R-comps and ambient temps

Inspired by the direction of the what-class-for-Miata thread...

After the better part of a decade nursing castoff A008Rs on my FSP 2002, a year or so ago I finally got to run my newly-built SM E30 on a set of Victoracers. When the weather was warm, it was a great combination.

However, even in Summer in temperate Oregon, if I wound up in the morning run group, it seemed like I'd be ice skating. I played with tire pressures. I picked up a tire pyrometer (a Longacre with the probe, not an IR unit). I don't have my notes handy, but if it was 50 degrees out, it just seems like there wasn't much I could do to get the tires working.

If it's 50 degrees out, would a performance street tire be faster than an under-temp R-comp? I've never driven a modern "ultra high performance" street tire.

In retrospect, I should've driven the few miles to the event on the Victoracers, as the minor thaw of five freeway miles might've made all the difference as compared to having them in the trunk all night (I'm not a morning person, and try to pack everything up while I'm conscious) and mounting them at the venue.

Or is this where a not-just-R-comp, but autocross-specific tire like a Hoosier A-series makes the difference?

At least I think I have my brother in law talked into coming out when I get another car put together, so perhaps having a tire-warmer will help

You aren't crazy. All tires have a happy point--street oriented tires tend to have a lower happy point than R-compounds. I've found that R-comps really aren't happy under 60 degrees ambient---and Street tires tend to index better overall when it's in the 40s or 50s.

tire warmers are VERY important for cold temps.

Per Schroeder wrote: tire warmers are *VERY* important for cold temps.

Are tire warmers legal? Um, I guess I should pick a sanctioning body; let's say SCCA, though I'm curious about who does or doesn't allow them.

I've even noticed that what appears to be a minor switch from Victorracers to V710s makes a noticeable difference in cold temps. Where I could not get the V700's to work much, the 710's started to work a lot earlier.

And this was for events were we run hot laps.

It also sort of highlights that super wide tires may not work perfectly, too. if you can't get heat, they may be pointless.

I meant tirewarmers in the co-driver perspective---tire warmers (the devices) are not legal in SCCA Solo.

In reply to Per Schroeder:

Oops! Right, like in the last line of my own initial post. Where's my coffee?

when I was SM-ing my E30 on Nitto NT01's, I tried to do a big inappropriate burnout leaving the line. Many times the timing lights aren't even within 30-40 feet of the start so I don't think it cost me much time. And it did help, at least I didn't wind up backwards anyway.

Co-driver tire warmers are definatly the way to go. Early this season autocrossing on Hankook C71s on my Miata I won my class more than once when the weather was cold. My daughter co-driving helped warm the tires and the tires didn't have enough time inbetween runs to cool off. Others in my class were single drivers cars, one with Hoosiers on a Solstice and another Miata on Azenis (later Star Specs) had problems hooking up while I had no problems and was a couple seconds ahead of them. On times my daughter couldn't make it I struggled just like them. Now that it's warmer the guy with the Solstice w/Hoosiers beats me and I come in second.

Well, what do you think the term "cold tires" means, exactly?

One "fancy dismount" off into the scenery in a cloud of dust and a hearty "oh, the tires must be cold" will ingrain the fact into you mind forever. I started that.

I don't think that street tires will be outright faster than R-comps even at low temps, but they'll feel easier to drive.

I've driven on A6s in 30-40 degree situations, and I felt as if I was ice skating for the first few runs, but I'd still rather have them (at least on my heavy ESP/SM cars) than street tires.

In reply to Will:

Aren't A6s a sort of special case? In that they're really autocross-specific, and designed to operate at lower temps than the autocross/track-day/race tires like the Victoracers and so forth?

IIRC, I've read that there are people who start spraying their A6s down at 110F, whereas the ideal working temp of a Victoracer V710 starts at 180F...

Of course, given that you can spray them when it's warm out and have half a chance of a reasonable operating tempt when it isn't, perhaps by "special case" I really mean "better for autocross"...

I can never keep this straight - V700s are road race, V710s autocross? I have a really old used set of the V70s (road race) for my autox tires, and I learned about ambient temps in a big way the first event of 2011. It was earlier in the year than usual and maybe 50f out. I could not get the power down at all* and even surprised myself with a 360 groundloop through a simple offset following a relatively open 90. On the way home I wondered if I shoulda driven down on the Vs or even run on the street tires, too. The next event, which was a month later and 20 degrees warmer, I was FTD with no changes to car, tires, or setup.

I own a set of V710s, and I cannot answer that question.

I thought the 710 was an evolution of the 700, or assumed as much.

Looks like I may be re-proving that whole what-you're-doing-when-you-assume thing? Somehow I didn't stumble into anything that suggested otherwise to me... I did a bit of research.

A couple of things that would help you here:

Switch to Hoosier A6
Switch to Hankook C71 compound
Get a tirewarmer (co-driver)
Get tire "warmers" that are actually heat trappers. These are legal, they do not provide any heat, they just trap the heat in.

Hotlink for your viewing pleasure.

ransom wrote: I own a set of V710s, and I cannot answer that question. I thought the 710 was an evolution of the 700, or assumed as much. Looks like I may be re-proving that whole what-you're-doing-when-you-assume thing? Somehow I didn't stumble into anything that suggested otherwise to me... I did a bit of research.

The V700s have symmetrical tread and internal construction, and are molded with more tread pattern than the V710s. The V710s (as you obviously know) are asymmetrical in tread and construction, and are molded as practically slicks. The V710s also seem to have a rather softer compound.

What I actually have are Victoracer V700s, not Ecsta V700s (thanks ever so much for the unambiguous naming scheme, Khumo) which are asymmetrically built like the Ecsta V710s but treaded more like the Ecsta V700s, and the two versions of the V700 are called "companions". The two 700s have a UTOQ of 50 while the 710 is 30. This led me to the conclusion that the 7*0 designation had to do with the compound differences. Kumho's literature emphasizes autocross for the V710 and not so much for the other two.