The ins and outs of crank sizing. Help required....
bristolpete
Posts: 2,255
Hi ,
I was wondering if someone could shed any light on something that has sort of blinded my common sense and I cant see the wood for the trees.
To advise, I ride a 54 Pinarello Dogma which has a tob tube of 555. I run it with a 100mm stem which I like as I am not a small 5' 9" guy, neither am I big. 14 stone in fact. However, the seat tube of which Pinarello measure is 54 which seems fine. For reference I cannot stand riding compact geometry, I just cant ride it so the taller seat tube suits me.
However, I feel that I have dropped the seat post a tad too much and sometimes feel like I am riding on the top tube though I am not. It is exasperated by the fact I also ride different bike as my commuter/hack/winter machine.
So I was thinking, in order for me to keep the saddle slightly higher I could change my crankset from 172.5 to 175 but soon realised the issue is relative as although I am higher on the top of the pedal stroke, I would in turn be the same distance at the bottom, pushing the pedlal further away. So, my other option is to change it to a shorter crank, perhaps 170mm which will bring the pedal closer to my seat clamp and allow me plenty of leverage on the down stroke. trouble is that a couple of people have told me that shorter cranks give you less power climbing, but I wonder if I would notice it...?
Can anyone shed any light on this, other than me staring at a ruler wondering how on earth such small measurements make that much difference ! Even if I had dropped a frame size we are talking tiny amounts but do they really make that much difference to a layman rider like me?
Appreciate any advice here.
Pete.
I was wondering if someone could shed any light on something that has sort of blinded my common sense and I cant see the wood for the trees.
To advise, I ride a 54 Pinarello Dogma which has a tob tube of 555. I run it with a 100mm stem which I like as I am not a small 5' 9" guy, neither am I big. 14 stone in fact. However, the seat tube of which Pinarello measure is 54 which seems fine. For reference I cannot stand riding compact geometry, I just cant ride it so the taller seat tube suits me.
However, I feel that I have dropped the seat post a tad too much and sometimes feel like I am riding on the top tube though I am not. It is exasperated by the fact I also ride different bike as my commuter/hack/winter machine.
So I was thinking, in order for me to keep the saddle slightly higher I could change my crankset from 172.5 to 175 but soon realised the issue is relative as although I am higher on the top of the pedal stroke, I would in turn be the same distance at the bottom, pushing the pedlal further away. So, my other option is to change it to a shorter crank, perhaps 170mm which will bring the pedal closer to my seat clamp and allow me plenty of leverage on the down stroke. trouble is that a couple of people have told me that shorter cranks give you less power climbing, but I wonder if I would notice it...?
Can anyone shed any light on this, other than me staring at a ruler wondering how on earth such small measurements make that much difference ! Even if I had dropped a frame size we are talking tiny amounts but do they really make that much difference to a layman rider like me?
Appreciate any advice here.
Pete.
0
Posts
Bike set up is determined by the rider, not the bike - I'd try and replicate the same position on all your bikes - having different ones can compromise your performance.
Crank length is as much influenced by your own pedalling style - whilst shorter cranks give you less leverage, if you can spin more smoothly in a lower gear then you may find it can improve you climbing. Only you can tell what difference it makes and can only really be determined by actually try riding a pair