McLovin1181

I got to finally take my 1992 RS to my local Autocross.
put down some ok times with rebuilt suspension.
The 2 instructors drove my car and said it needed drastically better tires. (Using stock 245s)
they said everything else felt fine.

I Planned on buying 18in 9.5in Vette rims and 275 35 18r Michelin Super sport tires.
run a square stance and eventually upgrade to C7 brakes.

​​​​is that a bad combo?

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Beater79TA

Bigger wheels and tires will definitely help. We currently run 315/30/18 BFG Rival S tires on a set of Forgeline wheels for the 400 or so autocross laps we do per year. There are some questions to ask yourself though:

1. Will these wheels and tires be dedicated to track days and not driven on the street?
2. What class is the car running in? Does it have tread wear rules?
3. How long do you expect the tires to last? As a rule of thumb, the stickier the tire the shorter the tire life.

You could just run a set of BFG Sport Comp 2 tires on your current rims. We spend a lot of time working with the BFG Share the Ride program giving spectators rides on the autocross track at a number of events and those are the tires used on the dedicated rideshare cars. They aren't the stickiest tires on the market but they do well on course and are a true street tire that will last well as a daily

I'm assuming you are running SCCA CAM classing on the car so I won't recommend any slicks. The Michelins will work. If they aren't expected to make a lot of street miles, the Falken 615K+, BFG Rival S, and Bridgestone RE71 are the hot tires for the top end drivers in CAM. None of those 3 options will last that long as a daily use tire though. Tire life on course will be dependent on the quality of the surface where the group runs. The rougher the surface, the less tire life you will get.

There are also a lot of options out there for suspension and steering upgrades after you finish the brakes you have planned. Stiffer springs and better shocks go a long way as does removing the poly bushings from everything but the swaybars. Take a look at UMI for bolt on type suspension components. Detroit Speed also has some great parts but some of theirs require more fabrication skills. And Ridetech has some items on the horizon.

We chronicle the build and competitions we put the car though on FB at this link if you want to look at what we're doing with ours.

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paul_huryk

As Beater said, make sure that the both the size of the wheels and tires and the tread rating does not bounce you into a class where you don't want to be - that also goes for suspension modifications - read the rulebook!

A 275 width tire (whether it be a 275-40-17 or a 275-35-18) will have a huge impact on handling and balance, plus those sizes are the same diameter as stock and also have many tire options.

What parts did you replace in the suspension and what did you get?

TEDSgrad

iTrader: (4)

C'Mawn Man
Can you be more specific?
DSE's Camaro is getting press!

McLovin1181

Every rubber bushing was replaced.
New Moog 750lb front spring
150lb moog rears
New steering
Inner and outer SFC
kyb shocks/struts front and rear
J&M strut mounts
Wonderbar
After the tires, I'd planned on ground control springs and koni yellows.

Most people just run in the novice class, so anything goes basically.
​​​​​​
As far as tires,
Either the comp 2 or Michelin SS would work.
The SS have better grip, but the comp 2s are more street friendly

Beater79TA

I wish. I'll see the team from Ridetech later this week and ask them if they have any updates on availability.

Beater79TA

With this suspension setup, I wouldn't go any larger than a 275 tire. Those shocks and springs will allow enough compression no hard bumps and cornering, that I wouldn't feel safe recommending anything wider.

The Comp 2 is a great tire for a novice. Sticky enough to give you grip on corners but not sticky enough to cover up for poor driving habits or other deficiencies in the car.

McLovin1181

I didn't plan on going any wider.
Motor trend did a article about a track day 3rd gen and he was using 275s on 4 corners.
but yes, better springs and shocks are next

The comp 2s sound like a good tire though.
I haven't heard anything bad About them.

paul_huryk

Definitely need to upgrade form those KYBs - they are not going to maximize your autocross experience.

I have driven 3rd gens on 275-40-17 comp 2's and they feel really good. But I prefer the Falken 615K in the same size - just don't expect to drive in a monsoon with them.

McLovin1181

I live in Washington so it rains a lot here.
Makes the comp2s very appealing.
I agree the KYB are just stock replacement, and not performance struts.

Also, how'd you get 17s to work with 275s?
I read in several threads a 17in by 9.5 hits the tierod or gets super close.

paul_huryk

When you have the right Backspace, a 9.5" wheel works with a 275-40-17 tire. It's close, but close is the ideal for max width.