Dura Ace - Crank Set 53 x 39 - which MM 172-175 ???

[jaffstar]

Looking to upgrade old Dura Ace Crank set with a new one.

The old size = 53 x 39

 

I notice 3 x options in mm  such as :

 

170 mm

172.5mm

175 mm

 

Not sure which option I need ? How would I know / compare to current set ?

[Butterbean]

It actually matters very little in the big scheme of things.

 

Generally, however, riders on frames 56 and up will use a 175, riders on 50-56 will use a 172,5, and those on frames smaller than 50cm frames ride with 170.

 

For anecdotal evidence, I went from 175 to 172 and stopped experiencing knee pain. But it may not have been the crank at all?

[jaffstar]

I am on a 54 so 172.5 is the sweet spot.

How would I know what my current one is (out of interest ?)

 

Could not find anywhere, I see 53b

['Dale]

Standard is 172.5 for road and 175 for mtb, unless you're exceptionally tall or short.

That's a good enough principle.

 

Bradley Wiggins is as tall as my house and rolls with 170.

So, it is a matter of preference.

[gummibear]

I am on a 54 so 172.5 is the sweet spot.

 

How would I know what my current one is (out of interest ?)

 

Could not find anywhere, I see 53b

It'll be stamped on the back of the crank arms.

[Weimaraner1]

I have also researched this and it would seem as if most people ride a longer than what they should crank just because this is what buying a complete bike dictates.

 

Have a look at this website and then decide.

 

http://bikedynamics.co.uk/FitGuidecranks.htm