Results 1 to 21 of 21
  1. #1
    Exclusively Single
    Reputation: long hazy daze's Avatar
    Join Date
    Oct 2005
    Posts
    673

    Rotors that stay true....

    I've been running Avid Mech's for a couple years and have never been able to keep my rotors entirely true(160mm). I've always been able to keep them relatively flat but I'm absolutely fed up with them at this point. I spent about 2 hours with some c-wrenches trying to get my totally wacked front rotor at least tolerable and it just won't have it. These things are just freakin' flimsy.

    What are some good rotors that keep their shape better than the Avids?

  2. #2
    A wheelist
    Reputation: Mike T.'s Avatar
    Join Date
    Dec 2003
    Posts
    5,603
    I saw some massive great big rotors on a 500hp Corvette today. I'll bet they stay true. Maybe you should retrofit some of those.
    Mike The Bike's home wheelbuilding info - dedicated to providing Newby wheelbuilder information and motivation.

  3. #3
    Nightriding rules SuperModerator
    Reputation: crisillo's Avatar
    Join Date
    Jul 2004
    Posts
    20,764
    Quote Originally Posted by Mike T.
    I saw some massive great big rotors on a 500hp Corvette today. I'll bet they stay true. Maybe you should retrofit some of those.

  4. #4
    Exclusively Single
    Reputation: long hazy daze's Avatar
    Join Date
    Oct 2005
    Posts
    673
    Quote Originally Posted by Mike T.
    I saw some massive great big rotors on a 500hp Corvette today. I'll bet they stay true. Maybe you should retrofit some of those.
    Big help. Thanks a bunch.

  5. #5
    mtbr member
    Reputation: EliM's Avatar
    Join Date
    May 2006
    Posts
    374
    Hope has some rotors with an inner piece...it looks a little stronger than the usual setup.

    http://www.rideonline.co.uk/img/big/15613.jpg

    edit: universal cycles sells them

    http://www.universalcycles.com/shopp...hp?category=27
    Well, I was just riding along when...

  6. #6
    A wheelist
    Reputation: Mike T.'s Avatar
    Join Date
    Dec 2003
    Posts
    5,603
    Quote Originally Posted by long hazy daze
    Big help. Thanks a bunch.
    You probably recognized my reply for what it was - a faecetious remark. I guess it was meant to make light of the fact that bike disc brakes have to be just that - light. And this is accompanied by all kinds of trade-offs. We want 'em as light as XTR v-brakes but we don't want 'em to squeal or fade and probably a few other things.

    I think bike disc brakes, in the weight department, hit rock-bottom about four years ago with the ultra-light Formula B4SL Magnesiums. They weighed (on my scale and recorded here on the Brakes FAQ page) a miniscule 630 grams - the same as a small full waterbottle. A large full waterbottle weighs 200 grams more. Mine are still going strong but others had many problems. Formula abandoned them for heavier brakes.

    So, because we still demand brakes as light as possible, we're stuck with 2mm thick rotors banging off rocks and trying to absorb and dissipate the heat of a long downhill. No wonder they warp. A couple of pounds of mass would make a huge difference. Because of their trade-offs we become good at truing them and my buddy Paul Morningstar becomes filthy-rich selling us drumstix.
    Mike The Bike's home wheelbuilding info - dedicated to providing Newby wheelbuilder information and motivation.

  7. #7
    MTB B'dos
    Reputation: LyNx's Avatar
    Join Date
    Oct 2004
    Posts
    17,903
    Well that is about the most useful answer you'll get, to be frankly honest. You are running a single piston brake system that pushes the rotor from one side towards the other stationary rotor, this of course will cause the rotor to not stay true since most rotors are only about 2mm thick - especially if you ride the brakes a lot. Get dual piston brakes and lessen the problem, but you will never eliminate it as bicycle disc rotors are just to damn little material.

