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  1. #1
    El CicloPath!!!!!!!
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    Absoluteblack Rotors

    Received a small package from over the pond today. I had to run over to REI to buy the tool to take off the centerlock ring. After some muscling, finally got the old rotor off. (A non-icetech XTR, that was fantastic btw.)

    I've been having some rear triangle flex in the drop out area ever since day one. Havent really pinpointed the exact cause of the flex, but for a lot of us, it has resulted in brake rub, squeeling, and shuddering.

    I got rid of the shudder by always centering the caliper over the rotor, then setting the pistons and pads to the centered rotor.

    I seemed to have cured the rubbing and squeeling by FIRST: going to organic pads. SECOND: by setting the pads while weighing the suspension down. Aand THIRD: by doing a good bleed and by lubricating the pistons very carefully with mineral oil.

    But when I did some searching, I discovered that Marcin began offering his free floating rotors.......I became inritgued. There's not a whole lot of information on them, but from what I read and from watching his videos, they seemed like they could be a plus. I decided to purchase one for the rear. (My front has so far never had any issues.)

    The rotor and the lock ring were expensive. More so than any rotor offered by Shimano, Hope, or even Formula. But I figured....they were not going to be cheap. Highly specialized product offered by a single individual with a resolute passion for his stuff. Okay...let's try it out.

    Got it installed.............went to bed in the pads......so far so good. No rubbing, no noise, the pads still need some breaking in.

    So............yes, it really does float. Fit to the hub is perfect. The machining of the spider is very well done. The Rotor ont he otherhand......though it is laser cut, it's not nearly as well finished as say a Shimano rotor. There were a few metal burrs I had to remove, and the cutouts in the rotor are not perfect, but all in all, it was ok. The actually surface of the rotor is very well finished.

    I think I will go for an extended ride tomorrow with a bit of fire road downhilling to test it out. Please stay tuned!

    Absoluteblack Rotors-img_4038_zps7da438bc.jpg
    Absoluteblack Rotors-img_4037_zpsa2df932e.jpg
    Absoluteblack Rotors-img_4036_zpsef080adf.jpg

  2. #2
    El CicloPath!!!!!!!
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    Ok....did a local ride this morning. About 6 miles of fireroad climbing followed by an equal downhill. No squeel. No shudder. No rubbing. and best of all....no fade. There was one stretch for about 1 mile that I was constantly on the brake. Not full on, but I wanted to drag it. The heat did build up, but I still had full power.

    THese were the Shimano organic pads. I'm going to try out the metal ones in the future after these wear out.

    So far, I'm very happy with the performance of this rotor.

    The best part for me is.............NO NOISE!

  3. #3
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    Can you tell me when you spin the wheel, do you see any wavyness to the rotor? Is the rotor perfectly true or is there some small warpage?

    Thanks

  4. #4
    El CicloPath!!!!!!!
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    Quote Originally Posted by cfrea View Post
    Can you tell me when you spin the wheel, do you see any wavyness to the rotor? Is the rotor perfectly true or is there some small warpage?

    Thanks
    The rotor is perfectly true. With the brake lever depressed, once the rotor has gone one full revolution, it will even out between the brake pads. It really is "floating."

    Before installing it, I checked for warpage. There was none. perfectly flat. After the ride, I checked again. Perfectly flat. I think that the floating feature discourages warping because within the given tolrances, the rotor cannot bend.

    My only concern with the entire rotor package is durability. Marcin specifically gives maximum weight data and does not encourage the use of this rotor for downhill bikes, but I know that even most of us that do cross country rides, will encounter some rough downhilling, so I'm going to test it out some more.

    The spider is cut out as much as possible to reduce weight, but I dont know a thing about it's long term durability. It's even lighter and has less material than the XTR rotor.

  5. #5
    El CicloPath!!!!!!!
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    I want to also comment about brake rubbing in general. Brake rub is almost always caused by one, some, or all of the following.

    1. Misaligned caliper
    2. Sticky Piston
    3. Rotor warpage
    4. heat effect of fluid/piston and rotor
    5. frame/fork flex
    6. loose hub bearings
    7. and some others...

    Brake Squeel is caused by the above too, because in order for the squeel to occur, there has to be some rubbing. It doesnt take a whole lot for the squeeling to occur, but we can all attribute it to two main causes.

    1. Contamination of the pads/rotor leading to:
    2. Harmonic resonance
    3. Heat causing expansion causing rubbing and fading

    Shuddering of the brake can be caused by the above, but I've attributed most of the shudders that I've experienced to misaligned calipers. The Rotor should be as perfectly centered orver the rotor and bolted to the frame/fork as best as possible.

    Here's my issue. When the rear suspension is in weight bearing, and all it takes is a push down on the seat, there is a very minute shifting of the left drop out, or flexing of the left side of my XT hub, that allows either the caliper or the rotor, to move ever so slighly; enough to cause all of the above. Squeeling.....when coasting, when turning to the left. All of the symptoms that we have heard and read about over the years.

    I did manage to get rid of it all by.


    1. Doing a good bleed to ensure the best piston action and retraction. That is one really important aspect of the brake.
    2. I went from sintered pads to organic. They still squeeled, but not as much, and they stopped squeeling altogether once I:
    3. Properly aligned the caliper and the rotor.

    I was able to get the best clearance and alignment of the rotor and caliper as best I could.

    The Absoluteblack rotor with the floating feature actually helps a lot. I think it actually removes or reduced the whole harmonic resonance factor because even if there is a slight rub, the rotor moves away from the friction.

    All in all...................it's almost a Nirvana moment. I can actually do an entire ride with out the stigma of the brake issues that I have been battling for the last 6 months.

    The bike, so far, has been totally quiet.

  6. #6
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    Quote Originally Posted by Fachiro1 View Post
    I want to also comment about brake rubbing in general. Brake rub is almost always caused by one, some, or all of the following.

    1. Misaligned caliper
    2. Sticky Piston
    3. Rotor warpage
    4. heat effect of fluid/piston and rotor
    5. frame/fork flex
    6. loose hub bearings
    7. and some others...

    Brake Squeel is caused by the above too, because in order for the squeel to occur, there has to be some rubbing. It doesnt take a whole lot for the squeeling to occur, but we can all attribute it to two main causes.

    1. Contamination of the pads/rotor leading to:
    2. Harmonic resonance

    Shuddering of the brake can be caused by the above, but I;ve attributed most of the shudders that I've experienced to misaligned calipers. The Rotor should be as perfectly centered orver the rotor and bolted to the frame/fork as best as possible.

    Here's my issue. When the rear suspension is in weight bearing, and all it takes is a push down on the seat, there is a very minute shifting of the left drop out, or flexing of the left side of my XT hub, that allows either the caliper or the rotor, to move ever so slighly; enough to cause all of the above. Squeeling.....when coasting, when turning to the left. All of the symptoms that we have heard and read about over the years.

    I did manage to get rid of it all by.


    1. Doing a good bleed to ensure the best piston action and retraction. That is one really important aspect of the brake.
    2. I went from sintered pads to organic. They still squeeled, but not as much, and they stopped squeeling altogether once I:
    3. Properly aligned the caliper and the rotor.

    I was able to get the best clearance and alignment of the rotor and caliper as best I could.

    The Absoluteblack rotor with the floating feature actually helps a lot. I think it actually removes or reduced the whole harmonic resonance factor because even if there is a slight rub, the rotor moves away from the friction.

    All in all...................it's almost a Nirvana moment. I can actually do an entire ride with out the stigma of the brake issues that I have been battling for the last 6 months.

    The bike, so far, has been totally quiet.
    You make some interesting points. In regards to a misaligned caliper I don't understand the best method to align it?

    Lets assume I install the wheel with the rotor installed. I then loosen the caliper fixing bolts and line up the caliper to perfectly center with the rotor. But then the second you spin the wheel the rotor rubs with the pads. Unfortunately to remedy this I'm forced to further adjust the calipers either on the top or bottom in order to avoid any rub. How are you supposed to fully line them up then?

  7. #7
    El CicloPath!!!!!!!
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    Quote Originally Posted by cfrea View Post
    You make some interesting points. In regards to a misaligned caliper I don't understand the best method to align it?

    Lets assume I install the wheel with the rotor installed. I then loosen the caliper fixing bolts and line up the caliper to perfectly center with the rotor. But then the second you spin the wheel the rotor rubs with the pads. Unfortunately to remedy this I'm forced to further adjust the calipers either on the top or bottom in order to avoid any rub. How are you supposed to fully line them up then?
    I did the same thing when I first ran into problems.

    But thru trial and error, this is what I came up with.

    1. The brakes need to be properly bled. The important thing that needs to be done, is to get the pistons pushed back as far as possible with out any issues. Then, the pistons need to be properly lubricated so that they move evenly both left and right. With Shimano brakes, I lubed the pistons with the Shimano mineral oil using a q-tip before puching them back in. With the caliper off the mount, brake pads out, push the lever slightly to push out the pistons. Then use the q-tip. Also, when I pushed the pistons back in, i had the bleed screw at the lever cracked open to allow the excess fluid to come out of the resevoir.

    It is extremely important to get the pistons to move as evenly as possible. Most of our brakes don't do this, so you have to see if lubing them will help. It did for me.

    2. Once the pistons are pushed back, you install the pads. This should allow ample clearance between the rotor and the pads.

    3. Now comes the tedious part. The Shimano caliper is kind of made in two halves. Not exactly, but there is a line denoting the left half and the the right half. I use this line as a reference point when bolting the caliper on. While using the front and rear lines, I sight thru the opening in the top of the caliper and line it up with the rotor. The actual bolting needs to be done carefully. Any Slight shift while tightening down the bolts can mis-align everthing. I do this slowly and alternately tighten the bolts little by little.


    Absoluteblack Rotors-photo-4_zps15f4e009.jpg.

    While going thru these steps.....once the pistons are pushed back, I DO NOT PULL THE LEVER. I don't use the loose screw and squeeze while tightening method. It's never worked very well for me, although I know a lot of us use that method.

    4. Once the caliper in on, I take the bike out and while sitting on the bike, supporting the bike with a foot on the curb, I weight the suspension as if in the my riding position and THEN I SQUEEZE THE LEVER. I squeeze and hold, squeeze and hold. I then get off the bike and check the gaps, ride around a bit and check the stopping power. It is during this part that the pistons and the rotor acheive my riding alignment, and so far. it has worked for me. No rubbng, not squeel.

    The important things to consider again are...alignment, lubbed and properly moving pistons, clean rotor, ample gap. I really feel that if you can acheive and maintain these factors, it will help eliminate any of these brake issues.

    Of course, the most important thing is that the brakes work and feel proper. They need to be able to stop the bike. I ride a lot of extended climbs and descending trails, and the brakes absolutely have to function at optimum.

    After much trial, error, and expense, this is what has worked for me. it may not be everyone's solution, but I hope it can help.
    Last edited by Fachiro1; 03-29-2013 at 12:02 AM.

  8. #8
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    Quote Originally Posted by Fachiro1 View Post
    I've been having some rear triangle flex in the drop out area ever since day one. Havent really pinpointed the exact cause of the flex, but for a lot of us, it has resulted in brake rub, squeeling, and shuddering.

    I got rid of the shudder by always centering the caliper over the rotor, then setting the pistons and pads to the centered rotor.

    I seemed to have cured the rubbing and squeeling by FIRST: going to organic pads. SECOND: by setting the pads while weighing the suspension down. Aand THIRD: by doing a good bleed and by lubricating the pistons very carefully with mineral oil.
    Have you tried a different rear wheel in the frame to isolate whether the movement is a frame or wheel issue? With a Shimano cup and cone hub have you adjusted the bearing preload to try and eliminate any play in the hub bearings?

    You could also try a DT RWS skewer as that will clamp the rear end together tighter than a standard Shimano quick release skewer.

  9. #9
    El CicloPath!!!!!!!
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    Lol..the only reason i havent tried a different rear wheel is that I dont have access to one! But yes, i know that may be another reason. But i did have the wheel checked out and was told the bearings are fine. I have also considered going with the dt rws, but ive read that the 9mm version is about the same performance wise as other 9mm skewers as opposed to the thru axel version. But i might want to try it in the future.

  10. #10
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    Can you feel any side to side play in the hub bearings if you hold the tyre with your hand and rock the wheel sideways?

    Re-greasing the hub and adjusting the bearing cones on a Shimano hub is quite straightforward. You just need a pair of thin cone spanners.

    Park Tool Co. ParkTool Blog Hub Overhaul and Adjustment

    It's either the hub or possibly you've got some play in the rear suspension pivots. Have you checked the tightness of all the pivot bolts on your frame's rear suspension to make sure they aren't loose? If there is something loose in the rear suspension it could end up damaging the frame over time.

  11. #11
    El CicloPath!!!!!!!
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    There is no discernable play in the hub.


    Quote Originally Posted by WR304 View Post
    Can you feel any side to side play in the hub bearings if you hold the tyre with your hand and rock the wheel sideways?

    Re-greasing the hub and adjusting the bearing cones on a Shimano hub is quite straightforward. You just need a pair of thin cone spanners.

    Park Tool Co. ParkTool Blog Hub Overhaul and Adjustment

    It's either the hub or possibly you've got some play in the rear suspension pivots. Have you checked the tightness of all the pivot bolts on your frame's rear suspension to make sure they aren't loose? If there is something loose in the rear suspension it could end up damaging the frame over time.

  12. #12
    El CicloPath!!!!!!!
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    Absoluteblack Rotors-photo-4_zps87c85397.jpg
    I did a three hour ride yesterday at a local locale..Bonelli Park, which consists of a multitude of different terrain..firerod, singletrack, rock gardens, short high speed descents, short steep climbs, road; a good test of different braking situations.

    The AB rotor performed flawlessly. I didnt experience any problems and there was zero noise, zero rubbing. I periodically checked, especially after each descent that required hard braking. No issues.

    I think the only thing I'm still concerned with is thr durability of the spider/rotor juctions. Afer this short test period, there is no forward/rear play (only the lateral free floating play) but I want to see it long term.

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