Ive definitely decided I want to put these wheels on my car. ITs not a daily driver, and I do drag race it, so they look nice and are functional for racing too.

Two things
I don't know whether to put 15 x 6 in the front and 16x8 in the back, or 15X6 in front and 15x8 in back. There are a lot more choices in tires for 15" wheels, skinnies in the front, and drag radials or ET streets in the back, with 15" wheels. Besides 15" should be lighter, faster etc. I just hope it won't look strange, since 15" are more of a muscle car look. Also it might be wierd putting smaller on the front than the back .what do you think

I tried to order today with some tires through Discount tire and they told me that Weld is changing their two piece wheels to one piece, and have not stock of the two piece in the 15 x 6 size. They won't have them till Fall. WTF??? I finally get ready to order wheels and the wheel company is going through some big change or something

 

why do you want the XPs?? i like the regular ones not the XP series. also i personally like the 15x4, 15x8 combo. that's what i'm going to be running as well. a 165R15 in front and a 28" ET street for the rear.

 

Xp's are nice preston has em on his car.

 

go with 15s. you can get more sidewall. make sure the tire is tall too. it will look good with a tall sidewall.

 

What are the "regulars" as opposed to the XPs? Ive only seen the Prostar XPs. I like the looks, I like that they are strong and light. What have y'all heard about this business that they are changing their production from two piece wheels to one piece and that there is not much 15" stock available anywhere right now?

YEah, I was thinking 15 x4 or 5 and 15 x 8 on the back. Do you think it would be weird to have 15s on the front and 16s on the back? I dont know why really, stock size on back is 16. Theres a lot more tire selection (Drag radias, ET sTReets, slicks, etc) for 15 than 16. There seems to be such a big deal about big rims these days I guess Im brainwashed. I cant think of a logical good reason to go with 16 instead of 15.

 

mismatched rim size always looks weird on a thirdgen. you can get away with it on certain trucks, or other cars but it never matches the lines of these cars too well.

i wouldn't recommend a 16" on the back and a 15" up front at all. I'll have to post up some pics in a month of my 15x4 15x8 combo that i'll be running.

 

A lot of the LS1 guys run 16" Welds on the back and 15" Welds up front, mainly for brake clearance on the rear. Otherwise they have to grind the calipers and/or use a spacer.

I run 15" Draglites on the rear at the track and I had to grind the fins off the caplipers for clearance. Keep in mind this is only a problem with the PBR calipers. If you run bigger than stock brakes then the XPs might be your only choice.

 

I run the standard disc brakes that come with the WS6 package for 1991. So the disc grinding only applies to regular Prostars, not XPs right?

Would I have clearance issues with the regular Prostars?
The XPs are made for for cars with bigger brakes right?

What is the advantage of regulars or XPs besides the brake clearance issues.

 

I'm going to be running the 15x4, 15x8 setup on my car with draglites. I'm getting the mickey thompson sportsman fronts and some 255/60's for the rear. My question is, what have you guys with 15x8's found is the best back spacing for this wheel?

Thanks.

 

4.5BS to answer your question. although with larger slicks i know one person 88IROC350 or something like that who used 5.5BS on his rims.

i'm going with 4.5BS and will hammer the inner fenderwell as needed, and i already rolled the outer lip with a baseball bat to ensure proper clearance.

 

I still don't know the difference between regular PRostars and XP, and whether I should buy one or the other. Anybody got any ideas?

Im thinking of 15 x 8 rears and either 15x4 or 15x5 in the front

 

I'm not exactly sure what brakes came on the 91 Firebirds, but I *think* they are PBR's.

But to answer your question, you might have clearance problems on the regular Prostars and PBR calipers.

The only advantage going to XPs are clearance. Overall they are still a little heavier, and you are still limited to tire selection.

