I'm a running with the wrong crank lengths? (Mtb)

[RoboLuke]

I like to spin at around 85 rpp and for climbs around 90. When I come up the back Breeds Nek from the Shebeen I saw that I cant quite get there... even at granny gear. (2x10)

 

I do suffer from knee pain the day after when I start grinding gears that is why I started spinning more. Also I've found it works better - my performance bottleneck is not energy/cardio but leg endurance so I try to spare the legs over those long rides with lots of climbing. The only discomfort I have in a ride is a bit of lower backpain on those 100 km rides with steep climbing thrown in, and my hip will burn on the climbs at the flexors.

 

So I started wondering if I was running too long cranks?

 

The bike comes standard with a 175. Unfortunately - by body is not standard. 173 tall with a leg length of 78,79 cm .

 

When I troll the google the recommendations seems to come out to:

170

168

164

165

167.5

So basically 2 x 170 and 2 x 165.

 

But then again all of these articles seems to be for roadbikes and there is a general view that for the same person your mtb will be 5 mm longer.

There are also some view on the net that people cant really feel a diff on 5 mm. 1 cm yes but not 5 mm.

 

So what's the jury say?

165, 170 or stay the same?

[Mr X]

I`d say go with 170mm if you have a choice. The longer cranks for mtb comes from the old idea that steep climbing is better with longer cranks, which is probably not valid.

[David Marshall]

Go with 170mm. 165 would be hard to find anyway.

[gummibear]

Go and have a proper bike fit done.You might find something else is the problem.

 

I've seen some tiny ladies riding 170mm cranks so sure you'll be fine and should be good on the 175 to.

[NINER_boy]

Get a proper bike fit done.

 

Shorter crank arms will require more torque to turn due to the shorter "lever".

 

Hope you come right soon

[milky4130]

If I'm not mistaken the 175 will give you the high cadence you want.

[Solstice]

175 have worked well for me...

I'm 163cm

[DIPSLICK]

Go and have a proper bike fit done.You might find something else is the problem.

 

I've seen some tiny ladies riding 170mm cranks so sure you'll be fine and should be good on the 175 to.

Sweet avatar

[SwissVan]

my inseam is 91.7 and i ride with 175

Your inseam is 78.8 and u ride with 175

 

Try the 170's at least your pedals will clear the rocks a bit more if nothing else