Different crank lengths on different bikes

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HillRPete
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by HillRPete

So the consensus in the archives here seems to be that crank length is mostly a "getting used to" issue, and one should use what feels best. Which would be 175mm for me.

Now the thing is, I have a spare 172.5mm crank around, and am tempted to put it on a "hack" MTB, to ride once or twice a week (with 3-4 road sessions). Do people think the constant switching between lengths will be detrimental to riding?

by Weenie


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Juanmoretime
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by Juanmoretime

I change all thine. Starting from shortest to longest: Fixie = 165mm, tt bike = 170mm, road bike = 172.5mm and 29er single speed 175mm. All work and no issues going in-between.
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bikerjulio
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by bikerjulio

I too have "several" (ahem) bikes with crank lengths ranging from 175 through 177.5 to 180. I switch around all the time. No problem.
There's sometimes a buggy.
How many drivers does a buggy have?

One.

So let's just say I'm drivin' this buggy...
and if you fix your attitude you can ride along with me.

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drchull
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by drchull

I ride from 172.5 on my track bike, 177.5 road and TT and 180 MTB.
I don't know how much of what I feel is psychological but the 177.5 on the road just feels right, I have tried switching around from 175-180 on road and always end back at 177.5.

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Tinea Pedis
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by Tinea Pedis

I review a fair few bikes. A lot come with 172.5

I personally use 175.

It's fine. I can feel the difference, but it's certainly not hampering me in any way.

Geoff
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by Geoff

Everyone is different. I personally cannot do it. If I ride 170's, I feel like I am going to hurl. The 175's are better, but still not 'right'. You'll have to try it and see.

CarpetFibre
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by CarpetFibre

170s are my crank length of preference, and I run it on all of my bikes now. However I used to have 165s on my winter bike and whilst it felt different, I got on fine with it.

But, given that I didn't swap regularly between the two bikes (I used to ride the winter bike for a long time and then swap to my nice bike and ride that through the nice season), I'd say that I wouldn't have liked to swap regularly between them. It takes me a while to get used to a new set up until I feel powerful and smooth.

dvincere
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by dvincere

My question is similar to OP's. I'd like to try smaller cranks on my bike. I am riding 172.5 but I am not very tall and it has been brought to my attention that short cranks may help me. 167.5 seems ideal. I'm not exactly rich and I don't see any way to test ride cranks. Is it possible to even see a performance difference on cranks 2.5mm or 5mm different? Not just "I feel it's big/small" but "my pedal stroke is better/worse because of the size difference."

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Juanmoretime
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by Juanmoretime

You may get a performance benefit but in many cases in just feels right which makes it worth the change too.
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metal
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by metal

I run 165 on track, 167.5 on crit bike, and 170 on training bike.

Generally, the higher the constant rpm, the smaller the cranklength I run. But the other advantage is that 165's on track are good for velodromes to avoid pedal striking at low speed, 167.5 is good for crits because you have a few mill extra than most riders before striking a pedal, and 170's teach you how to spin circles well :)

Really, it's not much different a feel, and if it was a blind test, I doubt I'd be able to tell you what is on the bike without looking, so it's probably more mental than anything.

Ride what you feel most comfortable with. Given most road bike are 172.5 to start, try a size up and size down from 172.5, and see if your body responds well to the change.

Cheers,
metal

mentok
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by mentok

170 track, 175 road, 180 ss. I rock strike pretty regularly on the mtb which leaves me tempted to use a 175 in the hope that it might make a difference, but other than that i feel no detrimental effects.

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Tapeworm
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by Tapeworm

metal wrote:...But the other advantage is that 165's on track are good for velodromes to avoid pedal striking at low speed,


Probably an outlier, but there was one track World Champ who used to ride 200mm cranks on the boards with no issues... though he didn't go very slow. Just sayin'

My road and TT bikes are both 172.5, mtb 175 and 172.5, track 170 and 175.
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nathanong87
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by nathanong87

metal wrote:But the other advantage is that 165's on track are good for velodromes to avoid pedal striking at low speed


not so much with the bank i'd think, but if you are riding on the street 165 is better than 175 when it comes to pedal strike

also on that note, toe overlap is reduced slightly especially with some of the steep angles for heatubes and close(r) clearances.

when i used to own track bikes, thankfully despite the small frames, i didn't have any overlap with 165 cranks and medium mks cages (street shoes). That's a plus when doing wycked fixie track stands at teh red lightz

5 8 5
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by 5 8 5

dvincere wrote:My question is similar to OP's. I'd like to try smaller cranks on my bike. I am riding 172.5 but I am not very tall and it has been brought to my attention that short cranks may help me.

As has been mentioned you need to try them to see how they feel. I notice small changes in my setup, saddle too high / low etc but when I tried 175s (from 172.5s) I felt I had a little more leverage and it didn't adversely affect my cadence so I stuck with them.

A few months ago I picked up a cheap Campag UT 175 chainset for my winter bike so I've got the same size across the board.

dvincere, see if you can pick up a cheap 170 chainset on the Bay just to experiment with.

by Weenie


kulivontot
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by kulivontot

Different crank length changes the knee angle. Make sure you adjust the fit accordingly.

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