[Sandwich]

Is there any reason, right now, to pick one rotor over another? Excluding shimano's forced-standard centerlock rotors, what's the way to go?

Sicklines has Avid's G2 as the lightest, but Magura Venti rotors and Hopes have a floating section which is claimed to dissipate heat. Is it worth the 30grams?

How about 9" rotors? Hayes has a 9" kit that's just a little bit more money and includes an adapter...so I suppose it would come out to just 10$ more. Anybody on those?

 

[boogenman]

Go with what costs the least. You are not going to notice a difference in any of them.

 

[- seb]

Formula Oros (The Ones etc) are lighter than Avids I think, though not by much. (And depends on whether you want 180/200 or 185/203 etc).

Lots of aftermarket ones like A2z are silly light, but look too aggressive, they'd chew through your pads in one hard day I reckon!

 

[xy9ine]

i use these. light, work just fine, look kinda neat (for what it's worth), and are dirt cheap @ $20ea:

 

[Jm_]

Is there any reason, right now, to pick one rotor over another? Excluding shimano's forced-standard centerlock rotors, what's the way to go?

Yes, because the fact that shimano sells the caliper without the rotor and "forces" you to choose between their available 6-bolt and centerlock rotors, which means they're "forcing" you to use centerlock.


BTW, the point of the hope-style rotors is that the braking surface is pinned to the carrier. When it heats up the steel braking surface can expand radially. With a one-peice rotor the rotor may warp back on itself it it gets too hot, because it's held in place by the bolts, which are fixed.

 

[mandown]

I've found that rotor widths vary slightly and that in some rare cases it can be an issue for concern, but most modern brakes are self adjusting for pad-wear which generally accomodates for such differences.

 

[Sandwich]

Yes, because the fact that shimano sells the caliper without the rotor and "forces" you to choose between their available 6-bolt and centerlock rotors, which means they're "forcing" you to use centerlock.


BTW, the point of the hope-style rotors is that the braking surface is pinned to the carrier. When it heats up the steel braking surface can expand radially. With a one-peice rotor the rotor may warp back on itself it it gets too hot, because it's held in place by the bolts, which are fixed.

hey there angry stuff,
I know the reason that hope and magura use their alloy carrier/steel braking surface rotors. I'm wondering whether it works, or offers any other benefit/detriment out on the trail. I've heard the Hopes rattle, but was unsure of magura's, which are only $5 more expensive than standard rotors right now.

As for the Shimano standard, no, they aren't forcing you into it, unless you buy a shimano hub. I suppose you could buy an adapter, but what's the point. The last thing mountain biking needs is more "standards", like IS front/boxxer/40/post mount, or 6bolt/centerlock/hope-4bolt rotors, or ISCG/ISCG05/whatever is next. I apologize if I think shimano is centered around the bulk of it, with their Saint derailleur/axle mount and now center lock.

 

[- seb]

I think it does work, only rotors I've ever used that didn't end up bent/warped. Definitely the most drag-free way to go.

 

[4xBoy]

hey there angry stuff,
I know the reason that hope and magura use their alloy carrier/steel braking surface rotors. I'm wondering whether it works, or offers any other benefit/detriment out on the trail. I've heard the Hopes rattle, but was unsure of magura's, which are only $5 more expensive than standard rotors right now.

As for the Shimano standard, no, they aren't forcing you into it, unless you buy a shimano hub. I suppose you could buy an adapter, but what's the point. The last thing mountain biking needs is more "standards", like IS front/boxxer/40/post mount, or 6bolt/centerlock/hope-4bolt rotors, or ISCG/ISCG05/whatever is next. I apologize if I think shimano is centered around the bulk of it, with their Saint derailleur/axle mount and now center lock.

I liked the saint bolt on derailleur I have used it to save people from a walk out before.

 

[Sandwich]

i use these. light, work just fine, look kinda neat (for what it's worth), and are dirt cheap @ $20ea:

those are silly cheap. They work fine? Alligator makes some crappy stuff.

 

[mattmatt86]

What brakes are they for? That can make a difference, I used an avid rotor with my Formulas once and the braking performance wasn't the same. Although, as its been mentioned this could be because of differences in rotor widths. And if I'm not mistaken, Formula rotors are also lighter than the G2 rotors from Avid.

