Tire/wheel sizes for handling

[71FormulaRA3]

'71 Firebird lowered about 2 inches with Hotchkis suspension. I'm going to 18" wheels and tires around 27" tall. I'm looking for help on the width - front and back. What provides the best handling and street performance?

Wide all the way around, perhaps 275/40/18?
Not so wide but same all around, 255/45/18?
Decent in front and wide in back, 245/45/18 and 285/40/18?

Does a wide tire in front cause any handling problems? If so, how wide starts causing problems?

What works for you?

[PARKERRS]

I've got a 73 Camaro and use 245 front and 275 rear, it will clear a 285 in the rear but I went on the safe side to start and will step up with the next set. I'm not sure on the bird as they have slightly larger wheelwells but on a Camaro with 8" wide wheel and 4.5" back space anything larger than a 245 contacts the sway bar at full lock. Ive seen 275s on the same size wheel but as I said you can't make a full lock turn due to sway bar contact with a stock sub-frame and bar. The rear wheel size I use is 9.5" wide with a 5.5" backspace.A wide front tire will not hurt your handling as in tight autocross the wider rear will tend to push you straight with the smaller front contact patch but it is a balancing act as to how much you can get up front and if you are willing to live with rubbing issues. The sizes I stated have no rubbing at all on my car.
Tommy

[71FormulaRA3]

I know a guys with 255/45/18's on 8" wheel on his '72 Firebird, but not sure of the backspacing he has.
Will a wider tire fit on the front with more backspacing?

[71FormulaRA3]

Seen this?
http://www.popularhotrodding.com/tech/0509phr_1976_chevy_camaro_nitto_nt555r2_tire_insta ll/index.html

They are using 17x9 with 6" B.S. and 275/40/17 tires on all four. But they have the thicker Baer rotors that allowed it to fit. They say anything more then 8.5" wide wheels on 5.5" b.s with stock components will interfere. I assume they mean with 17" and larger wheels that allow for some more room.

Does anyone know if 275/40/18 tires on 18x9 with 5.75" b.s. will fit in the front of a second gen? I figure if they got the 6" b.s. to fit with thicker rotors on 17" the 5.75" b.s. on 18" should fit without the thicker rotors...??
I think that's what I'd like to do on all four if they will fit without rubbing.

[NOT A TA]

Tire fitment on the 2nd gen camaros and Firebirds is different. Also early and later 2nd gen Firebirds are different. Also different brakes, suspension setups,weights and types of usage will allow or prevent using certain tire/wheel combos and backspacing so don't just order based on what others run. Measure measure measure, then measure again!

I have custom made 17" TT II's with 275's up front and 315's out back on my 70 bird with no fender or wheelwell mods. Fronts will just hit the fat Hotchkis swaybar at full lock so I don't turn that far.

[71FormulaRA3]

I understand each car can be different with the different setups... I'll be taking mesurements to decide what will fit for sure.

How about the original quesiton; What sizes provide the best handling and street performance?

[68Formula]

I understand each car can be different with the different setups... I'll be taking mesurements to decide what will fit for sure.

How about the original quesiton; What sizes provide the best handling and street performance?


Like you said, different with the different setups. In general wide front tire will increase the tencency to oversteer. But whether you have an oversteer problem depends on suspension setup. If your suspension is completely Hotchkis, then you should ask them as I am sure they tested this setup and know exactly what it will do.

Most likely they will recommend a staggered setup, in which case teh 255/45 285/40 would be a good combo.

[formulafr]

the biggest problem is to find 18x9 wheels. actually, i'm looking for 18x8 4.5bs and 18x9 5bs at good price (and good look of course), and i don't find anything.

18x8 are common, but i can't go larger than 255 tires for the rear.

[woody80z28]

18x8 and 18x9.5 is what I see all the time staggered on 2nd-gens. Both will fit with 0 offset.

Right now I'm looking at 18x8.5 wheels for the front with 35 offset. This way I can mount them and check clearances and figure out just how much more room I need and space/adapt accordingly.

[formulafr]

18x8 and 18x9.5 is what I see all the time staggered on 2nd-gens. Both will fit with 0 offset.

that's what i see too, but when you're looking at summit or other shop, i don't see 18x9 or 18x9.5 offset 0. :dunno:

[71FormulaRA3]

Summit doesn't have squat for selection on what's out there.
Check out www.rimzoneonline.com and www.wheelsforless.com
The Foose Legend wheels come in 18x8 and 18x9 with a few different back spacings. I've decided to go with 18x8 5" b.s with 245/40/18 tires and 18x9 5.75" b.s. with 275/40/18 rears. Everything will fit without any mods or rubbing. Should be able to go as wide as 285/40 on the rear and maybe more.

[71FormulaRA3]

BTW, the mentioned package I'm doing with Nitto NT555 tires will cost less then 2 grand mounted, balanced, center caps, and lugs delivered to my door thru rimzoneonline. There is also a guy on here selling foose wheels for about the same price I think his website is driverzinc.com Not sure who I'll buy from yet...

Another option is www.Coyswheel.com nice looking wheels, but not that great of service. I don't recommended them for anything other then GM bolt patterns...

[formulafr]

thanks for the links, but i already know wheelsforless. i'm only searching for rims, cause shipping is excessive for a pack cause of weight. but we don't find 285/40/18 tire here, only 275/40.

i prefer to use rims with no spacer.

what's the problem with the coys?

[71FormulaRA3]

Wheelsforless has free shipping on all wheels/rims (but not the tires). I don't like spacers either, the mentioned sizes I'm installing will not have spacers.
Coys customer service is poor if you need much help, but as long as you just need their standard GM 5x4.75 bolt pattern and ordering what they have in stock then you shouldn't need much customer service. (just hope they send you the correct stuff)
The problem with other bolt patterns is they don't normally stock them and they have to be 'special made'. A friend of mine order the C55 Chrome Coy for his 66 Mustang... they drilled the holes out to the Ford bolt pattern 5x4.5 from 4.75 so they were egg shaped... and the worst part is they did it AFTER they were chromed. His chrome is peeling and he has been working with them for ~6 months to get them replaced.

[formulafr]

if i buy those wheels, i don't think that i'm going to buy to them directly.

the story about your friend is distressful :scared: hoppefully, i don't like chrome.