They are optimistically known as mudders, and until recently we had little use for this class of tire.
The casing is the first important building block of any tire. In the case of light truck tires, there is no point in being cheap and buying a passenger car tire. With the rim sizes and load factors of today’s half-tons, light truck tires are a must.
Tire manufacturers have a classification system based on more than carcass design or having the M+S designation on the sidewall. M+S is more a passenger car designation that may mean it qualifies as a winter tire.
However, to merit the full winter tire designation, a tire needs to have the mountain with a snowflake logo.
Everyone I talked to agreed that you can’t tell how good a tire is by looking at it. There are many design issues that can affect how well a mud tire performs.
There is general agreement among manufacturers, dealers and users that good mud tires must have tread extensions on the sidewall to help grind through the soft stuff or climb out of a rut.
There was near universal agreement that the tread needed a block-like design with an obvious traction/ flow pattern that flexed to keep the tread from filling up with gumbo.
Brand loyalty comes into play. End users preferred the tire recommended for their particular vehicle by the dealer. This may be a ringing endorsement for the tire industry, but I don’t think it does much more than prove that all companies make good mud-type tires.
Another interesting point is that it’s best to stick to stock sizes unless you modify your truck for bigger tires.
As for a mud tire, you first have to determine how much time you are going to spend off road. Different mud tires have different wear ratings, based on the different rubber compounds.
Tire lugs must flex to do their job properly. If the rubber is too soft, the lugs wear down quickly and can’t move mud as well. If the rubber is too hard and doesn’t wear, it may not flex well enough to get the mud out of the tread pattern.
Excessive flex causes a tire to wander on pavement as if the vehicle needs a wheel alignment. This tire squirms under braking, causing the truck to move about in the traffic lane during a hard stop. It may also cause the ABS to intervene sooner and stopping distances will increase.
When lugs flex on pavement, they create heat that cannot be dissipated by mud. When they get hot enough, chunks come off and the tire may blow out. Your compromise is between all out traction and wear/survivability of the tire on the road.
Noise is another issue manufacturers work around. Mud tires are noisy on pavement because the lugs constantly slap the road.
Many jurisdictions have noise bylaws. The wrong tire can make a vehicle too noisy to be used legally. In addition, a noisy tire can cause excess driver fatigue or cause a driver to not hear something important such as an emergency vehicle siren.
Every company I checked with makes aggressive off-road tires and they all make several compromise tires. Your tire specialist can help figure out what you need out of the tire.
These things aren’t cheap. Why someone would spend a grand or more on tires just so their truck looks good is beyond me. I would rather spend the same money on tires that look good, do what I need and last more than a year.
The right tire for you is out there, but it’s up to you to find it. Your life may depend on it.
Charles Renny is an automotive columnist and a member of the Automobile Journalists Association of Canada.