A few days ago, I bought a set of used 13 x 8 Keizers from David
and Jim Hedderick. They came with some small formula car Hoosier
slicks. Obviously, that won't work well for Miatas.
I'm pondering which tires to get for the rims. I plan to stay
away from true slicks. I'd rather not autocross in E Modified
locally since Scott McQueen's 3-rotor terror is in the area. He beat
me by 6-7 seconds a day at the Ft. Worth National Tour. :-(
Car bio:
I'm going to use the rims on my 94 Miata Turbo. They are
pre-machined to work with 94+ brakes. I only have to do a bit of
grinding on the front calipers now. I finally have a good reason to
get a Dremel tool kit or maybe even a 4" grinder. Insert Tim Allen
grunts here. :-)
With the turbo kit and a good rollbar, the car's heavier than a
stock Miata. It's lowered about an inch with Flyin Miata progressive
springs (it's a street car). I also have big sway bars to keep the
car from flopping about like most Miatas do.
The chassis is basically CSP-legal but not prone to pop fillings
like full-bore SP cars that aren't street-useful anymore. The static
camber is 1.5-1.75 degrees all around. More can be found but I
prefer to maintain the car's streetworthyness so I can surprise some
V8 cars. :-) I'm also not going to invest in a trailer and tow rig.
The ~250 HP drivetrain really kills the 195 and 205 Kumhos I've
stolen from my B Stock Miata. :-) I can't apply much power while
turning. I need more meat but I don't want to hack up the fenders.
I won't go the Guy Ankeny route. :-)
What I've discovered so far:
Kumho doesn't make a short fat 13" tire. Their 205-60-13 is
too skinny and tall. Yokohamas are now ancient history even if they
do make a nice size (never looked). BFG doesn't make 13" g-forces.
However, I can still get 13" R1s from Tire Rack. I'm sure they're
two years old too. :-(
The 215-50-13 size R1 could work for me. I have about 5 years
experience with R1s. They helped me with my camber-impaired Miatas.
I could reacquaint myself with their care and feeding without totally
killing a set.
If I don't get the R1s, I guess my only other option is
Hoosiers. I have zero experience with them. I read a few websites
and the radials seem to need high pressures. They also want high
negative camber. How much on a Miata?
The 225-45-13 looks really short. It's 2" shorter than a
185-60-14. I'll have to see if it's actualy _too_ short for my car
and its suspension. Braking via steel on concrete isn't the best
idea. ;-)
I also noticed that Hoosier Autocrossers are still available. I
haven't seen them used in a while. I've never heard of the Street
TDs before. I think that's Hoosier's bias-ply track tire.
According to what I've read, the bias-ply tires seem much more
forgiving of a lack of camber. They are also available in short 225
widths. However, I'm spoiled by precise tires. I thought bias tires
had high slip angles and mushy turn-in. Then again, this dog can
learn new tricks.
Applications:
In addition to autocrossing, I do the occasional lapping weekend
at race tracks. I doubt Hoosier's autox compound would like 130 mph
at Texas World Speedway. :-) I was leaning towards making my first
set of 13" tires a road-race compound anyway. Wouldn't they be more
forgiving of chassis tuning errors?
What to do:
It seems that my choices are:
1. Old R1s (215-50-13)
2. Hoosier Radials (225-45-13)
3. Hoosier TDs (225-45-13)
4. Anything else I'm missing?
Thanks for the help!
Mike Lowe
96 Miata R (commutes with good ol' RE71s on OEM alloys)
94 Miata FM2 Turbo (needs good shoes for new Keizer feet)
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