a bit of brake judder advice required
Discussion
Hello
I am currently using a Renault Twingo RS for track days.
It is a great car for this, however I am going through pads and discs at an alarming rate. So far in 6 track days and 1000 track miles I am on my 4th set of discs and 3rd set of pads.
Discs - used slotted ebc and green stuff. Lasted less than 200 miles, the discs warped massively and the slots acted like a cheese grater and sliced the pads to 1mm.
Since then I have used, OE discs, and OE pads, Mintex Discs and OE pads and Mtec discs and OE pads. All result in the same significant judder under hard braking after a days hard lappery. My most recent set of pads have done 300 track miles and are 50% worn which I don't think is too bad. But the discs/pads on the car are undrivable at race speeds.
So I am assuming that the soft pad compound is transferring material to the discs to make them warp. But I might be wrong.
Would a race pad like a ds2500 Ferodo limit this effect?
Should I get my existing discs skimmed/skimmed to the hub?
Anything else you can think off that will reduce that amount of braking parts I am currently using.
I would like to think that a skimmed disc would allow me to use a Ferodo pad for 4-5 track days, with the pads maybe lasting 2-3. Or am I dreaming?
tia.
I am currently using a Renault Twingo RS for track days.
It is a great car for this, however I am going through pads and discs at an alarming rate. So far in 6 track days and 1000 track miles I am on my 4th set of discs and 3rd set of pads.
Discs - used slotted ebc and green stuff. Lasted less than 200 miles, the discs warped massively and the slots acted like a cheese grater and sliced the pads to 1mm.
Since then I have used, OE discs, and OE pads, Mintex Discs and OE pads and Mtec discs and OE pads. All result in the same significant judder under hard braking after a days hard lappery. My most recent set of pads have done 300 track miles and are 50% worn which I don't think is too bad. But the discs/pads on the car are undrivable at race speeds.
So I am assuming that the soft pad compound is transferring material to the discs to make them warp. But I might be wrong.
Would a race pad like a ds2500 Ferodo limit this effect?
Should I get my existing discs skimmed/skimmed to the hub?
Anything else you can think off that will reduce that amount of braking parts I am currently using.
I would like to think that a skimmed disc would allow me to use a Ferodo pad for 4-5 track days, with the pads maybe lasting 2-3. Or am I dreaming?
tia.
Edited by Dynion Araf Uchaf on Wednesday 15th January 07:54
Use plain discs if at all possible. They're cheaper, less liable to fatigue failure due to heat stress and reduce the pad wear compared to slotted discs.
You need to choose pads that are suitable for the temperature range your brakes are reaching. You can find that by trial and error or be measuring the disc temperature immediately after a session.
If you can find a way to duct cold air to the brakes, that will reduce the peak temperatures significantly. I don't know what is practical on that vehicle but options you could consider are a simple deflector plate clamped to the front wishbone, or a flex duct anchored in place with zip ties.
You need to choose pads that are suitable for the temperature range your brakes are reaching. You can find that by trial and error or be measuring the disc temperature immediately after a session.
If you can find a way to duct cold air to the brakes, that will reduce the peak temperatures significantly. I don't know what is practical on that vehicle but options you could consider are a simple deflector plate clamped to the front wishbone, or a flex duct anchored in place with zip ties.
OK, a few random comments on issues/points/questions that you raise on my 3 x TD cars.
Slotted discs are fine as are "dimpled" which are only part drilled through rather than fully drilled but avoid fully drilled. Be completely fastidious when changing pads/discs & make sure the hub/disc interface is perfectly clean & the caliper sliders are 100% free & working correctly.
Having said that some manufacturers do it better than others. Mtec discs and EBC pads are cr@p IMHO, and OE/standard pads are not ever going to last on track. I would get 1/2 to 1 TD out of OE/standard/EBC pads.
One manufacturer that I have used many times is Evora (not the lotus car) and they are fairly readily available & cheap on ebay.
As above additional cooling is VERY beneficial. Not sure about discs on your car, are they vented? If not then cooling is going to be even more critical. I just used fog light apertures in the bumper & some flexible ducting to create some additional air to the area of the discs/calipers.
Ferodo DS 2500 are not race pads, they are little better than EBC yellows & they are truly sh!t.
