are rotors turnable? the bike shop says NO!?

[midnight1980]

The rear rotor is looking kind of groovy like man


http://www.youtube.com/watch?v=v-073rIldKs

and needs a shave..
my small town shop told me, a dude ,we here will not cut any bike rotors, because there not turnable? is this true. i thought there like car rotors that could be put on a lave and cut down some .

[MotoMartin]

I also was told that bike rotors are not turnable. I think the guy said it was because they are stainless steel not like car rotors.

[midnight1980]

MotoMartin
i think the shop is wrong check this website out..
http://www.framestraightsystem.com/BrakeRotor.htm
Brake Rotor and Break Drum Repair $10.00 to $80.00 ea.

[TomB]

I have a lathe at home and have turned my disc rotors up with no problems.

Use Tungsten Carbide tipped tools here

[Czekus21]

I've seen bike rotors, (XS) rust. I thought stainless was just that. Stainless.
I think that they are turnable. Anything's possible with the right $$$$$$$
Even if they're stainless, silver, platnum, gold, they were made, therfore, they can be altered.
In your manual, there should be a sentance in there saying what the max. run out is.

[Pat Kelly]

The hardness of the metal make turning them on a conventional brake lathe impossible. The bit will chatter and destroy the rotor.
They can be ground, much like a flywheel.
The problem is that the minimum thickness is so close to the original thickness that turning them would pass the min thickness.
Ford Aerostar front brake rotors are like this. By the time they need to be turned they need to be replaced.

[TomB]

The hardness of the metal make turning them on a conventional brake lathe impossible. The bit will chatter and destroy the rotor.

What is a ''Brake Lathe''?

Any steel, stainless or not, up to a hardness of 62 Rockwell-C (think drill bit), can be turned on a normal Toolroom lathe using tungsten carbide tools, the nearer to 62 the more difficult it gets but its possible.

XS Brake rotors, at a guess (from turning mine), would be about 50 Rockwell-C and present no problems turning.

The minimum thickness is a problem, I overcame this by only removing the high points of the rutted rotor leaving a smooth good looking rotor.


Tom, Toolmaker 26years.

[Douglas Money]

In reality we like our rotors to look really pretty when we are done. The only reason to turn rotors is to true them up. The grooves need not be removed, only the hills taken off. The elimination of pulsation is the real reason. Actually they should be ground with a rotor grinder, but since most don't have them and others don't know how to use them, they use a lathe.

[TADracer]

Dont know if they can be turned or not but remember, the rotors are a heat sink. Brakeing is nothing more than converting kinetic energy to heat and taking metal off diminishes a rotors heat sinking ability and may cause brake fading under hard stoping.

[TomB]

Taking metal off with a lathe tool or a brake pad its all the same.

The thickness of XS rotors is way above that of modern bikes so I think the heatsink difference will be negligible.

[prometheus578]

"To disagree, is to provoke thought, and maybe learn something new."

Most shops will not turn rotors. In the years that I've been playing this game, I can't think of anyone who's come in asking for that to be done.
That's not to say that I haven't seen many rotors that could have had a good smoothing...
The cost of the equipment is substantial.
No shop will invest the money... for something that will give them almost nothing in return.(to pay for the machine)
Now then... as fer good machine shops(not a bike shop) that have the means to do all sorts of great things..., yes, they can handle it.
But as was mentioned, the tolerances are so close as to what is stock and what is the minimum useable thickness, makes this enterprise a waste of time.
Switching to a harder brake pad compound will often, over time, grind the highspots back down a bit, provided you want to listen to the harder compound pads screech everytime you hit the brakes.
Yes, pulsation is an issue... but that is more due to warpage than grooves and such.
Our rotors are rather thick... and hardly warp(at least in my limited experience)
Doesn't take much warpage to make brakes pulsate. (what's happening is the rotor gets warped, and as you apply the brakes, when the warped area hits the pad, it trys to shift the caliper over to the side a bit, and caliper sdon't like to move much. that is the pulsating effect you feel.
I replaced, I think, about 10 rotors on Triumphs last year. The wear limit.. warpage standard, I believe was 0.032.
That really doesn't seem like much of a deviation from true... but when applying brakes... it makes for a really jerky stop.
Triumph's response was to make a thicker rotor, less prone to heating and warpage.

[Brian_D]

Seem to recall that Bob Jones at Merriam Cycle was offering to turn brake rotors. Of course it has been years since I was in his shop, and even then his prices were prohibitive.

[HobbyMan]

I don't see why someome with the right equipment couldn't take the high spots off the rotors. Every time I put on new pads I take some light sand paper to the rotors. That way the new pads effectively take the high spots down. I am going to watch Easy Rider now. What a classic movie!

[prometheus578]

easy rider.

Phil Spector's body guard reminds me of "Snapping Turtle Turk" from "Yellow Submarine".
As I say to my sons when going on trips,
"If we're going... we're going, let's go!"
"I'm sort of a freak myself," (Karen Black)
"Neyt, neyt neyt... Indians." (George)

"Owhh.. my head hurts."
"You keep that up, you ain't gonna have a head, Man!" (Billy)
"It's not every man that can do his own thing in his own time." (Wyatt)

Why do I even know this stuff?
There's something wrong here.

[81xsproject]

check out this thread

http://www.xs11.com/forum/showthread...turning+rotors