70 Chevelle with 305/45r18's

[tt69camaro]

I just placed and order. Rears= 9.5" rim with a 5" BS and 305/45r18's. Fronts= 8" rim with a 4.5" BS and 245/45r18 tires. I would also like to drop the car an inch or two. Will I have a problem with rubbing front or rear?

[214Chevy]

I don't think it'll rub. It will be cutting it close at a 2" drop though. At 1", you'll be fine. I had 245/40/18 which is a shorter tire and didn't have a problem. I doubt very seriously the rear will rub because I had 305/30/20 with a 6" backspacing and it didn't rub.

[tt69camaro]

I know people are running the rear combo with 5.5" BS and it works but the rim I chose (Boss 338) only came in a 5.03 BS. What size rim width did your 20's have?

[barrrf]

I know people are running the rear combo with 5.5" BS and it works but the rim I chose (Boss 338) only came in a 5.03 BS. What size rim width did your 20's have?

You can always run a 1/2" spacer if need be. Also the rear fender lip is rollable for clearance if necessary.

[tt69camaro]

I wouldn't want a spacer. My concern is that it will be to close to the fender. I don't mind rolling the fender more if needed. I measured the face of the drum to the inside and outside of the wheelwell. The inside measured 7-5/16" and the outside measured 6-7/8" to the rolled lip. My calculations say it will work but the majority of people go with 5.5" BS. I just don't want to get the new wheels here and they won t fit!

[tt69camaro]

I cancelled the rim order and going with a different wheel with a 5.5 bs. I just didn't want to take the chance. Anyone run this tire combo? If so, how much can you lower your car? 0,1 or 2 inches?

[mild2wild]

I cancelled the rim order and going with a different wheel with a 5.5 bs. I just didn't want to take the chance. Anyone run this tire combo? If so, how much can you lower your car? 0,1 or 2 inches?

I have a 70 GSX replica with 19X10.5(6.5 BS) rear ZX3R with 295 tire, and front 245 on 18X8(4.75 BS). Complete Ridetech air suspension, no rub. This should be a pretty good spec, but each car may be different.

[214Chevy]

.....What size rim width did your 20's have?

I had 20x11's.

[71OLDS]

I'm running 255/45/18 fronts on 18x8 and 305/45/18s on 18x10. Can't speak for a Chevelle but on my 71 442 on the rear stock spring height is perfect for the 28.8" tire. Front is lowered about an inch with my coil overs. Now I also like the sidewall to show (with my RWL) and I like having enough ground clearance with my headers to drive over speed bumps and basically be safe for all street driving. If you like the lowered look (usually you would have a smaller sidewall - like a 35 series) and you don't mind having less ground clearance, you could go an inch or two lower on both the front & rear.

My old 18" rims with the same size tires, and STOCK size rotors and fornt end had a BS that was 4.5 and 5.5 for the 8" & 10" wheels respectively But.....when I put on the B body spindles and 13" rotors on the front and 12" rotors on the back it pushed everything out. New BS for the new wheels is 5.25 front and 6 rear. My old wheels would NOT fit with the new spindles and rotors. Something to consider if you haven't done that yet and are considering it. I had to roll the rear wheel well lips too. Here are some pics:

http://i303.photobucket.com/albums/nn156/jl71442/71Olds%20upgrades/NewGen5002.jpg

http://i303.photobucket.com/albums/nn156/jl71442/71Olds%20upgrades/NewGen5005.jpg

http://i303.photobucket.com/albums/nn156/jl71442/71Olds%20upgrades/NewGen5001.jpg

http://i303.photobucket.com/albums/nn156/jl71442/71Olds%20upgrades/NewGen50010.jpg

http://i303.photobucket.com/albums/nn156/jl71442/rocketcaps6.jpg

http://i303.photobucket.com/albums/nn156/jl71442/rocketcaps7.jpg

[tt69camaro]

The stance looks good on your Olds. Are those your original springs?

[71OLDS]

The stance looks good on your Olds. Are those your original springs?

Thanks and yes for rear no for front. I explained above. I'll repaste here:

"on the rear stock spring height is perfect for the 28.8" tire. Front is lowered about an inch with my coil overs"

[tt69camaro]

I understood they were stock springs just not sure if they were "new" stock or "Original 42 year old" stock springs that have sagged over the years. Thanks for the clarification. I wonder how much they did sag/ drop vs. a new stock spring.

I just ordered a 2" drop spring from BMR, I hope they aren't too low. If they are I could add a little air in the air bags to get the height I'm looking for?

[71OLDS]

I understood they were stock springs just not sure if they were "new" stock or "Original 42 year old" stock springs that have sagged over the years. Thanks for the clarification. I wonder how much they did sag/ drop vs. a new stock spring.

I just ordered a 2" drop spring from BMR, I hope they aren't too low. If they are I could add a little air in the air bags to get the height I'm looking for?

I think you should be OK if you put about 10 lbs in each airbag. I run those too (about 5 lbs each). That will also help with backseat passengers if you ever have them. If you ever go to the track you could also leave the drivers side at 10 and increase the passenger side to somewhere between 15 -20 for preload. My only concern is those 305/45/18 tires are almost 29 inches tall. If you get the tire too far tucked up into the wheel well, it gets skinnier and skinnier. Only one way to find out. Good luck! It definitely takes some trail and error to get everything dialed in how you want.