Choose the Best Chassis for Your EV

CHAPTER 5 Chassis and Design

A 20-hp electric motor will easily push your 4,000-lb. vehicle at 50 mph.

The chassis is the foundation of your electric vehicle conversion. While you might never build your own chassis from scratch, there are fundamental chassis principles that can help you with any EV conversion or purchase—things that never come up when using internal combustion engine vehicles—such as the influence of weight, aerodynamic drag, rolling resistance, and drivetrains.

This chapter will step you through the process of optimizing, designing, and buying your own electric vehicle. You’ll become familiar with the chassis trade-offs involved in optimizing your EV conversion. Then you’ll design your EV conversion to be sure the components you’ve selected accomplish what you want to do. When you have figured out what’s important to you and verified your design will do what you want, you’ll look at the process of buying your chassis.

Knowledge of all these steps will help you immediately (when reading about Chapter 10’s pickup truck conversion), and eventually (when picking the best EV chassis for yourself). The principles are universal, and you can apply them whether buying, building, or converting.

Choose the Best Chassis for Your EV

The chassis you pick is the foundation for your EV—choose it wisely. That’s the message of this chapter in a nutshell. Since you’re likely to be converting rather than building from scratch, there’s not a lot you can do after you’ve made your chassis selection. The secret is to ask yourself the right questions and be clear about what you want to accomplish before you make your selection.

Like a youngster’s soapbox derby racer, you want a chassis with an aerodynamic shape and thin wheels, so that you can just give a shove and it runs almost forever. But its frame must also be big enough and strong enough to carry you and your passengers along with the motor, drivetrain/controller, and batteries. In addition, if you want to drive it on the highway, federal and state laws require it to be roadworthy and adhere to certain safety standards.

The first step is to know your options. Your EV should be as light in weight as possible; streamlined, with its body optimized for minimum drag; optimized for minimum rolling resistance from its tires, brakes, and steering; and optimized for minimum drivetrain losses. The motor-drivetrain-battery combination must match the body style you’ve selected. It must also be capable of accomplishing the task most