Its much more important to have the correct size frame before obsessing about crank arm length, that’s right isn’t it?

The reason I ask is that I’ve just ordered ‘standard’ (175mm) cranks as that’s what I have always used and have on my other bike, although on the web calculators I should use smaller.

Surely you just get used to what you have?

Chill out mate. Your first statement is correct.

There is some evidence to suggest that we all have an ‘ideal crank length’ but generally I’m inclined towards the argument that 175 or thereabouts is about right for most of us. Obviously the very long legged could go longer whereas the very short legged could go shorter.

Besides the relevant anatomic differences dictating crank length there are some variations in crank length resulting from the type of cycling undertaken: For example track riders use 165mm (I think for ground clearance and to increase pedaling speed) but BMXers use 175 in order to exert maximum leverage on the gear…

Ultimately…if you’ve never noticed a problem using 175s then chances are there is no problem.

Frame size is much more important indeed.

That said, if you’ve experienced any problems using 175mm cranks, or are particularly short (or tall), it can be worth trying shorter (or longer) cranks out. There is also an element of personal preference to crank length too. I know some shorter people than me that wouldn’t dream of using anything shorter than a 175 as they like the extra leverage, I use 170’s religiously as even though I’m not short at 5ft 11 with 33″ inseam, 170’s aggravate my knees less, and I get more pedal/ground clearance on my full sus bikes.

Its only 5mm but I used some 170mm cranks and it felt well just wrong. I only have a 32-33inseam but 175 always feels spot on.

roadie_in_denial – I’m perfectly chilled out thanks. 😉
Having not purchased cranks before (other than on stock bikes) I was just questioning the different sizes. But yes your right no problems so far so I’ll stick with.