Ello all

[Dangermouse]

Now then its been a few months since I was here, anyway the missus has had the knee op and this time it seems to have worked, so I will be building her a bike.
One little question though, as her right leg hasn't got as much muscle and the bend isn't as good as her left leg, could I put a 170mm crank on the right and a 172mm one on the left, I cant see it being a problem but just thought I would ask first.

 

[Archie_tect]

Sounds good!
Might make her bike a bit odd to ride, but might as well try it to see DM... can always put it back. Though wouldn't longer crank lever be better so it's less effort to turn the pedals?
Nice to see you back.

 

[vernon]

I once had a 170mm crank on one side and a 175mm crank on the other and didn't notice anything odd. I only discovered the mismatch when I was matching spare cranks up to make up cranksets to sell off.

 

[vernon]

Might make her bike a bit odd to ride, but might as well try it to see DM... can always put it back. Though wouldn't longer crank lever be better so it's less effort to turn the pedals?

Just did a back of a fag packet calculation and there about 1.5% difference in effort required between the two crank lengths.

 

[Dangermouse]

Sounds good!
Might make her bike a bit odd to ride, but might as well try it to see DM... can always put it back. Though wouldn't longer crank lever be better so it's less effort to turn the pedals?
Nice to see you back.

That's the point Archie, her leg straightens now but doesn't fully bend yet so a shorter crank may not be suitable for her down stroke but ideal for the upstroke by not putting too much bend or stress onto the new joint until she has built some muscle around it.

and its good to be back, didn't want to come here till we were both back out on bikes but too much temptation mate

 

[Dangermouse]

Just did a back of a fag packet calculation and there about 1.5% difference in effort required between the two crank lengths.

So nothing in it really and it should help

 

[Archie_tect]

Sounds logical DM! [Cheers Vern]

 

[Dangermouse]

Another thought.....wouldn't it be easier to get a built up cycling shoe?

Not really RM as it would put her knee too high up on the upstroke, the downstroke would be good though

 

[Dangermouse]

Different length cranks would (hopefully) only be temporary until her knee is strong enough bend fully