Re: Launching with four drag radials
....I think this is a really cool subject....
Dunno if this helps SyTy`ers, but there is a pretty good article on tires at [url="http://www.fscmag.com/techstory/issue1004/techstory1004.html."]
http://www.fscmag.com/techstory/issue1004/techstory1004.html.
[/url]Hoosier also has a bunch of "tire tips" on the internet (found via google).
...with regard to launching....
There seems to be a world of difference in opinions between compounds,
tire manufacturers, radial vs bias tires, tread designs, and sizes (not even
considering tire pressure, tubes vs no tubes, the use of stickie compounds or
bleach, and suspension settings like caster, toe-in, and camber). Adding the
confusion of gearing (rear end, transmission, and whether posi-traction, spools,
or open diff`s are used in the front) I think comparisons between vehicles is difficult.
Not too mention Dot drag radials, vs slicks differences, or light weight rims.
We all know that caltracs, spring rates, shocks, suspension limiters, and
wheelbase lengths (Sy vs Tys) plus vehicle weight (battery placement, etc) all
make for different 60 foot times. Not to mention coil over, 4-link, watts, or
ladder bar installations. I guess even tracks differ as well.
Im also amazed at the different boost pressures people launch at (some with
transbrakes, some with brake line multipliers or hydra-boost; others with
6 piston calipers or larger rear master cylinders; and yet others with a combo
of rpm limiters, boost controllers, and line locks. There does seem to be consensus
on internet that overheating tires is not good (bleeding off certain compounds to the surface);
and that underheating is not optimum (ie a certain amount of "cleaning" is required).
Some say temps of 6-7 degrees above outside temps is good. Others look
at the "patch" of rubber laid down to see dark/light spots (to determine tire
pressure and stickyness). And others swear at dry-hopping.
I have seen pics of three rwd Typhoons that could pull the front ends routinely:
Deans, Tom F. and now Mike/RPM`s. Never seen this done to this degree
with a Syclone or an awd-nontransbrake Typhoon however. It may be due to launching,
tires, suspension, or weigh or ???.....<dunno>.
Anyways, I found it interesting that some racers use Nitrogen (see below).
So talking about this subject is very informative. Especially with those getting
great straight line/low 60` numbers.
"Nitrogen is generally used in racing tires. It's not so much that it reduces thermal gas expansion (the tendency of gas to expand its volume when heated), but rather that it makes this expansion more predictable. The water content in compressed air will vary from source to source, changing the rate and degree of heat expansion. Moisture-free nitrogen always acts the same way when heat is applied, so if the engineers know the rate of heat generation in a tire they can accurately predict hot pressure."
-Larry
