Singlespeed & Fixed Gear - How do I decide on my crank length?

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cmcenroe
12-10-05, 01:39 PM
I am new to fixed gear riding, and I am looking at the IRO Mark V as a first fixie. Anyway, I have been noticing that a lot of fixed gear bikes have shorter cranks than stndard road racing bikes. I am 6'0 and ride a 175 mm. How should I decide what size I want to ride?
Gnarboots
12-10-05, 01:54 PM
If you're riding a 175 you run the risk of clipping an inside pedal on a turn. A friend was badly injured this way! Shorter cranks will lose you a bit of torque, but keep you out of the hospital. May I suggest 165s, or 170s with yer pedals filed down (or track pedals).
Shorter crank arms are better for avoiding pedal strike. On the conversion I'm riding now, I have 175s and big huge BMX platforms. I've never had a problem with pedal strike on it, so I don't know how much of an issue it really is... I've used 165, 171, and 175 on fixies and never really noticed a difference...
I think it's all pretty much personal preferance.
humancongereel
12-10-05, 02:12 PM
if you don't lean into turns much you might be okay. but i'd go with 170s. 172.5 if you want that extra 2.5...heh. but yeah, also go with clipless pedals. since they don't stick out as much, they greatly reduce the chance of pedal strike. nowadays, even on my geared road bike i pedal around corners, and with 172.5 cranks and clipless, i haven't had any problems. 175 might be asking for trouble, though.
cmcenroe
12-10-05, 02:53 PM
Ok, I will look for something smaller. For learning, I will use track pedals/clips and then possibly go to clipless after I am more comfortable on the machine.
Rev.Chuck
12-10-05, 03:47 PM
Shorter is good for your spin, if you are using for winter training as well as reducing the chance of clipping(Which is very not pretty)
genericbikedude
12-10-05, 05:26 PM
^^^Good for spin and makes it easier to use a smaller gear. the difference between 165 and 170 in my opinion is about 4-5 gear inches.
humancongereel
12-10-05, 08:08 PM
Shorter is good for your spin, if you are using for winter training as well as reducing the chance of clipping(Which is very not pretty)
the one time i did that, my seat nearly took out my boys. instead, i just ended up with a strange cut on my inner thigh. not to mention skinned up where i hit the road, but i was pretty concerned with the guys down there at the time.
I am new to fixed gear riding, and I am looking at the IRO Mark V as a first fixie. Anyway, I have been noticing that a lot of fixed gear bikes have shorter cranks than stndard road racing bikes. I am 6'0 and ride a 175 mm. How should I decide what size I want to ride?
the height of ur bottom bracket too, i mean mine is 175 and i barely strike, although it is quite scary :o
just be careful
Rev.Chuck
12-10-05, 08:53 PM
I have pedaled down a couple of times. It is pretty spooky, throwing the whole bike into the air. Kinda like the first time you forget to keep spinning and the bike tries to toss you over the bars.
tlupfer
12-10-05, 10:44 PM
q factor is equally important to pedal strike and almost never mentioned. kids running around with 165mm bmx cranks aren't much* better off than someone with tight** 175mm road cranks.
Placid Casual
12-10-05, 10:57 PM
If you measure from below the balls, it's cheating.
Now, what's all this about q factor?
matthavener
12-10-05, 11:00 PM
i've clipped my shoe in clips with 165 mm cranks so ymmv
tlupfer
12-10-05, 11:36 PM
If you measure from below the balls, it's cheating.
Now, what's all this about q factor?
the further your pedal is from the center of the bike the less the angle of lean will have to be for it to hit the ground. example--tilt your bike slightly to the side and imagine your crankarm is 1/2" further from the center of the bike.
Lunigma
12-11-05, 12:46 AM
it's easier to spin down hills with shorter cranks. it's kinda like the difference between swinging your arms in big circles and swinging them in small circles.
a lot of clipless pedals keep your feet really close to the frame, this makes it easier to pedal and makes it easier to corner.
not many cranks mention q factor, but i have found that usualy when they do, it's cause it's a low q factor, which is good. i would stay away from bmx and mountain bike cranks if you want better cornering/q factor. when the cranks are really far away like those found on cranks with triples it's almost like your walking bow-legged.
you should read what sheldon brown has to say about fixies. im pretty sure this is addressed
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