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Anyone know from where on my chainset do I measure the length. i.e 175 180?
"thebaron38" Wrote:Anyone know from where on my chainset do I measure the length. i.e 175 180?

That's the length of your crank arm, guessing its from the centre of the crank bolt whole to the middle of pedal thread hole but not sure, think 175 is what is mostly used.
centre of the bb axle thing to the centre of the pedal axle I think.

Isn't it useful when somebody is vague!  Big Grin
it's sometimes written on the backside of the crank, and it's from the centre of the hole at the pedal and to the centre of the hole at the bb end.
Keep it foolish...
175mm is the most common for medium - large bikes.
Small bikes often have 170mm cranks
[quote author=]175mm is the most common for medium - large bikes.
Small bikes often have 170mm cranks[/quote]

Big Grin Big Grin
"Laggingbehind" Wrote:Big Grin Big Grin

Go to <!-- m --><a class="postlink" href=""> ... e=Mountain</a><!-- m -->

Click on technical specifications, search for crankset.

So Specialized do it, not entirely sure other manufacturers do but I wouldn't be surprised.
The 175mm cranks would give you a little more leverage for getting up the tough stuff and the
170's would give you a little smoother spin. To keep the comparison exact, you'd have to compare
turning the 170's 3% faster to produce the same output - essentially going from a 32 tooth cog
to a 33.

Remember that the 3% difference covers a range of human size that varies by more than 25%, and not
many complain about their cranks not fitting.

It seems that mountain bikers are way less picky about crank lengths than road riders: roadies can
generally find cranks from 165-175mm in 2.5mm increments (though the majority are 170 or 172.5).
Almost all the mountain cranks I see are 175mm.

Moreover, "leverage" seems to be a false god. You can get the same leverage with a smaller
crank by lowering your gearing (thus requiring the same amount of torque at the pedal to move
the bike forward).

Furthermore, shorter cranks have two minor advantages and one huge advantage for most MTBers: the
minor advantages are that they can be made slightly stronger and lighter, and the major advantage is
better obstacle clearance.
I've actually considered changing out from 175 to 170 for better obstacle clearance. Pedal strikes have caused me to come off a few times now, the worst of which my collar bone broke. It also resulted in that comedic video of Buzz coming off. Which I will now attempt to find and post below ;-)
Gents, I thankyou.

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