You will be driven (pun not intended) wholly by what is available for your car but some good ones to look out for are:
Ferodo DS UNO
Ferodo DS 1.11
Pagid RS29
Pagid RS19
Slotted discs are fine as are "dimpled" which are only part drilled through rather than fully drilled but avoid fully drilled. Be completely fastidious when changing pads/discs & make sure the hub/disc interface is perfectly clean & the caliper sliders are 100% free & working correctly.
Having said that some manufacturers do it better than others. Mtec discs and EBC pads are cr@p IMHO, and OE/standard pads are not ever going to last on track. I would get 1/2 to 1 TD out of OE/standard/EBC pads.
One manufacturer that I have used many times is Evora (not the lotus car) and they are fairly readily available & cheap on ebay.
As above additional cooling is VERY beneficial. Not sure about discs on your car, are they vented? If not then cooling is going to be even more critical. I just used fog light apertures in the bumper & some flexible ducting to create some additional air to the area of the discs/calipers.
Ferodo DS 2500 are not race pads, they are little better than EBC yellows & they are truly sh!t.
You will be driven (pun not intended) wholly by what is available for your car but some good ones to look out for are:
Ferodo DS UNO
Ferodo DS 1.11
Pagid RS29
Pagid RS19
there are few pad options available beyond green stuff ebc and OE or OE equivalent. ferodo are the only other option, I've used them before on the race car and I thought they were ok. They may be ok on lighter cars.
Discs are vented, I could maybe look at some cooling, but I might try in the first instance a home attempt at skimming the disc.
Discs are vented, I could maybe look at some cooling, but I might try in the first instance a home attempt at skimming the disc.
I'd look at banging lots of new standard discs on for what they cost. Remove the disc backing plates, duct some cooling to the discs and then treat the discs as disposoble item.
Put the best pads you can on. Fit good brake fluid.
I would have though that spending 2or 3 times the price on discs wont get you 2 or 3 times the life, whereas standard ones you can afford to swap more regularly imho.
Put the best pads you can on. Fit good brake fluid.
I would have though that spending 2or 3 times the price on discs wont get you 2 or 3 times the life, whereas standard ones you can afford to swap more regularly imho.
the car doesn't have any backing plates. At the moment the issue is using standard pads, they are too soft and transfer material onto the discs. Carbon Lorraine do a pad for the Twingo but they are £200, which is the cost of 5 pairs of discs. And I suspect may stop warping but may not last longer enough to justify the price.
I am inclined to continue with the standard set up and the current upgraded brake fluid, I don't get any fade. But I have purchased a wire wheel to grind the imperfections off my old discs as they are still up around 24mm thickness, if it works then I may be able to recycle my collection of discs for sometime. I'll know in a month or so.
I am inclined to continue with the standard set up and the current upgraded brake fluid, I don't get any fade. But I have purchased a wire wheel to grind the imperfections off my old discs as they are still up around 24mm thickness, if it works then I may be able to recycle my collection of discs for sometime. I'll know in a month or so.
Edited by Dynion Araf Uchaf on Wednesday 15th January 07:55
Dynion,
You have correctly diagnsed your problem - standard pads are too low temperature for track use.
You have tried Mintex - what grade of brake material? LIke all manuafacturers, they offer a range of temperature materials, from 1144 (road), 1155 (fast road/track day/race) to 1166 whihc is a full race material. I've been very happy with 1155, which stops adequately wh cold and, with vented discs has abolished the fade i used to suffer.
So try to find 1155/66 pads, and se if you can fit vented discs!
John
You have correctly diagnsed your problem - standard pads are too low temperature for track use.
You have tried Mintex - what grade of brake material? LIke all manuafacturers, they offer a range of temperature materials, from 1144 (road), 1155 (fast road/track day/race) to 1166 whihc is a full race material. I've been very happy with 1155, which stops adequately wh cold and, with vented discs has abolished the fade i used to suffer.
So try to find 1155/66 pads, and se if you can fit vented discs!
John
update, have purchased some new mintex discs and CL rc5 pads. Initial use whilst bedding them in yesterday on the road is comical. Sooooo, much more stopping power, maybe 50%. ABS much easier to trigger, Was not expecting that!
Looks like pad is not sitting right in the calliper as only about 50% of the disc face appears to be be used. Will be interesting to see how it goes on track
Looks like pad is not sitting right in the calliper as only about 50% of the disc face appears to be be used. Will be interesting to see how it goes on track
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