Crank length: 172.5 to 175mm

cjcp

Evening all

Ive run 172.5mm cranks for the last few years, but have the opportunity to buy discounted 175mm cranks for the cross bike and have been struggling to find 172.5mm cranks.

Now, I've never ridden a cross bike, nor 175mm cranks. Is this going to make a difference in the grand scheme of things, or can I simply compensate by lowering the seat fractionally?

Cheers.

redddraggon

Should be fine

cjcp

Cheers.

Chrissz

Unlikely you'll notice any difference at all mate - I just changed from 172.5 to 175mm after years and never noticed any difference in either feel or performance.

cjcp

The news gets better. I was a bit worried about how the knees would react.

redddraggon

cjcp wrote:

The news gets better. I was a bit worried about how the knees would react.

Assuming you haven't got short legs and you shouldn't be on 165mm cranks, and 172.5mm is about the right length, 175mm will be fine.

I use both 170mm and 172.5mm on my bikes and it's fine.

cjcp

redddraggon wrote:

cjcp wrote:

The news gets better. I was a bit worried about how the knees would react.

Assuming you haven't got short legs and you shouldn't be on 165mm cranks, and 172.5mm is about the right length, 175mm will be fine.

I use both 170mm and 172.5mm on my bikes and it's fine.

I've never thought I have short legs. I'm usually 32in leg. I think.


EDIT: spotted this - http://www.sheldonbrown.com/cranks.html

roger_merriman

cjcp wrote:

redddraggon wrote:

cjcp wrote:

The news gets better. I was a bit worried about how the knees would react.

Assuming you haven't got short legs and you shouldn't be on 165mm cranks, and 172.5mm is about the right length, 175mm will be fine.

I use both 170mm and 172.5mm on my bikes and it's fine.

I've never thought I have short legs. I'm usually 32in leg. I think.

your around my height aren't you, I'm 34in leg, so on the leggy side.

cjcp

6ft. You might be a tad taller?

roger_merriman

cjcp wrote:

6ft. You might be a tad taller?

na just the hair....

cjcp

That settles it then.

Roastie

You bought them yet? I must admit that I go against the grain of this thread and would probably rather go shorter than longer. Longer promotes a slower cadence and also gives less pedal clearance. The first may be an issue in terms of maintaining traction, the second (though I have no cross experience to back this up) could be a factor on more technical circuits.

cjcp

Not yet. They are in the "basket". I was mulling over RD's post in bed and thought perhaps I should go for 170s. Hmm.

Fair points, although the lack of bike handling skills in cross is likely to play a bigger part :oops: .

Roastie

I'd def go for 170s over 175s if that is an option. Probably won't make *that* much difference, but ...

redddraggon

http://www.chainreactioncycles.com/Mode ... elID=41366

There's a nice cheap cross crankset, Gossamers are heavy but very stiff and reliable and the chainrings are really good.

For cross I'd (me personally) go for 170mm just to give a little extra clearance from the ground.

cjcp

redddraggon wrote:

http://www.chainreactioncycles.com/Models.aspx?ModelID=41366

There's a nice cheap cross crankset, Gossamers are heavy but very stiff and reliable and the chainrings are really good.

For cross I'd (me personally) go for 170mm just to give a little extra clearance from the ground.

Hehe, that's the one in my "basket". Not too worried about weight - I have plenty of that as it is. Reliability is a better option whilst I'm starting out. I can think about upgrading next year.

I'll go for the 170s. Cheers, chaps.

Clever Pun

I needed to put the seat down a little

it's really good for hill as the increased leverage is really helpful and of course for putting the hammer down in larger gears

Roastie

cjcp wrote:

Not too worried about weight - I have plenty of that as it is. Reliability is a better option whilst I'm starting out. I can think about upgrading next year.

Ditto. I'm running a square taper BB & crankset I originally bought for touring ....

greg66_tri_v2.0

Chrissz wrote:

Unlikely you'll notice any difference at all mate - I just changed from 172.5 to 175mm after years and never noticed any difference in either feel or performance.

+1.

In fact, a couple of years ago i was fiddling around changing mine (again) and noticed I was running a 170 on one side and a 172.5 on the other. Hadn't noticed. Didn't notice when I remedied it either.

I'm razor-sharp, me.

Clever Pun

Greg66 wrote:

Chrissz wrote:

Unlikely you'll notice any difference at all mate - I just changed from 172.5 to 175mm after years and never noticed any difference in either feel or performance.

+1.

In fact, a couple of years ago i was fiddling around changing mine (again) and noticed I was running a 170 on one side and a 172.5 on the other. Hadn't noticed. Didn't notice when I remedied it either.

I'm razor-sharp, me.

Back problems?

just saying

greg66_tri_v2.0

Clever Pun wrote:

Greg66 wrote:

Chrissz wrote:

Unlikely you'll notice any difference at all mate - I just changed from 172.5 to 175mm after years and never noticed any difference in either feel or performance.

+1.

In fact, a couple of years ago i was fiddling around changing mine (again) and noticed I was running a 170 on one side and a 172.5 on the other. Hadn't noticed. Didn't notice when I remedied it either.

I'm razor-sharp, me.

Back problems?

just saying

Not at the time

cjcp

Plumped for the 170mm to give me a little more clearance. And just in case I do have short legs.