[ultraNoob]

I'm just about done building my DHR... aka frankenbike, and I figure it's time to think about the crank length. I have a 175mm mounted right now. Since I plan to race this at fontana, and I really wanna go fast along the wall, that the 175 is fine. I googled the topic and got mixed hits. Some say a 155 is about as short as you wanna go for DH, other say nothing less than 170. So... I'm a bit in the fog.

Any input you guys have would be greatly appreicated.

 

[sanjuro]

The shorter crankarm has two advantages for dh: clearance and spinning.

The longer arm will hit rocks, particularily when the bike goes through its entire travel.

But shorter crankarms will also spin faster

 

[CrabJoe StretchPants]

The shorter crankarm has two advantages for dh: clearance and spinning.

The longer arm will hit rocks, particularily when the bike goes through its entire travel.

But shorter crankarms will also spin faster

true, however they have 2 advantages as well: power output and stability.

it's really like anything else, it's going to be a tradeoff either way. if you race on fast, open, not so tight stuff, get 175s or 170s. if you race in tight, rocky, tech stuff, get 165s or 170s. i personally opt to split the difference and run 170s.

i ran 175s on my DHR last year and found they were to long and i clipped nearly every rock, so i'm running 170s this year (i race in the northeast).

 

[TreeSaw]

I think most DH cranksets are 165. I run 170s on my XC but I am short and I like the spin better. My DH bike has 165s.

 

[Secret Squirrel]

My 170's treat me right for all conditions. They're pretty dinged up just cause I suck...but they are a good compromise.

 

[jonKranked]

also depends on body size and bb height. i'm 6'1", but since my bb is super low i have to run 165's, and i STILL smash the crap out of my pedals. I'd like to get back up to 170's. right now working with the builders to redesign the rear swingarm to tweak the geometry some.

 

[ultraNoob]

Being that I'm still a noob at the DH game, I think I need some extra insurance clearing those pesky rocks. I'll be shopping for a set of 165's. Tenks very mucho!

 

[sanjuro]

One other thing: It will be most common to find 175mm crankarms, then 170's and finally in a distant 3rd place, 165.

I wouldn't pay extra for shorter arms unless you are absolutely sure that is what you want. I run 175's, btw.

 

[ÆX]

i am going back to 175's this year.

i have use from 160-175 and for most

i would not go below 170. you just loose

to much leverage.