4wd tyres come in a variety of different sizes and tread patterns and sometimes are made for very specific uses. Most standard 4wd vehicles will come with a Highway Terrain (HT) or All Terrain (AT) 4wd tyre. The HT tread pattern is usually a less aggressive tread design than the AT with the HT tyres designed to be used mainly on-road. The HT tyres have little ability to handle much in the way dirt or mud as the HT tread design is more shallow and less aggressive than the All terrain and Mud terrain tyres. All Terrain tyres are able to handle more dirt and mud in between its tread, and provide more grip and drivability, because of extra depth and aggression in the design of the tyres tread pattern. Whilst being more aggressive than the HT the AT is still designed to be used on-road without any adverse effects. Mud Terrain (MT) tyres are 4wd tyres made primarily to be used for serious off-road driving, they have a very aggressive, deep tread design, made to handle large amounts of dirt and mud. These tyres are very knobbly and when used on-road can create a noisy, uncomfortable ride at high speeds. Most drivers using Mud Terrain tyres understand the limitations of these tyres and they are perfectly safe to be used on-road but inexperienced drivers should take care to understand the handling characteristics of these aggressive tyres when used at high speed.
source: http://www.tyrescentral.com.au/4wd-tyres.html
source: http://www.tyrescentral.com.au/4wd-tyres.html
