How Do Bump Stops Work?

Suspension travel has its limits; bump stops keep that travel distance from going too far.

David Gluckman | 

Oct 4, 2024 | 2 min read

Austin Lott | Capital One

A vehicle's suspension has a limited range of travel both up and down. If you pass over a large speed bump too quickly, for example, you may feel the suspension reach both the top and bottom of its limits. Car suspensions are designed to operate within an expected range of travel in relation to the type of surface you drive on most of the time. Bump stops, as their name suggests, stop the suspension from traveling too far in one direction.

Manuel Carrillo III | Capital One

What Is a Bump Stop?

Typically made of rubber, polyurethane, or foam, a bump stop acts as a dampening pad between a moving suspension component and a fixed point on the vehicle. Bump stops are generally static objects meant to cushion the blow of a big suspension movement — sort of like how a wall-mounted door stop prevents the knob of the swinging door from crashing through the wall.

Manuel Carrillo III | Capital One

What Does a Bump Stop Do?

Bump stops are designed to keep a vehicle's occupants relatively comfortable and make the vehicle easier to control when approaching the limits of suspension travel. They prevent the wheels and axles from moving beyond the intended range, and they can often prevent an overloaded vehicle from scraping its underside on the ground. This does not, however, make it safe to load too much weight in the vehicle, so be mindful when piling bags of cement in the back.

Suspension engineers tune the bump stops' material, size, and shape to achieve appropriate control and keep metal from hitting metal. Stops can take several forms, largely dependent on the type of suspension design employed — above a solid axle, on a suspension component such as a control arm, or as part of the damper within a strut assembly.

Some vehicles use hydraulic bump stops that function almost as an extra damper to better control the last bit of suspension travel. These are most common on off-roaders, which have heavy wheel-and-tire combos.

Can I Install Bump Stops Myself?

Some bump stops are relatively easy to access, such as those mounted to a truck's frame above an axle or set of leaf springs. Others, like those in a strut-type suspension, require a lot of disassembly to access. These are doable jobs for a home mechanic, but if you have any hesitation, it's probably better to take the vehicle to a professional. Bump stops are a wear item but thankfully don't usually require frequent replacement on normal passenger vehicles.

David Gluckman

David Gluckman has over a decade of experience as a writer and editor for print and digital automotive publications. He can parallel park a school bus, has a spreadsheet listing every vehicle he’s ever tested, and once drove a Lincoln Town Car 63 mph in reverse. When David’s not searching for the perfect used car, you can find him sampling the latest gimmicky foodstuffs that America has to offer.