Crankarm Length - 170mm vs. 172.5mm
 

I just ordered a new Ultegra crankset. I ordered a 172.5mm, but received a 170mm. How much of a difference will this make? Should I go through the hassle of trying to return it? I've been riding a 172.5mm for years (it's what came on my bike), am just a touch under 6ft tall, and don't know my inseam. I like long endurance rides and hills. Thoughts? Thanks.

Six foot may be tall for 170mm (inseam and femur length would be better info)...

There are crank length calculators, use Google...

I ride 170mm and I am 5' 7" on a good day...

Some will argue too short, some will say its only 2.5mm...

You will be able to spin, spin, spin...

Longer cranks...more leverage for those hills...

I vote too short...

You might notice the difference the first ride, but after that you'll settle in without worries. I really don't think, three months from now, you'll be kicking yourself for not going with the 172.5's. "Aw man ... if only .... ". No, I doubt that.

jw

I ride 170s and 172.5s without even noticing a difference, although I am 5'11 with the legs of a 5'6" person so I like shorter cranks.

I have 175mm on my climbing bike and 172.5 on all my other bikes.

I'm 5'11" and I used to use 170mm cranks. A while back I bought a new Cannondale that came with 172.5mm cranks and I was thinking I might want to swap them out for 170's. I rode the bike as it came and didn't even notice the difference.

If you ordered 172.5, you should get 172.5.

And even if you can't "feel" the difference, you will "know" that there is one... Trust me, you don't want this sort of poison in your head during a painful ride...

Ditto, plus I think you will be able to tell the difference.

I started with 172.5, switched them for 170, then switched them back. I noticed a difference and prefer the longer crank.

I went from 175's to 170's and noticed a definite difference but I'm 5'8". You might want the 175's.

175 to 170 is a big difference. I'm thinking I"ll probably try them out and see how it goes. If I try to exchange I'm stuck riding a spin bike at the gym this weekend...

I'm a 6'2" cat1. I ride 170's because I race quickly. I like to stay on top of the gear and only mash when I get really tired. I have used 180's as well, back in the 90's, when it was the rage. You adapt to anything in time. Stop worrying about the 2.5mm.