Ducati Monster Forum

Moto Board => Tech => Topic started by: stopintime on August 24, 2009, 05:27:15 AM

Title: Need I worry about this scratch? Bought used rotors.
Post by: stopintime on August 24, 2009, 05:27:15 AM
I got these in today - there's a scratch - can't feel it when running a finger across, but a nail will.
There's nothing sticking up higher than the rotor surface.
Seller had them checked (don't know where or how) for straightness - I haven't double checked that info.

Need I worry?

(http://i329.photobucket.com/albums/l394/stopintime/skiver003.jpg)

(http://i329.photobucket.com/albums/l394/stopintime/skiver002.jpg)

(http://i329.photobucket.com/albums/l394/stopintime/skiver001.jpg)
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: Howie on August 24, 2009, 05:56:17 AM
I can't say anything decisive from the photo, but that rotor looks pretty beat up.  Besides the scratch, there is some nasty stuff around the holes.  As far as the rotor being straight, the only proper way to check on a floating rotor is to separate the blade from the carrier and check the blade on a surface plate.  I doubt this was done.  You might also want to take a micrometer to the rotor to check wear.  Minimum thickness is stamped on the rotor.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: stopintime on August 24, 2009, 06:47:56 AM
There's no detectable wear on the edges of the area where the pads grip, so I guess wear is not a problem.

If I don't have them checked (buttons off, on a surface plate) - is the second best method to try them on cautiously?

Would you buy new rotors if you saw this on your bike? (Assuming they perform well)
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: DrDesmo on August 24, 2009, 07:29:34 AM
Yikes.  I'd check the runout / deflection before you put those on ... Brakes are the one area of your bike not to pinch pennies on.

Cheers,
Adam
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: erkishhorde on August 24, 2009, 07:58:11 AM
I don't know much about brake disks but to check for warping can't you also put them on and then spin the wheel by hand to see if they wobble? Those chips around the holes are disconcerting to me and I'd probably replace them if I had the money for that reason alone.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: ducatiz on August 24, 2009, 08:07:20 AM
as long as they are not warped and the thickness is within spec, that scratch will not harm braking. 

the decrease in grab going over that area will be small.  the chips around the hole are not by themselves problematic as long as the surface is not raised.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: stopintime on August 24, 2009, 11:23:31 AM
According to the seller they're checked and OK'ed by The Frame Man http://www.motorcycleframeman.com/ (http://www.motorcycleframeman.com/)

Does that sound like it should allow me better sleep? (don't know how they check it though)

Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: ducatiz on August 24, 2009, 02:04:19 PM
double check it with them.. you should be fine.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: He Man on August 24, 2009, 04:00:43 PM
doubt it will make a difference. but you wont know till you clean them up, install them, and put a layer of brake material on them.

WHat id be more concerned about is, why did you buy them if u knew they were in that condition. you can find some pretty good conditioned used rotors out there.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: ducpainter on August 24, 2009, 04:07:11 PM
Those look like full floating iron rotors to me. I may be wrong.

I'll run 'em if you don't want to. ;D
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: ducatiz on August 24, 2009, 04:21:15 PM
Ducpainter is correct.

These are iron.  Make sure to get compatible pads.  Nice.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: stopintime on August 24, 2009, 06:40:37 PM
Quote from: He Man on August 24, 2009, 04:00:43 PM
doubt it will make a difference. but you wont know till you clean them up, install them, and put a layer of brake material on them.

WHat id be more concerned about is, why did you buy them if u knew they were in that condition. you can find some pretty good conditioned used rotors out there.

Bought from US - I didn't have the chance to see them first.
Seller says he didn't notice and didn't check very hard as they were ok'ed by The Frame Man.


IRON rotors? What make you guys think so?
They supposedly came off of a S2R 1000 and look exactly like in the pictures of it.
All I can read is "Min.th 3.6mm" and the offset seems to be ~5mm. On the back the buttons are the flower shape.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: ducpainter on August 24, 2009, 06:51:00 PM
Quote from: stopintime on August 24, 2009, 06:40:37 PM
Bought from US - I didn't have the chance to see them first.
Seller says he didn't notice and didn't check very hard as they were ok'ed by The Frame Man.


IRON rotors? What make you guys think so?
They supposedly came off of a S2R 1000 and look exactly like in the pictures of it.
All I can read is "Min.th 3.6mm" and the offset seems to be ~5mm. On the back the buttons are the flower shape.

The color and the surface appearance led me to believe they were.

Like I said I could be wrong.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: Speeddog on August 24, 2009, 07:49:52 PM
If they're iron, I'd think twice before running 'em with that scratch.
Stainless, I wouldn't worry much.

It *looks* like someone deburred the edges of the holes where the scratch is.
That helps a lot of it's been done.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: ducpainter on August 26, 2009, 01:31:04 PM
Quote from: Speeddog on August 24, 2009, 07:49:52 PM
If they're iron, I'd think twice before running 'em with that scratch.
Stainless, I wouldn't worry much.

<snip>
care to explain that?

I really don't understand why.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: Speeddog on August 27, 2009, 12:46:42 AM
Quote from: ducpainter on August 26, 2009, 01:31:04 PM
care to explain that?

I really don't understand why.

While ductile iron is good, it's a cast material.
Stress risers like deep scratches, I'm more concerned about them in a cast material.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: Norm on August 27, 2009, 06:56:51 AM
You shouldn't have any problems with cracking or breaking of Ductile rotors.
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: ducatiz on August 27, 2009, 07:40:46 AM

OP's rotors are prob not iron as they are stock.

The pics color balance made them look like iron
Title: Re: Need I worry about this scratch? Bought used rotors.
Post by: stopintime on August 27, 2009, 10:10:32 AM
Here's another picture, with flash, three days after washing them.

I will wet them overnight to see what happens.

It could have been nice/interesting if they were iron 8)

What makes me believe they are not iron:
   sold as steel stockers from a S2R 1000
   looks exactly like that   
   buttons have the flower shape washers on the inside = semi floating? (aren't all iron full floating?)
   traces of rust looks like on my own steel rotors
   (anything forgotten?)


(http://i329.photobucket.com/albums/l394/stopintime/rotors003.jpg)