So I decided to test how fast do the base game vehicles allow to drive you in reverse. The first test was with the default Gavril D-15, and I reached a top speed of 109 km/h (68 mph). Then I started playing with the final drive ratios, and I got a 2:1 diff up to 180 km/h (112 mph) before I lost control. Further testing with Alder Dragger tires, a Stage 3 supercharger and lowered reverse gear ratios reveled that the truck became uncontrollable around 215-220 km/h (134-137 mph) on stock suspension. Upgraded suspension helped remedy the problem and get past 240 km/h (150 mph). Then I removed all the unnecessary weight of the cab and bed, Out of curiosity I tested the result's top speed forward, and it went up to 450 km/h (280 mph). In reverse it got up to 273 km/h (170 mph) before losing control. Then I went on with the best power-to-weight ratio in the game - the drag Moonhawk. In base form it only goes up to 118 km/h (73 mph) in reverse. But add a 2:1 final drive, and the top speed goes up to 197 km/h (122 mph). However, uprated suspension and a regeared reverse yielded a top safe speed of 334 km/h (208 mph). Removing the body made the chassis capable of 394 km/h (245 mph) before one of the front tires gave up. This is all for today. So you can get up to 240 mph in reverse, but at this point you'll realise that suspensions are made for keeping the car stable forward, not in reverse. You may wanna play with the suspension setups, but I'm running out of time.