[JohnEZ]

I know, I know. Get the ISIS... XTR sucks... but my LBS knows how to properly install XTR splined BB/cranks. Just get it TIGHT! AND TIGHTER!

The real question is 4-arm vs 5-arm XTR - the 4-arm can be had for $225, and the 5-arm is virtually unfindable. Cambriabike.com has it for $325 (EXCUSE ME?).

Why does everyone say 5-arm? Ring compatibility?

There is a different gear setup:

5-arm: 48-36-26
4-arm: 46-34-24

I ride in Tex, where we don't have lots of sick climbing, so what diff on the gearing? I race, and like to go fast...

 

[riderx]

Why XTR? I say go XT, half the price and it weighs less (647g vs. 685g), and the rings are way cheaper to replace. Personally I go with 5 arm since other people make compatible rings.

 

[RideMonkey]

I had a lot of problems with the crank/bb interface on my XT cranks. I'd never buy them again.

 

[riderx]

RM - using the splined model I assume? How old are they?

I'm still using square taper on my bikes. Cranks just last and last for me, but when I do finally replace them, I'll go ISIS.

 

[RideMonkey]

yeah splined. I had trouble with them from the day I put them on last spring. They are in the scrap pile now.

 

[novice]

dude, go isis if you are going to spend that much money. The isis spline pattern is far superior to either of shimano's. I have an ultegra crankset on my road bike that I absolutely hate to take off. The pattern is more difficult to get lined up and you have fewer options than with isis. With isis you can get both a light weight setup and not spend a ton of money. While it is true that the xt cranks are lighter than the xtr, the es-70, the bb required for that crank, is far heavier than xtr bb, or an isis bb. That is unless you decide to use the xtr cranks with a dura-ace bb, whichh is light, but the setup will cost you.

I reccomend Truvativ Stylo Team cranks with either a raceface bb, or if you really want to go light at Bill Shook bb. Bill Shook's website .

But if you are really set on the xtr stuff than the five arm is prefered because, I think this is right, it comes it a spider. Whereas the four arm version has the spider built into the big ring. This means that replacing that big ring is very expensive. Plus, this leads to another downside of the xtr crankset, those shimano rings cost a fortune. You could use replacement rings by another company, but then you would have to find a spider to fit you crankarms. My $0.02.

 

[novice]

and as for installation, you just torque the sh!t out of both type of spline. Well, at least until you hit the reccomended torque spec.

 

[oldfart]

That's right. The 5 arm spider XTR will take aftermarket rings. I don't think there are any aftermarket 4 arm XTR rings, but I've never checked. Yes XT cranks are lighter than XTR cranks but the bb that goes with is heavier. So the weight of XTR cranks and bb is lighter than xt cranks and bb.

As fas as I'm concerned, the jury is still out on ISIS because its still new. I've read lots of complaints about Truvativ ISIS bb's being ****e but that might be their lower end model. Don't know about Race Face. Some of their product is good, some not so good. I fing their QC to be spotty. Don't know about you but I think the best warrantee is the one you never test. I read so much about how good Race Face's warrantee department is. That indicates that it gets tested too often, which means their stuff fails.

For me the Shimano stuff is excellant. I'm light but I ride pretty hard XC type. I don't jump much. Its really muddy here and I ride all year round in it.

 

[novice]

notice that I didn't reccomend a truvativ bb, which are all new for 2002. The raceface bb that I have is really nice. look at this

Four bearings and a large steel spindle. Isis might be newer than shimano's spline, but there are far more people working on isis stuff: truvativ, chris king, fsa, raceface, bill shook (aka american classic), and bontrager (made by truvativ).

 

[Gutty]

I have been useing LX 4arm splined on two bikes for almost 1.5 years now without a problem. Don't find they come loose as long as they are done up nice and tight. I weigh 80kg and do mostly DH and Dirt jumping and a bit of urban. I use a blackspire 36T ring on the middle ring position on both sets. When they where new they did creak alot and come loose but after about 2 weeks settleing in i gave them a retighten and not a problem since. Have no idea what they weigh(not concerned). Happy enough with my first set to put a set on little bro's Norco.

 

[Ranger]

Servus!

RM, I'm shocked! I'm a clydesdale and abuse the piss out of my XT cranks (splined BB) and haven't had squeal one out of them.

Sometimes you get a great product, sometimes you get sh!t. The bike-part business is like that I've found.

I wanted the XT five-arm model, but finding one here in Germany is alot like trying to find loose diamonds in the front lawn.