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170mm Vs 175mm Cranks


When I first built up my Red Rocket Single Speed, I used 170mm cranks. I emailed a few guys and they all seem to give me some scientific and mechanical input as to why the 175 would be better. But I didn’t listen.

During my first ride, I didn’t feel any difference at all. So I stuck with it until my next ride, a 12 miler. Man, by mile 4 I was already worn out from spinning too much with the 170. I was completely miserable the whole ride.

So yesterday I finally swapped out the cranks for a 175mm set and boy I can feel a HUGE difference in the power, cadence and my energy. I can REALLY tell that the 175mm makes a big impact on my riding.

Now I’m wondering if 180mm would be better…as Jeremy likes to say, “Bigger is always better.” Kinda makes me wonder if that goes the same for crank arms…

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There are 9 Comments to this article

Quinn says:
07/25/2008

you have Strong knees!! 180mm cranksI can’t ride cranks longer than 170mm on any bike.

John says:
07/25/2008

crank length is usually more for proportioned to your leg and what you’re used to. smaller cranks are better suited for spinning (i.e. road)

going between bikes with different crankarm lengths a lot can feel wierd.

you might be better off with 172.5

tornadoes28 says:
07/25/2008

180mm cranks and you might start hitting the pedals more on rocks.

Ghost Rider says:
07/25/2008

Don’t believe the hype (or the “placebo effect”). 180mm cranks are only for really tall folks or folks with unusually long legs (neither of which you possess).

While theoretically you can get more leverage from a 175mm crankarm, 5mm of length difference doesn’t amount to a whole lot. And by “whole lot”, I’m talking fractions of a percent.

Check out this brief article:
http://boulderreport.bicycling.com/2008/01/blinded-by-scie.html

RL Policar says:
07/25/2008

Wait…are you saying I’m short?

Ghost Rider says:
07/25/2008

Well…I wasn’t as diplomatic as I usually am, but yes — you aren’t LeBron James or anything…

RL Policar says:
07/25/2008

I don’t know about that…I’ve yet to be told that I’m short…any one else in with Jack about this?

Ghost Rider says:
07/25/2008

The important thing is that you don’t have long legs…and I’ve seen photos. If you were endowed with walking sticks like Gabriella Reece or a pro NBA player, I’d say go with 180s. Otherwise, stick to 170/175. Believe me, all the differences you felt were in your head.

RL Policar says:
07/25/2008

I beg to differ that it was in my head…it was in my legs.

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