Would 165 cranks be too short for a SS? I have these XTR 165s lying around, basically I have the wrong spider on it, so it wont work with my DH bike, and my 175 RaceFaces would work with my DH bike. I know levergage/torque wont be as good as say 170s, but has anyone run into problems with this?

They would be fine. Even better on a fixie due to ground clearance.

They won't work at all. My best advice to you is to clear up some space and mail those cranks to me. I will dispose of them properly.

Hahah, thanks guys.

You're welcome

In general, crank length should be matched to your leg length and type of riding. Short legs or spin alot? 165 might work. Single speed MTB or longer legs? 175 or 180. Fixed gear or avg. height? 170 should do.

No of this making sense? Of course not. Throw them on and see if they work. I'm 6'0" and run 175 on my SS MTBs and 170 on my fixed. Take it for what it's worth.

as was explained to me at my LBS the other day; It's five mm people. It's REALLY not gonna make the big a difference.

you'd be suprised. but this isnt exactly professional level riding we're talking about, this is recreational riding, so I'm sure it will make no difference!!!

It actually does when you've got 170 on one side and 165 on the other...

It's five mm people. It's REALLY not gonna make the big a difference."

thankyou. THANKYOU.

Its amazing how much overanalization goes on.

Well, for the math challenged, it's really 10mm if you compare it to what he's currently running on his MTB (175). And from the little info provided I'm going to assume he's talking about building an SS MTB, not a road bike. And I will say this, it's a lot different ball game cranking an SS MTB up a steep singletrack hill than it is cranking a fixed gear up a steep paved hill. Most people will notice a 10mm difference. Just for the hell of it, do this: drop your seatpost 10mm on your fixed gear and ride for 20 or so miles and see if you notice it. I bet most will.

All that said, just try the cranks. They are bought and paid for and you haven't stated your height, so they might be right for you anyway.

"drop your seatpost 10mm on your fixed gear and ride for 20 or so miles and see if you notice it. I bet most will."

difft situation though; certainly leg extension is critical to efficiency/comfort...but leg extension is adjusted relative to the bottom of crank i.e., if your running 165s, your seat should be approximately 5mms higher than when running 170s. much bigger impact to the larger scheme of things than cranklength.

here i go...overanalyzing again...

just ride.

Here my high school math thinks that you would want 5mm lower.

True, but the point of the example is, most riders who are on the bike on a regular basis can notice a 10mm change in a lot of situations, say like stem extension. Dropping the seatpost would not be intended to mimic a change in crank length, it's just an exercise that is easy to try.

College math says Stevo is right Longer cranks = shorter seatpost extension.

"Here my high school math thinks that you would want 5mm lower."

shouldve stayed off that jameson back then...

" but the point of the example is..."

point taken...

"point of the example is, most riders who are on the bike on a regular basis can notice a 10mm change in a lot of situations,"

point taken.

I used to think that, and felt 5mm wasnt much, but I can actually feel it. The 165s seems much less powerful than my 170s, but I will give them a shot.