Disc skimming in the North East

[djroadboy]

I have 4 288mm rotors that I need to get skimmed due to pitting and corrosion.

Anyone have any recommendations and prices too if possible.

Cheers

Dan

[walkem1]

I know revolution in Gateshead offer disc skimming they don't do it themselves as far as I'm aware so give them a ring see who they use.

[ttcool]

Be mindful of how much material is removed. A reduction in mass equates with less braking efficiency.

Joe

[rhinochopig]

ttcool said:

Be mindful of how much material is removed. A reduction in mass equates with less braking efficiency.

Joe

Can to explain why?

Surely the only thing reducing mass will do is effectively reduce the size of the heat-sink. Thus meaning the disc will heat up faster and bring on the onset of brake fade sooner. The braking efficiency will surely remain the same though up to the point where the temp exceeds the spec of the friction material.

I used to run specially skimmed and drilled discs on my westy which equated to a reduction in unsprung mass of about 3.5 kilos. A big advantage on a track car. It certainly didn't reduce the efficiency of the brakes. They heated quicker though.

[ttcool]

rhinochopig said:

ttcool said:

Be mindful of how much material is removed. A reduction in mass equates with less braking efficiency.

Joe

Can to explain why?

Surely the only thing reducing mass will do is effectively reduce the size of the heat-sink. Thus meaning the disc will heat up faster and bring on the onset of brake fade sooner. The braking efficiency will surely remain the same though up to the point where the temp exceeds the spec of the friction material.

I used to run specially skimmed and drilled discs on my westy which equated to a reduction in unsprung mass of about 3.5 kilos. A big advantage on a track car. It certainly didn't reduce the efficiency of the brakes. They heated quicker though.

Your first paragraph is what I was referring to. It depends how you define brake efficiency. It doesn’t matter when brake fade occurs it still gives the same result. If the discs heat up too quickly and brake fade kicks in sooner, then that is not good. By reducing disc mass too much the brake efficiency is adversely affected IMO. How can the brake efficiency remain the same when the components that make up the stopping power have been compromised? Brake fade surely means braking efficiency has been reduced. It doesn’t matter whether it occurs on the 1st lap or the 5th lap.

I’m not trying to make mischief here. I thought I was helping the original poster. He says his discs are corroded and pitted which suggests that maybe too much metal might be skimmed off. Usually 2mm less than the original thickness is the limit. You appear to have answered your own question, so far as I can see.

Reducing unsprung weight is good but not at the expense of acquiring the early onset of brake fade. The use of lighter alloy wheels for starters is a better way to reduce unsprung weight IMO. He doesn’t say whether he races or does track days so most of this might in fact not be so important.

Regards and no angst intended.

Joe

[rhinochopig]

ttcool said:

rhinochopig said:

ttcool said:

Be mindful of how much material is removed. A reduction in mass equates with less braking efficiency.

Joe

Can to explain why?

Surely the only thing reducing mass will do is effectively reduce the size of the heat-sink. Thus meaning the disc will heat up faster and bring on the onset of brake fade sooner. The braking efficiency will surely remain the same though up to the point where the temp exceeds the spec of the friction material.

I used to run specially skimmed and drilled discs on my westy which equated to a reduction in unsprung mass of about 3.5 kilos. A big advantage on a track car. It certainly didn't reduce the efficiency of the brakes. They heated quicker though.

Your first paragraph is what I was referring to. It depends how you define brake efficiency. It doesn’t matter when brake fade occurs it still gives the same result. If the discs heat up too quickly and brake fade kicks in sooner, then that is not good. By reducing disc mass too much the brake efficiency is adversely affected IMO. How can the brake efficiency remain the same when the components that make up the stopping power have been compromised? Brake fade surely means braking efficiency has been reduced. It doesn’t matter whether it occurs on the 1st lap or the 5th lap.

I’m not trying to make mischief here. I thought I was helping the original poster. He says his discs are corroded and pitted which suggests that maybe too much metal might be skimmed off. Usually 2mm less than the original thickness is the limit. You appear to have answered your own question, so far as I can see.

Reducing unsprung weight is good but not at the expense of acquiring the early onset of brake fade. The use of lighter alloy wheels for starters is a better way to reduce unsprung weight IMO. He doesn’t say whether he races or does track days so most of this might in fact not be so important.

Regards and no angst intended.

Joe

Just wanted to clarify what you meant with respect to reduced efficiency.

Most discs have a min thickness limit anyway so as long as he remains within that limit he should be fine - especially if they're for road use.

OP - there are lot of vendors that sell some pretty decent pattern parts that are often cheaper than getting the originals skimmed. For example I can get a set of Brembo pattern discs for my car cheaper than a skim - I've not used them but others that have rate them pretty highly.

[carlymart]

northern re-bore services in Newcastle used to do it used them lots (family relation)
http://www.northernrebore.co.uk/

looks like they still do on there site

[djroadboy]

ttcool said:

Be mindful of how much material is removed. A reduction in mass equates with less braking efficiency.

Joe

Thanks. I have a fair idea what I'm doing and there is plenty of meat on the rotors.

Cheers for that Carl. Will give them a shout. You still got your Elise?

Dan

[Gad-Westy]

Hi Dan. Hope all is well. Assume these are Elise discs? Just a word of warning. I tried getting some skimmed off the car a while ago and the run out on them was terrible. I'd look for a place that will do them on the car if I was doing it again. I've got a feeling F1 do it if you can't find anyone else.

[Deva Link]

I think many garages have the kit to do this - even the little place in our village does it.

There's an index (which isn't a complete listing) here: http://www.skimmydiscs.co.uk/Find%20a%20lathe2.htm...