Crank length

[Petrus111]

Hi Guys,

 

Im new to this platform so hopefully this is the right place to post this.

 

I am only 1.65m in length and are looking to get myself a shorter crank, between 160mm and 165mm. Firstly, does it really make such a big difference and if so, where on earth do I get shorter cranks?

 

Thanks

[Dubber]

Hi there. Welcome...

 

I don't think you get much smaller than a 170 mm.  But if you do they are no doubt few and far between (and most likely pay for it ).

 

I'm not much taller than you and have been running 172.5mm for ever with out any issues.  

 

Get a proper bike fit - they will tell you what crank length is best suited...

 

Enjoy

 

Edit:  When I say proper bike fit I mean from a qualified Bike Fitter (let us know where you are and we will point you in the right direction) .

[Petrus111]

Hi Thanks.

 

Okay do you know where to look for such cranks then, 170mmmand 172.5mmm. I asked a very well known bicycle dealer in my area and they just said they dont have and dont know where to find it. So I am a bit reluctant to use them for a fitting after their reply.

 

But thanks for the feedback. Helps me narrowing down my search.

 

Appreciated

[PeterF]

Your best bet is probably Chain Reaction Cycles.  There you will be able to get as short as 165mm.

[Captain Fastbastard Mayhem]

Chain reaction cycles. The end.

[keithbe]

I went from 175mm to 170mm. Haven't noticed any difference in the change pedal efficency wise...huge improvement in reducing pedal strikes.

Ordered from CRC - *seems SA only use 175mm - (race face aeffect) on a Wednesday morning and new crank installed Friday afternoon.

 

*tongue in cheek comment

[100Tours]

There are 3 advantages of shorter cranks the I know of. They're not all immediately obvious, and they're not necessarily a function of your height. (Sheldon Brown suggests that you can go down to 145mm without much effect, but I am still sceptical of that claim).

 

1. bigger toe-to-hip gap at the top of your stroke. If you reduce your crank length by 2.5mm then you will gain 5mm greater clearance between your foot and your hip over the top of your pedal stroke. this may help with lower back pain issues from flexing too much with a longer crank. So, more comfort.

 

2. Higher cadence. less circumference means you can get your foot round the arc faster. You should be able to go faster at the top end.

 

3. Less pedal strike - pedals sit higher off the deck

 

Having said that I ride mostly 172.5 cranks, and my wife either 165 or 170mm. 2.5mm is a meaningful change in size. 160mm will probably seem extremely short. 

[100Tours]

And chainreactioncycles. It is rare to see short cranks anywhere else.

 

172.5's you'll find in the classifieds

[Moriarty]

Look on ebay, there are many lengths available.

[Thomo]

170mm has become a lot more common and you may even find some in the classifieds.

Shorter may be a bit more of a challenge.

[Fast-er]

I think it will be best to go for a bike fit. You might be 1.6m but your legs might be a bit longer than the normal 1.6m guy and you will have to get a 165mm or ever 170mm cranks. I had the same issue. had to change my crank arm length because i have legs like an ostrich.   

[Ttocs]

Read this then ask yourself if you really need it.

 

I have ridden pretty much every crank length over the last 30 years and cannot tell the difference and further have never seen an improvement due to crank length.

 

https://cyclingtips.com/2017/09/crank-length-forget-leverage-power-fit/

[Bream]

This is a good introduction summary video on this subject from the GCN guys: https://www.youtube.com/watch?v=vUygkHlcVMQ

[Eugene]

What size crank do you have at the moment? I cannot see how 2.5mm - 5mm is going to make a difference. I've also ridden different sizes and also could not feel the difference.

[ALLMTB]

The only reason I went from 175 to 170 is because the frame I bought at the time had a much lower BB height and pedal strikes were becoming a problem. 

Could not feel a difference in term of pedaling power etc though. 

[Paddaman]

Crank length affects knee angle when under load (which should not be more than 90 degrees).  The one short and abstraction (SHA) or rule of thumb is to measure your femur bone (or hip to knee) and half that measurement.  (However, foot size and whether you ankle flex may influence this as well) So your height (168cm) is irrelevant.

 

I ride 170mm on my primary road and Mtb bikes, but also have a 175mm on one mtb.  It takes a bit of adaption of the muscles to adjust to the longer cranks, every time I ride that mtb.