Track Car Braking Woes

[axsaxoman]

Originally Posted by KamRacing

Can we see pictures of the pads please. Also maybe tell us how often your brake fluid has been changed and if the braking recovered afterwards..

The CL brake pads are formed by sintering the metal particles together. My understanding is that process bonds the pad together using pressure and heat rather than resins. Its one of the reasons these pads do not require a bedding in process with the disc. That pad material is brazed onto the backing plate as well.

I've been a CL Brakes dealer for a long time and really the only overheating issue we have seen is increased wear as the metals soften at high temperatures. The RC5 has been used on competition saxo's with standard discs and calipers without issue. You will be running cooler than they do, but most now use the RC6 as its more durable when extremely hot.

I don,t think its a pad/make /material problem --just front brakes being over worked due to set -up --every pad will melt if over heated-- thats why F1 use carbon discs etc -but 5k for front brakes is not the cure --get it set -up right

[KamRacing]

The fluid is usually the first to fail though so I think its that vs the pads. The CL Brakes compounds are rated to well beyond the fluid boil points and will cope with hard race use beyond what the Saxo should be getting to temperature wise.

[AndySAXOp]

Originally Posted by Chipwizards

Such as?

They gave me extremely bad brake judder I try three ds3000 pads with my ap cp5040 and every set gave me judder to the point I didn't feel safe. Also got uneven pad wear. Changed back to CL rc5+ and rc6 pads and been totally fine on the same disc. Then i did some research and seem common with the ds3000 pads to judder. Honestly didn't think much of them at all. This is just my experience. Never had any issues with CL pads on my setup.

[Chipwizards]

The only time I've had judder with DS3000+ was when I used them on discs previously used with other pads and the resin that had previously transferred 'clumped' and caused judder.

Besides that I've found them to be excellent. I have the lap record at every circuit I've raced at with the exception of Cadwell, so the performance is there.

My brakes run at typically around 750 degrees peak and I never get fade, ever. If the temps go much higher the wear rate increases greatly, but I've only had that once when the brake duct became dislodged and in a twenty-minute race one side wore 8mm more than the other. Still had no fade though.

[axsaxoman]

I have never seen brake judder caused by pad material
has always been warped discs and or calipers not swinging freely and or pads binding in carriers not allowing free movement to conform to slight run out of disc or fitment of disc to hub flange
race car pads certainly need to be a "rattling good fit "--cos things get hotter and clearances close up due to expansion of all parts
even seen calipers which were a tight fit under wheels --say 3-4mm clearance --when hot expand such that they touch the inside of the rim --everything grows as it gets warm different metals expand at different rates .eg alloy caliper and iron disc + iron pad backings

[KamRacing]

Originally Posted by Chipwizards

The only time I've had judder with DS3000+ was when I used them on discs previously used with other pads and the resin that had previously transferred 'clumped' and caused judder.

Besides that I've found them to be excellent. I have the lap record at every circuit I've raced at with the exception of Cadwell, so the performance is there.

My brakes run at typically around 750 degrees peak and I never get fade, ever. If the temps go much higher the wear rate increases greatly, but I've only had that once when the brake duct became dislodged and in a twenty-minute race one side wore 8mm more than the other. Still had no fade though.

If you can get them up to temperature they are very good.

[AndySAXOp]

Originally Posted by Chipwizards

The only time I've had judder with DS3000+ was when I used them on discs previously used with other pads and the resin that had previously transferred 'clumped' and caused judder.

Besides that I've found them to be excellent. I have the lap record at every circuit I've raced at with the exception of Cadwell, so the performance is there.

My brakes run at typically around 750 degrees peak and I never get fade, ever. If the temps go much higher the wear rate increases greatly, but I've only had that once when the brake duct became dislodged and in a twenty-minute race one side wore 8mm more than the other. Still had no fade though.

Like I said I was going from experience. The ds3000 where used on brand new rotors. And still use the same rotor now on the CL pads no problem with CL pads but 3 sets of ds3000 pads all had issues.

I wanted to use ds3000 as they are cheaper but just had issues so changed to CL pads. I knew cl pads after using them with hi spec billet 4. When I got AP brakes got ds3000 had issues so went back to cl pads.

It all comes down to personal preference. I had issues so will not go back to ds3000.

But after using ds3000, rc5+, rc6 the ds3000 and 5+ feel about the same in terms of stopping power. The rc6 feel a lot better for me, which is why I am goimg back to them for next year. It all comes down to testing only way you truly know what best for yourself I was just offering my opinion from experience.

