[Land-speed] Tire Diameter

[Elon]

Thanks for the information, JD.  Yes, I have looked at the Dunlops but have
never been able to get a speed number from the manufacture.  As you say,
manufacturers are secretive about engineering data when it comes to
liability. I have had a Dunlop bookmark on my computer for 3 years waiting
for a new 200 mph tire for the Lamborghini Murciilago (supposedly a 208 mph
car). It was all marketing swill and the tire was never available to the
public. What I have found with Dunlop is the numbers (when you can get them)
are all in Km/H units and when you do the conversion they fall out in
different 160-180 mph ranges. My Goodyear LSR tires set a max speed of 300
mph (in writing). In fact, the Goodyear LSR tire is the ONLY Goodyear racing
tire that even lists a speed. I heard the MT tires (before the last
brouhaha) also mentioned a finite speed.

I appreciate you cautious approach with the Dunlops and I was aware of the
rule book caveat. However, I thought it had to be backed up with
manufacturer's data. I still have a set of Blue Streaks (stamped for racing
only) that would not be safe over 150 mph.

Its not about finding a loophole or doing an end-run around the rules. It
is about showing up after a year's work and not being sent home on the
trailer! I thought tech was looking for factual information or engineering
data, about a safe speed. I didn't realize that rubber stamped RACING ONLY
was a free pass.  -Elon


-----Original Message-----
From: J.D. Tone
(snip. . . ) What does the line right under speed ratings say??? All
together now page 18
"In excess of 200 MPH: Special tires for racing as designated by the
manufacturer"

 I guess you have never looked at a Dunlop. Embossed in the rubber are the
words "DUNLOP RACING". That was good enough for me when I started using them

on a 196 record. I was not the first. At this time I believe enough
competitors have used them to get an idea of their limits. I do not know of
anyone using them who has not been cautious. There is a gas roadster which
has run them 236 and has not shown a problem. I do not know the weight of
the vehicle or whether it spins the tires.

Remember the SCTA is not in the tire business. Many tire manufacturers will
not answer speed inquires. How many records over 250-400 were set on 40 year

old Firestone Indy tires?