    Quote Originally Posted by long hazy daze
    Big help. Thanks a bunch.
    One day your life will flash before your eyes, will it be worth watching??
    MTB Barbados
    My Phantom pics

  8. #8
    A wheelist
    Reputation: Mike T.'s Avatar
    Join Date
    Dec 2003
    Posts
    5,603
    Quote Originally Posted by LyNx
    Well that is about the most useful answer you'll get, to be frankly honest. You are running a single piston brake system that pushes the rotor from one side towards the other stationary rotor, this of course will cause the rotor to not stay true since most rotors are only about 2mm thick - especially if you ride the brakes a lot. Get dual piston brakes and lessen the problem, but you will never eliminate it as bicycle disc rotors are just to damn little material.
    I had the original Magura Louise for three years, have extensively tested Avid BB7 and I mechanic for a lady racer who has been using BB7 for three seasons - all single piston/flex rotor brakes. There hasn't been one occasion where a disc warp was caused by one of those single pistons pushing its rotor against the stationary pad so I can't agree with ya LyNx. I agree with your last nine words though.
    Mike The Bike's home wheelbuilding info - dedicated to providing Newby wheelbuilder information and motivation.

  9. #9
    MTB B'dos
    Reputation: LyNx's Avatar
    Join Date
    Oct 2004
    Posts
    17,903
    Depends on if you keep the single piston brakes very well adjusted so that the movement is very minimal, in the <1mm of travel to the stationary rotor - most people do not do this as it requires constant adjustment.

    Quote Originally Posted by Mike T.
    I had the original Magura Louise for three years, have extensively tested Avid BB7 and I mechanic for a lady racer who has been using BB7 for three seasons - all single piston/flex rotor brakes. There hasn't been one occasion where a disc warp was caused by one of those single pistons pushing its rotor against the stationary pad so I can't agree with ya LyNx. I agree with your last nine words though.
    One day your life will flash before your eyes, will it be worth watching??
    MTB Barbados
    My Phantom pics

  10. #10
    ride hard take risks
    Reputation: dogonfr's Avatar
    Join Date
    Jan 2005
    Posts
    25,589
    Galfer Rotors & dont bounce off anything.
    Formotion Products
    http://www.formot

  11. #11
    Exclusively Single
    Reputation: long hazy daze's Avatar
    Join Date
    Oct 2005
    Posts
    673
    Well at least a couple of you chimed in with responses that aren't based on the assumption that I'm a retarded 12 year old with no mechanical sense.

    I know all rotors are basically the same thickness, I wasn't asking about thicker, heavier rotors. The truing issue I believe has more to do with the rigidity of the rotors' spider than the thickness of the material. the Avids I've used have very flimsy spiders and I've never used any other rotors so I have no frame of reference as to rather or not there are rotors available that tend to warp to a lesser degree.

    I ride single speed and hence use my brakes as little as possible (i.e., I don't constantly drag them down hill, and I'm quite light on them when I do use them), I've never once "bounced" my rotors off any rocks (not sure how this would happen other than a very awkward crash), and I adjust them pretty much every ride to keep the rotors as close to the inboard pad as is possible without any rubbing and the outboard adjusted to keep the lever throw as short as possible without any rubbing. And if weight was a big concern of mine I'd run V's.

    Now, having said all that, do you brake forum guys have any useful information that pertains to my initial question?

  12. #12
    Exclusively Single
    Reputation: long hazy daze's Avatar
    Join Date
    Oct 2005
    Posts
    673
    Quote Originally Posted by EliM
    Hope has some rotors with an inner piece...it looks a little stronger than the usual setup.

    http://www.rideonline.co.uk/img/big/15613.jpg

    edit: universal cycles sells them

    http://www.universalcycles.com/shopp...hp?category=27
    Nice. Those Hope 2-pc rotors look like they'd be much more laterally rigid, and a couple of their other models look to have much more beefy spiders than the typical rotor.

  13. #13
    Nightriding rules SuperModerator
    Reputation: crisillo's Avatar
    Join Date
    Jul 2004
    Posts
    20,764
    Now, having said all that, do you brake forum guys have any useful information that pertains to my initial question?
    get off the high horse... and read again..

    the rotor thinkness (and weight by consequence) HAS to do with warping... with the way bike rotors are.. they will require truing every now and then... in some brakes you have more "room" in others less...in the bb7s you can adjust this, but as others have said..there can be advantages/disadvantages to each setup... compromise and be done with it

    the hope floating rotors are not any more rigid than standard ones..but they are harder to true...

