165mm crank length - talk to me!

[legrandefromage]

I have a nice set of Sugino cranks that I'll use in place of some miss-matched Nervar but they are 165mm insted my usual 170/ 175mm MTB/ Road mix.

I have an inside leg of 33 inches

What should I expect?

Ta.

 

[fossala]

Can you tell the difference between 170mm and 175mm? I can't, I don't even know what is on my bicycles at the moment. If you are used to 5mm one way you must be able to manage 5mm the other. Either that or I'm wrong and your legs will fall off! :shock:

 

[rogerzilla]

Re:

Try puting your saddle 5mm higher thsn you would for 170s - the leg extension will then be the same and you might get more power. They are slightly easier to spin, although you only really notice when going from 175 to 165. A lot of fixies have 165s for this reason - downhills are a bit less fraught. Better cornering clearance, useful on bikes with low BB height.

 

[legrandefromage]

Coolio!

Many spanks

will be trying these out tomorrow

 

[velomaniac]

Also useful if you take a fixie offroad.................ok I'm the only one that does that but its still useful

 

[Nob]

You notice when you start getting knee pains........ I've only ever stuck to one length after the age of 21 when bones interlock.....

 

[ScillySuffolk]

The idea that crank length is related to leg length is a canard that limps from the Seventies into the 21st century thanks to the opportunity that the internet affords idiots.

Fortunately, even a cursory search of the internet provides adequate ammunition to debunk anyone who says otherwise.

As does a rudimentary consideration of the "problem": whilst pedalling you describe a circle and if anyone would like to explain how the length of one lever is dependent upon another, I'll happily post a .GIF of a waving hand, followed by "the finger".

Shorter cranks will stiffen-up your gearing, the reduced foot-speed (for the same cadence) is beneficial if you're turning a fixed wheel and the reduction in flexion can reduce knee/ankle agitation, otherwise it's placebo/bias-confirmation.

Crank length, like Q-factor, falls within the gamut of self-selectable criteria that you are (unconsciously) capable of adjusting for: ie ride what you have/like/want and ignore anyone who tells you otherwise.

 

[legrandefromage]

I did trawl through a lot of chuff before asking the question. If I notice it, darn! If not, the cranks can stay for the time being.

Thanks again!

 

[Tad]

Re:

You'll find crit racers use shorter cranks like 165s, crit specific frames may have a slightly higer bottom bracket too. Some of the circuits are very short & twisty.

 

[torqueless]

Re:

It's a toeclip thing. On a road bike with a ten and a half inchish BB height, 170mm cranks, and 'medium' Christophe toeclips on Campagish pedals, when you walk your bike along, every time one of the cranks reaches the bottom of it's revolution, the 'toe' of the toeclip catches on the ground, jarring every bearing between it and the BB spindle. 165mm cranks were introduced to prevent this from happening. Unfortunates whose feet were big enough to need 'long' toeclips were probably forced to invent a clipless pedal system...