[Chipwizards]

I'd like to understand how pads cause judder myself.

[welshpug]

by leaving deposits on the disc.

[AndySAXOp]

Originally Posted by Chipwizards

I'd like to understand how pads cause judder myself.

Well I only changed the pads and fixed my problem with judder. I changed after researching and reading many others with ds3000 seem to have this problem. I then went back to CL pads and haven't had the problem since. Again same rotors the whole time.

[Chipwizards]

I've been in and around racing my whole life and things that rotate cause judder, not static things. Judder is a reciprocal motion and can only be caused by another reciprocal motion or a rotational one.

As I already said, when changing types of pad material you can get judder because of resin clumping on the disc surface, but it's still the disc that causes the judder, it can't possibly be the pad because it doesn't move so it can't cause any other motion.

If your judder was with pads and NEW discs as you say, they must not have been true.

Every time you fit discs, without exception, you should get the DTI out and check they are true. In my book, entry fees are too expensive to risk throwing a race meeting away due to duff parts fitted. On top of that, if they are duff you can return unused parts for replacement, you can't replace used ones generally- not in the motorsport world you can't.

There are lots and lots of garbage brake parts manufacturers now, much of it made cheaply in China. I ONLY buy AP Racing, Alcon or Brembo when it comes to hardware; because I've had issues with everything else at one time or another. Most cheap aftermarket stuff is much worse than stock stuff.

[welshpug]

without those pads you wouldn't have had deposits on the braking surface.

so yeah, the pads caused the judder.

[Chipwizards]

I already said that in an earlier post, but he said he had fitted new discs each time with new pads, so his symptoms doesn't make any sense.

[Chipwizards]

And in any case it's still the uneven disc mu value/thickness that causes the judder, not the pad itself.

[AndySAXOp]

Originally Posted by Chipwizards

I already said that in an earlier post, but he said he had fitted new discs each time with new pads, so his symptoms doesn't make any sense.

Are you talking about me here? As I stated I have used the same rotors the whole time. Only changed the pads.

[Chipwizards]

Originally Posted by AndySAXO

Are you talking about me here? As I stated I have used the same rotors the whole time. Only changed the pads.


Like I said I was going from experience. The ds3000 where used on brand new rotors. And still use the same rotor now on the CL pads no problem with CL pads but 3 sets of ds3000 pads all had issues.

Sorry, my bad, I assumed you fitted new discs with pads when you changed the pad type, because that is what you really should do to avoid resin transfer problems.

So, to clarify, you had juddering brakes and DIDN'T change the discs and the juddering stopped with just a pad change?

If so, that is totally, utterly unbelievable. How a pad change could change the localised mu values of the disc form being uneven to being even, defies physics.

[axsaxoman]

we are back to what i suggested -
-calipers sticking or pads tight in carriers as things warm up -not allowing them to move free enough +causing judder

[AndySAXOp]

Originally Posted by Chipwizards

Sorry, my bad, I assumed you fitted new discs with pads when you changed the pad type, because that is what you really should do to avoid resin transfer problems.

So, to clarify, you had juddering brakes and DIDN'T change the discs and the juddering stopped with just a pad change?

If so, that is totally, utterly unbelievable. How a pad change could change the localised mu values of the disc form being uneven to being even, defies physics.

It fine you don't believe me but that what happened, as below it could be the pad tight, which is the pad issues and been badly made from manufacturers. So again I blame the pad. The pad size shape ect is the one recommend for my cp5040 and used the same shape ect CL pads without an issue.

If I could afford to change the rotors everytime I would but I don't have unlimited money. I am trying to have some fun and just do some form of motorsport which is a little more than track days.

Originally Posted by axsaxoman

we are back to what i suggested -
-calipers sticking or pads tight in carriers as things warm up -not allowing them to move free enough +causing

The ap are always cleanEd and checked after every race meeting. You could be right on the pads been too tight, So again I would then blame the pad. All I can say is I wouldn't use the ds3000 again on my setup and offering my advice on experience I had with them. I didn't want to get into these debates. I am not going to say I know everything I just going off my experience.

[KamRacing]

Two things. The CL Brakes are undersized to not stick in the caliper when hot. That does not mean it will solve a problem with the caliper itself

The other is as its sintered metal it does not transfer pad material to the disc surface. I've always pondered whether it could clean a disc surface of old pad deposits so Andy may well have experienced that situation.

[ESD1711]

Originally Posted by KamRacing

The other is as its sintered metal it does not transfer pad material to the disc surface.

Is it not pad deposit shown on my disc pic earlier in the thread though?