 

[Sandwich]

Saint 810s.

 

[Jm_]

As for the Shimano standard, no, they aren't forcing you into it, unless you buy a shimano hub. I suppose you could buy an adapter, but what's the point. The last thing mountain biking needs is more "standards", like IS front/boxxer/40/post mount, or 6bolt/centerlock/hope-4bolt rotors, or ISCG/ISCG05/whatever is next. I apologize if I think shimano is centered around the bulk of it, with their Saint derailleur/axle mount and now center lock.

Well, again, they aren't forcing this stuff on us, they are offering a choice. I think that the new "standard" takes hold if it's really better and offers definite advantages. Not sure how you can fault shimano for that. They've learned a lot and especially have learned that you can't force a new product anymore, like rapid rise, etc. That whole boxxer-mount thing has been RSs deal from the beginning, non-standard compared to all of the other fork manufacturers (when at times everyone else shared the same standard). I happen to like the saint bolt-on derailer (a lot more now that I have good cable routing to it). It's so solid, it's crazy the hits it will take and how it keeps shifting flawless. It's so damn heavy though and the rear derailer is a place where people have already made a concious decision that it's a "lightweight disposable part". When confronted with SLX, Saint, XO, XTR and so on, way too many people still choose XO and XTR, for the weight savings. So the bolt-on derailer, while still out there, maybe didn't take over quite as much as shimano thought it would.

Anyways, I didn't meant to imply that you didn't know what the "floating" rotors were for, but lots of other people don't really understand the point of them, and that they are "pinned" rather than "floating" IMO. Magura gustavs (and some of the brakes on the airplanes I fly ) employ a floating caliper, which is allowed to move back and forth to accomidate any disc warpage. IMO that's a much better use of the word "floating", but the common term for the hope, shimano and other pinned rotors is "floating" as well.

I guess whether you like shimano or not, they're trying to provide choices of product lines and products with as much cross-compatibility as possible.

 

[Steve M]

Is there any reason, right now, to pick one rotor over another? Excluding shimano's forced-standard centerlock rotors, what's the way to go?

Sicklines has Avid's G2 as the lightest, but Magura Venti rotors and Hopes have a floating section which is claimed to dissipate heat. Is it worth the 30grams?

How about 9" rotors? Hayes has a 9" kit that's just a little bit more money and includes an adapter...so I suppose it would come out to just 10$ more. Anybody on those?

I ran the Hayes 9" rotor on the front of my bike for a while. Other than the fact that the rotor weighed about 300g (normal 203mm rotors are about 200-220g) it was fantastic - it gave more power and was significantly harder to overheat the pads with (though I still managed it a few times - LX brakes). I now have the M810 Saints though, and even with the 203mm rotor they're spastically powerful. The pads in them are also roughly 26% larger in terms of surface area than the older Shimano pads (XT/Saint/XTR) so they can take a bit more heat before crapping out too. I've still got my 9" rotor lying around, and I'd love to give it a crack with the 810s - should be insanely powerful.

Other than that, yes some rotors are better than others. Old Hayes rotors, for example, sucked nuts because they wore out in a concave manner - the thin parts between the holes, in the middle of the braking track, would wear faster than the sides of the braking track. Some other rotors, like those Red Raven ones I'm told, had cooling issues where the outside rim of the rotor was cooling faster than the rest of the braking track, causing them to warp like crazy. I currently have Hayes V8 rotors and they seem to be trouble-free, as do all the Shimano rotors I've used. Oh yeah and the old Avid Polygon rotors weren't too flash either, they didn't seem to scrape the pad clean enough, and due to the variations in contact area with the pad, they tended to vibrate/pulse a bit at the lever.

 

[Sandwich]

"pinned" rather than "floating" IMO.

It's funny that you bring that up. Mountain cycle came out with a disk brake back in the day that had a legit floating rotor. The rotor slid back and forth on plastic bushing off the hub or spider. Neat idea, but like the gustav, you can't get rid of drag, ever. It will always be there, even if it's just audible and not parasitic.

I ran the Hayes 9" rotor on the front of my bike for a while.

I currently have Hayes V8 rotors and they seem to be trouble-free, as do all the Shimano rotors I've used.

