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Member #1303
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Discussion Starter · #1 ·
i have retyped an excerpt from the july 2004 four wheeler magazine, as a further explanation in a different thread. i felt that it deserved its own thread to reach a wider audience.
perhaps even sticky status :wink:

Biased Against Radials
Radial tires are great - for Corvettes, BMW X5s and those pesky commuter cars, or basically anything else on pnumatic tires that rarely goes on a trail. On pavement, the radial delivers a longer tread life, better handling and muched reduced rolling resistance. That's because a radial tire's tread area is made to be very stable, with steel belts to stiffen it, concentrating instead the necessary movements to thin and very flexible sidewalls.
Bias-ply tires conform equally well from bead to bead, providing maximum flexibility for flotation and conformability - except that the tread blocks are usually made to resist movement to make the tire work better on pavement. We can fix that with a grooving iron, because we want a flexible tread area, since a well - conforming tire works much better on the trail, be it for sand, snow, mud or rocks. We also want those thick sidewalls the very same ones that create heat nd reduce mileage on the highway. They are so much better at fending off sharp rocks and roots than a radial's thin, fragile sidewalls. It doesn't hurt that bias-ply tires are less expensive and they they can last much longer in trail use.
We gladly trade the on-highway mileage penalty (both fuel and tread wear) just for a bias tire's much higher cut and impact resistance. Unlike a radial, bias tires are also reparable to within 1.5 inch of the bead. That a bias tire is easier on the driver, vehicle and terrain, thanks to its superior conformability is a nice bonus. Finally, that conformability leads to much better trail traction, and isn't getting max traction what we really want?
So, radials are great for your commuter car and tow vehicle, but not for trail use.

Radials Rule. Really!
These drawings (No scanner, sorry can't show you. There are two images of a tire cross-section rolling, one with only half the tread on the ground, labeled Bias-Ply. The other image is a radial, rolling, with 90% of the tread on the ground, labeled Radial.) illustrate the difference between bias-ply and radial tires in a cornering situation. A portion of the bias-ply tire loses contact with the road as both tread and sidewalls distort under a cornering load. The radial tire deflects in the sidewall area, keeping the tread flat on the ground, which reults in greater surface contact.
Michelin introduced radial tires in 1949; since then, the automotive industry has embraced them as the standard on all new vehicles. The reason is simple: The advantages to radial construction, which employs stabilizing belts under, and as a foundation for, the tire tread, help to reduce tread distortion. As the sidewalls deflect, the belts hold the tread firmly on the ground, minimizing tread scrub and greatly increasing tread life. Longer tire life means fewer tires have to be produced, thus saving resources. In addition, less fuel is required due to lessened tire friction, minimizing gasoline consumption.
For the average 'wheeler who drives his truck to and from work on paved roads during the week and only ventures out on the trail on weekends, radials are the best choice.
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