Hi all.
been offered an xt crankset cheap of a freind.the only thing is that it,s 170mm.i normaly ride with 175mm so is that 5mm that noticable.
i,m sort of medium height 5,8 with normal sort of leg lengh,regular jeans size leg.should i go for it…

No, not on a geared bike. You should be riding with 170mm cranks anyway at your height.

Yes it is noticeable. I didnt like 170mm cranks but I am 6ft2

You'd never tell. Guaranteed. The type of people that tell must be *very* sensitive to adjustment- time triallers or something.

Try dropping your saddle 5mm from your usual height, can you notice that? If you do then you may notice crank length difference.

cheers samuri it,s just both my bikes came with 175,s on them so never realy thought about swapping them so if it,s 170 for my height all the better.
sound advice once again from the crew..cheers gang.

I don't tend to notice such small adjustments.

I'm 6ft 1 & have ridden 165s happily (still have them) as well as 180s (road chaimset)

they very slightly alter the effort you put into each gear ratio but they also make your feet move different sized circles & it all works out just fine IME

If I had to dump one or other I'd get rid of the 180s, just for ground clearance

Yes

No

Maybe

1 Print* out each of the above onto a separate piece of paper.
2 Fold paper.
3 Put all pieces of paper in a hat
4 Pull out one piece of paper unfold and read.
5 Pull out next piece of paper and read that too.
6 Finally remove the final piece of paper unfold and read.

*If you do not have access to a printer you can simply post the question on STW and get exactly the same result.

IME the difference in crank lengths is quite noticeable. It's primarily initially because of how big a circle your pedals/feet are moving in, but I do also notice a difference in helping turn a big gear with long cranks, and easier to spin fast with shorter ones.