Tire & Alignment Info
18 inch OZ Mito Modular Wheels
& Pirelli P Zero Tires
B.F.Goodrich
g-Force Comp T/A R1 This is the new R1 - more grip, longer lasting, less filling,
great taste. Made for track use but you can use them on the street but you'll probably
only get from 5,000 to 10,000 miles out of them.
Yokohama A032R This
is the B.F. Goodrich R1's major competition, it's a made for the track tire. This is an
RX-7 mail list favorite but it is a very noisy tire.
B.F.Goodrich Comp T/A R1 The
old standard, it's being replaced by the g-Force (above) and is a made for the track tire.
Yokohama Nexus Their
highest performance street tire.
Pirelli PZero System
Their highest performance street tire, my personal favorite.
Proxes RA-1 DOT- Approved Street-Legal Competition Radial
A rising competitor for the BFG R1 race tire, great reviews from the RX-7 mail list, lasts
much longer than the BFG R1.
The Tire Rack's Home Page Lots of great
info on tires with prices and sizes.
Mail List Discussion
I run SO2s on the street on my 968 and I
use R1s on the track on both my 968 and my RX7. I have also used the R1s
on the street on the RX7 a limited basis, mainly just for fun between track events.
The
SO2s are a great street tire and perform respectably on the track, but they don’t
have anywhere near the grip of the R1. At a track like Mid Ohio I would guess
that the R1s are good for about a 2 second per lap advantage over the SO2s. If you were
only going to use them on the track the R1s would obviously be the better choice.
For both street and track use its a harder decision. I think the most important
factor in your decision is how often you have to drive in the rain. The R1s
don’t have many grooves to begin with, and the ones they do have start to disappear
rapidly as you do track events (EGOD problems excepted :-). You can get the car home on
R1s in the rain if you have to, but I don’t think its practical to have to worry
about this on a daily basis. The SO2 on the other hand performs great in the rain. If rain
is not an issue then I think the R1s would be great for combined track/street use. As far
as price goes however, its true that you could almost get two sets of R1s for one set of
SO2s, but I expect to get as much as three times the wear out of the SO2s as I would out
of R1s. Another tire to consider if you can live with the noise is the Yokohama A032R. I
don’t have any first hand experience, but by all accounts they are almost as good as
the R1 on the track *and* they have great rain performance. I originally wanted to
get these instead of the SO2s on the 968, but my wife balked at the noise problem and she
drives the car more than I do.
A032Rs are phenomenal in the rain. I had a first hand demonstration of
this last weekend when I attended a PCA event at Mid Ohio in my 968. Saturday was dry and
I ran my BFG R1s, but it rained all day on Sunday so I switched to my
street tires, Bridgestone SO2s.
For Sunday’s last session it was raining pretty hard I was third in line to go out
behind a 3rd Gen RX7 and a ‘87 NA 944. The previous day in the dry on the
R1s I was able to blow past the 944 like he was standing still, and the RX7 always had to
let me by and I could steadily pull away from him. I figured it would be the same on
Sunday, but I didn’t realize (until after the session) that both of these guys were
on A032Rs. We went out and the RX7 just took off. I had absolutely no hope of catching
him, let alone passing him. The really shocking thing was that I could only barely keep up
with the 944. I would eat him up on the straights and under braking, but he would pull
away in the turns. Every time I tried to match his pace in the turns I would slide
dangerously off line. I couldn’t believe how much stick he had. After the session I
talked to both of them and saw the tires they were running and then I understood what
happened. My SO2s are good in the rain, but the A032Rs are so much better its incredible.
They are on a completely different level. In the dry I would say that R1s are faster than
the AO32Rs, but in the rain the A032Rs definitely the ones to have. Even the SO2s are
faster than the R1s in the rain.
Jim Child
I use the the S02's for the street and have A032R's
for the track. It is easy to compare the two since I change back and forth between them.
