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305/650/18 on 18x11" wheel fits the S197 very well front and rear
These
Rolex series Continentals are measured like real racing slicks and are very different tires than the
CTSCC Series Contis that are measured like passenger tires, which are very similar to a DOT Hoosier R6. The DOT type tires have a LOT more steel belts in them and tend to weigh a good bit more. The real racing slicks tend to have
the spring rate of the tire measured and marked on each carcass.
The same 305/650/18 on an 11" wide wheel (at left) is much more square than when on 10" wheel (at right)
We really don't know much about these Rolex Contis yet. What we have are the "GT-O" compound/series tires, which I have been told were made for the high banks of Daytona and are different both structurally and in compound from the GT-R and other versions that are used on Rolex DP cars. Technically our Mustang is heavier than these tires are designed for, but we don't make a fraction of the downforce of a DP car so it likely all evens out.
These 305 and 320 Contis were such a good deal it was hard to NOT buy them, and we've sold a couple of sets and so far everyone has been happy with them. I wanted to see how they'd fare head-to-head against the A6s, so we mounted a set of 320s to one of our 18x12" Forgestar sets and left some well worn 315 Hoosier A6s on the other set and brought them with us to the track that day.
Amy and I got to ECR at 9:30 am that Saturday right as the film crew guys arrived. As we unloaded the Mustang, Brandon showed up, then Olof and his buddy Steve arrived. Sofi rolled up in her truck towing a trailer with two of her motorcycles, too. So we had a big Vorshlag contingent early on.
We also had some of our testers/customers join us, so we could do some shock testing and car set-up work with them. Mike, Jan and Shannon brought one of their Mustangs and a Miata we had some new prototype Bilstein Motorsports shocks on. This racer family has 5 track cars between them, and we see them at tons of track events every year.
The day started off a little cool (46°F) but quickly warmed into the high 50s then low 60s, with the sun shining bright. I went out at about 10:30 am on the Contis and tried to get them up to temperature, to see how they felt and hopefully get in some lap times. After about 4 hot laps they just were not working, so I came into the hot pits and Olof took tire temps and bled the tires down (We tried from 30-38 psi, with little luck). The hottest we saw the tires get to was 109-110°F, which is not nearly enough heat. So I went back out and tried another 5 laps, grip was terrible, and I couldn't barely run a 2:00 lap. Came in hot and again, still around 110°F on the touch probe pyrometer for the tires. WTF? The A6s would be
boiling after a run like that.
I guess the only conclusion we can say is they don't work in 60 degree temperatures with only a handful of laps. It is an endurance tire, but we didn't think they were
that hard. I was driving on these like a wild man, trying to scrub them in and build some tire heat, but the Contis just laughed at my attempts at hoonage and stayed dead cold. I was not at all happy with the performance of the Continental GT slicks and could not wait to get them off the car. We punted on the remainder of the test, but I vowed to try them again in the warmer months - maybe then we can get them warm enough to work? The
March 29-30 TrackGuys event at TWS is likely where they will get used again. There was zero visible tire wear on the Contis, as you would expect.
Hoosiers On + Filming for the Show
So while Olof and I swapped over to the Hoosier A6 scrubs we brought, the rest of our big group was out tracking their cars or motorcycles; they run the bikes and cars in different run groups every 30 minutes on these Member Days. Mike was pounding miles on the prototype Miata Bilsteins, Jan and Shannon were both having a blast on the MCS equipped Mustang, and Sofi was running both of her bikes.
Left: Olof and Steve assisted with a coolant leak on Mike's Miata. Right: Our Ops Mgr Sofi had fun running her 2 bikes on track
Amy ran a couple of sessions on the Hoosiers, giving rides to folks and ran some 1:59 laps. I then took over and ran a couple of sessions, failing to get a single clear lap. It was a member day so there weren't a
lot of cars out there, but there were enough to clog up any given lap, all while we were out there with two cars and a camera car trying to get footage (that ended up being really tough to do). With everything from full on race cars (nearby Pinnacle Motorsports had a few cars out there testing) to very clearly street cars on the track, and lap times from sub 2 minute to 2:30s and beyond, it was impossible to get a single clear lap. But it was fun anyway, and they likely got
some footage to use.
We tried some lead-follow stuff where we were supposed to change places (Corvette street car vs Mustang race car) and not lose the camera car, but that didn't work out so well. We needed a much faster camera car. And both of us wanted to occupy the same space on track and both cars had similar acceleration rates, so needless to say there was more than one off that day, heh. Mine was pretty good and I stuffed it off the entry to Turn 6, pretty hard, and dug a trench about 70" wide in the soft dirt. Tore up the splitter mounts and dislodged the lower bumper cover, which kept Olof busy for a bit doing some hasty track-side repairs. He got it put back together well enough that you wouldn't know it was borked know unless you crawled underneath.
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