How much tire does a stock '88 GT really need? (Page 1/3)
Modesto APR 11, 11:04 AM
So the tires on the GT I bought this past week are 8 years old and showing all the warning signs. I'm committed to the stock wheels because I love the way they look and the car is a low mileage (57k) relatively unmolested example. Only real upgrades are a performance clutch kit, short throw shifter, and KYB suspension. Pretty much I've narrowed it to 2 choices:

Cooper CS5 Ultra Touring (retaining stock sizing) at $90/tire


Toyo Proxes R888R (would have to move to 235/50s for the rear and 225/50s for the front, both are about 3.5% smaller than stock diameter) at about $170/tire


I'm not too worried about the cost difference, and I'm not going to drive when there is any potential for snow. The Coopers are a "performance" all-season while the Toyos are a DOT rated track tire. My main question is, are the Toyos overkill? Does the car need substantially more power and braking ability to really take advantage of them? I suppose the cornering would still benefit without modification.

I guess I don't see a reason for the extra cost and somewhat compromised performance in the rain and cooler weather if the car is not really benefitting otherwise. Thanks for the input!
Shho13 APR 11, 11:17 AM
I have those Cooper CS5s on my daily driver 2006 Subaru Impreza for a few years now and they have been very good to me in all conditions. When my Firestones on my 88 wear out I would put them on my Fiero with no hesitation.

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"Discord"
Red 1988 GT under restoration!

Let's Go Mets!

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Gall757 APR 11, 11:18 AM
Using a 50 series tire on stock wheels will make the speedo inaccurate, make the car run higher rpm on the highway, and be a harsher ride. For normal street use, the cheap tires will make you happier. If you like drag racing at stop lights.....you will win more races with the expensive tires.

[This message has been edited by Gall757 (edited 04-11-2020).]

88Fingers APR 11, 11:21 AM
Hello Modesto, I have 2 stock '88 GTs and went with the Coopers but for the rear I upsized to 225 from the 215s. I like a bit of extra rear grip. Happy with the Coopers for a year now. I think the Toyo's are overkill. JMHO...Enjoy the '88
olejoedad APR 11, 11:52 AM
We've run the Cooper's for a long time.

215/60/15 front, 225/60/15 rear.

I think the upsizing is beneficial to the handling.
Blacktree APR 11, 12:00 PM
Wow, those are polar opposites. You're comparing an all-season tire to a "track only" tire. Do you race it... like, on a race track? If not, then the Toyos will be a waste of money. IMO you'd be better off with some high-performance summer tires.

Regarding tire sizing: A tire with good tread compound and a well-engineered tread pattern in the stock tire size will out-perform a crappy tire that's wider. Just a thought.
cvxjet APR 11, 12:10 PM
I have been using General Tires for a long time; Less expensive, well made tires that get good reviews and LIGHTER than most tires. I am running 205/55 and 225/55 G-max AS-05s on 16x7 rims...Sadly, they don't make that tire in the stock Fiero GT sizes.

They do make those sizes in their AltiMAX RT43 Grand touring tire..... and they are 3-4 lbs lighter than the Coopers. $82 and $87 at Tire rack.

The lighter un-sprung mass will make your car handle and ride better, and less ROTATIONAL mass will make it accelerate and brake better.

Link to the Tire rack AltiMax RT43 page; https://www.tirerack.com/ti...+or+V-Speed+Rated%29

[This message has been edited by cvxjet (edited 04-11-2020).]

Modesto APR 11, 02:06 PM
Good stuff so far! I deliberately chose two very different tires to help get the discussion going. In reality I'm going to be driving spring-fall and have been wanting to try out autocross for years now. So the premise stays the same: what tire will squeeze every ounce of performance out of a relatively stock setup?

The answer almost certainly is somewhere in between. The challenge is finding one in a 15" rim that is close enough to the stock size that is doesn't cause problems. I find the ~3.5% difference of the Toyos completely acceptable. As far as width is concerned, at this point its largely a function of availability since 15" tires are becoming more and more scarce. I think ideally you would end up with a tire in the same dimentions as stock but with a compound and tread that was able to fulfill the premise. Keep the thoughts coming!
cvxjet APR 11, 02:41 PM
If you are serious about tracking it, you should probably go with one of the extreme performance tires- and few companies make anything that will fit a 15x7 rim. They make a few 15" tires in extreme performance- but the overall diameter is MUCH smaller than what was stock- creating problems in both Speedo accuracy and maybe ground clearance. Smaller diameter would help on short tracks as far as Gear ratio- better acceleration. The 7 inch wheel width is not good for tires over 225 width. (Like a 245 mm wide tire)

It may be better to buy what is relatively cheap and fits, then run some track events, and, if you are "Hooked", then maybe spring for better wheels that will accept better tires.

Just a bit of info; 40 lbs off the wheel/tire package total equals 200 lbs off of the car itself....I cut my weights by 3 lbs on each rear and 6 lbs on each front and it felt like a whole other car.....Weight is really important on tires and wheels!
Frenchrafe APR 12, 04:27 AM
I use exactly those Toyo Proxes tyres on my car in exactly the same sizes.
Yes the ride is harsh (suspension mods as well).
Yes you can nail those corners at high speed without scrubing the front tyres or losing the back end (spinning out), in the dry.
No, you can't take the car out on a wet day! Not unless you like wheel spinning burnouts at each gear change and losing it totally on the same corner that you did so well at the day before when the sun was out!!

Saying that, I wouldn't put cheap "normal" tyres on my car any more. I like the precise feel that the Toyo's give.

Regards,
Rafe

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'87 Fiero GT. 3800 turbo. Sticky tyres. Driven hard!