Picking the correct chassis for your door car is key to getting the type of performance you want. There are so many terms that get thrown around, but many racers have a hard time coosing between a single frame rail car, and a double frame rail car. With all of the different options out there, it can make things difficult. But fear not, as Tim McAmis is here to give you all the information needed so you choose the right chassis for your racing needs.

The basic definition of each chassis type is pretty straightforward: single framerail cars have supports that run from the four link area, to the foot-box area of the chassis only. In a double framerail car, there is an extra, top level of tubing that mirrors the bottom tubing from the four link area, all the way to the front of the car.

An example of a single frame rail chassis.

Where things start to get complex in chassis choice is trying to figure out which design is best for you, and the answer from McAmis is, it depends on what you want to do with the car. A single framerail is still outstanding for quick cars, where a bit more flex and power absorption is not an issue.

Top Sportsman tends to be the point where you see the single versus double framerail debate take off due to how much power the cars make, and how quick they are.

A double frame rail car from McAmis

If you’re looking to make big power in your door car, say, using a screw blower, big turbos, or a big cubic inch nitrous combination, the double framerail chassis is the way to go. That much power requires a stiffer chassis that can take the abuse, and put the power down properly.

McAmis really recommends looking at your program’s goals to see if double framerail chassis is needed, and will be used to its full potential.

Check out this full video from Tim McAmis Performance Parts that really goes into great detail about the differences between the two chassis and what one will work best for you.