170mm cranks for 5ft 10.5inch rider?

Discuss light weight issues concerning road bikes & parts.
pdlpsher1
Posts: 1526
Joined: Thu Jul 19, 2012 6:09 pm
Location: CO

by pdlpsher1

Funny thing is, I won't notice a 2.5mm change in saddle height but I do notice a 2.5mm change in crank length. I think this is because a 2.5mm change is really a 5.0mm change since the crank rotates around the axle. The crank is longer at both the 12 o'clock and 6 o'clock positions.

Go for the 170mm. You will like it.

Allen254
Posts: 144
Joined: Sun Feb 07, 2016 3:05 am

by Allen254

Shrike wrote:Also have a 31inch inseam. Industry standard seems to be 172.5mm, but would like to try 170mm.

http://bikedynamics.co.uk/FitGuidecranks.htm

Seems most recommendations are a bit shorter than industry standard.

Also apologies for question spam recently :P

any rider of any height can rider which ever crank length but you will have to adjust saddle height.

DaReef
Posts: 158
Joined: Mon Dec 19, 2016 2:36 am

by DaReef

I'm 5'11.5" and use 170mm.

Racingevo
Posts: 21
Joined: Tue May 17, 2016 2:36 am

by Racingevo

I have the same inseam and I use 170 when I upgraded my crank to Ultegra 6800. I definitely did notice a difference for the better. My cadence increased slightly but it's hard to empirically prove that. I can climb out of the saddle a lot longer with the shorter cranks and if I were to do it again I'd go for 165mm but I'm stuck for the time being since I got a stages crank arm power meter.

Bridgeman
Posts: 642
Joined: Wed Jan 12, 2005 6:04 am
Location: USA
Contact:

by Bridgeman

I need more money.

mattr
Posts: 3499
Joined: Fri May 25, 2007 6:43 pm
Location: The Grim North.

by mattr

stormur wrote:Is thickness of all road shoes equal ? Or can vary even 3-4mm ? insole thickness ? Sock ? Pedal stack ?
none of which make the slightest difference to the circle to which your foot has to pass through. Crank length does.
Allen254 wrote:any rider of any height can rider which ever crank length but you will have to adjust saddle height.
they'll also need to have their knees operated on eventually.

RussellS
Posts: 720
Joined: Wed Feb 03, 2010 1:31 am

by RussellS

I am 5'11" tall. I use 175 cranks on my seven geared road bikes. 172.5 and 170 on my two single speed bikes. Mainly because those are the cranks I had in the spare parts box when I built the single speeds. Never notice any difference when riding geared and single speed bikes on back to back days. I can spin 90 rpm comfortably all day long on any crank length.

racingcondor
Posts: 194
Joined: Fri Aug 27, 2010 4:22 pm

by racingcondor

I'm 5'11" (33 inseam and UK size 12 feet!) and moved to 170 cranks after riding 165's on track.

I can feel the difference but I doubt that there is a measurable performance difference. I'd imagine the only difference in reality is the reduced likelihood of pedal strike when riding through a tight corner.

RedCoke
Posts: 35
Joined: Fri Oct 28, 2016 8:54 am

by RedCoke

I think inseam is more impoart factor than height only.
inseam(mm) x 0.216?

Mr.Gib
Posts: 3119
Joined: Fri Mar 18, 2005 4:12 pm
Location: eh?

by Mr.Gib

RedCoke wrote:I think inseam is more impoart factor than height only.
inseam(mm) x 0.216?


That number doesn't seem correct. A factor of 0.216 would have me on a 190 mm crank. I am 6 feet (183 cm) with average proportions. I am happy with anything up to 175 mm. I prefer 170 mm due to past knee injuries, and spinal injuries.
wheelsONfire wrote: When we ride disc brakes the whole deal of braking is just like a leaving a fart. It happens and then it's over. Nothing planned and nothing to get nervous for.

tinozee
Posts: 700
Joined: Wed Jun 01, 2011 7:53 am

by tinozee

Checkout slowtwitch forum for more comprehensive discussion on this. Short crank arm is fine. Watch out for nutty ideas like Lennard Zinn's long cranks.

joeyb1000
Posts: 107
Joined: Thu Mar 03, 2016 8:37 pm

by joeyb1000

LloydP wrote:I'm very close to your proportions and use 170mm cranks. It works fine for me. Try it and see!


same here.

Allen254
Posts: 144
Joined: Sun Feb 07, 2016 3:05 am

by Allen254

mattr wrote:
stormur wrote:Is thickness of all road shoes equal ? Or can vary even 3-4mm ? insole thickness ? Sock ? Pedal stack ?
none of which make the slightest difference to the circle to which your foot has to pass through. Crank length does.
Allen254 wrote:any rider of any height can rider which ever crank length but you will have to adjust saddle height.
they'll also need to have their knees operated on eventually.


:roll:

RedCoke
Posts: 35
Joined: Fri Oct 28, 2016 8:54 am

by RedCoke

Mr.Gib wrote:
RedCoke wrote:I think inseam is more impoart factor than height only.
inseam(mm) x 0.216?


That number doesn't seem correct. A factor of 0.216 would have me on a 190 mm crank. I am 6 feet (183 cm) with average proportions. I am happy with anything up to 175 mm. I prefer 170 mm due to past knee injuries, and spinal injuries.


It is "inseam(mm)" not height. Please check this.
http://www.stevehoggbikefitting.com/bik ... which-one/

RedCoke
Posts: 35
Joined: Fri Oct 28, 2016 8:54 am

by RedCoke

Also, this site would be helpful.
http://www.peterwhitecycles.com/

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