Crank arm length

[development_cycle]

Been here for a while but never frequented the R,.! Forums, nope can’t say the word.

Anyway a friend has talked me into getting a r,.! bike, nope still can’t say the word, working on it so in true retro style I have picked up a 1990s steel frame and forks and managed to scrounge some bits already.

On a mountain bike I know what crank length works for me, but are things different in that respect on a ro,,..) bike? Nearly said it!

I often make impulsive dirt cheap purchases and it’s really important that the cost remains so low on this.

Advice (rather than blind speculation) gratefully received.

 

[KermitGKona88]

Re:

Well if you use a 170 on an MTB use the same on a R... bike, if you use a 175, use a 172.5 on a R... bike, 180, 175 so on.

 

[development_cycle]

Re:

I use 175mm on MTB’s, so 172.5mm on the roooooaaaad bike, yes!!

Why the difference out of curiosity?

 

[KermitGKona88]

Re:

Mainly because there are more choices on a Road bike and the bottom bracket is lower. The main thing though is not to get too hung up over the length as it only makes a minuscule difference

 

[tintin40]

i've got some 172.5 mm mtb cranks and i can't tell the diff from 175. My MF has 170 they feel a little short. Or is it all the mind?

 

[development_cycle]

Re:

I also had a set of 170’s on an MTB and could tell, but never tried 172.5

 

[KermitGKona88]

i've got some 172.5 mm mtb cranks and i can't tell the diff from 175. My MF has 170 they feel a little short. Or is it all the mind?

Probably a bit of both in reality :facepalm:

 

[Splatter Paint]

Re:

Everyone tells me I need 172.5 mm - it feels just wrong. I ride 175mm, I think it makes minimal torque difference and power.

 

[KermitGKona88]

Re:

Ahem

viewtopic.php?f=22&t=382777

 

[development_cycle]

Re:

Probably looking for low to mid range Shimano.

When I said cheap, it’s on a whole different scale.

Frame forks bottom bracket headset stem and bars £20
Sti shifters and brake callipers £1.78