The new fourwheeler magazine (jan 2002) did a comparison of 6 "new" tires. All except one of the tires were radial tires, the other was a bogger. The thing that I noticed was allot of tire manufacturers like BFG, Goodyear, Parnelli Jones, etc are developing new aggresive tread tires aimed at the rockcrawling market. I attribute this to the recent increase in rockcrawling popularity. The question I have is.....why aren't these companies making bias ply tires. The best choice for a bias ply is still super swamper, and mickey thompson seems to be the only real competition. Why not bias ply?? Is the process to produce radial vs bias ply really all that different that these large companies do not want to purchase the new equipment?? Or are they just lazy??

Basically because Bias is old tech.

The major weakness of a radial is the sidewall strength, and if a tire company can overcome this with a radial that is comparable to a Swamper in sidewall strength, bias will be obsolete.

A radial has a better contact patch and will conform better to the rocks at a given pressure than a comparable bias.

ARCA winners don't only run M/T-R's cause Goodyear sells them cheap.

The DirtGrip 38.5" looks pretty tempting next to a 39.5" Boggy, considering that at 10 psi the Dirtgrip will swallow a rock that a Boggy wouldn't begin to flex on at 6 psi. Add in that the DG's measure alot closer to the specified size than a Bogger and they look even better.

Take Lance's recent switch from worn out 39.5" Boggys to 37" M/T-Rs. More clearance with a smaller tire. Best of both worlds.

Just my $.02

Re sidewall weakness: unfortunately, bias tires aren't obsolete, viz. the new SSRs. We are hearing more and more stories of ripped out sidewalls, The tire companies persist in calling 2 and 3 ply polyester sidewalls with thin rubber "strong sidewalls". The only radial with respectable sidewalls is of course Michelins. In 8.25R16 (9X34), 9.00R16 (10X36), 11.00R16 (11X39) and 325/85R16 (13X39). Not Michelin's "RV" or "SUV" offerings but their military/industrial tires.
Charlie

the flexible carcass of the radials that are on the market is because of the thick sidewalls. The same thing that makes the tires work good also causes their weakness. BFG Baja TA's and Project Ta's are also radials with stiff sidewalls that perform more like bias ply tires on the trail than radials.

Originally posted by Gordon
the flexible carcass of the radials that are on the market is because of the thick sidewalls. The same thing that makes the tires work good also causes their weakness. BFG Baja TA's and Project Ta's are also radials with stiff sidewalls that perform more like bias ply tires on the trail than radials.

This is a very good point! however I think they can have a compromise between Baja TA and MT and ahve a great rock tire, well maybe not great for Johnson Valley...

While on this topic anyone using the PJ's??? I want something good for Moab/rubicon, mud, and better milage then a bogger or bias swamper. These look like a good option, and they are big for there labeled size (I like the 35x12.50)

I don't want to know whether bias ply or radials are better. I want a bias ply tire. I want the thick stiff sidewall. Why?? The biggest reason is bias ply will outlast a radial. No not in mileage but simple time. I can leave a bias ply sitting around for years and not getting sidewall rot. I'm not going to argure foot print or whether the only way to achieve a strong sidewall in with a thick stiff side wall. I just want to know why the companies aren't making them any more. Is it because bias ply is considered old school?? Then why are they still produced for drag racing?? bias ply are not old tech, simply specialised. Someone got an idea why the big companies with lots of R&D money aren't making bias ply?? I think it's just another example of big companies being lazy and influencing the publics view.

Tire companies aren't making bias plys because radials ride much better on the street, therefore the road going public is going to buy more radials, and THAT is where the money is. It's all about volume and how many of a certain model a tire is going to sell. For instance, why doesn't Goodyear make the 37 cheaper, and/or make wider models of the MTR? I think it is because they wouldn't get enough sales volume. The bigger manufacturers probably have a volume/price break, where in order to sell a tire for a price which they think the comsumer will accept, they have to sell a certain number of them. If they can't sell that number, they can't reach the break even point, and they would have to increase the price of the tire dramatically, as is the case of the 37 inch MTR.

Some manufacturers are geared towards making money by serving small niches, like Interco, but that kind of volume simply doesn't interest a company geared towards mass marketing.