Which brake rotors to go for?

Northwind

I've pretty much settled on the idea of a set of 717 rims with XT centrelock hubs, for a spot of weight weenieage at a reasonable price. Now, looking at brakes to suit. Or, specifically, brake rotors.

Obviously, Centrelock restricts things a bit, so looking at Shimano. SLX seems to be the main contender, £135 all in with the SLX rotors. But, the XTR rotors are obviously more sexeh. I'd assumed they should give a decent weight loss but from reading weightweenies, for the 160mm discs the weight quoted between XT and XTR is almost identical. Likewise, the weights for 6-bolt vs splined, including the lockrings and bolts respectively, are almost identical. I'd read elsewhere that the centrelock fixing is lighter?

Nobody seems to have weights for SLX either, even shimano helpfully, but they seem to be in the same ballpark. Is it just the case that the 160mms all come in much the same?

supersonic

Centrelock hubs are lighter than the 6 bolt equivalents, that is for sure.

As for the actual rotors, I don't know what SLX are. If you go non shimano with the brakes, make sure the rotors are compatible.

Northwind

Yeah, I'll be keeping shimano throughout if I go this route, I do like the way they've made their rotors compatible through the range. (I could also use shimano rotors with my tektros, if I didn't want to replace them at the same time, but I'm moving all this older kit onto a different bike so it makes sense to get a build that all works together)

So, do you reckon teh weightweenies numbers are just wrong then?

nicklouse

i would have said that the 6 bolt with adaptors was the lightest.

toasty

Handy link here. Rotor wise, I think a 6 bolt with ti bolts is still the lightest, partly due to lack of expensive centerlock options though, if Hope or someone would start making decent centerlocks I think it'd progress.

Good comparison here for example, Hope Floating rotor + DT Swiss adapter and the same rotor with 6 light bolts. 6 bolt being 24g lighter!

The difference is minor though, my SLX brakes from merlin came shipped with deore centerlocks bizarrely (SLX 6 bolt was standard, I had to request the swap), they weight about 160g, XTRs weigh about 128g afaik.

As super mentioned though, the hubs make up for the difference. Take DT Swiss 240s for example, 258g for centerlock, 273g for 6 bolt. Aside from the couple of grams, I found centerlock a million times easier to fit and swap, I'd ditch the whole 6 bolt system entirely given the choice.


Christ I'm becoming such a weight weenie

The Spiderman

If you want light.......

http://www.merlincycles.co.uk/?fn=product&productId=1660&categoryId=176

toasty

Hehe, I did see those and go off hunting down reviews. I've not heard of any breaking but people don't seem to rate the braking performance massively. Still, I'd rather have a set of those of the Stans light ones, I trust that even less :?

http://julmtb.com//composants_legers/Disque/disc_generation_II_140mm_3_.jpg

!!

uk_mr_brownstone

I'll sneak a quick Q in here-

got my fav wheelset which has XT centrelock hubs with 160mm deore or LX (cant remember which) rotors. Using them on a bike with Hayes stroker trail- alignment is fine but the front squeaks like hell- done the usual cycle of pad scrubbing and rotor cleaning (all the recommended things except teh copper grease behind the pads) to no avail. Before I try the copper grease or new pads, could it be the rotors arn't 'compatable'? (I can't see how this could be as the fit looks ok, but im not an expert!)

toasty

If the width is fine and the lever bites in about the right position I'd assume they were fine. I'd personally do as you say and get a decent set of sintered pads, Superstar do them for pretty cheap.

Have you given them a decent long ride after all the washing? Wonder if it's cleaning products of some sort of something? I get the odd bout of squeeky breaks but it normally sorts itself out after a brief ride, the pads heat up and burn anything off pretty quick.

uk_mr_brownstone

Yeh I've done some heavy braking / stopies. I washed the bike (took pads out), and when dry cleaned the rotors with IPA (not Indian Pale Ale), and gave the pads a little scrub with wet n dry. The pads haven't done that many miles but they're the standard ones, and have experienced a lot of mud/grit on a couple of rides. I've already bought some standard superstar pads- not their sintered ones, but the standard superstar ones seems to have a higher metal content (jsut by looking at the amount of shiny bits in them!) than teh standard hayes ones.

Will try another round of wet n dry, add some copper grease to the rear of the pads, some stoppies and then try the new pads.

Also, would 160mm to 180mm front rotor be noticeable?

toasty

The biggest difference with a bigger rotor for me is it doesn't overheat as quickly. My breaking goes to bits and judders when it overheats.

I didn't mean quick bursts on the brakes by the way, go for a little 30 min ride and let them warm up and cool down naturally You're not trying to bed them in as such, just heat them up.

Northwind

Way to confuse the **** out of me guys The main thing I see here is lots of similiar numbers, what do you reckon to just using the SLX rotors and never thinking about it again?

The Spiderman

Sounds the perfect solution,Northwind.

GT Destroyer

Northwind wrote:

Way to confuse the **** out of me guys The main thing I see here is lots of similiar numbers, what do you reckon to just using the SLX rotors and never thinking about it again?

You could do that - And you'd probably not even tell the difference between them and using some hi-tec superlight ones, BUT, the XTR rotors are extremely sexy as you say, I have (or should I say had) 203m front and 180 rear in XTR and they were awesome.

In fact I am looking at them right now, still attatched to a set of XM317 wheels in black with black spokes. I must get them onto the classifieds bit.