...what little sweet spot there is.

With the cold temperatures this weekend the "sweet spot" was more clear than ever. It took 2 laps at Putnam Park raceway to warm the tires up. After 3 laps they were gripping 100%. Bad news is that grip only lasted about 5 more laps. After that they start to overheat and basically melt.

Worse news is that every session out after that "sweet spot" gets smaller and smaller. Still took about 2~3 laps to get them warmed up but the window would decline from 5 to 4 laps and once overheated the grip would decline even faster than before. To the point where there was less grip than when they were cold.

I was talking to a club racer at the event and he mentioned that his experience shows that typically once a tire overheats it never really comes back for at least 24 hours. With what I witnessed this weekend, I agree. He even showed me the tell tale signs of tire overheating and pointed them out on my front tires.

So I guess the search is on for a tire that can stand the higher temps and provide a more consistent grip throughout a session. Any tips? I'm getting a new set of wheels for daily driving so I'm open to many options. Grip can be similar to the Advans, more or less, but as long as it can endure better and more consistently I'd be happy. Toyo's RA1's? A Kumho tire? One guy actually recommended having the Advans shaved and see what happens. Considering the prices of Advans I more than likely won't be using these again.

I also need a new solution to track pads. I killed a set of Ferodo 3000's (front only) in 3 days. Days where most of the time it was raining and I shouldn't have been that hard on them. I'm also still getting a slight pad transfer problem on the front even with the track pads, plenty of cool down time and Rotora slotted rotors. The braking on the Evo is becoming a very frustrating factor for me. Maybe it's the pads, but it just never feels "right". They seem inconsistent with bite and pedal feel is what I would describe as rough even before pad transfer and w/o ABS activation. I might have to start leaving a street pad on the rear and a track pad on the front. Maybe there's inconsistencies with pad operating temps.

I'm also condering looking into those cheap rotors offered on rockauto.com. They could be my new disposable track rotor solution.

Most of this is just a rant, but I'm open to comments and suggestions.

 

I abused a set of Toyo RA-1s at an autocross test and tune day, and they handled the heat really well. We're talking like 20 autocross runs back to back with maybe 60-90 seconds between runs. The tires were so hot that I needed gloves just to check the tire pressures, but the Toyos seemed to take it fine. The tires did "go off" a bit during the first session, but I'm sure that's because the front tire pressures rose up into the upper 50s. In later sessions, starting with an appropriate cold pressure, the tires were great.

That same autocross day prompted me to switch from the stock brake pads to Porterfield R4S pads -- the stock pads were definitely fading with the heat. The R4S pads should handle heat better, but frankly I don't really know because I haven't done anything since then to abuse the brakes...

 

What were the tell tale signs?

 

This is of course what I was told so I don't know what truth may lie in this. I can only go on the guys experience.

One point was how the outside edge tread blocks have turned into a tapered shape. Very low and worn at the leading edge and much higher at the trailing end of the block.

He also pointed out the melted looking texture of the tires in general. Especially in the hot zones like the outside edge. I don't know how to explain it, but it's not the normal smooth tread block surface that you're used to seeing.

After some looking around on more track related forums it seems the Toyo RA-1's may be my answer.

 

If they are back in stock, you may want to try the Dunlop Super Sport Race R compunds tires. They were a fair bit cheaper than the RA-1's (which I've never used btw), and at Putnam last fall, they heated up in about a lap and a half. VERY predictable at the limit - you'll have plenty of time to enjoy, then save a slide (over the crest going through 4 for example). I put 2 days worth of track miles on them and they still look great. My only complaint about them is that going into turn 1 I experienced some sidewall squirm a few times. Once I was ready for it though, it was no big deal. I did post up a not so great review on them last fall, but in retrospect unless you're looking to shave tenths and have money to burn, they are a very respectable tire for the money.

The texture of the tires you are speaking about is called graining. Usually it happens when the tire is overheated (left front, anyone?). What kind of lap times were you running that you killed a set of DS3000's? I used a set of DS 2500's enough to melt the tape weights and the tape over them completely off of both front wheels, and the pads are still on the cars and have plenty of meat left. Maybe I'm not braking late enough?

 

I was averaging 1'26" and had a best 1'25". Honestly I think my Rotora slotted front rotors killed my DS3000s. I got a full season out of a front set last year with OEM blank rotors. Luckily I finally found a vendor that will sell me blank rotors. Rotora rotors actually for $107/per. www.injectedperformance.com for those that want a cheaper solution for performance and not bling. Call them, it's not listed on their website. I'm also switching over Hawk Blues for the front and sticking with DS2500s in the rear. Hopefully the Hawk Blues will completely eradicate my pad transfer problem that is ruining my track days. I'll also start using designated rotors for the track so every rotor only meets one pad compound.

Tape weights? I'm not sure what that is.

It most certainly was the left tire overheating for sure. The right front a little too. When they start going they all start screaming in every turn, left or right. That's when I know just to call it quits and pit.

I think I'm going to end up with the RA-1s. I've heard nothing but good things from them. I'll have to wait for my Advans to wear out first though.

 

Hmm, looks like injected performance may be local to me, thanks for the link! I do get some pad transfer with the 2500's, but after a lap or so they come right around. Those are some good lap times on stock tires (and suspension?).

I had tape weights on my wheels for balancing and covered them with duct tape. The whole assembly melted right off of both front wheels. This year I'm using the hammer on weights. I never would have guessed the wheel and surrounding area would get hot enough to melt all that adhesive.

I've heard good things about the RA-1's, but they aren't a very good auto-x tire, so I figured I'd try the cheaper Dunlops. I haven't run an auto-x with them yet, so I don't know how they willl perform in those conditions. Hopefully the weather cooperates this sunday.

 

Yes, stock suspension. Right now, I don't see a need to go with an aftermarket suspension. At least as far as springs/shocks/bars go. I'm considering the Works rear pillow ball mounts and camber plates though.

 

Slotted rotors will completely destroy your pads. Stick with plain rotors.


Just be careful with the Hawk Blues: they generate this sticky, tenacious dust that is VERY corrosive. They will destroy the finish on your wheels. If you don't clean your wheels immediately they can corrode to the point that they become unsafe. I've had to toss out a set of BBS cross-spoke alloys wheels on my old BMW because of my Hawk Blues!

I would suggest you try Carbotech XP-8's or XP-9's. They work just as well as Hawk Blues but are non-corrosive. Easier to modulate, too.


RA-1's are great. They're not too sensitive about negative camber and they hold up VERY well for R-comps.

Emre