The Rotax Max group of classes were designed by Bombardier to provide cost-effective but high speed racing. The engine used is a fixed-gear 125cc reed valve engine which is sealed, and only authorised "Service Centres" are allowed to carry out maintenance. Rebuilds are recommended after 50 hours compared with 2-3 for other two-stroke engines.

There are several different versions of the engine. The original has a power-valve and produces around 28hp, and is used by racers aged 16+. The Junior engine has no power-valve and produces around 22hp (age 13-16), and the Minimax has a restrictor plate in the carburettor which restricts it to about 18hp. There is also the RM1, which has two gears and is direct drive in that the axle goes through the engine without need for a chain.

The concept was introduced to karting in 1998 and almost immediately began to gain market share from other slower and more expensive classes.

Rotax organises the Rotax Max Challenge for racers all over the world, who compete at a national level. The top drivers in each national series are invited to compete at the World Finals in a holiday destination such as Lanzarote with all their expenses paid.