Your wheel selection will determine what sort of road your kart does best on.

Flat profile tires (especially at lower pressures) offer a larger contact patch and grip but have relatively high rolling resistance. They may handle well in corners but will not accelerate as well or have a high top speed.

Round profile tires (especially at higher pressures) have very low rolling resistance but have smaller contact area. They will reach higher top speeds but may slide easier under tight cornering.

Tall wheels like bicycle wheels will not have to rotate as fast as go-kart wheels at a given kart speed, but are more prone to folding under extreme cornering loads or bumps.

Foregoing suspension will mean lower weight, complexity, and cost.

The benefits of suspension are comfort and coolness. In my experience, handling and speed are a wash between the two options.

If you make suspension, you must make it well or it will hurt the kart's handling and speed. My first iteration severely impacted my cornering ability.

Your suspension must have as little slop and unpredictability as possible. Use only high-quality parts and materials, double-check all your measurements, and make sure your welds are good.

Do NOT use the inline ball-joint linkages shown in the upper right of image 2. They have too much play for a suspension system, and were replaced shortly after this picture was taken.

These lower members really need to be beasts. they'll have the shocks attached to them so they're bearing the load of the entire kart. Even if you're going for a lightweight kart, don't skimp here.

Tube-end weld nuts serve as the attachment point for the spindle-end ball joint, and a pair of bushings will rotate about a 3/8" rod attached to the frame. This allows the arms to swing up and down but not side-to-side.

Gussets help absorb the stress on the frame end welds.

For the rear suspension, the shocks are mounted on tabs above the member. For the front, shocks are mounted directly to the suspension members.

The suspension I use on all 4 corners is unequal-length A-arm. The top arm is shorter than the bottom arm so the wheels will show negative camber at bump and positive camber at droop.

• This keeps the wheels perpendicular to the road under cornering to maximize the contact patch. If you're using round-profile tires, equal length A arms will be easier.

The shocks aren't attached to the upper arms so they won't be bearing much load in any direction besides compression. I felt free to make these lightweight and not very strong: the main arm is 1/2" EMT.

Higher-quality steel tube at the frame end allows for precision bushings, and a 3/8-24 ball joint attaches to the spindle end for suspension articulation as well as steering/alignment.

I mounted the suspension to the frame using 3/8" rods with bushings on the suspension members.

Except for the top rear arms (pictured in middle image), the 3/8" rods are held to the frame via simple cotter pins.

Shocks are attached to the frame via welded-on studs. Be careful when working out suspension placement; it can get very crowded with arms, shocks, tie rods, wheels, the frame, etc.

The spindles are the thing that brings your suspension together. They connect the upper and lower arms, hold the wheels and the brakes, attach to the steering system, and are the single biggest pain in the butt about this project, especially if you're trying to minimize weight like I am.

Some go-kart suppliers sell ready-made spindles for karts with brackets that weld directly to the frame. If you've opted for no suspension, these are probably a good idea as spindles are the component I find myself revising the most often.

If you do opt to make spindles yourself, there are 3 or 4 parts you will have to make: kingpin (vertical element that is the axis of rotation when turning), axle (for the wheel), drag link arm (for turning/alignment), and (optionally) mounting points for brake hardware.

Be careful what materials you choose for the kingpin and the axle, as they must be sturdy enough to support the weight of the kart under stress, even if you have suspension. Use your most precise tools when drilling holes for spindle parts, as they must all be at the correct angles or steering/suspension geometry will be off.

To accentuate the camber change of the unequal length A-arm suspension, use a total kingpin length slightly greater than the height difference between the upper and lower suspension mount points on your frame.

Here you'll need to tap some threads into the ends of the kingpin for the ball joints to thread into. I used a 3/8-24 ball joint on top and a stronger rod end on the bottom which I attached via a 3/8-16 fully-threaded stud.

If you have to tap two different thread sizes, be sure not to confuse top and bottom.