When you start talking 600hp + :confused: and 10 second et's, why do people say that a 28" tire will et better than a 26"? Wouldn't you lose gear?

One reason...
A 28" tall tire makes a larger "footprint" than a 26" tire, assuming the same width.
Larger footprint equals better traction.
Guys running a 28" tire(or 30" or 32", etc) take that into account when choosing rear gear ratio.

Yes you lose gear but you gain torque and don't need the gear,heck Top Fuelers and Funny Cars run a 3.50 gear(I believe)with those big meats. You also gain contact patch going to a taller tire which helps traction.

If you have good power and torque the car will require an ideal size tire.....simply put, if the car picks up with a larger tire then you may have too much torque multiplication with the tire and gear combo you had. When possible run the largest tire you can with the appropriate gear simply because its easier to get it to work(hook).

Going from a 26' tall tire to a 28" tall tire makes for about an 8% decrease in effective gear ratio; making a 3.73 and 26" tire about equal to a 4.11 and a 28" tire.

By the time you are talking 10 second passes in a Chevelle there is a serious amount of torque being made, and the longer contact patch of a taller tire becomes more important.

If nothing else, a longer contact patch will get you more consistent launches. At best it will make for quicker 60' times.

Thomas

All of the above responses are on the money..I run a 28" tire with my gears for the reasons stated above.

I was asked about this the other day and I didnt quite understant it either. The way I see it:

Increase in diameter = increase in circumference
Axles and tires turn one to one.
Therefore, wouldnt a larger diameter tire with a larger circumference lead to more distance covered with one tire/axle revolution?

Am I missing something here?

MaTt

You're right matt. That's why you need to choose a rear gear to work with your tire height. If you had really tall tires, say 32", you wouldn't use a 2.73 gear. You'd need a higher number rear gear to account for the really tall tire.

The taller tire also has a longer footprint, front to rear. This is one reason why taller tires are desireable. You just have to choose the rear gear to match.

The taller tire is also as a general rule, heavier and requires more torque to turn. This resistance helps traction to some degree. The Fuel and funny cars make so much torque ( about 5-6 thousand lb-ft) that if they are coupled up solidly they just spin the tires, thus they use a eight or ten stage slider clutch with pnuematic controllers to couple the engine gradually to the tires. The rear end gears in these cars are as high as possible and a few years ago were capped off at 3.2-1 by NHRA in an attempt to limit top speed. They would likely be faster with less gear but might require a larger ring and pinion than the already staggering 12" ones in order to keep them from breaking.