175mm crank ???

Whats the deal with them. Lets see, they're cranks and they're 175mm from center of the pedal hole t' middle of bottom bracket hole.

They're 5mm longer than the standard 170mm and 10mm shorter than the TA's I used to time trial on.

Not really much to say, given that you don't say how big you are or what type of riding you do...

swampy1970 said:

Whats the deal with them. Lets see, they're cranks and they're 175mm from center of the pedal hole t' middle of bottom bracket hole.

They're 5mm longer than the standard 170mm and 10mm shorter than the TA's I used to time trial on.

Not really much to say, given that you don't say how big you are or what type of riding you do...

haha,

to be more precise, what kind of riding are they usually used for? Im 6'2" with ~32" in-seam so i think im pretty average for leg length. I do road cycling with minimal hills. I dont race. does that cover it?

sixteenornumber said:

haha,

to be more precise, what kind of riding are they usually used for? Im 6'2" with ~32" in-seam so i think im pretty average for leg length. I do road cycling with minimal hills. I dont race. does that cover it?

32" inseam - that's about right for 175s. If you're not in the business of going really hard then I don't think you'll notice much difference. I find that longer cranks help with the big gear work on the flat and out of the saddle on the hills.

I'm 5'11" and have a 34" inseam and have used everything from 165's to 185s, except 180mm cranks. I prefer, and so does the powertap, the longer cranks but my back doesn't.

sixteenornumber said:

... what kind of riding are they usually used for?

Crank length is something that can be almost as debated as the ways to lube your chain...
Some people claim to be very sensitive to differences, some can ride pretty much anything, even unmatched lengths w/o anything much happening.
Since cranks tend to cost a bit, and don't readily wear out not many people have gone to the effort of really experimenting with them. There's some work done by a guy named Zinn(if I remeber correctly) but I don't know if it's available online.
People who do mixed riding usually prefer longer cranks on MTB's than on their road bikes. Makes sense, as MTB rides often include getting out of the saddle and putting some extra grunt in to get over short obstacles. Shorter cranks are supposed to be better for keeping your cadence up.

Bottom line: don't expect much improvement unless your current setup is giving you trouble.

My knees are prone to trouble, and I switched from 175 to 170 on my commuter last fall. Best I can tell it seems like the loss of leverage acts like a built-in reminder to downshift or get out of the saddle faster than what I did with the longer cranks. My knees seems to appreciate this.
I can still ride my MTB (with 175mm cranks) w/o suffering. But if I take it on the road I have to remind myself not to force it out when I hit some resistance.

Here's an article by Leonard Zinn which mentions his earlier testing:
Custom Cranks for big and tall cyclists