crank arm length on my road training bike vs xc mtb

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hi all,

just after some advice and opinions please.

i race xc and my current mtb set-up has a 175mm crank arm. i've just bought a new road bike for training (i will also prob race it) and it has a 172.5mm crank. my thoughts are that although if i were purely riding and racing road then i'd probably change the road bike to a 170mm crank. given the situation i'm in and the types of riding i do, i was thinking the crank on my road bike would be ok as it'll mean less of a 'jump' in terms of transferring between my road and mtb. from a performance and potentially injury potential issue do you guys think this is correct?

i'm 5'7'' by the way.

many thanks in advance.

supersonic

I personally think it is very difficult to notice a 5mm difference, let alone a 2.5mm difference! The pedal design usually has more of an effect.

Crankmeister

im only 5 "7 and i find and have found that 170mm crank arms suit me best i used to run XT 170mm arms on my sworks and got on with it great.i then spent extra cash on an XTR 175mm crank and it really messed up my rythm or cadence.it may just be that having used 170mm for so long i got used to it and how it worked.175mm just seems to big for me.
i guess my leg length just suits 170mm.you could maybe ride your bike then compare with a friends bike at 175mm,172.5mm,170mm and see what suits?

good luck i hope you find what suits

icedmind

im 5"7 as well and i ride my 16 inch anthem(i have short legs)
got 175 xtr chainset on my anthem
and have 170 chainset on my training rb

the thing is on rb yo have a chainset with much more teeth and on mtb you have only 44t but require more energy when you ride it

i found it good as it come with and feels the same coz im in different position when i ride my rb and mtb

you can try move the seat more forward or backwords on your rb to make it feel almost the same as your mtb
good luck

SuperCove

I recently moved from 175mm to 170mm and then moved back 175mm.

Upon moving down to 170mm I had to make alot of other adjustments on the bike to get back into the same rythem as when I rode before but it never felt quite right so had to make the move back again.