Over-sized, low-pressure, knobby, mud-terrain tires are used. Most vehicles have a low-geared transfer case to make the most torque in the low speeds used for rock crawling. Suspension-wise, rock-crawling vehicles sometimes have after-market lift-kits installed, raising the chassis and increasing suspension flex, though the rock crawlers running the tougher trails often have fabricated suspension systems, or home-assembled leaf packs to cheaply achieve the goals, making it easier to drive over larger obstacles with less risk of damage to the vehicle. Most suspensions are made to be highly flexible, allowing for the maximum amount of tire area to contact the ground, while keeping the vehicle as low as possible. Due to the conflicting nature of the dynamics and needs of rock-crawling and highway-driving vehicles, it is not unusual to modify a vehicle solely for off-road recreational usage.

Once a vehicle is deemed "off-road only" i.e. not driven on the street and tailored to trails or OHV parks (Off-Highway Vehicle), then the modification possibilities are endless.

Those with the financial resources can build their own rock crawler. The biggest benefit of this approach is that the owner has complete control over what their vehicle is capable of, since each part of the vehicle can be custom designed. Acquiring sponsors can help to cover some of these costs.