28"x9" tire clearance

[Sparky714]

Anybody run the Mickey Thompson 28x9x15 slick? Wheels they're mounted on are 8" wide with 5 1/2" backspacing. Car is an '89 LX, no quad shocks and MM control arms with adjustable spring perches. I massaged the inner fenders with a BFH. Looks like it should be enough clearance to me, but wondering what you guys think. I usually run a 26" tire, but want to give a 28" a try to see if I can improve times a little.

 

[JD1964]

How much will that tire grow in diameter at high speeds? There doesnt look like much room for expansion or suspension travel

 

[Sparky714]

How much will that tire grow in diameter at high speeds? There doesnt look like much room for expansion or suspension travel

That's why I'm asking. I've never run a 28" bias ply, just 26". I know there's lots of guys that do. Looking for some real world experience and any tips.

 

[Bullitt347]

I have 275 Drag Radial on my 89'
Measures 28" X 10"
On a 10" wide double bead-lock 15" wheel
Rolled the fender lip and a little 5 lb hammer near the upper spring perch.

 

[Sparky714]

I have 275 Drag Radial on my 89'
Measures 28" X 10"
On a 10" wide double bead-lock 15" wheel
Rolled the fender lip and a little 5 lb hammer near the upper spring perch.

No rubbing issues on launch? My fenders are rolled also. I know a bias will grow a little at speed, but if you don't have issues with that tire stuffed in there, I think I'll be fine. Great looking car too!

 

[General karthief]

I have 275 Drag Radial on my 89'
Measures 28" X 10"
On a 10" wide double bead-lock 15" wheel
Rolled the fender lip and a little 5 lb hammer near the upper spring perch.

All meat and potatoes

 

[Bullitt347]

No rubbing issues on launch? My fenders are rolled also. I know a bias will grow a little at speed, but if you don't have issues with that tire stuffed in there, I think I'll be fine. Great looking car too!

No issues on launch.
The only time I get rub is going around a corner or over a bump.
Sidewall flex is the cause. Only 17-18 psi in the tire.
I never had any issues with the 26 X 8.5 Hoosier.

Here are two pics, first is stationary at the line, the other is at launch.
You can see that the rear fender is higher at the hit, it maintains that gap during the whole run.

 

[93gtmustang]

Anybody run the Mickey Thompson 28x9x15 slick? Wheels they're mounted on are 8" wide with 5 1/2" backspacing. Car is an '89 LX, no quad shocks and MM control arms with adjustable spring perches. I massaged the inner fenders with a BFH. Looks like it should be enough clearance to me, but wondering what you guys think. I usually run a 26" tire, but want to give a 28" a try to see if I can improve times a little.

I bought 28x9 Hoosier Slicks and thought the clearance was too tight. I even bought a fender roller. I never ran them.
My car really squats when it launches. I knew they would rub. I went back to the 26x9's.
My car is a 93 GT. Less clearance than a LX I believe.
I had them on 8" wide rims 5-1/2" back spacing no quad shock too.

 

[Bullitt347]

I bought 28x9 Hoosier Slicks and thought the clearance was too tight. I even bought a fender roller. I never ran them.
My car really squats when it launches. I knew they would rub. I went back to the 26x9's.
My car is a 93 GT. Less clearance than a LX I believe.
I had them on 8" wide rims 5-1/2" back spacing no quad shock too.

If it squats on launch, then the rear suspension geometry is not correct.
The rear should lift. It is planting/driving the tires into the ground a that point.
If it squats, it is trying to lift the rear tires off of the ground.

 

[93gtmustang]

If it squats on launch, then the rear suspension geometry is not correct.
The rear should lift. It is planting/driving the tires into the ground a that point.
If it squats, it is trying to lift the rear tires off of the ground.

I guess stating that "it really squats" was the wrong terminology lol.
I don't know.
Looks like a good launch to me.

 

[Bullitt347]

If anybody really wants to learn how your rear suspension works and how to make the appropriate adjustments to it,
Join a Heads-Up small tire drag class.
I went 8.5 Outlaw racing where you are limited to a 26 X 8.5 slick or a 235/60/15 Drag Radial.
If you want to hook up on that small of a tire you have to have the rear suspension sorted out really well.
I managed to get a 1.26 60' in a 3,150lb car.
Went 5.33 @ 134mph in the 1/8
I was one of the "slow" cars...

26 X 8.5 Hoosier ^^^^^^^^^^^^^^^^^^^

 

[93gtmustang]

If anybody really wants to learn how your rear suspension works and how to make the appropriate adjustments to it,
Join a Heads-Up small tire drag class.
I went 8.5 Outlaw racing where you are limited to a 26 X 8.5 slick or a 235/60/15 Drag Radial.
If you want to hook up on that small of a tire you have to have the rear suspension sorted out really well.
I managed to get a 1.26 60' in a 3,150lb car.
Went 5.33 @ 134mph in the 1/8
I was one of the "slow" cars...

26 X 8.5 Hoosier ^^^^^^^^^^^^^^^^^^^

Thats not slow! I'm slow!
1.6 60'
7.5 1/8 mile 12.2 1/4 mile 3030 lb. car with driver.
It's only a 345hp bracket car. BMR control arms. Stock springs. Drag shocks.
I race at Lebanon Valley Dragway. They have No Time No Rules 1/8 mile small tire, big tire, a few other classes I can't remember.
I swear some of those cars are doing under 4 seconds in the 1/8. It's crazy. You should come down and run it.

NO TIME NO RULES Drag Racing

NO TIME NO RULES Drag Racing, West Lebanon, NY. 3,001 likes · 120 talking about this. Sports Event

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[Noobz347]

4 seconds in the 1/8

That translates to what... a 7 or 8 second 1/4 mile? That [is] crazy.

I remember when 10 second cars were like unicorns. Often talked about but rarely seen.

 

[Bullitt347]

That translates to what... a 7 or 8 second 1/4 mile? That [is] crazy.

I remember when 10 second cars were like unicorns. Often talked about but rarely seen.

A 4.80 in the 1/8 would be a solid 7.5-7.7 1/4 mile run.

When I was running 5.55 in the 1/8th the car went 8.60 in the 1/4 mile.

 

[Sparky714]

I bought 28x9 Hoosier Slicks and thought the clearance was too tight. I even bought a fender roller. I never ran them.
My car really squats when it launches. I knew they would rub. I went back to the 26x9's.
My car is a 93 GT. Less clearance than a LX I believe.
I had them on 8" wide rims 5-1/2" back spacing no quad shock too.

I've got adjustable shocks and control arms with adjustable spring perches, so I don't think the squat will be a problem. Going to bolt them on and do some street launches and see how they do. If they give me too many issues, there may be 4 wheels and tires for sale.