I get some toe overlap with my cross bike – tiny amt but it irritates me intensely. I have tried shifting my cleat position but didn’t get on with it and now thinking about shortening my crank arms (well actually fitting shorter cranks!) Currently they are Tiagra 175mm. Happy enough to buy decent cranks but don’t want to shell out loads and then find I hate the shorter ones or that they haven’t solved the problem!
So will 172.5mm cranks be noticeably different to ride? Will they make enough of a difference (only just snag it – but is 2.5mm enough?)
Also – will mtb cranksets fit with a road type Hollowtech II bb? If so it widens my options for finding something cheap and nasty to try out before committing to something expensive.
Finally – anyone got 172.5mm cranks surplus to requirements? Does not matter what state the rings are in but the BCD needs to fit compact
50/34 rings…..
Thanks!

Can you move your cleats back on your shoes to see if 2.5mm is enough?

i run 175 cranks on my MTB and 172.5 on the CX bike and don’t notice it at all

Managed to build up a bike with 175mm on the left and 172.5mm on the right (don’t ask, too many ‘spares’ in the garage…) and never noticed for a bit, though imagine it’d knacker your knees if done longer term.

Fair chance you’ll not notice 2.5mm, but are you only clipping the wheel by 2.5mm or less?

Also – will mtb cranksets fit with a road type Hollowtech II bb? If so it widens my options for finding something cheap and nasty to try out before committing to something expensive.

With a couple of spacers you’d find on the equivalent mtb bb either side it should fit, though that might not leave enough thread inside the frame. Whether the cranks would work on a cross bike, I’m not 100% sure, the inner granny ring/granny ring bolt tabs might catch the stays.

Alas, it’ll be try it and find out. No definitive answer.