Need better tires and advice

Coelacanth

Coelacanth

Active Member
Joined
Jul 7, 2014
I've been doing a lot of work on my GN the past few seasons and I'm already seeing major limitations of my 235-60-15 rear tires. They're mounted on 15 x 8.5" Centerline Auto-Drag wheels and I want to keep those wheels; it's a look I've always liked. But with the rather modest performance upgrades I've done thus far (see signature), if I do a brake-stand, the tires begin spinning, just after boost barely begins to register with the OEM dash boost lights. Needless-to-say, that's not going to result in good launches, and I'll just burn rubber even more as I upgrade the fuel pump, hotwire it, and upgrade fuel injectors and such.

A theoretical ideal size would be 255-55-15, but that doesn't exist in reality...and I've researched that the maximum recommended tire size to put on 8.5" wheels is 255; so I'd like to go with 255-60-15.

Some questions:

1. What are some good tire options for that size, that will help the launches and not just burn rubber?

2. I currently get some minor tire rubbing the fenders when I hit a big bump or big swoop in the road, and that's with 235's. I've upgraded the rear springs to variable-rate springs, which helped a lot with the rubbing, but I still get a bit of rubbing...I'd rather have NO rubbing. I imagine that upsizing from 235's to 255's is only going to make it worse, so what are my options, keeping my existing wheels? I hear about rolled fenders...how is that done and does a body shop charge a lot to do it?
 
Mickey Thompson ET Streets are the ONLY tire that will hold under power. Other than slicks.
 
Sounds like your wheels are not the correct wheel backspace if those tiny tires are rubbing
I ran 12.20s on BFG mud and snow radial tires. 255/60/15
So, yes a wider tire will rub worse on the 1/4 panel. What is your rear wheel backspace?
4 inch would set the tire back farther, I'm guessing yours are 3.5 backspace
 
I'll see if I can get the backspacing info. When I bought the wheels direct from Centerline, they assured me they would fit...but that's about it.
 
There is a guy that rents the Eastwood fender roller here for $50 + shipping cost back to him.
Just search "eastwood fender roller" and you'll find him.
Sorry, if I was smarter I could and the link.
Good luck.
 
1986 Buick GX1 said:
There is a guy that rents the Eastwood fender roller here for $50 + shipping cost back to him.
Just search "eastwood fender roller" and you'll find him.
Sorry, if I was smarter I could and the link.
Click to expand...
Does rolling the fenders require repainting, or can it be done without harming the exterior paint?
 
I'm guessing you warm the fender/ paint with a heat gun as you roll.
It would be best to check with the renter as I'm just guessing.
 
If you're going to roll the fender, have a shop do it. Find a tuner shop around you. It's worth the $50-100 for someone experience to do it, I don't care what anyone else chimes in about doing it themselves. I've done it, never again.
 
If you want grip on the street you gonna need DR's and like Quick 6 KC said if your rubbing with 235's you have the wrong back spacing. I have ran 275/50/15's DR's which are shorter but with no rubbing issues. I currently run a 255/50/17 Nitto and changing to a Nitto DR 275/40/17 on a 8 inch rim. Yeah a 9inch wide rim would be better for a 275/40 but it can be done on a 8.
 
TURBOELKY said:
If you're going to roll the fender, have a shop do it. Find a tuner shop around you. It's worth the $50-100 for someone experience to do it, I don't care what anyone else chimes in about doing it themselves. I've done it, never again.
Click to expand...
I've seen some YouTube videos from ricers trying to roll-their-owns...and it didn't look pretty! I'll definitely get it done properly.
 
Coelacanth said:
But with the rather modest performance upgrades I've done thus far (see signature), if I do a brake-stand, the tires begin spinning, just after boost barely begins to register with the OEM dash boost lights. Needless-to-say, that's not going to result in good launches, and I'll just burn rubber even more as I upgrade the fuel pump, hotwire it, and upgrade fuel injectors and such.
Click to expand...
yup,if you have a really hot stocker setup even a mt et street ss 255/60/15 will have a hard time leaving on minimal boost on the street,on the track with some heat it will dead hook.what is happening is the stock turbo comes up so fast it hits the tire hard and shocks it into wheelspin this is where you need more sidewall or better softer sidewall/contact patch that can take the hit like an et street r.the 255 60 15 if I remember right is 27in tall and fit perfectly on the stock gn rim you should be able to put a bigger tire on the 8.5 rim but you may need a rolled lip and a spacer as the rears are never centered anyway.
 
Thanks for the advice. Centerline Auto Drag wheels have been used for drag racing for decades, I have no concerns about their construction. The backspacing could indeed be an issue, though. I see that Centerline offers Auto Drag wheels with 3-5/16" backspace (what I probably was sold) but also 4-7/8"...I was sold these wheels close to a decade ago and I'll have to check the boxes to see what model numbers I bought. If I were to buy a pair with 4-7/8" backspace, it would bring the rims in over an inch and a half from the fender...as long as that amount of backspacing doesn't make the wheels rub something on the inside. Heck, I could even go with 9" wide wheels and be able to mount 275's and still have no rubbing issues, as long as 4-7/8" backspace isn't too much.

What's the maximum amount of backspacing for rear wheels on our cars, without notching the frame? Has anyone mounted wheels with 5" or more backspacing without notching the frame?
 
Your car probably doesn't make enough power to break a 2 piece wheel..... ZING!! ;)

4 inch backspace is ideal
 
A 5 inch backspace will rub on an un-notched frame and 4 7/8s will probably rub too.

With a Sawzall and a steady hand you can trim the lip on your fender wells almost as closely as rolling them. For minor rubbing, there is the BFHH approach to the frame.:D
 
My research digging into the backspacing question seems to indicate a 4.5" backspace is the maximum that will not cause rubbing against the frame. Who here is running rear wheels with ~4.5" backspace and unnotched frame? Anyone? :)
 
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