When you say "Dunlop specific issue" are you only comparing them to the Cup2s?

I switched from my 20" factory Dunlops to 19" Bridgestone RE-71Rs and changed nothing else. I am running the same tire pressure range on the track as well.

I am getting the EXACT same wear pattern (middle worn like crazy, inside worn a little, outside hardly worn at all) on the Bridgestones as I did the Dunlops.

I'm not going to doubt your sources, but their driving surfaces and conditions must be different.
Above 35 PSI hot on both Dunlop and Bridgestone the tire gets greasy and moves around more than I'd like. At around low 30s hot both tires have max grip and feel great. I would never run those hot pressures on the track.

 

That's very disappointing - was hoping the Bridgestones were going to be the answer (waiting for OEM sizes).

 

From everything I have read on Rennlist the answer appears to be firmer springs as usctrojanGT3 is the only one I have seen with perfectly even treadwear on the Bridgestones so far.

I'll try to remember to take a pic of my front tire tonight.

 

Yesterday I ran 6 x 7 minute sessions at LLandow, it is a low speed 1.45 Km, track doing 48-50 secs per lap ? My Tyres are probably worse than yours, again it was the front left which was hammered, I just ran with standard Porsche recommended road use pressure. The wear rate was really alarming and was much worse than anyone else on the track, I did not notice any understeer, I was driving hard but not enough to tax myself or the car, as I was concerned about being safe as it was the first time taking the car out.

 

Does this mean you were using the factory recommended cold pressures on the track? This will result in very over-inflated tires when hot.

Or were you using the recommended cold pressures as your hot targets when on the track (this has a better chance of working and is hopefully what you meant).

 

Hi Grant
I was totally unprepared and lazy and just went straight on track without adjusting pressure, I thought 6 mins at a time from cold was acceptable on a slow track

Lesson Learnt

 

Ok, yeah the tires heat up pretty quickly and the pressure really can climb pretty high without bleeding some off. It's a lesson I've had to learn more than once

 

Hi Grant

Still had fun though.

It wasn't a race but nothing could catch me and I passed everything in front of me, so worth every penny of tyre wear.

I have a Porsche experience day due at Silverstone and a Track day at Castle Combe, So I will pestering everyone for Tips for the day soon.

 

I have tried the Cup 2's personally and found middle tread wear to be much less than the Dunlop and other GT4 on track had the Trofeo R and again middle tread wear is much less than the Dunlop. Maybe the other two tires hold up better than the Dunlop. I also found anything above 33 hot would not grip at all. The sweet spot hot is from 30-32.

 

I think everyone chunks the center blocks of the Dunlops because the hot pressures are too high. I sent my stock setup 2015 GT3 pressure and pyrometer readings from a track day at Laguna to Dunlop. One of the engineers and one of the race team drivers responded anonymously through their customer support rep. Consensus was to lower the hot tire pressures. I now run 30 - 30.5 front and 30.5 - 31 in the rears (previously 34-35). I have run 5 full days on track and there is probably another day left in them. So 6 track days is pretty darn good. A good lap for me at Laguna is 1:41 (with a big lift for sound) so I am certainly not as fast as Joe and Ben. I love the feel of the Dunlops on track so I plan on getting another set.

 

Getting faster, though! I like the feel of the Dunlops as well and prefer it to the cup2. The wear rate is the deal breaker. The center tread line wear is a problem on the cup2 as well, just not as bad as the Dunlop. I was definitely running higher pressures than you (34/36), so that may have been a factor. The conflicting info from manthey and Germany that tells us to run higher pressure than cup2 is what is confusing. Ben tried to run lower pressures to combat center tread wear this past Saturday, but it's still wearing unevenly and his lap time was more inconsistent (still got a 1:37, though).

 

Here is something Michelin put out on the Cup II you might find interesting.

Recommended pressures were higher than I expected for the track.

Hot
Front - 32
Rear - 36

 

That brochure is actually for the Sport Cup 1. Not 2.

 

What about weekend spirited drives through winding roads? My tire pressures hot are 34/36. should i lower them?

 

recommendations for MPSC2 tire pressures:


INFLATION PRESSURE ADVICES

On the track for majority of car (*)
Cold tires
• Inflate the MICHELIN Pilot Sport Cup2 with a pressure between 1.7 bar (24 psi) and 1.8 bar (26 psi) front & rear
• Never allow the pressure to be below 1.5 bar (22 psi)

Hot tires
• The optimal operating pressure of the MICHELIN Pilot Sport Cup2 must be between 2.3 bar (33 psi) and 2.5 bar (36 psi) Front & Rear
• Never allow the tyres to run below 2,0 bar (29 psi) HOT