The A032R's are superior in performance IMHO. I've run the S02's around TWS, and then
switched to the A032R's the very next run. However, the A032R's are LOUD! The whine from
the tread design is very noticeable. I suspect you could get used to it ... if you're
running a cat-back it might drown out the tire noise. However, the performance is very
nice... works well on the street, in the rain, at the track for both road racing and drag
racing. At $135-$140 at the tire rack, they are a good bargain.
Jon A. Drake
I have run my TII and 3rd gen. at track events for a few years and here is what I have
found. There is no good tire for street and track use. For track only I like the BFG R1's
and now G force tires. If you are unwilling to change brakes and tires for events then a
mediocre compromise would be the Porterfield RE4 pads and pick a tire based on the miles
you drive. If you drive less than 5k a year you could probably get away with a true track
tire. If you drive more, the A032 might be a good choice. My rational is to buy long
wearing street tires to save money, and use the funds to run track tires. Lots of people
are selling used stock wheels. Long wearing street tires also allows you to run more
negative camber without eating up the insides of your street tires. Alignment has a HUGE
effect on handling. The new BFGs are also more negative camber hungry than the old R1's.
Trey Jones
Drag Tires
Simply a stiff suspension and stiff sidewall tire, they don't match
for launching. Depending on what you are looking for, a tire to drag race with that is
legal for the street and reasonable for point A to point B would
leave you with only one choice. An M&H DOT tire. They have a very soft sidewall and
hook like you've got spikes in your tires. Let's put it this way, I'm putting out about
460 hp at the rear tires and can dump the clutch
at 6000 rpm and have almost no wheelspin. They eliminate all wheelhop. BUT! they are not
good for sharp corners or rain. They do fit on a stock rim and under the stock wheel
wells. They cost about $160 a tire and last about 3K to 5K miles depending on your
driving. If you can get a seperate set of rims it's perfect. Take 10 minutes to switch
rear tires depending on your plans. The M & H's are huge though. 11.5" wide by
26" tall vs. about 8.5" x 24.5" stock. As far as the wheel hop goes,, stop
letting the wheel hop happen, it will kill your rear diff and can cause severe damage to
the rest of the driveline. As an example I used to get real bad wheel hop with my 93 about
2 years ago until BANG! The ring gear broke apart and punched a 5"x5" hole
through the side of housing and poured gear lube all over an intersection of downtown
Minneapolis at 3AM. If you've got any additional questions let me know.
Kevin T. Wyum
Stock wheels
245x45x16
Front 1.5neg camber, max caster, 1/16 toein
Rear 1.3neg, 0 toeing
Pressure at road race track, 27psi cold.
Pressure on street 28 psi (I wore out my first set in the middle of the tread by running
34-36psi on the street to try and make them not as noisy. The second set are much quieter,
maybe some design difference?
Heat cycled prior to install by Tire Rack.
Mileage from 1st set purchased 12K miles till little tread in center, still fine for
track. Am noticing some wear at track on inside 1/3 of tire. In my experience, 30-32 psi
at road track is to high.
Do you run the Yokohama A032R's on the street as well?
YES
If so, how do you like them?
A lot, although noisy
Would you recommend anything else for pure dry grip on the street?
Unless you live somewhere it never rains, for the money, nothing
Sandy Linthicum
Have to disagree. By all accounts the A032's have great wet performance, but the wet
performance of the Toyo RA-1's has been nothing short of inspiring on my
car. They perform better in the wet, whether on wet roads, in heavy rain, or through pools
of standing water, than any tire I've had before - including all season tires like the
GT+4's and "high performance street" tires like the BFG Comp TA Z's.
And the RA-1's are slightly cheaper than the Yokohama A032's to boot. I
think both the Yoko Ono A032's and the Toyo RA-1's are better dry tires
than the BF Goodrich R1's when it comes to the street simply because the
BFG R1's have a tendency to wander on the highway.
The Toyo Proxes RA-1's are great. RA-1's are all the craze here. I am
seriously contemplating getting a set. How much street mileage do you foresee squeezing
out of yours? Guys here say they last ALMOST twice as longh as R1's.
No question the BFG R1s will be faster but you have
to be willing to live with them on the street. It depends on how much street driving you
will do and your tolerance for the noise and harsh ride. The Michelin Mxx3s
are another alternative. The Tire Rack did a comparison test with them. You can see it on
their web site.