 

OK, thats what I thought. There is much more rim and tire selection for the regulars, I saw that. I should go with the 4.5 backspacing too I guess. Im assuming they will bolt right on without adapters and stuff. Im going to call Jegs and see if they have any in stock.

thanks

 

Well I got the prostars on the front with some thin tires. The rims are 15x6. I love the looks of the rims. The looks of the tires Im not sure about, I got them for drag racing and I know they will help for that with less rolling resistance and all. I don't drive the car in the rain, and its not a daily driver so there is no concern there. I guess its a matter of taste on the looks. What do you all think? Might look better if the front was lowered slightly. There seems to be a bit of space between the wheel and the body although these are only a hair smaller in diameter than the original tires. Maybe its just an optical illusion, or I just didn't notice it before.

I love the rims, now I have to save up for the rear ones. Im planning on 15 x 8 with either drag radials or ET Streets

 

forgot to attach the pic

 

i like the look of those rims. simple 5 spoke design. I'm not as crazy about that fender gap thou. I'm sure you'll sort it out before you're all done.

i bet it'll look even better when you get the backs on.

they make those rims in 16 and 17's?

looks good,
brandon

 

I love the Prostars, and as soon as I get my car on the road I will be ordering a set. I am pretty sure I will be running the 15x4, and 15x8 combo. I love the skinney, drag radial look on a otherwise stock appearing car. Lets people know, like fools in crustangs, that you mean business!

Hopefully mine will look as good as this...

 

That does look nice, I like that body style for the bird. Whose car is that?

I ended up putting 15 x 6 on the front, and they seem plenty skinny and light. You could still put a wider tire later if you wanted to corner better. Look at the width of these tires. I don't think you want to go much skinnier on a street car

 

The width on those seems nice, any less would be pushing it on a street tire. As for the picture, I don't know who owns it? It was for sale on the Canadian Auto Trader and I thought it was a cool pic, so I saved it. The only difference with my car is mine is black. But at least I know the pro stars look good on a GTA!

I will be using the pro stars for drag racing 99% of the time. They may see some car show action and one or two cruise nights, but the rest of the time it will be track use only.

 

larry,
what size tire did you go with up front?

 

from another thread

 

I have 15x3.5" fronts with 165R15 pepboys tires and 15x8 rear with 28x10.50 ET Drags. I run 5.5" backspacing in the rear so they tuck under the car nicely... Only problem is the tire rubbed the lower/front of the wheelwell due to the tire height. The tire also is a little bulgey on the rim so that could have made the clearance worse. a 27" tire would have fit perfectly.

 

I know some guys dont wanna run the 15x10's w/ 5.5" BS out back for whatever reason, but I run them and love the fact I can stick a 10.5 tire out back with no banging on anything and the slicks are'nt affected as much for contact patch since the sidewalls are'nt bowed way out. The Hoosier quick time pro's 28x11.5 are about as wide as you can go and then when going to a full slick I run Hoosier 28x10 and they are a tad wider than the 28x11.5 DOT slick. I did'nt need a hammer anywhere, but did notice the wheel well lip was cutting into my tire and rubbing the paint off the inner wheel lip, so some massaging is needed before the new beast hits the track since it should squat even worse

I dont know how serious some of you are abour bracket racing, but more first hand experience on the front tires 165's, we switched to these on the truck because of the new fender dump headers-could'nt turn the steering wheel but 1 turn or so-...try cutting a light losing 2" in tire height over what we had. All the tracks seem to be finally switching over to LEDS which also quickens your lights a tad, then losing all that roll out with a 25.5" tire blows. It's easy to pick up your lights, but dammn near impossible to slow'em down. I and most would reccommend a minimum of a 27" tall tire up front 205/75-15 or a 28" tall one, think a 215/75-15. This way you have a better chance at not going red because of the short amount of roll out with a shorter front ire. We've taken as much air out of the back slicks as I care to drive it with to take some R/T out of the truck itself, went way down on the Transbrake 2 step rpm, and ended up going to 25psi in the front tires to get this thing where it needs to be for reaction times. Add this all up and we slowed down .15 in the 1/4mi over what we were doing, and it's still hard to not go red.

