Crank arm length

Bible Basher Biker

Hi folks! My once-in-a-blue-moon-visit-for advice....

How much difference does it make between 170mm and 175mm?

I think I've got 170 at the moment. I'd like to upgrade my chainset but the model that would suit my requirements is only available in 175....

Current set up is comfortable, no knee/back pain etc so is it very unwise to change to a different length, or do you barely notice it?

thank you!

The Rookie

Will make burger all difference and you won't even notice the change.

Underscore

I'm not sure that I would agree that you won't notice the change; I've convinced myself that I can feel the difference between the 172.5 that I've got on two of my bikes and the 175 that I've got on another... However, provided you adjust your saddle height so that your leg extension is the same at the longest (not quite the same as lowest) point and you are of average height or taller, you will probably be just as comfy on a 175mm as on your 170mm - it just means that your knee will have to come up a little higher.

_

desweller

For a while I had 175 on my road bike and 170 on my touring bike and they felt completely different. I have fairly short legs for my height and I found that 175 was just a bit too far between BDC and TDC; getting the saddle height right was quite difficult compared to the touring bike.

I've now switched to a 172.5 crank on my road bike and I find it much easier to use.

Bible Basher Biker

Thanks for this folks,
As it turns out my seat post is completely seized (old hardworking commuter bike, short on love!) so I'd better stick with getting the same as I've got.
thanks.