Straighten Warped Front Rotor

[duanelr]

Hey hubbers,

 

Any of you guys know how to straighten / flatten warped disc brake rotors?

 

the best solution i could come up with was to place the disc under a heavy book

 

any help would hopefully save me the cost of buying a new one

 

fanx

[Tumbleweed]

[Slowbee]

duane, from a very short long term memory, I have heard, the best method involves a stove, a large pot and a few potatoes.

 

Put potatoes into pot, place rotor on the stove top (only time I think an electric one is advantageous), place pot (with potatoes inside) on top of rotor which is on the stove. Boil potatoes. When done, let cool, enjoy supper, enjoy new rotor.

 

Disclaimer: never tried this, use at your own madness.

[BogusOne]

or:

 

http://image.made-in-china.com/2f0j00qvWEioBhfIbw/Circular-Hole-European-Style-Electroplating-Adjustable-Spanner-HAP014-.jpg

 

 

http://cdn.mos.bikeradar.com/images/bikes-and-gear/components/disc-brake-systems/1250674506665-bffm9ryols6q-670-70.jpg

[Mojoman]

I have used the shifting spanner method (rotor had a slight bend) but you just need to go slowly and make small adjustments, spin the wheel, check the rotor and adjust again. Its pretty easy to bend that rotor with the shifting spanner! I should add - check the spanner for grease and oil before using!

Edited July 2, 2013 by Mojoman

[RockCoach]

duane, from a very short long term memory, I have heard, the best method involves a stove, a large pot and a few potatoes.

 

Put potatoes into pot, place rotor on the stove top (only time I think an electric one is advantageous), place pot (with potatoes inside) on top of rotor which is on the stove. Boil potatoes. When done, let cool, enjoy supper, enjoy new rotor.

 

Disclaimer: never tried this, use at your own madness.

 

My centrelock thingy melted when I tried this.

 

[clyde79]

The tool and the shifting spanner do work. You'll be surprised just how much you'll need to bend the rotor to correct it. With some patience you'll get it to a usable state but it will never be completely straight again.

[duanelr]

Thanks guys, will try the shifting spanner with a thin clean cloth between the spanner and rotor. If that doesn't work I'll put it on the stove (what could possibly go wrong)

[Slowbee]

My centrelock thingy melted when I tried this.

 

 

[RockCoach]

 

 

 

 

I'm not being serious. Just pointing out that it only works with 6 bolt rotors as they are flat. And then it doesn't work with Hope floating rotors either...

 

 

[Skylark]

I have had great success with tapping the rotor with a small copper hammer, very light taps - rather hit 5times and check after every tap or so than 1 big tap that knocks the bend into the other side. The way to do it really properly is to roughly find the bend out section on the rotor and take a big permanent marker and colour in the section and then spin the wheel - the bent section will have the marker taken off, lightly tap in those areas , redraw on the mark pen and repeat till happy it is straight.

 

I found using shifting spanners the tolerance wasn't close enough to grip the rotor with enough feel becuase there is some looseness/play inherent in shifting spanners, a dedicated disc truing spanner should be good though.

 

It will never be possible to get the disc 100% true so when the wheel spins nicely ie pads just skimming/barely touching the disc leave it. Even brand new discs are often not perfect and too much fiddling will put serious waves into the disc and that's when it will be tickets...

 

Clean the remains of the marker pen off the disc once it's all done, I didn't notice any braking issues or pad contamination after using this marker technique, I used a fat cheapie black marker from Checkers.

Edited July 2, 2013 by Skylark

[Vetseun]

or:

 

http://image.made-in-china.com/2f0j00qvWEioBhfIbw/Circular-Hole-European-Style-Electroplating-Adjustable-Spanner-HAP014-.jpg

 

 

http://cdn.mos.bikeradar.com/images/bikes-and-gear/components/disc-brake-systems/1250674506665-bffm9ryols6q-670-70.jpg

you took the words out of my mouth. Best rotor tool ever. I use mine .... often

[Captain Fastbastard Mayhem]

I have had great success with tapping the rotor with a small copper hammer, very light taps - rather hit 5times and check after every tap or so than 1 big tap that knocks the bend into the other side. The way to do it really properly is to roughly find the bend out section on the rotor and take a big permanent marker and colour in the section and then spin the wheel - the bent section will have the marker taken off, lightly tap in those areas , redraw on the mark pen and repeat till happy it is straight.

 

It will never be possible to get the disc 100% true so when the wheel spins nicely ie pads just skimming/barely touching the disc leave it. Even brand new discs are often not perfect and too much fiddling will put serious waves into the disc and that's when it will be tickets...

 

Clean the remains of the marker pen off the disc once it's all done, I didn't notice any braking issues or pad contamination after using this marker technique, I used a fat cheapie black marker from Checkers.

 

Nice, Skylark...

[Slowbee]

I'm not being serious. Just pointing out that it only works with 6 bolt rotors as they are flat. And then it doesn't work with Hope floating rotors either...

 

I hide myself in the disclaimer !

[Mojoman]

I have had great success with tapping the rotor with a small copper hammer, very light taps - rather hit 5times and check after every tap or so than 1 big tap that knocks the bend into the other side. The way to do it really properly is to roughly find the bend out section on the rotor and take a big permanent marker and colour in the section and then spin the wheel - the bent section will have the marker taken off, lightly tap in those areas , redraw on the mark pen and repeat till happy it is straight.

 

I found using shifting spanners the tolerance wasn't close enough to grip the rotor with enough feel becuase there is some looseness/play inherent in shifting spanners, a dedicated disc truing spanner should be good though.

 

It will never be possible to get the disc 100% true so when the wheel spins nicely ie pads just skimming/barely touching the disc leave it. Even brand new discs are often not perfect and too much fiddling will put serious waves into the disc and that's when it will be tickets...

 

Clean the remains of the marker pen off the disc once it's all done, I didn't notice any braking issues or pad contamination after using this marker technique, I used a fat cheapie black marker from Checkers.

I have used plain old chalk sticks before to mark the disc.

[davetapson]

You can also just push it in what ever direction it needs to go with a thumb.

 

Maybe my rotors have never been properly bent, but I've always managed to get them straight enough just by pushing.