impact of crank length

[samsbike]

What difference , if any, does crank lenght make in the real world.

I have the option of buying a groupset but the cranks are 170, I currently run 172.5.

Thanks

Sam

[Brucey]

I am fussy enough to notice the difference and maybe even care, but plenty of people don't worry about a small difference like that, because they don't even notice it.

cheers

[yostumpy]

you may feel like raising your saddle to compensate. Just got some new shoes, and lifted saddle 2-3m as I DID notice it.

[andrewjoseph]

i go from my mtb at 175mm to my road at 170 mm and not notice it. both bikes have saddles same height above pedal axle at greatest distance/bottom of stroke.

[teh]

I ride 200mm cranks on all my bikes, and people tell me that it makes no difference!

What is your inside leg, cr*tch to floor?

[samsbike]

I ride 200mm cranks on all my bikes, and people tell me that it makes no difference!

What is your inside leg, cr*tch to floor?

89/91cm - depending on how hard I pushed up on the rod to measure it!

I think my mtb runs 175 and the road bike 172.5, but I cant say I have noticed it, but then I dont really ride the mtb.

[Mick F]

I ride 200mm cranks on all my bikes ..............

I've never seen 200mm cranks for sale.
Where do you get them?

[geomannie]

I have a tourer on 170mm and an audax bike on 175mm. Frankly, I can't tell the difference. Maybe I'm just unobservant, maybe they both just work?

cheers

geomannie

[teh]

I ride 200mm cranks on all my bikes, and people tell me that it makes no difference!

What is your inside leg, cr*tch to floor?

89/91cm - depending on how hard I pushed up on the rod to measure it!

I think my mtb runs 175 and the road bike 172.5, but I cant say I have noticed it, but then I dont really ride the mtb.

Call me Mr Controversial, but do yourself a favour and get some 180mm cranks (at least). My humble opinion is that going from 172 to 170 is going the wrong way.

[teh]

I ride 200mm cranks on all my bikes ..............

I've never seen 200mm cranks for sale.
Where do you get them?

hscycle.com, Zinn, and some guy in Germany who has given up making them: customcranks.de (I think). I'm never going back to short cranks!

[byegad]

Once the HPV racers find this thread we'll see the fur fly! A lot of them make extravagant claims about the benefits of short cranks, 150mm or less!

Hang on and I'll get myself a beer and the peanuts.

[Brucey]

170, 172.5, 175mm cranks are widely available. The further you stray away from these lengths the more difficult it is to buy cranks, more or less.

IIRC several tests have failed to show a strong relationship between leg length and crank length. My take on this is that

a) in most cases it doesn't make a big difference

b) habituation is more important than absolute crank length

Very short or especially very long cranks are not commonplace and are priced accordingly. Vary the crank length by more than 10mm or so and maybe you will start thinking that a custom frame is a good idea, so that you can keep a sensible BB height.... and so it goes on...

One of the few proven effects of other crank lengths is, I believe, a rapid emptying of the wallet...

cheers

[seph]

I built my latest ride up using 160mm cranks. I had a hunch that knee pain (which I've had on longer rides for some years) would be less if the circles I was pedalling were smaller. I think its worked! I can now ride 200 miles + with less discomfort during and after the ride. I know its only 10mm shorter, but I think it just allows my kne to get around with a less acute bend.

Regarding cost, £35 from spa, including the rings...

[teh]

I built my latest ride up using 160mm cranks. I had a hunch that knee pain (which I've had on longer rides for some years) would be less if the circles I was pedalling were smaller. I think its worked! I can now ride 200 miles + with less discomfort during and after the ride. I know its only 10mm shorter, but I think it just allows my kne to get around with a less acute bend.

Regarding cost, £35 from spa, including the rings...

How tall are you?

[teh]

170, 172.5, 175mm cranks are widely available. The further you stray away from these lengths the more difficult it is to buy cranks, more or less.

IIRC several tests have failed to show a strong relationship between leg length and crank length. My take on this is that

a) in most cases it doesn't make a big difference

b) habituation is more important than absolute crank length

Very short or especially very long cranks are not commonplace and are priced accordingly. Vary the crank length by more than 10mm or so and maybe you will start thinking that a custom frame is a good idea, so that you can keep a sensible BB height.... and so it goes on...

One of the few proven effects of other crank lengths is, I believe, a rapid emptying of the wallet...

cheers

So based on your theory and your deep knowledge and experience of being tall, and based on your understanding of biomechanics, you imply that a 6'8" guy with size 54 cycling shoes should ride 170mm cranks. Presumably you think he should take tiny steps when he walks or runs? Again we have the "everyone is like me" fallacy.