They look really nice on your car though. Just offering firshand experience from a guy that hits 1 or 2 tracks every weekend all summer.

 

Interesting what you say about drag racing with the smaller front tires. The tires on the front are 165 R15 86T, which seems to be a different designation than normal tires, like the Nittos on the rear which are 245 50 R16. I just physically measured by eyeball from outside tread to outside tread the diameter on the front and back, and they are both the same, about 25 1/2". My plan is to get 15 x 8 rims for the back, and put 27" drag radials or ET streets like you say is about the max size. Its funny because it appears there is now more space between the tire and bodey in the front, but the diameter is the same as before. Im tempted to put the old tire and 16 stock wheel on there just for the heck of it an measure it

I guess you are saying a 215 tire in front with a 27" hieght would be better for cutting lights than the advantage you woul get from a skinnier tire. But doesn't MT make a sportsman front that is skinny but 27" tall too? Is it street legal? I see it in Jegs all the time, but it doesn't say its DOT, so I guess it isnt'

 

I run just the cheapest set of 205/75-15 radials I could get up front. Cheap means light sidewalls and overall lighter than a good tire like you'd put on your daily driver

The 205/75-15 is 27" tall and you can easily use this up front. You can also use I beileve a 215/75-15 which is a 28" tire too and have plenty of room, had a freind order some hoosier 28x4.5 front runner on my reccomendation and he said they fit great.

Out back, it's hard to say with tire sizes since MT/Hoosier/Goodyear, etc...all use different measurements for their tires. I've only run Hoosiers out back so they're the only ones I can comment on.
With the DOT slicks you can go upto a 29x11.5 out back with no inner wheel well mods-but this is with my 15x10 with 5.5"BS I dont know how this all plays into the mix with the narrow 8" rim with shallower BSing.

I run and reccomend to anybody with our cars as a good all around rear tire go 28" tall. It looks good since it fills the wheel well and traction should always be there since you gain more contact patch with heighth over width.

I used to have a set of 27"x11.5 Hooier DOT QT Pro and they looked good, but there was still a wee bit more air gap between the top of the tire and bottom of the wheel lip than I thought looked good. I'm still leaning towards 29x10 slicks when I get ready to get this back on the track since I'll need all the help I can get in the traction department and a 10" tire.

The MT sportsman tires are street legal but in my catalog they only offer 26" and 28" for heigth. So now let me take a step back here. If your going to be foot braking you car, the 26" may be a better choice over the 28". I'm soo used to runniing with guys and we all use a 2 step and realese button so we tune our R/T with rpm chips. Back when I first started racing, I had a stock 305 running low 14's with 26" front tires being foot braked and I killed the tree. But if you plan on running a motor with alot of power, step upto the 28", you'll be happier in the long run since you wont take that chance of going red as easily as with a shorter tire.

Some guys with older underpowered cars...or just older drivers use tire size to help them also. If they're slow on the tree it's common to drop to a 26" tiore to help speed it up and then use air pressure to fine tune.

For example last year with my 27" tire, my regular track with incadesant bulbs i had to run 50psi of air up front and bump in 1 extra pump of the brakes once the stage light came on to get into the .teen lights. Smae car at the NHRA track with LEDS, I had to just trip the stage light, but only ran 25 psi of air front to stay in the .5teen lights.

 

I have 16x8 Prostar XPs for my drag radials. They were pricey but worth it, I'd like to see what they look like in 17" all around.

 

Those wheels look great! I thought of going with the XPs but I decided on the regular prostars for a combination of price (cheaper), weight (lighter), and I actually like the smaller open area between the spokes. Also I wanted 15" to have a larger choice of racing type tires like front runners, drag radials, and slicks. I guess if you have certain brakes you have to have the XPs to clear them. The regulars cleared my stock 91 formy WS6 brakes with no problems.

I didn't think they made 17" in the Prostar XPs. I thought Weld was more of a racing wheel company, and 17" wheels are more of a show car thing, but I could be wrong.

 

They make 17s for sure but they aren't cheap.