[Big Injun]

I am trying to figure out what 18" wheel combo I can use on a 2nd Gen Firebird (70-81). I'd like to run 18x8 up front and 18x10 on the rear.

What Back Spacing will I need and what size tires will fit.?

Thanks,

[aronhk_md]

Dave,

There are several factors affecting what will clear on a 2nd gen bird.

1) early 2nd gens dont have the hump for rear seatbelts in the wheel housing. Later they do. Many people hammer them in.

2) The factory did a so-so job welding the leafspring mounts on the axles, and there can be variations up to half an inch from one side to the other as to what will clear for backspacing. Need to measure yours specifically to be 100% sure. Use others measurements as a guideline only.

3) Do you plan to lower the car? If so it changes what will fit. I can explain better why later if you dont see the answers where I'm going to tell you to look.

4) Do you care if you get a little bit of swaybar rub when locking the steering to one side......like pulling into a parking spot?

With all that said.....the place to look for posts on this subject, and theres a good bit over there......is in the WHEELS section over on pro-touring.com in the forums. Just remember that 2nd gen camaros ARE a little different. They have a slightly smaller fitment to the rear due to their fender, but are otherwise the same. But there are lots of bird owners there too and its been discussed.

Year One sells their 17 x 9 honeycombs and snowflake wheels and they are designed to go at all 4 corners with no mods. Backspacing is 4 and 7/8 on one, and I think 4.75 on the other.

But I will say there are plenty of people going deeper on backspacing than that....and bigger wheels. I personally will be running 18 x 9.5 on all 4 corners until I can afford to go larger in the rear.

Good luck!

[Big Injun]

Thanks! I'm going to build a set of Jim Wangers Billet Rally II wheels to fit.

http://geetotiger.com/Wheel.htm

[aronhk_md]

Very nice Dave. I need to spend a lot less.....thinking the Vision Legend 5 model 142. Summit sells them also. For now it'll have to do...cant go more expensive.

Year One I think has new Rallys too.....but they are 17x9. I think a whole set is $750 or so. Lots of wheels to look at over where I sent you on PT too, but I understand if you like the stock look....lol

[b-man]

Take the 18" wheels from your wagon project and try fitting them on the Firebird.

You can use them a good point of reference. Use a straight edge and a measuring tape and you'll find it's not too difficult to figure out what fits and how much wider you can go.

[aronhk_md]

Or you can spend $60 on a wheel fitment tool, then resell it for $45 on ebay or pro-touring.com People dont realize theres a market to resell those things so they hesitate to spend $60 to use something one time, when you can really get back most of your investment quickly.

[JC455]

Hope this might help--- I have a 275 40/18 mounted on 18x9.5 Corvette C5 "wagon" wheels w/ billet spacers mocked up on the back of my 71. I don't know the offset right at the moment, but I want a larger tire- it'll handle it, No Problem!- just don't have the funds to goof w/ tires right now.

[70UglyBird]

I have 18 inch Boss 338's 8 in the front and 9.5 in the rear. Pretty sure it was 4.5 BS up front and 5.5 out back. They fit perfect, actually was surprised on the room at least on a 73. Inexpensive wheels nothing like those Billets. I had Fikse's on my last project amazing wheels someday the bird will have them too. But it needs to much right now to spend 5k on wheels and tires...

[aronhk_md]

Any pics of your bird with the 18's? I think I'm about a day away from buying a really cool set of 18's for my car......cheep, cheep! lol

[70UglyBird]

I have some on my other computer but I can probably get better ones tomorrow now that the garage is cleaned out a bit.

I think the Boss look way better than the Vision and I know a place where you can get them cheap shipped to your door. I think I paid 1349 with tires, lugs and lock shipped for chrome. Black and silver were 1149 I think..I know chrome is played but the wife really like it and I try to get her involved. On the Black car they look pretty good.

Bobby

[70UglyBird]

Here is one of the rear but not a good picture. You can see the wife likes her rims in the background. Really should have chopped out the cat litter too... Can't wait to get the Hotchkis kit installed!

[aronhk_md]

Bobby....this is the rim I think I'm going with. 18x9.5 with 5.25 backspace. I already have a set of 275/35/18 tires for the front, and 285/35/18's for the rear.

These wheels will run me $550 shipped. I thought about the Bosses.....and the Vision Legends.....had good reasons to consider both. But the wheels you see in the pic is actually a german made 2 piece wheel. Literally 2 piece...can remove the center if I want and send it out for coating later. Here is a pic of a set that went on an anniversary vette over in europe. Anniversary vettes were always a bit gaudy, but I think these wheels have potential. I might even get them widened later.

[70UglyBird]

If you can get Ronal wheels for 550 shipped than go for it!!! Those are a decent mid level wheel. A big step up from the Boss, Vision, Enkie etc. That is a steal. I think they will look decent too. I like the Boss "no lip" depth but if I could have got those for 550 shipped I would have done it.

Can't wait to see Pictures! Plus I want to see that rear tire sidewall, I went with 275's and I'm kicking myself.

[aronhk_md]

Might be able to get more than one set if it interests you, and they are available in 9" width too if you like to stagger. They are new. Keep in mind this is a BMW pattern, at 5x120.....but there is a proper and easy way to make them fit.

Just realized you have shaved door handles.......lol. Knew there was something different about that pic but couldnt figure it out. lol

[aronhk_md]

Since Big Injun started the thread and never came back I dont feel too bad continuing to hijack it...lol

One of the guys over on PT did a quick photoshop for me. Not exactly the way it will look, but a close approximation. The stance will change a bit with the real tires. 275/35/18's going on the front, 285/35/18's on the rear. If I like these wheels enough I'll get them widened at some point to run 335's on the rear.

Before......



After......

[70UglyBird]

Yeah I don't know if Photoshot can really give you a good idea...It's hard putting modern wheels on older cars. But that said the quality of the wheels and weight make those worth trying out and they are nice looking wheel especially in the gray with polished lip.

I'll try and get pics of mine tomorrow if it doesn't rain and I get it running.

Yeah I bought it with the door handles shaved. The guy acted like it was a huge selling point...I don't really know if I like them. When the car gets repainted in a few years I may put doors with handles back on....

[aronhk_md]

Yeah, the photoshop is just to get an idea. I actually lie the modern wheels far better, as long as the center part of the wheel isnt flush or close to the outside of the hoop of the wheel. The guy didnt have any of this size wheel with the satin black center in the pic, but gives me an idea what they'd look like if I decide to send them to be powder coated later.

Regardless, it'll be light years ahead of the centerline wanna be 15" rims that were on it. The fronts were skinnies. Uggghhh.....hate that. Modern low profile rubber will be a huge handling plus in addition to the suspension mods I'm doing. Big brakes will follow.

If you plan to replace the doors start looking now. Finding good ones may be tough. I think the doors changed after 73 or 74 and the striker is completely different. Theres a thread on that in the 70-73 section. Also the door handle slot was slightly longer to accomodate the 1/4" longer early style door handles. Might be easier to open yours back up depending on how they were closed.

[Silverbird]

StreetKing had this

18x8f 255/ /18
18x10r 295/35/18

[Rubbernose71]

I run 18x8 4.5 b.s. w/245/45/18 nitto 555 fronts and 18x9.5 5.5 b.s. w/295/45/18 555s on rear I did have to roll the lip on the Qtr. wheel fitment is perfect but I think I will go down to a 285/40 on the rear.

[70UglyBird]

I have 275/35's in the rear and they are really too short I need to get some 285's or 295's but the tires are brand new so it will be awhile. I wonder if the nitto 305s would fit an a 9.5 inch rim they run pretty narrow for a 305..