Thanks for the tips! I'll skip the 9" rotor for now. I have a feeling the Saints will be adequate for my usage without the huge rotor. That weight penalty is surprising, too, especially when compared to some other rotors out there.

Good to know on the v8s and Shimanos. I feel like most people run those, so I figured there was a reason.

I think I might pick up those Alligator rotors though. They are way cheap and I can buy two for the price of one real rotor, so worst comes to worst I'm out 30 bucks and a couple sets of pads, but I have a feeling they won't be too noticable....I hope. XY if you have any more commentary, please share. Most people who run them on DH bikes seem to say "they work fine" and that's it. Any pulsing or warping issues?

 

[Rick205]

Sandwich - maybe think about the new Alligator cirrus rotor: http://www.alligatorcables.com/DISC/STEEL.htm

Less 'aggressive' design and a little lighter - no pulsing issues for me either and i did get slight pulsing from the front using the Alligator saw rotor, this did subside over time - some seem to experience this and some dont as its likely a setup issue (the pad may contact a 'fin' on the rotor at a slight angle causing the pulsing sensation)

The rotors worked just fine for me - no better or worse than anything else i have used in the past, the newer cirrus rotors have been spot on since being installed.

Rick

 

[Bikael Molton]

Which era of Hayes rotors did this? I'm running 2005ish ones.

thanks

Old Hayes rotors, for example, sucked nuts because they wore out in a concave manner - the thin parts between the holes, in the middle of the braking track, would wear faster than the sides of the braking track.

 

[Steve M]

Thanks for the tips! I'll skip the 9" rotor for now. I have a feeling the Saints will be adequate for my usage without the huge rotor. That weight penalty is surprising, too, especially when compared to some other rotors out there.

Good to know on the v8s and Shimanos. I feel like most people run those, so I figured there was a reason.

The weight penalty isn't that surprising - Hayes 160mm rotors are ~110g, 203mm rotors are ~220g and 224mm rotors are ~300g. The arms of the rotor have to be a lot thicker if the diameter is larger.

Which era of Hayes rotors did this? I'm running 2005ish ones.

thanks

This style, before the V8 etc with the cutouts in the outer diameter:

 

[Bikael Molton]

thanks socket

 

[Bulldog]

Sandwich - maybe think about the new Alligator cirrus rotor: http://www.alligatorcables.com/DISC/STEEL.htm

Less 'aggressive' design and a little lighter - no pulsing issues for me either and i did get slight pulsing from the front using the Alligator saw rotor, this did subside over time - some seem to experience this and some dont as its likely a setup issue (the pad may contact a 'fin' on the rotor at a slight angle causing the pulsing sensation)

The rotors worked just fine for me - no better or worse than anything else i have used in the past, the newer cirrus rotors have been spot on since being installed.

Rick

My problem with super light rotors (e-problem, no real world experience, just armchair) is that to make them light - 1) the "spokes" are super thin = bendarooski, and 2) the braking surface has been almost completely removed! Don't brakes work via friction?!?!

 

[UiUiUiUi]

does anybody use the new saint brakes with hope vented disks?

 

[karpi]

My problem with super light rotors (e-problem, no real world experience, just armchair) is that to make them light - 1) the "spokes" are super thin = bendarooski, and 2) the braking surface has been almost completely removed! Don't brakes work via friction?!?!

thats so true, I wonder how it is that they manage to brake, haven most of the braking suface cut away with. I guess it comes down to less weight normally = less surface area = less braking... anyone care to comment?

 

[Steve M]

My problem with super light rotors (e-problem, no real world experience, just armchair) is that to make them light - 1) the "spokes" are super thin = bendarooski, and 2) the braking surface has been almost completely removed! Don't brakes work via friction?!?!

If the coefficient of friction between pads and rotor is constant with respect to pressure, then it wouldn't really matter all that much - the less area you have for the pads/rotor to clamp to, the higher pressure you have (pressure = clamping force/area). However the coefficient obviously isn't quite constant with respect to pressure (even if it's very close), because some rotors with big variations in contact area (eg those Avid Roundagon rotors) sometimes caused pulsing due to a non-constant braking force.

The lack of surface area is a legitimate concern though, particularly to do with heat dissipation IMO.

uiuiuiui - don't think the Hope vented discs work with anything except the Moto V2s, they're about 1.3mm thicker than a standard rotor which is quite a lot.