help wheel fitment 1968 firebird go or no go?

[Steve Firebird]

I am getting ready to order new wheels and tires and wanted to get some input. I have searched this site and few others and came up with this plan. First the car is a 1968 Firebird mostly stock suspension but 100% new / rebuilt with polyurethane every where. It has disc brakes on all 4 corners and a 9" ford rear that is only 1/4 inch narrower than the factory rear. Here is my plan.
Front 17 x 8 with 5" back spacing and 225/45ZR17 G force KDW2
Rear 18 X 9 with 5" back spacing and 255/45ZR18 G force KDW2



Do you think I will have any issues? I found a few cars with bigger wider tires on stock set ups that said they fit OK or had very slight rubbing when driving hard so I expect what I have planned to be ok but wanted to check other that have had experience with oversized wheels. Any comments welcome Steve

[JayR]

When you see diameters staggered, it's because the diameter used in back won't turn in the front wheelwells and in the case of a first gen, you can turn with an 18 up front so If you want a slight rake or want to stagger overall diameters, I'd do it with the tires and run the 18s all the way around. A good example of this can be seen in pictures of a red 69 Camaro convert in the Good Year booth at SEMA. It was running 17s and 18s and the rear was filled out nicely but the front tires were swimming in the wells with gaps all the way around.
If new Chevy Malibus, Mazda 3s and Pontiac Solstices come with 18s, you can squeeze them on your Firebird. New cars like that and particularly new performance cars are also good examples of contemporary styling cues that should always be referred to when going to as much trouble as you've already done getting your car looking good.
Just my $.02 but it comes from experience.

[customcam]

my word it come s from Experience awsome advice Jay
Steve theres ur answer
18 all round is were it at imo
look at SW 69

[awr68]

First I must say the car looks great! Those are my two favorite colors!!

The wheels will fit fine, the front is the 'works all the time' sizeing and the rear will work out to be the same as the 9.5" w/ 5.5" b.s (works all the time size).

The tire choice is limiting you a bit as they don't offer all the normal sizes. Your front choice is a little short for the car, I would like to see it be at least 25.5" tall (245/45/17), especially if you aren't really lowering it a lot. BFG's 245/40/18 @ 25.7" would be ideal. If you went with a 245/45/17 tire it would match very closely to your proposed rear tire sidewall size...I think if you go larger diam. on the rear wheel it still looks best to match the sidewall heights, this makes the whole package appear well thought out.

The rear tires are taller but I know you have some fender well to fill and I'm all for it. My car (68 camaro)
is quite low so this isn't as much of an issue for me. I think you are on the right track here! Just set your final ride height the best you can so you can really nail the tire fitment!!

If it were me and I was really wanting that BFG tire I would get the 225/45/18 and the 255/45/18. This would give you a very close sidewall height between the two (rear sidewall .25" taller) and more importantly the sidewall to rim would be stretched the same on both wheel widths...I think they would look great on your chosen wheels. This of course isn't the widest package you could run, but it should fill everything up nicely (as long as you have lowered it a little) and not have any rubbing issues!!

Again, I would measure what you need in the rear height wise as you can get that tire in quite a few heights....

Hope this helps!! BTW, Like Jason, I too have done this before...

[Steve Firebird]

I should have stated in the first post that I all ready have two 17 X 8 JYD rims that I picked up from a guy that changed his mind and never used them. I was going to put them on the back but got thinking they would fit on the front and I could get bigger ones for the rear. The problem then is 17 inch JYD rims only come as 7,8 or 10 inch wide and i am afraid 10" will not fit with out mods. Soooo i thought maybe the 18" X 9" would fit nice. I understand what you guys are saying about 18s all the way around but finding it hard to get my head around all the measuments and how they will look on the car. I do expect I may have to lower the frt of the car some what and maybe the rear as well. The more I think and study the more unsure I get. I can't afford to buy rims untill I find a combo the looks right this is a one shot deal.

[awr68]

Steve I gotta run right now, I will help you more later......

[Steve Firebird]

Originally Posted by awr68

The tire choice is limiting you a bit as they don't offer all the normal sizes. Your front choice is a little short for the car, I would like to see it be at least 25.5" tall (245/45/17), especially if you aren't really lowering it a lot. BFG's 245/40/18 @ 25.7" would be ideal. If you went with a 245/45/17 tire it would match very closely to your proposed rear tire sidewall size...I think if you go larger diam. on the rear wheel it still looks best to match the sidewall heights, this makes the whole package appear well thought out.

Hope this helps!! BTW, Like Jason, I too have done this before...

Thanks for the comments. It is great to get help from guys that have been down the road I am about to travel I am more stuck on the rims than the tires. Do you know a tire company that makes a 26 inch tire for a 17" rim? If I have 17" rims and 26" tire on frt and a 18" rim with a 27" tire on back then I can lower car as need to get the look i want right? I really like the idea of keeping the side wall size the same and am willing to change tire companys to get it.

[Steve Firebird]

Originally Posted by awr68

Steve I gotta run right now, I will help you more later......

OK I will check back later thanks alot Steve

[awr68]

Steve I found that Dunlop offers a 235/45/17 and or a 245/45/17 for your front and a 255/45/18 for the rear in their Sport 9000 tire. My cousin had this tire and really liked it for spirited street driving.

Basically you have the tire sizes you know will work now it'stime to go shopping! I prefer to use Tire Rack to see whats available, they have all the info you need. Just do a search by 'tire size' and go from there. Once you find a tire you like from the list you can check out the 'specs' and see if they offer the other needed size as well...I would start by searching 245/45/17.

[Steve Firebird]

Thanks for all the help. I am going to go with your plan 245/45/17 and 255/45/18. now I have to pick which tire brand.