How to run a 30inch slick?
 

I know that those stockers run some huge tires, cut low 1.4 and 1.3 60fts. What gear ratio goes with those big ol tires? I have 350+ hp plus 100hp NOS and a 2700lb car.

I dont see why you would need to go bigger than a 28. We put 29's on a friends car and we had to massage the crap outta the car with a hammer.

I doubt you could run 30's without seriously altering your car.

JMO.

I think your biggest problem will be stuffin those big meats in the little holes we call wheel wells on our cars. I run 28 inch slicks for a while on 15x8 rims and had to "Clearance" the inner fender wells.. My 28 inch tires only measured 27 inches. Now maybe when doing a burnout or launch they expand to 28 inches....

As far as what gear those guys are runnin. Good question, one ive thougth about a hundred times.. Anyone know

Bradley

I want the ET of the big tires, I would like to know the gear ratio to go with it?

do your slicks break loose if you try launching too hard?

You can run just bas fast on 28's as you can on 30's.

I dont see the point.


You have 28's and 4.30's now right. You could go 30's and 4.56 gears but I think you would run the same.

JMO,

With 20psi my 26x10's have a rollout of about 85 1/2 inches. Converting that to diameter, that works out to about 27 1/4. I really wouldnt want to speculate on how much a 28 or 30 inch tire rolls out, but if you could find out we could do the math.

When I selected my gear ratio I knew what MPH I needed to run, and what RPM (10% above peak power)I needed to run through the traps at. Knowing the rollout, the numbers calcaluate out to within 200 rpm of what I actually run.

Andy

26" tires and 4.30 gears would equal 4.96 gears with the 30" tires. thats just using some basic auto math.

88 what are u planing now?

The reson for this was this, If you look into stockers they run 11.30s, 3100lbs, 390hp, 29-30" tires. Well I am 2700lbs, 360+hp and just will go into the 11s. It dont add up. We come to find out the stockers turn over 7000rpm, thats where its at.

Just to let you know, I ran 9.50's on a true 28 x 10.5 in a 2900lb car with no problems.

I went Fri night. I ran with just the radials,
1. 12.46 @ 111.7 with a 1.94 60ft
2. 12.39@ 111.2 1.83 60ft
3.12.38 @ 111.42 1.82 60ft
4. 12.31 @ 13.03 1.83 60ft bumped the nos in 4th
5. 12.01 @ 114.22 1.89 60ft tried to gas off the line, spun bad, got on the rev limiter at 150 ft before the 1/4.
This was on a Grand Spirit Radial GT 275-60-15. My concern is this, I hit the rev limiter, so a tire or a gear change is in order. What should I do? The sad part of it all is that I never got a good start. With the same tires I have seen a 1.70 60ft.

A 275/60R15 is basically a 28 inch tire already, I'd be looking into a gear swap if you're banging the rev limiter.

Why not bump the rev limiter up?

Andy

How do I raise the rev limit?

A chip. The only trouble is not many people have the software for the Speed Density computer, but I'll bet Chris Johnson does.

Andy

I talked to Chris yesterday, he will only raise the rev limit for me. Tonight I will test a pair of 28" slicks.