Re-surfacing rotors?

[bkaushansky]

I'm looking for some help w/ re-surfacing a rotor. Minor imperfections, but since I just drilled it, might as well clean it up. The rotor is at 6.95mm, so there's plenty of metal left. I've heard that Blanchard grinding is the way to go, but can't locate anyone to do it in NJ (help if you know someone). Though about running 300 grit on a RO sander with very little pressure to surface clean the rotor.

Thanks.
b.

 

[pyrocentric]

Yes, I used a random orbital sander on mine, moving constantly. I can't remember what grit I used, probably started at 150, but 300 is safer. It's been on the bike for a while now, no shimmies.

 

[Rodguy1938]

Nice job

 

[XSLeo]

Why drill a slotted rotor?

 

[Travis]

^ probably just for the hell of it. or looks.

 

[gentlemanjim]

I'm looking for some help w/ re-surfacing a rotor. Minor imperfections, but since I just drilled it, might as well clean it up. The rotor is at 6.95mm, so there's plenty of metal left. I've heard that Blanchard grinding is the way to go, but can't locate anyone to do it in NJ (help if you know someone). Though about running 300 grit on a RO sander with very little pressure to surface clean the rotor.

Thanks.
b.

This guy did my Guzzi and XS - beautiful work. nolan.woodbury@vintagemotorcyclesonline.com

 

[bkaushansky]

XSLeo, I drilled a slotted rotor because there's a lot of surface area between the slots. While I know that slotted rotor will eat pad much quicker than drilled, they are more efficient at sweeping the full pad area. I also chamfered each of the holes to help reduce the potential for stress fractures.

Plus I thought it would look cool. I got anxious and hit the rotor last night with the RO sander w/ 220 grit. Smoothed out all the ridges and still remained flat or at least close enough based on my dial gauge. Still at 6.93mm.

b.

 

[5twins]

If you leave the holes sharp edged, the grooves and imperfections will eventually get polished out by the pads. I have totally smooth areas beginning to appear now on my mine after about 8K miles.

 

[Earz]

if you're like me, and don't have all the fancy tools to do this, there's a seller on eBay that offers this service. He offers cross drilling as well. I haven't used him yet, but plan on it in the future.

His eBay name is Smw70ss

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[yamaman]

Retiredgentleman made THIS tool to polish his rotors.

 

[retiredgentleman]

The drilled holes should not be chamfered. The sharp edge is what cleans the surface of the pads.

 

[jetero41]

I have always been under the impression that slots are designed to "clean" the pad surface while drilling is for cooling, helping toreduce brake fade and "reducing" warpage.
At least in automotive use.

 

[gggGary]

It's all about the looks!

 

[bkaushansky]

jerero41,

I right there with you. I come from the 4 wheel racing world. Slots clean, hole cool. Chamfering reduced chances of cracking at the holes. Either way, took a spin yesterday w/ the new rotor mounted. Immediately noticed better brakeing which could be attributed to new pads as well. Now I need to figure out how to dial out the massive nose diving.

 

[yamaman]

Interesting read HERE on the 2 slot or not debate

 

[XSLeo]

Nose diving, add oil to the forks. Remove the caps and springs, collapse the forks. Add oil to 6 inches down from the top of the tubes. This extra oil takes up some off the air space above the oil. This increases the air shock effect of the air. This reduces the brake dive.

 

[Earz]

Interesting read HERE on the 2 slot or not debate

Good read, but that is covering automobile rotors, which are very different than the rotors we're running. I don't know if the same principles apply.

Definately reduces unsprung weight, but there's got to be more to it for almost all M/C manufacturers to have a drilled and slotted rotor on almost every sportbike they produce.

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[XSLeo]

From what I have read the holes or slots should be sharp edged. As the pads wear the rotor the bits of metal lodge in the pads. This metal in the pads lessen the grip of the pads. The sharp edge of the holes shave this metal off the pads.
As far as cooling goes I don't think it matters which is used, slots or holes.
As the pads get hot they emit gases, these gases lift the pads from the rotors, the holes or slots let those gases escape.
The holes can cover the swept area of the rotor as well as slots.
I think I read something about the hole size vs the rotor thickness has an effect on performance, don't recall just what though.