170 or 175 cranks

wotdef

Does anyone know would there be a noticable difference between 170 cranks and 175 cranks?

penexpers

Sheldon says

http://www.sheldonbrown.com/cranks.html

Lumen

Yes.

172.5 FTW.

bcmf

I moved from 170 to 175. The difference is that my legs feel more 'comfortable'. I havent done much climbing on them but on the shorts hills I have done I find that I can sit in the saddle a lot longer and feel I can use more power. The difference is there but is very slight.

Ryder

I use 175 but am tall - 6'4". Dont entirely agree with sheldon...think that people can adapt to diff crank lengths within a range, but theres surely an optimum range for everyone.

Stokolan

I use 165 myself.

When getting the parts together for my bike I went and read a fair few setup guides to get an Idea for what I need. I found this one very good http://www.peterwhitecycles.com/fitting.htm which has an interesting setup for crank length and also using the formula - inseam measurement in inches x 5.48

Between the too ways I came up with 165 as the best option :P but there are probably other ways that would give me different size.

blorg

bcmf wrote: »

I moved from 170 to 175. The difference is that my legs feel more 'comfortable'. I havent done much climbing on them but on the shorts hills I have done I find that I can sit in the saddle a lot longer and feel I can use more power. The difference is there but is very slight.

The longer the cranks, the more leverage you have (it is effectively like having an easier gear.)

bcmf

yeah but I am still sh1t at climbing.

Lumen

blorg wrote: »

The longer the cranks, the more leverage you have (it is effectively like having an easier gear.)

Yes, but you have easier gears for being in an easier gear.

There is no consensus about ideal crank lengths.

I think the most important thing, if you have cranks already, is to convince yourself that the length you have is perfect (through whatever combination of leverage, leg angle, centre of mass and ground clearance arguments you care to mix).

If you don't have cranks or are upgrading, pick a theory that seems plausible, and buy cranks according to that.

The worst thing is to read around then convince yourself that the reason you're slow or uncomfortable is your crank length.

E@gle.

My theory is if it aint broke dont fix it.

What cranks are you using at the moment? Are you having any problems with them?

wotdef

Had 170's got new shimano SLX set and it was 175, its installed now and I tried it out and couldn't tell any difference really. I have tended towards a higher cadence before so maybe these will help the knees as well.

sy

wotdef wrote: »

Had 170's got new shimano SLX set and it was 175, its installed now and I tried it out and couldn't tell any difference really. I have tended towards a higher cadence before so maybe these will help the knees as well.

Shorter cranks put less stress on the knee. If you have knee problems stick with the shorter cranks.

davgtrek

They are installed now so not like u can throw them back anyway.
So ride away with them. the fact that 175 is the default worldwide leads me to think that it will be grand UNLESS you develop problems. If you do then you know whats wrong.
I have those slx cranks myself bought back in june. this months what mountain bike gives them 5 star editors choice so thats good.

wotdef

Been on my hairy canal commute today and they feel really good, much smoother pedalling and deffinitely able to push higher gears, especially on the rises. As for shorter cranks being better for the knees, not in my case, faster pedalling = inflamed knees:o

horizon26

I went from 175mm to 172.5 and found the the smallier crank lenghth to be more comfortable,but I have a dodgey right knee from a motorbike crash.

davgtrek

you would wonder is the cycling tech industry sitting back laughing here.
we are discussing variations of 5mm & in horizon's case 2.5mm in crank lengths.

surely factors such as saddle height and with 2.5mm in mind even the thickness of foam/compression on the saddle & even thickness of socks would be factors when getting this precise.

although to be fair its great all this minute techie stuff.

I'd say henry shefflin or philip maher were not worrying about 2.5mm variations in hurls on sunday last as they ripped into all around them.....

sy

For some people 2.5mm can make all the difference!;)