Just installed Porterfield R4 pads and new StopTech rotors. After bedding them, I found the pad’s contact area on the rotor to look a bit odd to be. Could there have been anything wrong with the install to cause the pads to only use half the surface area as they should? I’d appreciate thoughts.

 

 

 

That is not normal at all. I also see aftermarket rotors. I don't think it's the pads however. Check the rotor surface with a dial gauge

 

 

Rotors look to be to small for the Caliper.

 

Likewise, 4 sets of pads are off? How many miles total do you have on those rotors/pads?
I also don't like the color patters. The slotting may be the cause of this based on how the edge of the slotting is. Are you sure that they were mounted correctly (left.right)?

 

 

Thanks for the input guys. I'll note that the R4 pads do not use clips if that has any effect on the wear pattern thus far. A contact at the shop believes that the wear will normalize and look the way it should with additional bedding because of the lack of clips.

They have about 50 miles of street driving since bedding. Performance has been great so far so long as you ignore the obnoxious noise.

 

For reference, here is the factory rear rotor (used with factory pads...untouched since delivery) after a few track days and ~6K miles.

What the likeliness of the caliper itself being faulty or damaged?

 

That looks like a 380 mm front rotor to me, not a 376 mm rear.

 

Yeah maybe...I just opened the top box of the stack for the picture.

 

The wear on that rotor also looks a bit dodgy, maybe there is something wrong with your calipers?
But it doesn't make sense that all four calipers would be dodgy, what do the OEM rear rotors look like?

 

Here are all 4.

 

The rears look OK and the only one that looks a bit dodgy is the top left one (a front), the same one you posted earlier.
All I can think is the new Porterfield R4 pads are somehow chamfered on the inner edges as opposed to the normal chamfering on the ends, and even then I understand the R4 pads are not chamfered on the ends at all (for more contact area), unlike the R4S.
I don't think anyone has picked up on the point that you said the new pads are R4 (track compound) not the R4S street pads everyone else is using.
Are you sure they are R4 and not R4S as I hadn't heard before of R4 for the F-Type?
The plot thickens!

 

Correct, they are not chamfered nor do they use clips. I am positive they are the R4, not the R4S.

 

Wrong assumption. The title said RACE PADS,that implies R4. I spoke with Porterfield a year ago and they said that they do not make R4 for the F-Type, only street pads R4S. Several months ago, Stuart from VAP said he can get R4 pads...
Without chamfering, it's even more odd the wear pattern as the new pad has a 100% contact surface vs. a chamfered pad with about 60%

 

The OEM and R4S front 380 mm pads (and for that matter every 380 mm pad I have ever seen) does not use clips on the ends of the pads like the rear 326 and 376 mm pads, instead they all have mounting/locating prongs/tangs on the backing plates. Do the R4 pads have those prongs? I can't really see how the front pads would hold properly in place without them.
The front 380 mm calipers have anti-rattle clips/springs on the outside while the rear 326 mm and 386 mm F-Type calipers do not, instead they have small anti-rattle clips on the ends of the pads.
But other Jag 326 mm and 376 mm rear calipers do have anti-rattle springs on the calipers and different pads without anti-rattle clips on the pads which is why you can't use F-Type rear pads on other Jags and vice versa.
Point is, without those prongs, springs and clips the pads might not sit right and maybe that is what is going on here?
A long shot I know but maybe worth checking.