Drag Radials

[Coach]

I run mine on a 10 inch rim.

Coach

[Rick Schilling]

It seems that a 10" rim with a radial tire is probably the most popular combination being used right now. I understand the logic behind that, with increased air pressure and decreased rolling resistance, etc., but what about the somewhat old school approach of using a narrower rim and a tire designed to grow a significant amount, allowing the final drive ratio to raise as wheel speed increases. I seem to remember a time when some of the tire manufacturers offered "high-growth" sportsman tires. The variable ratio effect would seem to me to be a real advantage if utilized properly ( i.e. steeper gearing) or has the wide rim/radial tire combination actually been proven to be that much better?

[treessavoy]

Originally Posted by Rick Schilling

It seems that a 10" rim with a radial tire is probably the most popular combination being used right now. I understand the logic behind that, with increased air pressure and decreased rolling resistance, etc., but what about the somewhat old school approach of using a narrower rim and a tire designed to grow a significant amount, allowing the final drive ratio to raise as wheel speed increases. I seem to remember a time when some of the tire manufacturers offered "high-growth" sportsman tires. The variable ratio effect would seem to me to be a real advantage if utilized properly ( i.e. steeper gearing) or has the wide rim/radial tire combination actually been proven to be that much better?

The reason I brought this up is that at one time there was a theory that wide tires on a narrower rim would provide more "bite" at launch due to the flattening of the tire providing all 9 inches at the hit, also the tire growth on the other end.

The other theory was that a wide rim with a narrower tire planted the tire for a longer period as the car accelerated from the line.

Just wanted to hear which wheel everyone was using with the radial.

[Ian Hill]

i am new to the stocker game as well. i have a 3500 lb chevelle with 8" rims and the hoosier light weight 92.5 roll out tires - any advise for the starting point on air pressure?

thanks
Ian

[rallye bob]

Originally Posted by Ian Hill

i am new to the stocker game as well. i have a 3500 lb chevelle with 8" rims and the hoosier light weight 92.5 roll out tires - any advise for the starting point on air pressure?

thanks
Ian

Ian;
Are you running the #18209.... 30.0/9.0R-15 Hoosier, radial?
If so, I would start at 21 psi and work my way down (no less than 18 psi).
What do you run for a 60' time?

[72Malibu]

15x10 draglites with Hoosier 30x9x15 radial slicks, 94.5 rollout, C07 compound.

[Myron Piatek]

Originally Posted by Rick Schilling

It seems that a 10" rim with a radial tire is probably the most popular combination being used right now. I understand the logic behind that, with increased air pressure and decreased rolling resistance, etc., but what about the somewhat old school approach of using a narrower rim and a tire designed to grow a significant amount, allowing the final drive ratio to raise as wheel speed increases. I seem to remember a time when some of the tire manufacturers offered "high-growth" sportsman tires. The variable ratio effect would seem to me to be a real advantage if utilized properly ( i.e. steeper gearing) or has the wide rim/radial tire combination actually been proven to be that much better?

A radial slick will grow very little because of the radial design and rpm's are always higher when switching from a like-sized bias ply. So the growth theory would apply to the bias ply, but if the sidewalls are deformed too much and/or too often, the deformation can extend to the tread surface of the tire reducing it's footprint as well as simply wearing out the sidewalls. Lower pressures and narrow rims can also cause issues on the top end. But I've heard a few people say it works for them.

Worth noting is that a radial is more sensitive to track conditions. A bias ply will be more consistent and predictable under marginal conditions. But a radial is faster. So one has to figure out his/her priorities/needs.

[Dustin Ward]

Excellent response as usual Myron.