In short, when looking to replace my current chainset, is the crank arm length going to make a blind bit of difference? Both my bikes came with 175mm but before I took any sort of plunge into a replacement I thought I better run it past you chaps. I'm 6ft, the bikes are a size L, so a crank arm at the longer end of the scale seems to make sense.
SRAM have the ability to offer me 170mm, 172.5mm, or 175mm.
Now why on earth do they bother? 5mm difference???? Is that going to make the slightest bit of difference????! I mean I know you can change your stem length in 10mm increments or move your seat down, up, forward or back by fractions, but surely there is a tolerance for most people with a modicum of flexibility? So does a 5mm crank range serve any purpose?
I'm not saying that it doesn't, I'm just asking the question of more knowledgeable people
It's not even as simple as getting a bike fit, because from a bit of googling there are so many schools of thought on what is 'optimum' crank arm length that I'm not even sure that there is an optimum, so one bike fitter may tell me something completely different to another.
Reading between the lines, in 'the old days' it was thought that longer gave more leverage and power, but recently there's been a shift towards a more compact pedal circle providing a more balanced stroke?
To be frank, I'm confused. I've had knee niggles for a few years, but related to football, not cycling. I occasionally get slight discomfort but I presume I'd get that regardless of the cranks - it's just my dodgy knee, so the cycnic in me thinks I should just stick with 175. Both my bikes will therefore be the same, and the status quo will be restored. But what if it WOULD be more comfortable with a shorter crank? But then 2.5mm? What will that do??! Argh!
I guess what I'm looking for is a concrete reason to change i.e. at Xft tall with a XXinch inseam you WILL need a XXXmm crank arm length because...
a) it will be kinder on your joints
b) it will make me more efficient
c) it will increase my prowess with the ladies etc etc.
Help
SRAM have the ability to offer me 170mm, 172.5mm, or 175mm.
Now why on earth do they bother? 5mm difference???? Is that going to make the slightest bit of difference????! I mean I know you can change your stem length in 10mm increments or move your seat down, up, forward or back by fractions, but surely there is a tolerance for most people with a modicum of flexibility? So does a 5mm crank range serve any purpose?
I'm not saying that it doesn't, I'm just asking the question of more knowledgeable people
It's not even as simple as getting a bike fit, because from a bit of googling there are so many schools of thought on what is 'optimum' crank arm length that I'm not even sure that there is an optimum, so one bike fitter may tell me something completely different to another.
Reading between the lines, in 'the old days' it was thought that longer gave more leverage and power, but recently there's been a shift towards a more compact pedal circle providing a more balanced stroke?
To be frank, I'm confused. I've had knee niggles for a few years, but related to football, not cycling. I occasionally get slight discomfort but I presume I'd get that regardless of the cranks - it's just my dodgy knee, so the cycnic in me thinks I should just stick with 175. Both my bikes will therefore be the same, and the status quo will be restored. But what if it WOULD be more comfortable with a shorter crank? But then 2.5mm? What will that do??! Argh!
I guess what I'm looking for is a concrete reason to change i.e. at Xft tall with a XXinch inseam you WILL need a XXXmm crank arm length because...
a) it will be kinder on your joints
b) it will make me more efficient
c) it will increase my prowess with the ladies etc etc.
Help
Like you the165's on my fixed and the 172.5's on my geared bike feel the same, though its easier to spin up the fixed on the shorter crank.
Of course, to remain (slightly) on-topic: they would have needed very, very short cranks.
