[s-cars] DE Track Tire Question

[Manuel Sanchez]

Larry,

Thanks for the feedback. I usually do the HPDE events in the cool  
months of April and November (mornings mid 30'sºF/ 2ºC, afternoons  
60's-mid 70's ºF/ 18ºC).

I've been happy with the Eagles, I unfortunately had to run them when  
they were almost brand new at one event, as I could not mount the  
rims I was going to use due to a seized aluminum hub centering ring  
that I could not persuade loose. I was sure they would chunk, but to  
my surprise they did not.

The tires I've been running at these HPDE events lately have been  
Toyo T1 R's. I really have not been happy with them, the sidewalls  
rollover, and I have not found a pressure yet that keeps them from  
rolling over. I do think i probably beat on them, I do tend to take  
some corners too fast, juut because it's fun, I know it's not the  
fast way around the track. I got them as a tire and wheel package and  
I probably would not buy them again.

I have had a devil of a time figuring out tire pressures. With your  
autocross experience maybe you might have some suggestions? Generally  
I have been running 1 or 2 psi higher in the rear than the fronts, in  
an effort to get the butt to rotate a bit more (I think that's the  
right idea anyway). Stock pressure is 36psi I think and I have tried  
the following (a little but not much deviation from the left to right  
side):

Air Temperatures between 58ºF - 65ºF
Position		Cold Psi 	Hot Psi		Rollover beyond the Marks
Front		36			41-42		Yes
Rear		37			41-42		Yes

Front		39			44			Yes
Rear		37			42			Yes

Front		42			45-46		Yes
Rear		40			42			Yes

I actually don't know what the magic delta (if there is one) is  
between cold and hot pressures are supposed to be. Is there one? My  
hot pressures are usually recorded about 2-3 minutes after coming off  
the track, as a do some cool down laps in the paddock first, so maybe  
they are worthless?

Maybe the Toyo T1R's just aren't cut out for the track and Ms Piggy.

I did not get that much rollover with the Eagles and was able to keep  
the rollover limited to the sidewall marks.

Thanks again.

-Manny



On Oct 11, 2008, at 11:13 PM, LL - NY wrote:

