Pad Rotor Problem AP Disks

[Model Citizen]

Originally Posted by JRitt

Guys...sorry I didn't have time to write a full response earlier. Here's the scoop:
The issue is the J Hook discs, and what you’re seeing is normal. If you look at that pic above, every concentric ring being worn on the disc is at the end of a J Hook. The spent pad debris collects in the J Hook, and then exits the J Hook at its termination and causes the grooves. Other than a cosmetic issue, there shouldn’t be any performance issues. This happens more when the brakes are cold, since they’re working in an abrasive mode…they’re scraping the discs rather than sticking to them. When you heat pads up on the track, they’re scraping AND sticking to the discs (and you get a pad transfer layer). You will find that some pads do this more than others because some pads have more material break loose from the pads, or the material that breaks away from the pad is more abrasive than materials from other pads. To anyone who does not know what is happening, I can definitely see how this would be a concern, and I probably need to get something up on our website about it. Again, this is normal and nothing to be alarmed about though.

If you don’t like the grooves or are worried about them, we sell a plain-face version of the exact same disc, and they are $155 per disc.

Right hand side= part# 19 01 720
Left hand side= part# 19 01 721

Finally, J Hook slots can cause a little more whirring and scraping noises, similar to drilled discs because there are more leading edges for the pad to catch on.

i may be retard

but it isn't showing up on the site when i look

[Pat]

Interesting, thanks for sharing, Jeff. I expect I'll be getting the Sprint kit a year from now. The grooves do concern me, as I'll be running separate street and track pads. I expect HPS and DTC-60, but am open to hearing others' experiences. I would prefer to stay with Hawk as I get them at a discount.
If someone is using multiple sets of pads, wouldn't it make sense to want to minimize the grooves and go with plain rotors? I am not racing, just HPDE 4 and maybe TT down the road.

[post_break]

Hopefully the blanks stop reverse clunk, and the "cricket" sounds you get when driving with the windows down.

[acro]

If someone gets the plain rotors it would be nice if they could give a comparison between the two

[Fizz]

Originally Posted by Dezoris

But this season going to start with new rotors and street pads and see how they hold up.

I'm keen to see how you go with the new rotors and street pads, and whether you've managed to get rid of the squealing brakes. I'd love to get my hands of the Essex kit but I worry about the noise

[dradernh]

Originally Posted by Pat

If someone is using multiple sets of pads, wouldn't it make sense to want to minimize the grooves and go with plain rotors? I am not racing, just HPDE 4 and maybe TT down the road.

Plain rotors will work just fine for you. Another option, which you've probably already considered, is to buy two sets of rotors and hats; that way, you get to skip the re-bedding process when switching pads.

[Dezoris]

@JRitt

Thanks for the response Jeff, I think a majority of our issue has been temperature. We need to absolutely run the mildest pad on the street because like this week Saturday was 75 and today its 34 with flurries.

Last season we swapped around pads trying to find a middle ground and nothing would maintain a transfer layer for more than a few days which is probably why our disks were so bad they were always scraping.

The Hawk HPS you sent suck, fade out after 6 stops but honestly that's exactly what we need for the street because they heat up super fast and always keep a good transfer layer, so that seems to be a good option for those running this kit in colder settings who don't want to constantly re-bed.

[Dezoris]

Originally Posted by CSG Mike

I want my bling

I agree if you are running this kit, the Jhook makes much more sense for performance reasons. But I should not comment until someone tries the flat face disks and see how they compare.

[Dave-ROR]

Originally Posted by Dezoris

I agree if you are running this kit, the Jhook makes much more sense for performance reasons. But I should not comment until someone tries the flat face disks and see how they compare.

Since my BRZed is mostly a street car now I'm very tempted.. however I also rarely ever drive the stupid thing anymore...

[CSG Mike]

I think we can test a set of plain rotors... although I suspect we'll be sticking to J-hooks for our car.

[Dave-ROR]

Originally Posted by CSG Mike

I think we can test a set of plain rotors... although I suspect we'll be sticking to J-hooks for our car.

If I keep the BRZ I'd just bite the bullet and buy another set of hats if the plain discs eliminated the squeal. I don't even know why I care, it doesn't bother me, I'm just sick of "hey, get your brakes checked" comments all the time lol

[Hanakuso]

Originally Posted by post_break

Hopefully the blanks stop reverse clunk, and the "cricket" sounds you get when driving with the windows down.

I'm guessing the cricket sounds will go away but not the reverse clunk. I think the reverse clunk comes from the brake pads having some movement going back and forth.

[ZDan]

Originally Posted by Pat

Interesting, thanks for sharing, Jeff. I expect I'll be getting the Sprint kit a year from now. The grooves do concern me, as I'll be running separate street and track pads. I expect HPS and DTC-60, but am open to hearing others' experiences. I would prefer to stay with Hawk as I get them at a discount.
If someone is using multiple sets of pads, wouldn't it make sense to want to minimize the grooves and go with plain rotors? I am not racing, just HPDE 4 and maybe TT down the road.

HPS are by far the worst pads I've ever experienced. FAR inferior to OEM (S2k) pads. Soft pedal feel (i actually re-bled the brakes as it felt like air in the line), poor bite, and immediately faded at the merest hint of action. Centric PosiQuiet are much better street pads in every way.
HP+, on the other hand, I've gotten very good performance out of them at the track on the s2k despite them not being serious track pads, but they dust and squeal like mad on the street...

For the street, I wouldn't be looking at Hawk pads.

[ZDan]

For a street/track car, I prefer blank rotors over slotted/j-hooked/whatever. Plain gives longer pad life and there are enough pad compounds out there to find something that gives desired bite characteristics without requiring pad-shaving cuts in the rotors. Not finding the PO/builder-installed slotted rotors to give me any particular advantages on the FD vs. same xp10 compound with plain rotors on the z, will replace them with plain when the time comes.