Good street tires for 400+ hp

[84Ttop]

My exterior fender lips are untouched, ie not rolled at all. I did have to have the quarter opening stretched for the 30" tires though. That is a 315/60/15^

In all I'm just being a smart a$$..

 

[David Pepiton]

Thanks for the picture David.
I'm not sure if yours is lowered at all but I have Eibach springs that lower the car about an inch. I fogot all about that until I saw your picture and saw how much distance you have between the top of the tire and the fender lip. I'm not going to have nearly that much space.
It was pretty late when I started this last night so I need to look at it again and take some measurements.

As for the offset - w/ +18 offset on a 9" wide rim, I think that would give me 5.21" backspacing (4.5" + 18 mm/25.4 mm/in) - I need to just measure it though.

I'm not currently lowered but will be soon I'm going to drop 1.5 inches with no problems in fit or rubbing. your backspace/offset should be closer to about 6 inches or about 30-32mm of offset.

 

[oz]

hmmmm.... so with +18 offset my wheels will stick out too much?

I'll take a picture or two and post them later today of what I'm seeing...

 

[Illuminator]

You just reminded me that my exhaust was rubbing the tires before when I first put the shorter axles in. Think I had to massage the pipes a little. Makes me assured next tire size up would do the same.

 

[madspeed]

dont forget you can put 3" tailpipes on to gsin tire clearance

 

[Illuminator]

OK...after crawling under car I concluded I am pretty much at the limit width wise, and possibly height too. There's only perhaps 3/8" clearance max before hitting quads, and around 1/2" max before hitting pipes in the "massaged" area. From the side it looks like there's plenty of room(yes paint and tires are done...car has been sitting a cpl years) But that's without weight on it. Any suggestions? or just get really sticky rubber for size I'm at?
View attachment 133029

Bad angle but you get the picture(quad & pipe clearance)
View attachment 133032

..and top down view
View attachment 133035
from this angle looks like plenty of room...
View attachment 133038

 

[oz]

I just went out and measured everything and it looks like the gas tank was shifted to the right, which forced me to move the pipe to the right which made it rub the 225 tire just a little. I loosened the tank and pried it to the left as much as I could. Then I loosened the pipes and pushed both toward the tank. There's still 1/2" between the plastic tank cover and the right pipe - and I think the 275's may rub the pipe. - but I can probably put a big enough dimple in the tube to make it clear.
My other issue is that while I have 1-1/2" of clearance from the top of the tire to the wheel flange as it sits on the ground, the axle bump stops are at least 2" from the axle - so if I go over railroad tracks or have people in the back seat, the tire will rub. I think rolling the flange up will help but I don't know who can do this for me (not comfortable doing it myself...)

Here are a couple pictures - the 'T' on the scale is at 4-1/2" - which is the sidewall height of the 275's. The scale is 6" overall.

 

[madspeed]

3"tails? They run under the corners of the fuel tank rather than beside it giving more room.

 

[oz]

3"tails? They run under the corners of the fuel tank rather than beside it giving more room.

Do you have a picture?

 

[madspeed]

hard to tell, but i have about 1.5" clearance with 275/40's

 

[madspeed]

I can get a better pic of the clearance tomorrow

 

[Illuminator]

Looks like you have a nice suspension setup under there madspeed.. those pipes wrap below then out I see. Is that what you were referring to? And I guess lose the quads as well? You can sorta tell from those lousy pix that mine was rubbing pretty well at one point

 

[oz]

Madspeed,
It makes sense now. Did you have those pipes made or are they off the shelf? I might need some of those...

 

[Illuminator]

I hear ya oz....mine have so many spots with melted plastic bags I must have drove over, and melted tire chunks they must add at least 2o lbs....lol Any recommendations for headers? And I might have missed it but what was your backspacing maxspeed?

 

[madspeed]

mine are the standard 3" tails from Flowmaster. I do have coilovers, but if anything, they give you less clearance

 

[madspeed]

oh, i also have aftermarket control arms and no quad shocks

 

[Illuminator]

oh, i also have aftermarket control arms and no quad shocks

What adverse effect is there from removing the quads anyhow? Think I read elsewhere that some get wheelhop as a result? There are bbk control arms on mine fwiw

 

[madspeed]

the backspacing on my rears is 5.94". As for the quads, some get wheel hop some dont. Ita a easy bolt on/off so you can try it. Usually with aftermarket arms you get poly bushings which are the main reason they are an upgrade over stock and can lose the quads

 

[oz]

I looked at the Flowmaster site and the 3" pipes that go under the tank are not available for my GT.
I'm thinking I may have to buy some tube and fabricate my own or take it to a muffler shop and have them do it.

 

[madspeed]

Oh yeah sorry they are the LX style tails