I'm inspecting my brakes after my Homestead track day and noticing some grooves on my right front. About twice as much as on the left front. The pads are Hawk+ on RotorPros slotted rotors.

In the past, on my much smaller cars, SVT Focus and MR2, I have pretty much ignored the grooving and just put new pads on, etc.

When should you think about turning or replacing the rotors? Do you ever replace just one?

Right


Left

 

What do your pads look like? And why aren't you running a track pad on such a heavy car?

 

The pads have conformed to the grooves or the rotor to the pads, not sure I understand the question.

You are right about that, it is a heavy car but you hear all kinds of stories about this pad and that pad. A lot of guys like the HP+ for HPDE's and Auto-X. I thought I would give them a try. My plan was to stay in the Hawk line.

I am definitely going to a more aggressive pad after these though, I will probably try the Hawk Blacks next. Then you have your DTC series. There are really so many of them it's hard to decide.

Right now I am trying to decide whether to run the new pads on these rotors, turn the rotors, replace them or ?.

 

Grab a micrometer from a tool shop and look up what the factory limits are for front and rear brake rotors. Measure the rotors and if they are measuring below the limits, it's time for NEW rotors. If they are well within the factory limits, consider having them turned by a brake shop with a lathe.

You also might be able to rent a micrometer from Autozone or Advance Auto through their loaner tool program, but if you track the car often, you'll want to measure them similar to how you check pad depth before/after track events to make sure you have enough material left.

 

Just wondering if the pads were smooth and the rotors were grooved. Sounds like everything is groovy.

I would check the thickness of the rotor and if you have more than 50% remaining, get a real track pad like the HT-10. The HP Plus is a superb autox pad because it has great characteristics for braking at autox temperatures but it will not live forever on the track. Once it over heats, it's glazeville all the way to fadestown. Check LPIracing.com for the best Hawk prices I've seen plus free shipping. Run the HT-10's on there for a week of street driving and see if it doesn't "clean" your rotor races and get you smooth again. Then run them on the track and see if the rotor situation improves. If not, get a new set of blank rotors and try again with the HT-10. The HP Plus are ok for light cars and low-hp cars, not really what you have there.

Good luck and post back!

 

I have also been wondering about the bias. I have HPS's on the back. Of course there is a lot of pad left back there. The fronts still have 1/4 in, not sure they will stand a full track day but the backs definitely will.

What can I expect if I went with the HT-10's on the front and left the HPS's on the back? Some guys match up all four corners with the same pad and some don't for whatever reason. Any thoughts?

I do a lot of work on my cars myself but really hate thinking about what and how to do things. I really hate paying people to do things I can do myself. The thing is I would much rather just drive.

You go on those mustang forums and there are so many differing perspectives.

 

what track did you do I'm tryin to find a cheap way on to a track

 

welcome to going to the track... there is no such thing as cheap

 

It's a brake bias thing. On my Camaro the built-in rear bias, combined with soft springs (lots of weight transfer under braking) and less weight in the rear to begin with begs for much more braking capability up front than rear. If I run anywhere close to equal pads front and rear I can get MAJOR axle hop due to rears continually wanting to lock up and it is not easy to modulate. This may not happen to you (I know the rear is independent on your car) but it's worth keeping in mind. For daily driving I run HP+ up front and either stock or HPS in the rear...works well for autocross too, except that I feel the HPS are actually easier to modulate up front (the HP+'s tend to "stick" during hard braking). I would have gotten over 100k miles out of the original rear pads/rotors (including autox events) if I had never changed them, and the difference between front and rear rotor temps was over 400F last time I checked after a session.

I used HP+/HPS for my first track day but after that it was nice to have the capacity of a more dedicated pad, the last set I used was EBC YellowStuff front (HP+ rear), which worked great but they wear too quickly for a heavy car, the Bluestuff line would be better. Someone else will chime in on the Hawk HT series (I will probably try Carbotech XP8/10/12 next), but keep an eye on brake temps - temp-sensitive rotor paint or temp gun right after session, as extended high temps can damage calipers, melt boots etc. and cause more work for you.

 

I don't have any experience with axle hop but I understand your theory.

If you had bias control for the rear axle, you'd want to dial up max rear bias and work towards less bias vs. the other way around. So until you have too much rear brake, you don't really know that you have enough.

All theories generally point to you being able to run more bite in the rear due generally manufacturers setup more front bias for safety. Bluestreak, I would match all pads all the way around until you know that it doesn't work for you...you might be surprised that it solves your problem.