What is the difference between Heavy, Heavy duty and Offroad trucks?

[RMaSTeR]

just curious about this types of truck, I guess highway trucks are just to have repair trailers attached to be able to repair another trucks while in the garage area

[mendel]

Heavy Duty and Highway trucks weigh 5-8 tons. Offroad trucks weigh 8-16 tons. Heavy trucks weigh 13-29 tons.

Highway trucks are quite fuel efficient and can be used off-road, though they tend to not do well in mud. More so than with other trucks, you need to weigh their rear axles down with some ballast (cargo is free!) since they don't have front wheel drive where the weight of the engine provides weight for traction. For example, I have taken the Transtar with the fuel add-on beyond the logging camp in Smithville Dam to refuel a stranded truck; and I've taken the Ford CLT9000 with a maintenance add-on to the Imandra gateway on Lake Kovd. The GMC MH9500 is a very capable truck with the AWD upgrade that is hidden on the Kola Peninsula, but it can also do any task in Black River as you find it.
Challenge yourself and use these trucks!

Highway and Heavy Duty trucks do not have access to mud tires.

Heavy trucks are often restricted in the types of add-ons they can take, and may or may not have mud tires available.

P.S.: The garage auto-repairs any truck in normal mode, so to "repair another trucks while in the garage area" from a trailer is fairly useless -- and you'd be better served to put a van body or maintenance addon on the truck itself. In hard mode, it may make sense to position the repair trailer near a resupply point so that it can be refilled as needed. These are typically not near a garage.

[RMaSTeR]

Thanks! I want to play hardmode for the first PT, after finish the tutorial in normal