First off,
Hears what I have planed for my car.
408 6.0 Iron Block
Forged crank and H-beams
Wiseco -8cc piston
PRC 2.5 64cc 5.3 Heads
Custom Nitrous Cam(havn't had it spec'd out yet)
4.10's with a 28" tall tire.

Now,
I've notice turbo cars stay real high gears, 3.00 on a 28" and nitrous cars are around the 3.73 range on a 28" tire.
Why is this?

Also, I know a little about tire sizing, but I'm gonna ask the question anyway.
Why go with a 28" tire over a 26", or vise versa?

 

Damn!
Not everyone at once now...

 

In my opinion.

Most of it has to do with MPH and the power that a turbo car can make. Drivers most times need to calm the car down off the line and when under way the power band hits and they can finish out the run. Nitrous cars even when hitting 100% at the line still need to get the car up and out of it's own way and depending on the size of the shot (10hp = to roughly 1 mph) will make a car faster but not to the extent of what a high hp turbo car can see. I am also aware that high hp turbo cars may use 2 or even 3 step systems to control the car as well off the line.

Look at some cars here, they may run similar times but the turbo car should be out MPH then Nitrous car all day.

With the 28" tall tire, you get more side wall, and depending on rim width, your getting contact patch. the more you have, the often better off you are.

I am sure more will chime in, I am not a Turbo expert but this is what I have seen, some cars even going to a powerglide to calm the car down in the trans (also benefiting from a smaller, lighter trans w/ less parasitic power loss), I have some good exp with bigger cube n2o cars and that is where my info comes from.

 

Changing tire size also changes gear ratio correct?

 

Yes it does, the over all diameter can effectly increase or decrease the RPM you see at a given speed, and transmission gear.

Also a bias-ply slick can grow up to 1" so a 28 becomes 29 at speed. Radial tires do not deform.