Originally Posted by
Leisesturm
I
I have five single bikes, four tandems and two recumbents. There is every length of crank on them from 165 through 175 and I couldn't tell you what has what. It is simply a non-issue, that small a change. Well, if it isn't costing anything, why not. But to remove a perfectly fine set of 170mm cranks. Pay ... what, $100? $150? More? You'd better, if you want something decent. Or find them used. Now, can you make the swap yourself or do you have to $$$ to have it done by the LBS? For 5mm? I don't think so. That is all I'm saying and all I ever will say about it. A 3% change just isn't worth three figures to try out.
We have a
double recumbent tandem built for Dutch people. At 5'10" I can 'just' reach the pedals with the 170's that are in the Captains spot. At 5'6" my wife can 'just' reach her pedals. There isn't any way to fix that. Theoretically my wife should be alright but she would like some shorter cranks. The rule is "the Stoker is always right" so I am duty bound to make it right for her. I'm pretty sure her cranks are 170's just like mine. Taking my own medicine, I am not going to swap a full out tandem crankset. I will find some
crank shorteners. Happiness begins at 155mm. Go big, or go home. YMMV.
Those crank shorteners seem pretty sweet.
As I pointed out earlier, if you don't ride a good long distance you may never sort out the impact of crank length. But if you think about it, we have different stems, handlebar widths, frame sizes and adjustable seatposts, yet somehow one crank size fits all?? It may well, if you only do short rides, and I can't say if a randonneur is long enough to injure your knees. But I do know that if the bike is heavier, if the climbs are more pronounced, such as you see on the Tour Divide, that cranks length makes a difference- I've seen a lot of people blow their knees out and have to quit on that account.
I get the part about swapping cranks. Its not cheap if you want to do it right! The way I see it, my knees aren't cheap either- in that regard its just like riding with a MIPS helmet.