000 saab2000 is offline
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About 35+ years ago I switched to 175s because…. Lemond. About 20ish years ago I switched back to 172.5 because…… I’m not Lemond and found the shorter cranks to be more natural at spinning on fast group rides where I could pretend to be Lemond but not really be him. I’m still on 172.5s years later and would be open minded to trying shorter. It seems to be a trend though I’d like to see data to back it up. I’m not Pogaçar either though we’re not dissimilar in size (ant least height) and I think he uses 165s, so there’s that.
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  #33  
Old 09-18-2024, 05:54 PM
bigbill bigbill is offline
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I'm 6'1" with a 34" inseam and I started riding in the late 80s and my road bike had 170s. Around 1992, I went with 175s over the winter to adapt before racing season. I didn't notice much, but I've been on 175s ever since. I saw the older comment about shorter cranks on a gravel bike because of pedal strike, but that doesn't make much sense. IME, gravel riding is road riding on dirt and gravel and to be efficient, you have to settle into a rhythm, much like on the road. I have struck pedals before on the gravel bike, but that was due to a wrong turn and being someplace that was better suited for my MTB, which also has 175s.

I've had hip issues in the past year, but I have connective tissue disease and I'm not sure if shorter cranks will make it better. More than likely, I have hip replacement surgery in my near future. Unfortunately for me, there aren't any sports oriented orthopedics around, just surgeons who deal with old people and their problems.
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  #34  
Old 09-18-2024, 06:10 PM
FastCanon FastCanon is offline
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I'm a short biker (5' 2.5"). My mountain bikes are 175s, which I ride at night to train. During the day or weekends, I ride my road bikes, which are 170/165. I notice the difference, but I haven't felt any knee pain from any of them. For the road bikes, my gearing are 50/34x11/32 and I can still climb with either crankset. My power output for the 165s seems to be a tad higher.

I'm 54 so maybe it'll change soon.
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  #35  
Old 09-18-2024, 08:01 PM
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charliedid charliedid is offline
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If it's a matter of comfort in terms of range of motion it may be the tipping point that gets you there.
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  #36  
Old 09-18-2024, 08:07 PM
zmalwo zmalwo is offline
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Nairo Quintana is 5'5 and he used 172.5mm. 5mm difference is the length of the lead tip portion of a sharpened pencil. do you think you can notice the difference?

Last edited by zmalwo; 09-18-2024 at 08:09 PM.
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  #37  
Old 09-18-2024, 08:18 PM
nmrt nmrt is offline
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Watch out -- in the next three years, shorter cranks (155 mm to 170 mm) will be omnipresent on road bikes. They will do to longer cranks what disc brakes did to rim brakes.
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  #38  
Old 09-18-2024, 08:28 PM
XXtwindad XXtwindad is offline
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I use 172.5 cranks on my Crux. I’ve been setting all kinds of PRs. Is it the crank? The Crux? The Karma? Who knows?
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  #39  
Old 09-18-2024, 08:40 PM
nmrt nmrt is offline
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Since we're citing pros: Pogacar is 5 ft 9.5 inches and he used 165 mm in the TdF this year.
Quote:
Originally Posted by zmalwo View Post
Nairo Quintana is 5'5 and he used 172.5mm. 5mm difference is the length of the lead tip portion of a sharpened pencil. do you think you can notice the difference?
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  #40  
Old 09-19-2024, 01:23 AM
robertbb robertbb is offline
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Echoing what McM said a few pages back. Shorter cranks definitely require easier gears or you’ll feel like you lost an easier gear or two - I noticed this immediately. The other thing I noticed and wrote about in a separate post (and got hammered about) is the change to cadence. Same 38x11-42 cassette, I noticed far more disruptive changes to cadence when I switched to 165’s than on 170’s. Ppl say it’s all in the head but I swear it’s there and i’ll die on that hill.

The 165’s feel better than the 170’s for me but I’m considering reverting back to 170’s because I’m constantly gear searching in ways I never was.
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  #41  
Old 09-19-2024, 05:18 AM
oldguy00 oldguy00 is offline
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5'10 here.
Started on 175's back in the early 90's (also cause of Lemond!!).

Switched to triathlon and because of the comfort difference in aero, switched to 165. Could 'feel' a difference on the first ride, then never noticed it again.

