Anyone around 172cm (5'7.5"ft) tall using 165mm cranks?

I just listened to the most recent Fast Talk podcast on fit and saw on Pinkbike ( Why Shorter Cranks Are Better (According To Science) - Pinkbike ) that most people are running cranks that are way too long. I am 1.72m, around 5’7.5" and currently running 170mm cranks on my road, gravel and MTB bikes. Reading these articles makes me want to try 165mm cranks and see how it feels.

Anyone here around my height running 165mm cranks, or maybe someone taller running 170mms? If so, how is it?

Thanks in advance!

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i do. i used to have 170mm cranks but have switched to 165 after the recommendation of a fitter.

overall, i’m happier with the 165. I feel that my hip is a lot more open and i’m not getting hip issues on my longer rides (which would sometimes happen on the 170). i also find that my natural cadence is a bit higher and overall i’m not feeling as exhausted towards the end of my ride. my guess is it’s because i’m not grinding as much, but i haven’t really analyzed my rides to see if it’s true.

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Do it… you won’t regret it.

I’m 6’ tall and run 165mm cranks on my mountain bikes. 172.5 on my road bikes purely because that’s what came with the bike or I’d be running 165mm cranks there as well.

The short version of all the studies that have been done is that you can make more power with a shorter crank in virtually every case and you can more rapidly change velocity to meet changing terrain on shorter cranks. Basically, power is torque x angular velocity. For an average rider, it’s much easier to increase your radial velocity than it is to increase your torque. More specific to road riding, it creates a number of fit benefits as well.

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As far as I know from what I’ve read about this subject, save for extreme lenghts there’s no harm in going for shorter crank arms. I’m happy I did 170 for 181cm height, 83 inseam

5’9", 84.5cm inseam. 175mm road and mtb. Tried 170mm but didn’t like it. 172.5mm is OK tho. I think one will adapt to whatever is available. My experience: saddle + bar position, fine-tuned under power/load >> crank length.

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5’8" (with short-ish legs) and just switched out the 172.5mm on my CAAD12 for 165s on the advice of my fitter. So far so good. I don’t know that it’s a massive change, but my spin maybe feels a bit smoother. I’ve been riding 165mm’s on my TT bike for a couple of years. I think that’s more noticeable due to the aero position and hip angle.

I’m 172 cm but have long legs.

I ran 165 mm cranks on my gravel bike for a while, also due to various articles I found online and a mild obsession with tinkering my bike fit.
In the end, however, I switched back to 170 mm. It didn’t feel totally weird, but I don’t mind the 170s, either. I find that a zero-setback seat post and a short(ish) saddle opens my hips enough.

Unfortunately it’s not a cheap thing to try out. Otherwise I’d join the rest and say “try it”. Although, in the days of rare parts you could probably sell them again without a problem if you don’t like it.

177cm with 81.5cm inseam; 165mm on the TT bike, 170s on the road and gravel bike. I’d rather ride 165s than 172.5s. As others have said, there’s little real downside to going a bit ‘too short’, though some people find climbing can feel a bit ‘twiddly’.

Used to have 170mm. Now I have 167.5mm as 165mm was not available anymore in the crankset I wanted. Feels more natural.

Just set up a Tri bike with 165s. Bought used and was told they were 160s, close enough. I’m 185cm (6’1"). Works well, I barely notice a difference but I reckon it is more comfortable on the aero bars.

I’m 170cm tall with short legs. I’m happy on 170mm cranks, which is good because my size of bike generally comes with them. I wouldn’t go longer.
I put 165s on my old roadie, which is now mainly a trainer bike, as I needed new cranks and the shop had them sitting there. I honestly can’t tell the difference, and am totally happy on either.

I’m a Physio who has done a smidgen of bike fitting, but I’m not an expert, nor a physicist. I think reducing crank length makes sense biomechanically for people with some hip issues, and it seems pretty unlikely to do any harm.
Alternatively, I think longer cranks would be more likely to cause hip or back problems, and as much as I love what Adam Hanson does, I’m not sure if the longer cranks = going faster really makes sense. Watts still need to be produced. And for us punters it’s likely that comfort = speed moreso than crank length.

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What was the cadence you had with 170 vs 165? I noticed the cadences they used in one of the studies was pretty high (140?). Seem uncomfortably high but maybe I’m just using too long of a crank?

I am a physiotherapist and qualified Bike Fitter, road racer with 30 years experience at high level.
182 cm tall and with long legs; have used 165mm cranks for several years on all my bikes.
Due to biomechanical complexities, I never provide uninvited advice, but since you ask:
Yes, try 165, for the simple reason that your effort and torque
is better served with imroved momentum rather than greater leverage. Leverage is largely beneficial with very slow RPM, but I assume you ride with 80-95 RPM on the road. Best of luck.
anatso

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my cadence difference wasn’t high. maybe 20w? i used to do around 70 - 80 rpm to the 90-100 i do now. and as some others mentioned above, i do find my pedal stroke a lot smoother.

179 cm tall, using 170mm cranks on road and gravel bike. Tried 175mm once but didn’t like it.

TT bike has 172.5mm it came with but I’m considering going to 165mm soon - problem is DA 165mm cranks are out of stock everywhere I looked.

6’1/185cm, 34"/86cm inseam, 80cm saddle height, former “pro” road racer. My first SRM was 165cm by nature of it being free, and I loved it. Have since pinged between 165mm-170mm cranks. I tend to spin 90-100rpm most of the time, but also like mashing out of the saddle uphill for long stretches. When I get on a bike with 175mm cranks it feels funny, in kind of a lumbering way.

I’m also pretty certain a large chunk of folks out there obsess about it and couldn’t tell you how long their cranks were if tested blind.

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5’10" or 178cm and I run 172.5mm on the road bike, 165mm on the TT bike.

Can feel the difference when swapping between them but wouldn’t say it is night and day. Maybe I would feel different if it was different cranks on the same bike. I wouldn’t drop to 165 on the road bike and I definitely wouldn’t go up to 175s either. 170mm on the road bike might be better for me to be honest but I generally don’t have any issues bad enough for me to consider it a necessity.

I’ve been running 165 for about a year now… and I’ve made the change on all my bikes. It’s fantastic and worth the change.

Switched to 165mm rotor Vegast from 172.5mm Rival and saw a 2kmh improvement in my average speed on a 65km ride. Try it out, it might help you, or might not. In any case it’s cheap to try.

I’m 5’ 7" with super long legs. 32" inseam jeans. I changed to 165mm cranks and it was one of the best changes I’ve made. Some “qualified professional fitter” once told me 165mm cranks were for 5’ 2" women. I almost laughed. These “pros” actually think they know better than the people who inhabit their bodies. The irony was that this dude was a 6’ 3" behemoth and probably rides 175mm cranks - shorter than I ride, proportionally.

Anyway. I’m not going to say 165mm cranks are “better” at our height. We’re in a bit of gray zone. I’d say that if you like to spin fast and get aero, go for it. If you sit very upright and like to hover around 80-90rpm, even when going hard, stay with the 170s.

That being said, the difference in rpm necessary to equalize 170s and 165s is just 3%. A 10mm (5mmx2) shorter stroke really isn’t much to worry about, especially in this range. The biggest difference is going to be out of the saddle. You probably have a rhythm burned into your muscle memory, so you’re going to be uncomfortable initially. But this is a good thing, because it’ll teach you how to dance more lightly on the bike and spin up even when standing.