I got Tony Garmey to help me with tire temps this weekend, We did two
runs with a new set of speedsters, starting with 27 pounds hot and
going down, just in case I've been missing something at higher
pressure. Didn't have time for a real test and tune kind of effort
(and I was begging Tony's time so I didn't feel I could keep him from
the real customers) but it confirmed the tire pressures I've been using.
Had overheating problems all weekend. I didn't think it was a head
gasket because the leakdown didn't show it, but it was. A skinny
little leak that probably only happened at heavy load. I also had a
tie rod end come loose and give me about an inch and a half of toe
out, so I was plowing asphalt. Temps stayed lower longer without the
extra load, enough for me to charge up from the back and get second,
though I had to nurse it for the last two laps.
Fun weekend.
On Jul 13, 2009, at 7:41 PM, Bill Babcock wrote:
> Yeah, then I've seen the Street TDs and thought they looked pretty
> good, Tony Garmey had a set on the Corvette last weekend that I was
> lusting after. Too bad they don't make a 15.
>
> I'm sure the weight makes a big difference with the Speedsters. I've
> never seen such a sensitive tire, even the slicks on my Radical were
> more forgiving. At roughly 18 pounds cold / 20 hot on Peyote they
> give very even temps across the face but are .5 to 1 second slow. At
> 19/21 they pick up the second and are a little hotter on the inside
> edge and middle, at 20/23 they lose a second and are hot in the
> middle.
>
> Once they heat cycle out they become completely stable and will last
> forever on Peyote but they are two to three seconds slow. When I
> decide I need those three seconds they cost me $800 bucks.
>
>
> Incidentally, temperatures and pressures at the end of a session are
> all but worthless unless you're getting the reading at the pit wall.
> And you need to pick your track to get the best results. PIR for
> example, has a long back straight, then two relatively short turns
> that put almost no heat into the tire. So readings at PIR are
> worthless for camber because the outside edge gets too much cooling.
> Pacific Raceway has a right,left, right combination followed by a
> short climbing straight, a left and then a carousel called Big Indy--
> good for camber checks. Even better is a skid pad.
>
>
> On Jul 13, 2009, at 4:48 PM, Bob Adams wrote:
>
>> The Street TD's are the same compound/design as the Vintage TD's,
>> but they are molded without any tread save for a couple grooves that
>> run around the circumference of the tire. When asked if Hoosier
>> would make a 205/60/15 Street TD they basically said that they
>> "weren't interested".
>>
>> The Speedsters are ok tires, but the fastest SVRA Group 3 legal tire
>> they are not. We pull pressure and temperatures after EVERY session
>> and have tried everything as far as pressures go. As for alignment,
>> keep in mind that your car is a couple hundred lbs lighter than the
>> production bodied cars (SVRA min. weight is 1950# for the TR3-4's).
>> Tire for tire, they are not on the same speed level as the Street
>> TD's and the other decent radials. It also doesn't help that the
>> fast radials are manufactured and are vintage legal in 205/55/14
>> where the 15" cars are stuck with 205/60 (that's a .4" difference in
>> sidewall !). This isn't an issue for most, but when you are racing
>> for the podium in 50 car fields it is.
>>
>> Bob Adams
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