Q about OEM RE040s

[Leigh]

Did anyone that AutoXed these a lot notice a sharp drop-off in performance near the end of their life?

I was running terribly this last weekend - something like 6 seconds slower than I was the weekend before. Some of that I can account for the fact that I wasn't driving very well, but the last few runs yesterday I sincerely felt like there just wasn't anymore speed I could find without the car getting away from me - and that was still about 2-3 seconds down in comparison and on the exact same surface.

I've got about 10k on the tires, and something like 10-12 AutoXes, a practice day and a novice school on them(so probably around 100 runs?). Up until last weekend they'd been doing OK - though I have been noticing a moderate chunking problem since the end of March. I think this is partly due to the surface I run on most of the time... but its starting to concern me anyway.

The only other thing I can think of that might have caused it was that is was finally starting to resemble houston this weekend - so maybe it was the heat? It was in the low-mid 80s I think...

 

[DistantTea]

They might be a bit over heatcycled... if they start to chunk on you or you have ABS kicking on more than usual it might be a sign that they have given up the sticky ghost. If that was the first time its been nice and hot for a race on them you might have seen some pretty serious pressure creep during the day. What kind of pressures were they at when they started to unstick?

 

[Leigh]

ABS has kicked in a lot the last two weekends. I was just assuming I was braking harder though, but now that you mention it I kind of wonder...

Pressure wise it was pretty close to what I've been running(I've averaged about 46/36 I think) - Saturday they were about 46-48/36 and Sunday they were around the same for the front and I dropped the rear 1-2psi in an effort to get the back end around. Didn't do much to help though.

Grip fell off on run-by-run Saturday (my last run they just let go at the end and I went plowing through a wall of cones at the last corner) and just wasn't there at all Sunday, by the end of the day yesterday I was compensating a little by balancing the car differently, but it still felt... I guess sloppy is kind of a good word. I would take a corner and the turn-in would be slow and the car would push really bad. The tires seemed to be screaming at much slower speeds than usual - I was getting squeal no matter how easy I tried to take it.

 

[MSP Pro]

The stock Bridgestone RE040s will lose serious stick after the temperature goes over 80. The tire just heats up too much and gets very greasy. You can help cool the tires down by spraying them with water from a lawn sprayer between runs. This helps A LOT! And you can use the water sprayer to cool your intercooler and intake manifold between runs.

It also looks like you are running the front pressures pretty high. I ran street tire last year and set the pressures at 38 F / 35 R. The tires didn't roll over too much, but we have a smaller lot to run on (usually 30 to 50 seconds a run) and speeds are usually under 55 tops. I never had to shift up into third. If the car is pushing in the turns, you most likely came in too hot. This will also slow down your exit if the car is heeled over too far and the inside tire lifts too much. The LSD doesn't work very well if the inside tire gets too light. Try to get all your braking done in a straight line before the corner entry and then use the accelerator to balance the car through the turn, gently squeezing the throttle as you unwind the steering wheel as you exit. It's truly amazing how much time you can find this way.

Good luck and remember to get all the seat time you can!