Crank lengths - anyone gone shorter?

[midlandsgrimpeur]

As the title suggests, anyone following the trend for shorter cranks? I have always run 170mm but I am short and my guess is a bike fitter would likely tell me to run 160mm.

My main interest is more around fit. I have an overuse back injury which is probably long term. I have shortened my reach a bit over the last 12 months and am considering whether the shorter cranks will put less pressure through my hips and lower back.

Any experiences from those that have done it?

 

[teeonethousand]

I have been pondering it but I figured that I am less concerned with general performance but need all the help I can get on hills so will stick with 172.5 that came on the bike. Mines a gravel bike and so not really hunkered down and my belly is not in play😂

Would it be worth you getting a fit first to ensure you understand what need to change and how much.. might be other things too?

(I am looking forward to others thoughts and may well change my mind )

 

[albion]

I went down to 160mm. Long legs but with hip and problems I thought it 'might help'.

 

[Sharky]

I've been running short cracks for about 15 years.
150mm on three of my bikes and 145mm on my seldom used TT bike.

Shorter cranks, mean you can raise the saddle and is easier on the hip and knee joints. You get used to the short cranks very quickly.

All square taper, two were Sinz Expert cranks and two were drilled by Highpath Engineering.

 

[Sharky]

Sheldon brown talks about "gain ratios"
Gain Ratios--A New Way to Designate Bicycle Gears https://share.google/EyTagfCCvfl7K01Yr

Which takes into consideration crank lengths, as well as wheel, chain ring and sprocket sizes.

When it comes to hills, you just ride a lower gear.

 

[midlandsgrimpeur]

I went down to 160mm. Long legs but with hip and problems I thought it 'might help'.

Has it helped do you think?

 

[midlandsgrimpeur]

I have been pondering it but I figured that I am less concerned with general performance but need all the help I can get on hills so will stick with 172.5 that came on the bike. Mines a gravel bike and so not really hunkered down and my belly is not in play😂

Would it be worth you getting a fit first to ensure you understand what need to change and how much.. might be other things too?

(I am looking forward to others thoughts and may well change my mind )

I have thought about it. I had a fit years ago pre my current issues and that didn't alter my position much and I had kept to a similar position for many years after that.

The main issue is that I have not had a formal diagnosis for the back (have seen a physio but not a Doctor). I believe it is actually connected to an old shoulder injury on the right side which led to overcompensating on my left when cycling and lower left back issues (the physio said he thought this was the case too). I am a bit hesitant to go through a bike fit without knowing for certain though, just in case things are changed with exacerbate the injury.

 

[albion]

Has it helped do you think?

Possibly, possibly not. No certainties as I keep self adjusting to the reality.

 

[Webbo2]

I have lower back issues often compounded by jumping off bouldering walls. More recently having stopped doing that and doing some dead lifting my back is reasonably ok. There is a lot of anecdotal evidence to say deadlifts and the like can stop lower back problems.
With regard to crank length I have always being a bit of grinder which I thought might be due to my 172.5 cranks however I’ve been playing on the turbo and I ave now problem pedalling at 100 to 110 revs a minute. So it’s probably about gear selection.

 

[DCLane]

Mine vary: most of the road bikes are 172.5mm with a couple of bikes at 170mm.

However the track/grasstrack bikes are 165mm due to track regulations.

Do I notice? Not really, but that may be because the track/grasstrack bikes are fixed.

 

[Big John]

I'm 6ft 3in and have, until recently, ridden 170mm cranks without giving it any conscious thought. I came into possession of a nice looking double chain set which I decided to fit on one of my winter road bikes. I never looked at crank length until after the first ride. Something felt very different. This replacement chain set had 165mm cranks. Despite not liking this new 'feeling' I thought I'd give it a proper chance. It must have been on over 12 months now and I'm still not convinced. Each to their own, as the saying goes, but I much prefer 170mm cranks as opposed to 165mm.

 

[wafter]

My Fuji came with 175s which I swapped to 170s.

While I can't be certain I'd be able to differentiate between them in a proper blind test, I recall it did feel smoother and less cramped.

This particular swap was an easy sell due to significant toe-overlap issues and the knowledge that my legs wouldn't fall off since my Routier has 165mm cranks which aren't a problem.

The Routier does feel quite different to ride, but then it's quite a different bike. It feels highly-geared but then cranks aside compared to my other bikes it is (50/40 and 14-28 v. 48/36/26 and 11-34 on the Fuji).

I'd be interested to try some significantly different cranks (say 175 and 160mm) back-to-back on the same bike.

It seems that typically modern cranks are potentially both too long and lacking in range to accommodate natural variation on rider size.

The core 95% of middle-aged blokes in the UK apparently range in height from 162 to 188cm, women about 150-173cm. That entire range of 150-188cm gives a spread of about 25% of the minimum value, yet commercially available cranksets are typically only available in 165-175mm; a range of only about 7% of the shortest.

I'm a shade taller than average and have long legs; both the inseam and femur-length methods of determining crank length both suggesting 170mm would be optimal. This also suggests that there are a lot of people who could do with significnatly shorter cranks, of which there are few...

 

[midlandsgrimpeur]

From what I have read, my optimal crank length would be closer to 150mm, but few options for this plus I thibk that would be too short just on personal 'feel'. I have no issue with 170mm it is whether I would get a fit benefit from a 160mm. I am more a big gear, low cadence type l, which the leverage of 170mm probably helps. I am assuming with a shorter crank I'd have to adjust to a higher cadence perhaps.

 

[cyberknight]

Im considering shorter cranks in an effort to alleviate my ongoing knee pain saga,

 

[PaulSB]

I had a professional bike fit in the summer. I'm speccing a new bike at the moment and the question of crank length came up. I contacted my fitter, who is also a personal friend. This was his comment:

"Hi Paul,
The only reasons to change crank length would be if you are becoming impinged in the hip at the top of the pedal stroke.
Essentially shorter cranks allow you to spin a smaller circle and have a more open hip angle.
If you can spin a high cadence without tightness in the hip then shortening your cranks will have little benefits."

@midlandsgrimpeur if you have issues get a bike fit. If the results don't suit you can always go back to your previous position.