Wheels and Tires

How does the larger size tire affect the performance? Our project Big Red came equipped with 235-75-15 tires. The truck was designed to offer ride comfort low performance and zero looks.

We installed a set of 20” “Hang Tyme” LACED Wheels on favorite Toyo Proxes S/T 295-45-20. This not only improves the looks of the truck but they will make our new 383 c.i storker engine sparkle. The low profile tires will assist in the handling department, produce more top end speed (if needed) allow the motor to cruise at lower rpm’s and possibly be easier on gas consumption.

But how do these wheels affect our horsepower and torque numbers? Our stock tire diameter was 29.38” compared to 30.83” on our new ones. This equates to about 4.7% diameter difference. If compared on a gear chart this is what you would see at 2,000 RPM

GEAR CHART:

 235-75-15 with 3.07:1 gears

295-45-20 with 3.07:1 gears

Based on the chart we can conclude that at the same 2000 RPM you would gain 6.09 mph. This can also mean that at the same 80 mph you would cruise at less RPM and thus making it easier on gas.

As far as HP although not tested yet, we can conclude that a similar gain of 4.69 % would come from the tire change. A similar percentage would have to be sacrificed in the torque curve. But this is why we chose the 383 vs a standard 350.

Driving Impressions

Installing these big wheels made a difference in many ways. The truck has a sport feel to it. There is much more steering response and you get more feel of the road. Having a low profile tire decreases some of the weight transfer as if the truck had larger sway bars.

Although the un-sprung weight factor has in fact increased the truck feels more stable. Also the Toyo Tires have much better handling characteristics that increased our confidence level while driving the truck thru curvy cannon roads.