- Crank lengths, 170mm or 175mm?
Ok I know this has probably been answered before but its doing my head in!
I have a Cove Stiffe (still not built) and i’m still unsure about the cranks.
I have bought and fitted some 170mm saints reason? because 1 they are black and my frame is black so they look mint, 2 they have steel pedal inserts as the bike is going to be ridden hard at times, and 3 I should get more rock clearance with the shorter crank arm length.
Thing is not been able to test ride it yet as i’m still waiting for my brakes and pikes to turn up! i’m now unsure due to reading many conflicting reviews/opinions if the 170mm arms will be ok as iv’e always had 175 cranks.
I am 5ft 11″ and my inside leg measurement is 32″ who else is this height and leg measurement and what bike/cranks do you ride? will I see a huge difference and feel like i’m riding with a flat tyre as some suggest!!!!! (sounds obsurd to me but hey)
Anyone?Posted 8 years agoSamkMember
It’ll feel different not bad different, just different. 170’s will give you less leverage but at the same time will spin slightly faster per given gear (circumference that the end of the crank arms move around is shorter hence each rotation will take less time) The only way that the bike will feel like it has a flat will be if it has a flat.Posted 8 years agomatthew_hMember
will spin slightly faster per given gear (circumference that the end of the crank arms move around is shorter hence each rotation will take less time
What a load of bollocks. One revolution will take exactly the same time for the same speed and gearing. The only difference would be a slight decrease in the actual pedal velocity (with the 170mm cranks) as the actual distance covered per revolution is slightly less. Not that you would notice this.
Basically, you are fairly unlikely to notice a difference between running 170s or 175s and you’ll be fine. If you really want to have 175s then I’ll swap you for my 175sPosted 8 years agosimonfbarnesMember
One revolution will take exactly the same time for the same speed and gearing.
correct, but if the diameter of the pedal path is smaller then you’ll have to push harder to exert the same torque, so it feels the same as a (slight) increase in gear ratio. But probably too small to notice. 5mm in 175 is equivalent to one tooth on a 34 tooth sprocket…Posted 8 years agocrazy-legsSubscriber
175’s on all my bikes except the roadie SS which has 170’s.
Shorter cranks are easier to spin but generally most people only notice this on road/track bikes.
If you look on Sheldon Brown there’s a gear ratio calculator which takes crank length into account when working out gear ratios, it does make a (slight) difference.Posted 8 years ago
matthew_h me too not desperate as I havn’t even ridden the bike yet due to being p****d around with some forks and brakes that never turned up!Posted 8 years ago
As soon as the bike is finished which should be this weekend (brakes and pikes on order from someone else) I will let you know if I want to swap, are yours in good condition?
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