So Neal Agran & I ran the new RR tire in the 4.5 hour, day into night enduro at Autobahn in Joliet IL. As enduro rules are free for tires, we've run many different tires at this track. Hoosier R6, Hankook Z214, BFG R1, and Toyo RA-1- we've run them all, though most were in 3 hour hour enduros. This one was 4.5 hours. Neal & I have hundreds of laps, and reams of data on this 3.5 mile track, this this same 944.
We were directly engaged in a battle for the lead most all of the way there, and ran these tires
hard for the full 4.5 hours - in the end, we won E3 by only about a minute. Adding in the warm up before the enduro, total race time was 10 minutes shy of 5 hours. As an aside, I think this is the first race win on the RR tire, anywhere .
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This tire had been promoted very hard, which I took with a healthy amount of skepticism, but I now can say it
is very impressive. Before I get into Neal & I's impressions, what I don't know, and is pretty critical, is how it tolerates heat cycles. I also won't know soon, as found out after the race that some debries on track damaged the tires. I can say, that it is very consistent, and tolerates being driven hard very well over a long time. On my stint (the second one), I turned my fastest race lap 4 hours, and 15 minutes in. I'll get into what the tires looked like after the enduro later. When we ran the Hankooks at this same track,by comparison, they were useless, bordering on undrivable by this time.
So onto Neal & I's impressions of the tire:
1. Of all the two groove R compound tires we've driven (Hankook, BFG, Hoosier), the RR's have the friendliest grip and release characteristics. Great communication - both feel, and just a little audible squeal at/over the limit. I went within one second as fast as I ever have on the other tires just 3 laps in bolting them onto my car with no setup changes, and two seconds quicker than I had ever gone on the RA-1. To get up to that speed that quickly speaks volumes on it drivability. I would say mission accomplished on this aspect. We're going to have a lot of fun on this tire. It is NOT fussy or tricky to drive fast like the R-888.
2. Having a slightly stiffer sidewall than either the RA-1, or the BFG R1 I had side-by side, I guessed (incorrectly, as it turned out), that less pressure would be needed to start. I started them at 28 lbs. While we didn't get tire temps checked, I did get more shoulder wear, than center wear, indicating that a bit more starting pressure would seem to be indicated. The next time, I will start them around there I do the RA-1: 30-31lbs.
3. I also guessed they need less camber, and again would say that seems incorrect on our cars. My wear patterns would indicate that we need at least the same camber as the RA-1's, though tire temp testing would be more definitive. They were certainly well behaved, and very fast at the camber settings I run (-3.5F, and -2.75R)
4. These tires have phenomenal lateral grip. My best estimate by Traqmate data is that these tires generate a full 1/10th more lateral G's (1.2 vs 1.1 in a standard corner). They were as fast as any tire we've run at this track, and they did not go away, at all, through the nearly 5 hours of running (in cooler/ideal track conditions). Oddly, both Neal I noted that braking grip was not much better than the RA-1 (and subjectively a bit less than the BFG R1). On their web site, Toyo does rate "braking" of the RR the same as the RA-1, while "handling", is one full point higher. See comparison
HERE.. In combination with the tremendous lateral grip, this makes trail braking a more subtle process. Instead of really leaning on the front tires to get the car to to turn in decisively, you just turn in at what seems like a ridiculous corner entry speed, with the nose lightly set with trail braking, if at all, and the car tracks on through without drama. One side effect of this, is that we may be harder on suspension equipment with this tire - check those A-arms, and ball joints!
6. After the nearly 5 hours of sprint level racing, the center of the tires had nearly 2/3nds left, and the tires still had two grooves in them, but the left front was showing a hint of cord at the shoulder. I believe a bit more pressure would have made that wear a bit more even, but not bad for a first effort, without set up changes. I like that Toyo has put tread depth markers across the tire, even by the center. Here's a picture of the tire, and the damage:
I ran over some car part in the dark a a little over 3 hours in, that left deep slices across all the tires, and peeled a chunk off of one. Glad I didn't know how bad this was, as I ran them this way for over an hour! It felt like a minor flat spot
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In summary, these are the best handling tires I've run on a 944, and suit our cars strengths very well. They are also a large set up in performance - about 1 second per 60 in lap times, so far. They were as fast at this track as any we've run at that track. if they can match the heat cycles of a 4/32nds RA-1, (about 16-18 before they cord in my [aggressive] hands) they will be an awesome tire for us. They will also work very well with no setup, or tire pressure changes. The stiffer sidewall seems to be well balanced by the extra lateral grip they provide. I am very pleased (and more than a little relieved!) to report that this seems like a very good tire for our class in my initial impression, and very different (more friendly handling), than other near-slick R-compound tires.
