Radial tires make more surface contact with the ground then bias tires do. In general radial tires are better because of improved handling and traction. Each type has their own purpose, but overall the radials are better in my honest opinion. Here's a list of advantages and disadvantages over the two. First off, lets' start with the bias tires.
Bias Tire Advantages:
* Strong sidewalls, tough casing
*Better sidewall puncture resistance
* Good lateral stability (Hill Side Work)
* God in rough terrain and off-road
* Self-Cleaning
* Easily repaired
* Low Purchase Price
Bias Tire Disadvantages:
* Poor life expectancy, (50% of radial)
* Lack of flexibility in casing reduces foot print and traction
* Tread flexes more, generating heat and rolling resistance
* Greater rolling resistance and fuel inefficiency
* Profile of the tire increases soil compaction and reduces traction
Radial Tire Advantages:
*Good high speed capacity
* Longer lasting, (Up To 50% Longer)
* Wear resistant
* Low heat build-up
* Lower rolling resistance
* Better fuel economy
* Better floatation and larger contact area
* Less soil compaction
* Better stability and machine handling
* Smoother, more quiet ride
* Proliferation of tires in the last 10 years has mostly been radial
Radial Tire Disadvantages:
*More prone to puncturing
*More difficult to repair
* Higher purchase price
As you can see they both have their advantages and disadvantages. But if you decide on radials try and find the one with the highest ply rating, 8 is the largest that i know of. The original Bear Claws are 6 ply and pretty tough to begin with. I even had a nail lodged in one of the lugs and had it looked at by my local garage. He then called me and told me he just pulled it out and it was fine. Anyhow, just to show you the difference between the two read this: (
Bias vs Radial Tires : ATV Tire Comparison : Mud-Throwers.com) It'll explain the differences between the two, which is also where i grabbed the advantages/disadvantages info.