  14. #14
    Exclusively Single
    Reputation: long hazy daze's Avatar
    Join Date
    Oct 2005
    Posts
    673
    Quote Originally Posted by crisillo
    get off the high horse... and read again..

    the rotor thinkness (and weight by consequence) HAS to do with warping... with the way bike rotors are.. they will require truing every now and then... in some brakes you have more "room" in others less...in the bb7s you can adjust this, but as others have said..there can be advantages/disadvantages to each setup... compromise and be done with it

    the hope floating rotors are not any more rigid than standard ones..but they are harder to true...

    No high horse, just looking for a straight answer.Perhaps you should read my original post again, I'm quite familiar with truing rotors. My question was: are there any rotors that stay true better than the standard Avids? It's a pretty simple yes or no answer, unless of course you have no idea yourself .....
    Sheesh.

  15. #15
    Nightriding rules SuperModerator
    Reputation: crisillo's Avatar
    Join Date
    Jul 2004
    Posts
    20,764
    Quote Originally Posted by long hazy daze
    No high horse, just looking for a straight answer.Perhaps you should read my original post again, I'm quite familiar with truing rotors. My question was: are there any rotors that stay true better than the standard Avids? It's a pretty simple yes or no answer, unless of course you have no idea yourself .....
    Sheesh.
    as I and others have said... all are mostly the same.. so the answer is NO

  16. #16
    A wheelist
    Reputation: Mike T.'s Avatar
    Join Date
    Dec 2003
    Posts
    5,603
    Quote Originally Posted by long hazy daze
    Now, having said all that, do you brake forum guys have any useful information that pertains to my initial question?
    I guess not eh? Most of my info is all written down in the FAQ here. Rotor warp isn't an issue to me and I've had xc weight disc brakes as long as anyone around here. My experience is limited to Magura-Avid-Formula rotors and my findings are the same for them all. Which makes me wonder why you are having problems enough to frustrate you.

    I have the BB7 equipped bike here that I mechanic for a lady racer. It won a race last week (and the week before), I just checked it over (again) and the rotors are dead true.
    Mike The Bike's home wheelbuilding info - dedicated to providing Newby wheelbuilder information and motivation.

  17. #17
    Exclusively Single
    Reputation: long hazy daze's Avatar
    Join Date
    Oct 2005
    Posts
    673
    Quote Originally Posted by crisillo
    as I and others have said... all are mostly the same.. so the answer is NO
    Now that was easy, wasn't it?

  18. #18
    Nightriding rules SuperModerator
    Reputation: crisillo's Avatar
    Join Date
    Jul 2004
    Posts
    20,764
    Quote Originally Posted by long hazy daze
    Now that was easy, wasn't it?

  19. #19
    MTBR Demi-God
    Reputation: anirban's Avatar
    Join Date
    Apr 2006
    Posts
    832
    Quote Originally Posted by long hazy daze
    My question was: are there any rotors that stay true better than the standard Avids? It's a pretty simple yes or no answer, unless of course you have no idea yourself .....
    Just to reinforce the statement made by other posters, My answer: No.
    "Winners never quit. Quitters never win. But those who never win and never quit are idiots."

  20. #20
    mtbr member
    Reputation:
    Join Date
    Jan 2005
    Posts
    155

    hard to beat DRUMSTIX

    hey I've found it is hard to beat the drumstix for keeping rotors true- the set of three levers is great. morningstartools.com

  21. #21
    A wheelist
    Reputation: Mike T.'s Avatar
    Join Date
    Dec 2003
    Posts
    5,603
    Quote Originally Posted by Douglas Fir
    hey I've found it is hard to beat the drumstix for keeping rotors true- the set of three levers is great. morningstartools.com
    Those three tools, used in unison, isolate the warp and bring it back to true. Great tools from a great thinker.
    Mike The Bike's home wheelbuilding info - dedicated to providing Newby wheelbuilder information and motivation.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •