Warped front rotors

[Edbo]

Has anyone ever used the sandpaper that has adhesive on the back and attached it to your brake pads and then drove slowly and applied the brakes lightly so that the sand paper would sand down the high spot on the rotor ? A friend of mine that has a Harley said he did it on his bike and it took the warp out of the rotor. Any thoughts on this?

[Flyinfool]

I have never heard of this method. I would be skeptical. Our rotors are pretty hard.

That does not mean it cant work.

[uncledj]

I suppose anything's worth a try, but it doesn't seem like it'd work to me. The pads / calipers will move somewhat with the warpage, so I don't see how you'd just be removing the "high" spot, and, as mentioned, it seems like it'd take quite a bit of sandpaper to remove enough rotor metal to make a difference......I mean....even to remove .005 would take quite a bit of sanding. Color me skeptical.

[videoarizona]

I have to agree. It would take so long you would probably die of old age before you got the warp out. Either turn it or get a used one.

 

Pinwall is good for this....finding a used rotor.

 

The last time I put new front tire on the RSV (with it's thin rotors) the dealer warped one of the front rotors. My bad for not taking them off prior to.

Cost me under $50 for a used one with less miles than mine had on it. Was fine.

[steamer]

I picked up two rotors on Pinwall, don't remember cost but it was way less then new. If I remember right they are around $200.00 each new.

[jimmy99]

The sandpaper on the brake pads might actually work, but I don't think it is a good idea. I would consider getting them turned or replacing them.

[MikeWa]

Machining motorcycle rotors involves using a grinder rather than a cutter. It works but there is not a lot of extra meat available to work with on these rotors. I recommend replacing them. If on the other hand your goal is to clean up the finish remove scratches and deglaze a die grinder and Scotch Bright pad will do a very nice job.

 

Mike

[Eck]

Ah, let an old man jump in on this conversation.

 

I totally DISSAGREE that sandpaper took the warp out of his rotors or that sandpaper can even do such a thing.

 

Edited- My rationale:

The amount of heat that is instantly generated from the friction upon applying the brakes, even at 5 mph, would in no doubt generate more than enough heat to heat up and soften / melt that little amount of adhesive used to attach the actual sand (or "glass"), to the paper it is on.

And, I believe there is no way a little piece of sandpaper, the size of a Harley brake pad, could endure the instant abundance of "pressure" between the pads and rotor without it being shredded within 2 to 5 revolutions of the rotor.

I have used sand paper and sanding cloth on sanding machines that were bigger than I am to sand steel of all types and yes it can sand the steel and yes it does have lasting endurance but the sandpaper is MUCH wider and thicker that a brake pad and the amount of actual pressure used to sand the steel in hand fed pressure which is much softer than being foot applied pressure within a caliper setting application.

 

With that being said, when sanding wood with piece of sand paper the size of a brake pad, one has to constantly fold and re-fold the sandpaper due to the sand wearing off with what little pressure is used by hand sanding.

 

Sandpaper or "glasspaper" are generic names used for a type of coated abrasive that consists of sheets of paper or cloth with abrasive material glued to one face.

 

AL righty now... I feel much better whether anyone disagrees or not with me.

 

Sorry I previously said my panties were in a wad in my op Edbo

Edited April 12, 2016 by Eck

[Edbo]

Thanks for all the input, didn't want to get anyone's panties in a wad just wanted to see if it was something I can do. I have a slight warp in front rotor and just wanted to see if anybody has done this. If I ever do try it I wil post my results here for others to poke at.

[Eck]

@Edbo, Please forgive me for I did come across way to strong on my above post. I'm was not trying to put you down in any way. I said my panites are in a wad (per say) as a joke and after going back and re-reading my above post, it surely didn't come out the way I meant it. I again apologize for my words of choice and for posting them. In fact, I went back and made a big edit to my previous post in hopes of making it a more positive response.

 

Forgive me please

Eck

[Condor]

I agree with everything Eck said above plus I'd like to add my 2¢. Let's say the sandpaper didn't melt. The pressure would be applied equally to the high and well as the low sections and the end result would be a thinner rotor, not plumb. Rotors have a slight warp to them from the git go. Maybe a couple of thousandths. What this does is push the pad away from the rotor surface and reduce drag and heat generation when the brakes are at rest. Without it the pad would continue to stay in contact with the rotor surface and cause premature wear... Granted, if the rotor has a big wiggle to it...it's time to replace. I still can't figure out how a shop can warp a rotor by just changing a tire?? Ka-ching..

[Edbo]

@Edbo, Please forgive me for I did come across way to strong on my above post. I'm was not trying to put you down in any way. I said my panites are in a wad (per say) as a joke and after going back and re-reading my above post, it surely didn't come out the way I meant it. I again apologize for my words of choice and for posting them. In fact, I went back and made a big edit to my previous post in hopes of making it a more positive response.

 

Forgive me please

Eck

 

ECK you didn't offend me at all, It was really interesting that this subject could make anyone so upset. Every thing you said was what you believe and really made since, I'm not sure if it would work or not I was just bringing the subject to the knowledgeable folks on this sight to get everyone's thoughts. It appears that's what I got. All is good with me and you didn't owe me an apology. I'm not one to get my feelings hurt . Thank you for your input on this matter and for all the great advise you have given to all the nice folks here on this sight. I hope to be able to meet up with you some day. I'm not far from you and come to Huntsville a lot, so I will get in touch some day and meet up.

[MikeWa]

Can you use sandpaper to get the wad out of ECK's panties? ;-)

 

Mike

[videoarizona]

@Condor, "I still can't figure out how a shop can warp a rotor by just changing a tire??"

 

That's an easy one. The 2nd Gen rotors are thin...about half the thickness (it seems) of a 1st Gen. That said, just dropping or resting the wheel on the rotor could and has bent the sucker a few thousands more than necessary. That's why so many pics of cycle wheels with rotors on are sitting on 2x4's or such. Any rotor can be damaged by weight pressed on it's side. They are very strong but not made to take sideways abuse of a heavy wheel and tire.

 

How my rotor got bent I can't say but I do know I carried the tire sitting on it's 4x4's to the shop and brought it home the same way. I never even leaned it against anything. So somehow they did stress the rotor enough to warp it. Maybe putting it on the machine? Maybe it rolled away and dropped. Who knows?

 

Was not a comfortable feeling on my new tire test ride to ease on the front brakes and feel the shutter of the warp.

 

More info:

 

http://www.clarity.net/adam/tire-changing-doc.html

 

Pinwall to the rescue!

Edited April 12, 2016 by videoarizona
Added a link for more info...

[cowpuc]

I ran a dial indicator with its magnetic based stuck to the side of a stand for a dirt bike against the surface of a rotor I had tweeked in the process of a tire change (got a little to aggressive and in to much of hurry trying to break the bead of the tire by driving my car onto a 2x6). I spun the wheel on the Yam with indicator doing its thing and SMACKED the rotor a couple times with a lead hammer and it trued right back to within a few thou - sort of like truing a crankshaft between V blocks.. Figured I bent it,, I'd bend it back... It worked BUT,, I am in no way endorsing such madness!!!

I highly suspect the best way to fix a bent rotor is to replace it..

[Condor]

@Condor, "I still can't figure out how a shop can warp a rotor by just changing a tire??"

 

That's an easy one. The 2nd Gen rotors are thin...about half the thickness (it seems) of a 1st Gen. That said, just dropping or resting the wheel on the rotor could and has bent the sucker a few thousands more than necessary. That's why so many pics of cycle wheels with rotors on are sitting on 2x4's or such. Any rotor can be damaged by weight pressed on it's side. They are very strong but not made to take sideways abuse of a heavy wheel and tire.

 

 

If the rotors were that delicate they'd be damaged all the time with the 10's of thousands of tires being changed. I can't remember ever seeing this subject mentioned on this board?? in the last ten years. And I'm sure there have been just a few dropped on, stood on, and other on's. And if it were that big of a problem I'm sure any dealer busting tires would know that, and handle them with kid gloves.... My 2¢

[Eck]

.......... I hope to be able to meet up with you some day. I'm not far from you and come to Huntsville a lot, so I will get in touch some day and meet up.

 

Edbo, Thank you for your post, but I do feel I owed you and others here a BIG apology for my choice of words. I do feel after re-reading them that they were out of line. I wasn't really mad / upset about sand paper on brake pads and my panties were not really in a wad.. ha... I was playing and it didn't come out right.

On another note though, changing the subject here, I would enjoy meeting up with you to have breakfast, lunch or just an anytime M&E with you. I will be out of pocket though until the end of May (Traveling). I look forward to meeting you.

 

Can you use sandpaper to get the wad out of ECK's panties? ;-) No need for that Mike, for I more than sanded my panties already..

Mike

 

........... Let's say the sandpaper didn't melt.

Just for clarity purposes only here Condor, I meant for my post to read as; the GLUE would melt that holds the sand to the paper... Not the actual sandpaper melting,

-Condor=I still can't figure out how a shop can warp a rotor by just changing a tire??

Me either......

Edited April 12, 2016 by Eck

[cowpuc]

-Condor=I still can't figure out how a shop can warp a rotor by just changing a tire??

Me either......[/Quote]

 

careless kids can cause countless catastrophies

[Venturing Sole]

On my 2006 RSV I changed the front rotors at 91,000 miles. When removed, the rotors were pretty severely "dished" compared to the new rotors which were flat. My 2000 Millennium RSV has about 45,000 miles and I'm noticing some "dishing" on those rotors also. Just changed tires and got to wondering...can one flip the rotors over to allow the "dish" effect to flatten out over time? If one were to flip the rotors each tire change, might that keep the rotors from "dishing"? kind of like rotating tires on cars to keep the tread wear even. I was not able to try it this time because one of the rotor bolts hex heads rounded off on me and I didn't have any spare rotor bolts, so I didn't attempt to drill out or cut the bolt head to get it off. The one rotor I was able to remove appeared to be symmetrical with no obvious "this side toward wheel" indication.

 

Looking forward to anyone's thoughts on this.

 

Thanks

 

David

[bongobobny]

Unless you rotate them from left side to right side they can't, or at least shouldn't, be flipped because of the direction the cooling fins point!! And, if you change them from left side to right side, the curve will then be pointing the opposite direction then as long as you keep the fins pointing in the same direction!! The outside will then become the inside!