Monotube vs. Twin Tube Shocks: Which is Best for Performance

Aaron Lambert
Post by Aaron Lambert
September 27, 2021
Monotube vs. Twin Tube Shocks: Which is Best for Performance

Would you prefer water or an energy drink?

Ultimately, your decision depends on your goal. They’re both drinks, but they each have a distinct purpose.

The decision of monotube vs. twin tube shocks is similar. Both provide suspension, but they each have a distinct purpose.

While many people have opinions (even with the “water or energy drink” question), each suspension type can give you a marked advantage in certain scenarios.

We’ve compiled a list of the variables often considered when purchasing suspension, and layed out the differences between monotube and twin tube shocks. This list should make it easy to see which shock is best for you.

Which is Best for Your Performance: Monotube or Twin Tube Shocks?

The key element in determining which shock type is best for you comes down to the vehicle you drive, and how you drive it. Driving or riding something that doesn’t feel quite right will hurt your ultimate performance.

What is a monotube shock?

In a monotube shock, the shell case itself works as a cylinder, carrying oil, gas, and a piston valve. It’s a single tube, and a floating piston separates the oil chamber from the gas chamber. They’re used in most race cars because they provide a stiffer ride and their damping forces are more precise, giving the driver more control.

What is a twin tube shock?

In a twin tube shock there are two cylinders. One cylinder sits inside a shell case. The interior cylinder contains the piston valve. There is no piston or barrier between the oil and gas chambers. The main advantage of a twin-tub design is the packaging.

Monotube vs Twin Tube Shocks

Both monotube and twin tube shocks perform similar jobs; to make your ride more comfortable and to give you the edge when it comes to car handling and suspension performance.

Still, there are a few key differences to take into consideration, like how they’re built.

Shock Installation

Because of their design, most twin-tube shocks can only be installed in one position; if installed upside down, the shock will not perform. Mono-tube shocks have a separator piston that keeps the gas separate from the oil. So the shocks can be installed rightside up, upside down, or even laying flat like on a formula car.

Shock Design

In a monotube shock, the oil and gas chambers are completely separated by a floating piston. There is no aeration or foaming, and the valving becomes much more responsive. Higher gas pressure offers additional resistance, giving the monotube variable for tunability. Increased performance just when you need it!

Because the gas itself becomes part of the spring action, it compresses over smaller bumps and quicker through bigger hits, which improves control and response.

Monotubes have a larger surface area to spread the load, so they distribute pressure evenly over the entire shock. Typically resulting in a more efficient and better performance.

In twin tube shocks, either air or nitrogen is inserted at low pressure into the outer tube above the valve so that it doesn’t escape into the inner tube. This keeps pressure on that end of the oil, minimising aeration or foaming - that occurs when the shocks are under hard use (this will be important later).

Shock Cost

There are differences in cost between the two applications.

Twin tube designs are generally used in OE applications for their higher stroke vs. overall length compared to mono tube designs. Typically a twin tube is a cheaper shock simply because they are mass produced.

Mono tube designed shocks are typically hand built with performance in mind, making them more expensive, but custom for a specific application.

Shock Maintenance

Shocks suffer the same effect as any hydraulic circuit having air mixed inside - which can lead to poor damping when air mixes with fluid, which happens more easily in the twin tube design. This isn’t ideal for high performance.

Fading is also an issue. Constant pressure on the shock may lead to the performance of the shock fading (which happens with foaming in twin-tubes); hence the damping becomes weaker causing handling issues or changes. .

Mono-tubes are typically the shock design of choice for racers. They are easier to work on, allowing for easier maintenance or performance changes.

Monotube vs. Twin Tube: What Does This Mean For You

If all you're after is a shock to control your spring and give you a somewhat comfortable ride, while not costing you too much, twin tubes are best bang for your buck.

When it comes to performance, custom feel, and all out repeatability and reliability.. Monotube shocks are superior because:

  • Better damping force
  • Better heat dissipation
  • The free-floating piston stop the gas and oil mixing
  • Better changes from smooth to stiff suspension
  • Ease of installation
  • Higher performance

So there you have it. If you’re in a streetcar looking for comfort, the more cost-effective solution is a twin tube design. But for performance, it has to be a monotube. The benefits far outweigh the initial investment.

Aaron Lambert
Post by Aaron Lambert
September 27, 2021
After completing high school, Aaron joined Penske Racing Shocks in 2000 as a damper technician. Since then, Aaron served in multiple management and technical rolls in the company and oversaw all major sales markets including Short Track, NASCAR, Sports Car, and IndyCar. He spearheaded the company’s successful return to the Late Model market as well as the new S-link shock dyno product line. In addition, Aaron handles all dealer relationships and has been a driving force behind Penske Racing Shocks’ long term in-house manufacturing strategy . Aaron was promoted to General Manager in 2019, a position he currently holds.
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