> Manny,
>
> Having never run something as big as Miss Piggy on the track, I  
> would say R-compounds are going to be dicey in the early morning  
> cold. Admittedly, my issues were with a 2200 lb A2 chassis GTi, but  
> in high 30's temps, I got caught out several times where the rears  
> (remember a lightweight FWD car) just couldn't get enough heat in  
> them, and in trail braking, the rear totally lost it. Had to learn  
> to brake totally straight (which is probably best with Miss Piggy  
> anyway), then turn in and power out. Things did improve as the  
> temps of the day, and temps of the tires with laps, heated up, but  
> it was hard to mentally overcome the feeling of helplessness when  
> the car essentially snap spun the first time. Didn't help that I  
> was totally familiar with the track, so I just went into turn 1 as  
> hot as I usually did.
>
> I would imagine the Falkens will also be a bit temp dependent, but  
> not quite as bad as any of the R-compounds. That they are  
> significantly undersized will allow them to heat up quite quickly,  
> but IMHO, they are too small for a Miss Piggy running RS2 power.  
> They ARE significantly stickier than Eagle F1 GSD3's (the Eagles  
> are my street tires, so I'm familiar with them) but their small  
> size (the Falkens) just won't handle the weight of Miss Piggy,  
> especially with so much grip. To keep them from rolling over, my  
> bet is that you'd have to run unsafe pressures (as in over 40 PSIG  
> cold, which will likely heat right up close to the 51 PSIG max  
> quite quickly), so I don't think they'd be helpful. FWIW, when I  
> ran 225/45-17's Dunlop SP8000's on my UrS at an autocross shortly  
> after I bought it, they rolled over and split a sidewall even at 50  
> PSIG cold. Turned out to be quite a costly Autocross since that  
> meant I had to buy new rubber 1 week after picking up the car. If  
> 225's failed that easily, I don't think 215's stand a chance, IMHO.
>
> That leaves running on the Eagles. Since you say you are familiar  
> with them, and that you've run on them before, and they're safely  
> worn (less tread squirm), I'd say go for it. They're about right  
> size (I'd feel better if running 245/40-17's on at least 8" rims,  
> better if 8.5's) and you're familiar with them. Not only that, it's  
> an HPDE, so you're not running for times or competing. The only  
> downside is that you're likely going to kill them (by wear, not by  
> damage) at this track event, so just be prepared to spend for new  
> street tires after this HPDE.
>
> Just my $0.02
>
> LL - NY
>
> On 10/11/08, Manuel Sanchez <manuelsanchez at starpower.net> wrote:
> Fellow S-Heads,
>
> For an upcoming HPDE Track event on Nov 15-16 at VIR I am looking for
> some specific feedback from anyone actually running these 2 tire
> options or any general feedback.
>
> My objective is to find out which tire will get me around the track
> faster and/or which tire will keep me out of the ARMCO.
>
> I am trying to decide between 3 options:
>
> 1. But new R compound Tires
> 2. Use my used and mounted daily driver tires
> 3. Use some used tires I got cheap but have never run and don't know
> much about
>
> The event will probably feature low outside morning temperatures in
> the high 30's to low 40 ºF  and will hopefully warm up to low 60 º F.
> The car, my 4000 lb pig of an Avant, RS2 spec.
>
> 1. First general question is would a dedicated R compound tire be
> beneficial on such a cool day? I've never run R compound at the track
> before.
>
> Tires I currently own:
> 2. Goodyear Eagle F1 GSD3 - 235/45 ZR 17 (they are no longer new)
> Treadwear 280
> Traction AA
> Temperature A
> I think these were manufactured in '04
>
> I've run these on the street and at the track before.
>
> 3. Falken Azenis  215/45 ZR 16 (bought used, don't know how old they
> are)
> treadwear 200
> Traction A
> Temperature A
> I think these were manufactured in '03
>
> I got these on the cheap and they are mounted on my stock Avus rims,
> but I've never run them on the street or the track.
>
>
> As far as an R compound tire, I have not made any selection yet of
> what I might want. If anyone has experience with a specific type on
> our heavy cars I'd be interested on hearing your thoughts. Most of
> the R compound tires I've seen are similarly priced, around $250USD.
> If I went this route I'd likely go for something in a 17" size, as I
> have an extra set of aftermarket rims (probably around 22 lbs-not
> lightweights)
>
>
>   From reading the Tire Rack site, you can't really compare Treadwear
> ratings between tire manufacturers.
>
> The traction rating does NOT describe dry performance, but rather wet
> performance. It will likely be dry at the event (although it did rain
> last time), so this item isn't helping me determine much.
>
> Temperature rating-well the 2 tires I have at the moment have the
> same rating, so that factor isn't helping me much.
>
>
> Some of my biggest questions are:
>
> a. If I go with the Falken Azenis (215/45 ZR16) they are about 1"
> narrower than my other tire option. Aside from having more contact
> patch likely being better, Is this a significant difference?
> b. I have not weighed the 2 tire combo's, but I'm almost certain the
> stock Avus rims with the Falken Azenis 215/45 ZR16 tires will be
> lighter, which is of course supposed to be better. Big question is,
> will it be noticeably better and will this trait outweigh the
> perceived shortfall of the about 1"/20mm narrower contact patch?
> c. As mentioned previously, the track temps for the mid November
> event will be on the colder side. Would a street tire be better than
> an R Compound tire? If this were an event in the middle of summer I
> perceive this as a non-issue, but since the morning temps might be
> around the freezing mark I was wondering if it would be better to run
> a street tire. Not having run an R compound I would not know how long
> it would take them to warm up (sessions run about 20-25 minutes). I'd
> imagine Ms Piggy's weight would surely help warm them up faster.
> d. If I don't have to spend 1,000 bucks on tires that way only be
> marginally better in these temperatures, well then that would be a no
> brainer.
>
>
> Thanks again, and as mentioned if you have run either of these tires
> (or double bonus, if you've run both of these tires before) I'd love
> to hear from you especially, but all other feedback is appreciated.
>
> Regards,
>
> -manny
>
> 95.5 urS6 Avant (RS2'd)
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