Riding with odd crank lengths

Looking for some advice and general opinions here please.

I have a Canyon Speedmax with 170mm Ultegra cranks with a 4iiii power meter and a Giant Propel with 172.5mm Ultegra cranks with no power meter.

I only know that the crank lengths are different because I had swapped out my LHS crank on my Canyon to my Giant a few months back becuase I wanted to have power on my outside rides. Only today when I was looking did I notice that they are different lengths, so for a number of rides I have been riding with a LHS 172.5 crank and a RHS 170 crank.

I truly didn’t notice any difference at all and was surprised that they were different lengths when I looked today. So, the question is whilst I totally appreciate that they should be the same length each side what are the downsides of this and is it even okay to carry on riding this set up or am I starting to create long term problems here.

For context; 95%+ of all my riding is indoors on a trainer, I rarely ride outside for ‘fun’ as I tend to only ride outside on my Canyon TT bike for Triathlons/Duathlons (With the 170 cranks Left and right of course) and use my Giant for very occassional leisure rides with friends.


Woahhhh, you should not be riding with different crank lengths on the right versus the left. That is just asking to 1) develop some sort of imbalance, 2) develop an injury, or 3) both. I would swap that out before riding again as overtime that is apt to cause you problems.

Your assuming he doesn’t have a leg discrepancy, I have a 2.5mm difference in length between my left and right legs. However, cnigro is correct if you don’t have a discrepancy, its probably best to run equal length crank arms.

I have a leg length discrepancy so I think in essence I was riding with different crank lengths pre its diagnosis. I used to suffer from a clicky inside hip and when my bb bearings started to fail it (the hip would start to get sore). Whilst the latter let me know when to replace the BB I don’t think having different leg/crank lengths done me any good physically. It eventually caused my right leg (the shorter one) to bulk up tightening the ITB on the other side to compensate, which in turn pulled the right knee ligament out of alignment so it was rubbing against the bone and was agony. I managed it after seeing a physio for several years (lots of stretching) but it wasn’t until the leg length discrepancy was highlighted 8 or 9 years ago that it went away.

If you are already pulling the crank arm its pretty trivial to pull the right side crank too and swap them together

Absolutely agree, it’s just an easy job to move the other side too. That’s what I’ll do, I just didn’t notice until I saw them that they were different

Aside from the bike fit effects from the different crank lengths it changes the force required from each leg. The leg with the 170 will need to press ~1.5% harder for a given power output (assuming 50/50 L/R balance which isn’t a given on matching cranks, either).

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