After a few years and some knee pain, I switched about 5 months ago to 155. It felt weird for a couple rides, now it feels fine, even when contesting sprints on zwift. My power numbers do not seem to be affected at all.
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  #42  
Old 09-19-2024, 09:23 AM
pdxharth pdxharth is offline
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This thread is fun because there are so many different experiences!

For me, at 6’ even, I rode 175 on all my bikes since the early 90s. Then I switched my road bike to 172.5 and felt the difference immediately. It is easier to spin for me, smoother. I definitely notice it. Now I have two road-oriented bikes with the shorter size, and my commuter still with 175, and I notice every time I switch between them. My mtb is staying 175, but I prefer the shorter cranks for the road.
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  #43  
Old 09-19-2024, 10:42 AM
Ken Robb Ken Robb is offline
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I can feel a 5mm difference but not 2.5. I have had bikes with 170, 172.5, 175 and 180mm cranks at the same time because I bought/sold many used bikes. When I went from 175 to 170 I found the shorter cranks easier to spin at a higher cadence. When I got a bike with 180mm cranks I was at first thrilled by how I could muscle up familiar hills in taller gears. I soon noticed some twinges under my patella that told me 180 was too long for me.
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  #44  
Old 09-19-2024, 10:57 AM
benb benb is offline
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I have been experimenting with this lately and I disagree now with what I shared in May. All the studies show you're not really losing anything with the shorter cranks. So the question is what can you gain? With shorter cranks and the correct adjustments to your fit what you can gain is improved aerodynamics and comfort.

If you have huge range of motion in your hips (flexion) this might not matter as much. If you have normal or slightly less range of motion this can be a big deal.

If you have data from your fits look at your hip flexion angles at the top of the pedal stroke.

The latest stuff I've seen has had a lot of talk about the angle drawn between:

a) Your shoulders in a given bar position
b) Your hip
c) Your knee at the top of the pedal stroke.

They then mention 3 families of angles:

1) <= 66 degrees - problem zone
2) 66 > - < 69 degrees - potential problem zone
3) >= 69 degrees - safe zone

Dartfish for an example includes this angle. Mine at my recent fit this spring was 65 degrees on the hoods, so I was already in the danger zone on the hoods and way into it in the drops. And it should be noted I did not have a lot of bar drop. Usually most people would try to reduce my drop even more, down to 3cm or so. This probably fixes the hip angle at the expense of making the fit very draggy. The higher bar position on MTB seems to make this a non issue for me over the years. I have never tried to drop my bars to 5, 7, or 10cm below the saddle on the MTB since it compromises out of the saddle technical riding on descents, and I think that makes my fit work even with longer cranks.

I am trying 170s right now. I'm 185cm/6'1" and have an 88cm inseam which historically they would always have stuck me on 175cm. I would say I need to adjust my gearing if and when I do any real mountain riding. For right now where I live it's not necessary, but it's easy to tell you're riding lower gears on the climbs.

In any case it puts my hip flexion angle almost into that safe zone and it makes a rather large difference. My saddle is higher so my saddle to bar drop is more (still only like 7cm?) but I can pedal way more fluidly in the hoods & drops for much longer periods of time. Main effects are a) I can be more aero b) My lumbar region/back is way less sore c) My hips move far less on the saddle.

This article is one of the better ones on this subject I've seen, seems to be some kind of medical magazine:

https://lermagazine.com/article/at-a...e-and-hip-pain

This is an expensive thing to experiment with. For now I'm only trying it on my road bike since I don't really care about using the bar position to be more upright on my MTB and my commuter/city bike. I could definitely see trying 170 on my MTB at a convenient time though as even though it doesn't seem to give me any comfort issues I have sure spent a lot of time on technique to avoid pedal strikes over the years... the 175s are certainly easy to bash on stuff.

Last edited by benb; 09-19-2024 at 11:02 AM.
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  #45  
Old 09-19-2024, 12:38 PM
vespasianus vespasianus is offline
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Quote:
Originally Posted by nmrt View Post
Watch out -- in the next three years, shorter cranks (155 mm to 170 mm) will be omnipresent on road bikes. They will do to longer cranks what disc brakes did to rim brakes.
I don't think so. Shorter cranks work better the fitter you are. And the vast majority of people who ride bikes are not as fit as they think (myself included). I think 170 will still remain the base as it represents the best compromise or the current gearing - 50/34 compact and 11-34 cassette.

The only thing that could drive the move to shorter cranks would be much smaller front rings (like the 46/30) with 10-42 cassettes that would work with short cranks and also need to be replaced more often.
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