Solo II Car Setup (autocross)
>> Can anybody give me an idea of
where to start on setting up my 1990 GXL for SCCA Solo
II.
Sure, my ‘86 GXL is semi-retired, but it ran with some limited success for five+
years.
>> Probably will run stock ...
*HIGHLY* recommended. Your car can be regionally competitive with a good driver
in C Stock, but will require significant modifications to avoid being left in the dust in
C Street Prepared.
>> 1.Tire pressure?
Depends upon the tire. *Highly* recommended that you get a set of "race
rubber" (i.e. BFG R1) ASAP. For most tires, pumping up the fronts
6-10 psi higher than the rear helps balance the car and prevent rollover. On street tires,
I’d start high (i.e. 48 front/40 rear), measure rollover and reduce pressures
gradually. But focus on your driving first and foremost; tinkering with psi’s makes
little difference when compared to finding the right line and driving it smoothly.
>> 2.Tire size for stock 15" rims?
I found that 225/50-15’s best for the stock 6" rims. It’s stretching it,
but I thought it worked better than the 205/50-15’s that some other cars prefer on a
6" rim.
>> 3. Suspension settings?
Max out negative camber up front and use a slight (1/16 - 1/8 total) toe out to help
turn-in. Rear camber is non-adjustable and taking the adjustable link out of the rear DTSS
will bump you out of stock, so learn to live with a rear that can be a little squirrely in
transition.
>> 4. Brakes?
Of minimal concern for autocrossing. After several years on stock pads I did use
Performance Frictions up front, but mostly because I used the car at the track as well.
Bill Del Vecchio
Camber adjustment is kind of a trade off. You do want negative
camber, enough to keep the front tires planted in hard turns. Excessive negative camber
will wear out the inside of your tires pretty good so if it's a street driven car you
don't want to get too crazy with it. Also with excessive negative camber you give up some
braking power in a straight line due to the fact that the tires contact patch is slightly
diminished in a straight line due to the angle of the tire (tilted inward at the top). Toe
is also an important adjustment. If you Autocross generally you want more, for better turn
in. Usually the limit should be about 1/8" toe out. This means the front of the
wheels point outwards slightly. For Road racing you probably don't want any toe out
because at high speeds your car will be pretty squirrely. At most 0" toe. Excessive
toe out or toe in will again diminish acceleration slightly due to the fact that the tires
would be scrubbing speed at extreme toe angles. For whatever it's worth on my RX7 I turned
the strut mounting plate around on both sides to get as much negative camber as I could
and am installing next week a set of 1 degree offset urethane control arm bushings. I
figure this should give me around 2 degrees negative camber.
Also, I'm setting my front toe at 0 degrees first to try it out. I have to drive the car
to events right now so I don't want to go too crazy but I figured this should give me an
improvement in turn in. Hope this helps.
Jenaro Rodriguez
Here’s a way to set your tire pressures almost as
accurately as with a pyrometer (which many people don’t know how to use correctly,
anyway!). It does mean having a source of air pressure at the track, but that’s
fairly easy to arrange either with a tank or a cigarette-lighter powered unit (about $30).
If you absolutely can’t get air at the track, before setting off for the track,
hit a gas station and put at least 40 psi in all tires—you may find you need more,
but it’s a start if you have no other reference. Also arm yourself with a bottle of
liquid white shoe polish, the kind that comes with a sponge tip.
At the track, use the shoe polish to make 2 or 3 marks (at 12, 4 and 8 o’clock
positions around each tire) that run from the treaded, road-contact area down onto the
sidewall. Each mark should be about an inch wide.
Make your first run, then check the shoe polish. You are aiming to rub off the shoe
polish right up to, or no more than about 1/8 inch past the edge of your tread. If
it’s all scuffed off, your tires are rolling onto the sidewall and don’t have
enough air pressure. If you aren’t scuffing it off all the way to the edge of the
tread, you either aren’t driving fast enough :o) or you have too much air
pressure—a judgement call, here.
