Air Bag Pressure for clearance for my 275/60/15's Tire's ???

[ReaL99]

I just got my 275/60/15 BF Goodrich Drag Radial's.I have the Weld Drag lite 15x8 inch wheel with the 3.5 inch backspacing.I have to make sure that the car is up high enough because the tire's will hit the quarter's if my air bags don't have the right pressure.I probably only need the car up another inch or 2 in the back to make sure because I don't want to destroy my brand new tire's as well as the quarter's.Anybody know what the max pressure is with the air bags???

 

[freak007]

why didn't you just get the correct backspace?? I know Welds only come in 3.5, 4.5, 5.5 etc... but from what I understand a 4.5 with .375-.75" spacer clears with no rubbing/notching/rolling...

 

[ReaL99]

why didn't you just get the correct backspace?? I know Welds only come in 3.5, 4.5, 5.5 etc... but from what I understand a 4.5 with .375-.75" spacer clears with no rubbing/notching/rolling...

Yeah I was told to get the 3.5 inch backspacing.To me it looks like maybe 3/4 of an inch from the frame.Luickily the wheels are getting a bit worn looking but I worry about how close it would be to the frame with the 4.5 inch backspacing.For now Im just going to rely on the air bags as long as they hold up.

 

[BlackMetal]

I did the airbag trick when I had huge rear tires. Kept something like 20psi in them at all times, never heard any rubbing. Bouncy ride though.

 

[Taylor04]

I had a set on my GTO for the same reasons. I kept both around 8-12 psi for the street and played with the air pressures when at the track. The kit for the GN just arrived and its practically the same. I read on another forum that max psi was 50, but I think the real question is for how long? They seem pretty tough...

 

[ReaL99]

I did the airbag trick when I had huge rear tires. Kept something like 20psi in them at all times, never heard any rubbing. Bouncy ride though.

Yeah I noticed that the car doesn't absorb bumps in the road real well.I didn't know it was the air bags though that could have been causing it.

 

[freak007]

Yeah I was told to get the 3.5 inch backspacing.To me it looks like maybe 3/4 of an inch from the frame.Luickily the wheels are getting a bit worn looking but I worry about how close it would be to the frame with the 4.5 inch backspacing.For now Im just going to rely on the air bags as long as they hold up.

if you have 3/4" between the frame and tire now, a 4.5 BS and 1/2" spacer will give you a "true" 4" BS and should net 1/4" of clearance on the frame side... From what I understand 3.75-4" of "true" BS is about "right" for a 15x8 with 275/60/15s on a G body... a 4.5" BS with a .5-.75" (12-20mm) spacer should get you there... If it were me, I would roll the fender lip and then measure how much clearance is between the tire and the frame, then measure how much the tire sticks out past the fender... Order rims with deeper backspacing and use the spacers needed to center the tire in the wheel well... I know several people have 275/60/15s without rolling th fender, but you gain a fair amount of clearance and it makes tire fitment easier... One more thing - are you sure your body mounts aren't sagging?

Personally I am not a fan of using air bags/shocks to get a tire to fit because of the negative effects it has- especially on your ride and launch

 

[ReaL99]

if you have 3/4" between the frame and tire now, a 4.5 BS and 1/2" spacer will give you a "true" 4" BS and should net 1/4" of clearance on the frame side... From what I understand 3.75-4" of "true" BS is about "right" for a 15x8 with 275/60/15s on a G body... a 4.5" BS with a .5-.75" (12-20mm) spacer should get you there... If it were me, I would roll the fender lip and then measure how much clearance is between the tire and the frame, then measure how much the tire sticks out past the fender... Order rims with deeper backspacing and use the spacers needed to center the tire in the wheel well... I know several people have 275/60/15s without rolling th fender, but you gain a fair amount of clearance and it makes tire fitment easier... One more thing - are you sure your body mounts aren't sagging?

Personally I am not a fan of using air bags/shocks to get a tire to fit because of the negative effects it has- especially on your ride and launch

Yeah Im not a fan also of having air bags at all.I may have an inch or so from the frame.I measured the air pressure in the air bags yesterday and they were both at 22 lbs.Despite that the car is driven only on the street and is to bouncy for me.Its not my daily driver so it doesn't bother me too much.I have a brand new set of BFG DR Radial's going on this week.Even though I tested the spring in the back using some force I don't have complete faith if I hit a big bump.Luckily the wheels are a bit old and I will be looking to replace them some time with a wheel with 4.5 inch backspacing.My old BFG Dr Radial's have slash marks and rub marks on them from when I had lower pressure in the air bags.Another thing is that the air pressure sometimes goes down after a while if I don't pay attention to it.