Every time I browse a cycling website there seems to be an article on how the peloton are adopting shorter and shorter cranks. It’s all the rage right now. This was of course spearheaded by Tadej Pogačar running 165mm cranks and winning just about everything. So if that’s the case, then 165mm cranks must be part of the reason, right?
The thought process behind shorter crank is two-fold; firstly biomechanics, and secondly aerodynamics. The theory with shorter crank arms is that “the lower leg (with a big foot at the end of it) doesn’t extend as far down into the clean air around the lower part of the bike, and likewise, the knees don’t extend up as high.” Does a couple of millimetres really make all that much difference? Perhaps at the pointy end of the professional peloton it does. At amateur level, I’d argue it’s a moot point.
Now in 2025 some pro riders are going even shorter. Cue this article on Cycling News exclaiming that Jonas Vingegaard is now testing 150mm cranks! That seems crazy.
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What do you think? Are you a fan of going shorter? All of my road bikes have 170mm cranks and I have been running that crank length for as long as I can remember. There’s no real reasoning behind that choice other than it was what my first road bike had, so I’ve kept it the same for all my bikes.
I do have one bike with these trendy new 165mm cranks though! My time trial bike.
My TT bike “newer” and Cervelo likely kitted the P5 with shorter cranks for the aerodynamic reasons outlined above, but also because mine is a small 51cm frameset. Time trial and triathlon have been early adopters of the shorter crank trend.
I am curious and would like to give shorter cranks a test on my road bike.
I can’t really tell any difference between 170mm on the roadie and 165mm on the TT bike, but that’s not really a like-for-like comparison. Perhaps I’ll switch them over if I get motivated enough. I’m certainly not going to go nuts and convert all my bikes to shorter cranks just because it’s what the pros are doing. That would be an expensive exercise!
Have you tried running shorter cranks?
Two Wheels with TC 
My 35 year old bikes have 170 mm cranks. My 8 year old bike has 172.5 mm due to then-current thinking re: height, leg length, frame size. Back then we were being told that most of us were riding on too-short cranks. For most of us, I suspect it is just another way to get us to spend more $.
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I suspect you might be right! 💰
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I suspect it’s a bit of typical bike media overhyping over a fundamental fact. From my experience over the last few years, off the shelf bikes have always needed customisation – I’ve always hated the ultra wide “shopping trolley” handlebars my XL bikes had and swapped them out. The saddles always went into the spare parts bin, as with various other things. Changing the crank lengths is a much costlier investment, but – given the complex cycling dynamics – it’s unrealistic to expect that 175mm cranks will fit all large riders. I’ve changed the 172.5mm standard cranks on my new gravel bike to 170mm (power meter upgrade), and – compared to my 175mm cranks on my road bike – I actually feel a material comfort improvement, so much so that I’ll probably change my road bike cranks as well. It’s likely not the cure for all ills, but just an hitherto uncommon upgrade which many may benefit from, but yet many will survive nevertheless without.
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