Crank length

[SurferChild]

I'm a fairly tall oke (185) and I ride 172.5 on my road bike. I did however tried going for the 175 but felt weak on the hills... changed back, no problem.

Might be I didn't give it enough time, but my personal preference is the shorter of the two.

 

My MTB is the same, however my track bike is 170

[Long Wheel Base]

Since I put 180mm(had 175 before) cranks on the front(and 175mm on the back, had 170 before) of my tandem our results have been better............and I am training less. Maybe its just luck? Maybe it suits us better. But there is no way I will go shorter than 175 on my road bike. My toppie comes from a triathlon background and he always had 180 cranks on his TT bike.

What do the pro's ride?

[SurferChild]

I'm following the legend Peter Sagan    He's about the same height as me (185 vs 183) and he also rides 172.5 

I'd also go longer on a TT bike though

[Traveler]

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.

 

A very good response.

 

Any number of search results will list an extensive number of benefits of ideal crank lengths, not everybody needs a short crank. I am 1.78m and moved to 170mm cranks. I have not been back to a chiropractor since; I was taken of a bike in a hit and run years ago and ended with a broken pelvis, therefore I kind of accepted that cycling will go hand in hand with a regular chiro session.

 

Changing crank length is more about the change in the angle of your pelvis than then change in distance your feet travel (although it does not exclude that effect). 100Tours explained it well enough.

 

Here is some interesting reading....

https://www.trainingpeaks.com/blog/the-benefits-of-reducing-your-crank-length/

https://www.cervelo.com/en/engineering-field-notes/a-new-spin-on-crank-length

 

Both SRAM and Shimano do cranks from 160mm - 180mm, but you’ll have to import. If not CRC, then Holland Bike Shop or Bike24. Never underestimate the lack of product knowledge at ZA Bikeshops.

 

If you research more you will be surprised by the large number of pro riders in all disciplines who use shorter than 175mm cranks. Remember 175mm is just a way for bike brands to save money and make stock control and manufacturing easier, it is not the ideal length.

[Jewbacca]

Don't the TT guys run shorter cranks?

 

I'm sure I read somewhere that SKY have been using crank arms in the 165-170 region for their TT bikes and their road bikes.

 

In an aero tuck you want a less exaggerated knee movement so you can keep your pelvis at the right angle and still as can be without hitting yourself in the chest.

 

'Old school' is not always the most efficient school....   

[Traveler]

You are correct, there is nothing strange seeing 160-165mm cranks on TT bikes.

 

Walking around some bikes on the Giro Mountain Stages plenty bikes were on 160/5mm cranks.

[Rolling Stone]

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

[Rolling Stone]

Red hub in Randburg has on two ocasions

Imported 265 cranks for me.

A week or two waiting time and you have exactly what you need for not too much moola

 

 

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

[Rolling Stone]

Red hub in Randburg has on two ocasions

Imported 165 mm cranks for me.

A week or two waiting time and you have exactly what you need for not too much moola

 

 

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

[Rolling Stone]

Red Hub in Randburg

[iteachcoffee]

A very good response.

Any number of search results will list an extensive number of benefits of ideal crank lengths, not everybody needs a short crank. I am 1.78m and moved to 170mm cranks. I have not been back to a chiropractor since; I was taken of a bike in a hit and run years ago and ended with a broken pelvis, therefore I kind of accepted that cycling will go hand in hand with a regular chiro session.

Changing crank length is more about the change in the angle of your pelvis than then change in distance your feet travel (although it does not exclude that effect). 100Tours explained it well enough.

Here is some interesting reading.... https://www.trainingpeaks.com/blog/the-benefits-of-reducing-your-crank-length/https://www.cervelo.com/en/engineering-field-notes/a-new-spin-on-crank-length

Both SRAM and Shimano do cranks from 160mm - 180mm, but you’ll have to import. If not CRC, then Holland Bike Shop or Bike24. Never underestimate the lack of product knowledge at ZA Bikeshops.

If you research more you will be surprised by the large number of pro riders in all disciplines who use shorter than 175mm cranks. Remember 175mm is just a way for bike brands to save money and make stock control and manufacturing easier, it is not the ideal length.

Interesting rabbit hole to go down.

 

Add to the potential benefits, more aero apparently.

 

 

Also here (leave out the sales stuff, table near the bottom):

 

https://highpath.co.uk/crank-shortening/

[Knersboy]

Just bought a new Campagnolo Centaur 11 speed alloy groupset for my soon to be bogus sprayed 25 year old Hansom Reynolds 708 frameset. Was going to get 172.5 mm cranks just because that is what was one the bike, but have decided to go 170. I am 1.76, but most of that length is torso, got moer short legs. Will be interesting to see how it feels.

[besso]

I had some knee issues 2 years ago and ordered a 150mm crankset from Mark Stonich in the US, you can check his site at bikesmithdesign.com. I only used it a few times, still in excellent condition if you interested. 10 speed sram apex with 50/34 chain rings, bb and chain.

[Andrew Steer]

I'm 1.82, but have pretty short legs... would dropping to a 170mm crank be an issue you guys reckon? I must say I like the idea of a smaller spinning circle to up my cadence and reduce lower back/hip strain?

[Captain Fastbastard Mayhem]

I'm 1.82, but have pretty short legs... would dropping to a 170mm crank be an issue you guys reckon? I must say I like the idea of a smaller spinning circle to up my cadence and reduce lower back/hip strain?

No. Not at all. Just better pedal clearance, and a slightly higher saddle height as your crank's BDC is now 5mm higher than it was previously. 

[100Tours]

I'm 1.82, but have pretty short legs... would dropping to a 170mm crank be an issue you guys reckon? I must say I like the idea of a smaller spinning circle to up my cadence and reduce lower back/hip strain?

 

I'm 1.81 and I've got 170 cranks on my track bike, no issue. Please post back on your experience if you make the change.