A question of crank length

[spacecadet9]

I think the chain set on my Raleigh Airlite 100 is looking pretty worn, so I've been looking around for a replacement

I was planning to just get the same one again, it's a Shimano 2300 Compact

However I've noticed I can only get it (or a2350) with either a 170mm crank or a 175mm crank

However, looking at the specs of my bike I think it came with a 172.5mm crank!

Does 2.5mm make a huge difference?

Should I go longer or shorter with the replacement?

Any help would be gratefully received!

 

[HLaB]

The longer the crankset the I believe the more leaverage but more stress on the knees as its harder to spin. I may be wrong but I think 172.5mm is the happy medium for most folk.

 

[4F]

170 will be fine, I doubt you would be able to tell the difference between the 170 and your old 172.5.