Rule of thumb, adding 2 psi should move the scuff-mark about 1/8 inch toward the tread,
subtracting 2 psi should move it about 1/8 inch toward the sidewall. Renew your marks,
make another run, and check ‘em again. Once you get the marks where you want them,
check the actual psi in _each tire_ and record it for future. If you’re
heavyset, for example, you may find you need more psi in left front than in right front.
In future, you’ll still need to adjust pressure depending on heat of day, speed
and layout of the course, etc. etc. but by starting a few psi above your recorded figures,
you can get closer sooner. Mark and check your tires at every event, every
run—you’ll soon get a good feel for your own car and driving style.
(Anyone who was around in the RX-7 Club of America days will recognize this method as
taught by Dick Turner, and many others. It’s commonly called "chalking your
tires" but shoe polish works much better than chalk! The only reason you need 2 or 3
marks on each tire is that, sure as shootin’, when you pull to a stop one of the
marks will be at 6 o’clock position and unreadable without moving the car!)
When you’re done for the day, bleed the tires down to within 5 psi of your normal
cold readings. Don’t go all the way down to "normal", as your tires are hot
and pressure will decrease as they cool overnight. Check ‘em again the next morning
and adjust to the normal cold reading if necessary.
Do this before you drive home! An unexpected pothole on the way home can do serious
damage to an "over-inflated" tire. The extra pressure you want during
autocrossing is fine for that generally smooth, predictable pavement, but you don’t
need it and don’t want it on the street.
Sydnie
Tire Sizes
225/50R16 is 24.86" dia. - stock/OEM
235/50R16 is 25.25" dia. - besides the Yoko AVS Int., who makes this size, and
why?
245/45R16 is 24.68" dia. - used by many, a good choice
255/50R16 is 26.04" dia. - 5% speedo error, taller gearing... not a good choice
For the maximum contact patch for drag strip launches, M&H drag racing tires as
wide as 305 will fit the stock rims.
Big Tires
I have 285/35ZR18’s on the rear (MXX3’s)
and I’ll be replacing them with 285/30ZR18’s (S-02’s)
ASAP. There were minor rubbing issues. I’m hoping Bridgestone comes out with
255/35ZR18’s for the front.
I have successfully installed SSR Integral 17x9 38mm off
wheels on my 1995 RX-7 (bone stock). Fronts are 255/40, rears 275/40. Dunlop D40 M2.
The front tires are HUGE. A really big section width. Negligibly taller than stock. I
say that because I was comparing a new tire against my worn tires (Expedia S-O1). Plenty
of clearance around the wheel in all areas when straight ahead. The only interference I
have gotten is on the driver’s side plastic fender well in the front of the well. It
is a basically hollow piece there and interference is limited to a ¾" section of it.
Rubs consistently when at full right lock (3 pt turn or leaving a driveway). But the
rubbing is minor and it probably won’t tear off the fender liner.
No interference in the rear. The rears are noticeably taller than the fronts making the
car look like some kind of American muscle car. Fills up that nasty fender gap a bit
though.
The tires are much better than stock. They have seemingly no tendency to wander on rain
grooves. But if there is a rut in the road, the car tracks straight into it. Caught me off
guard the first time it happened. It was just, "shoop", straight into the rut.
Did I mention this whole setup looks really good? The bigger wheels make the car look
much smaller, which I like. Their design is simple and elegant, and plenty of sun passes
between the stock rotors and the inside of the wheel.
This setup is MUCH heavier than stock. I’d say at least seven pounds per
wheel/tire combo (arm scale). The stock setup is feather light. Tire Rack said the wheels
weigh 19 lbs each, which is quite light. Dunno about the tires.
Thanks to rxtrme7 (Kenny) for dealing the wheels, JVOB for being the first and
answering all my paranoid questions, and Brad Barber for comforting me and answering
questions I didn’t even ask.
Gene
Tire Web Sites
BF Goodrich Tire
Discount Tire
Dunlop Tire
Goodyear Tire
Michelin Tires
Pirelli Tires
The Tire Rack
Question about offset and backspacing?
See the Wheel offset diagram
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