Shock pumps for bikes: Pressure makers - pumps for MTB suspension forks & shocks put to the test

98 psi. According to the manufacturer's table, this is how high the air pressure in my suspension fork should be in order to optimally match my weight. However, exact adjustment is not easy when the shock pump only measures in increments of ten, these are only 3 millimetres apart and the pointer is already 2 millimetres wide. As you can probably already see, analogue damper pumps usually do not provide more than a rough estimate - even if the pump itself measures accurately. But let's start from the beginning.

Damper pump: you can't do without it

A damper pump is indispensable for setting up air suspension systems. It is the only way to adjust the pressure in the air chambers of the suspension fork and shock to the rider's weight - a basic requirement for optimum function. Many bikes are supplied with a simple standard pump, but online shops and bike shops offer a wide range of different models. We tested 13 shock pumps, eight analogue and five digital.

The crucial question: digital or analogue?

Which brings us to one of the most fundamental questions: Do I need a digital shock pump? If you want to adjust the air pressure to the exact psi, the answer is clearly yes. While we measured deviations of up to 6 psi with the analogue pumps at a pressure of 80 psi, none of the digital pumps are more than 1 psi off. Set-up nerds and psi foxes who work a lot on their suspension settings will therefore be pleased with the precise values and easy-to-read displays. And suspension lazybones who live by the motto "Set it and forget it"? They'll be annoyed when they want to check the air pressure after the winter break and the cold has sucked out the battery. Very few people are likely to keep the necessary button cell in stock.

Do-it-all or pure workshop damper pump?

Another criterion is the pack size. If you take the shock pump with you on tour, you should make sure it is as compact as possible. Expansive models such as the SKS USP or the Specialised Air Tool shock pump are only for the workshop.

You should also take a look at the valve head when buying. Very short or angled models may not reach all the valves on the shock or fork if they are hidden in the frame or sit deep in the fork crown. If you want to check the correct pressure when the shock pump is fitted, you will also need a decoupling function. Incidentally, this has no influence on whether the 98 psi specified by the manufacturer remains in the air chamber even when the valve head is unscrewed - you can find out more about this in the "Myth or truth?" box on the right-hand side.

The pumps in the test

Click on the respective model to access the detailed test with the complete evaluation.

• 3min19sec Damper pump >> e.g. available here
• Lezyne Digital Shock Drive shock pump >> e.g. available here
• Lezyne Shock Drive >> available here
• Pro Performance Suspension Minipump >> e.g. available here
• Pro Shock Pump Team >> available here
• Rockshox Fork/Shock Pump Digital >> e.g. available here
• SKS SAM Suspension Pump >> e.g. available here
• SKS USP Universal Suspension Pump
• Specialised Air Tool Damper Pumpe >> e.g. available here
• Syncros Shock Pump Boundary 1.0 SH
• Topeak Pocketshock DXG >> e.g. available here
• Topeak Pocketshock Digital >> e.g. available here
• Zéfal Z Shock >> e.g. available here

This is how we tested

In the lab To check the accuracy of the pumps, we have developed our own test setup. We fitted a steel cylinder with a volume roughly equivalent to that of a suspension fork with a digital precision pressure gauge and attached a Schrader valve to a second hole. We used this test cylinder to check the measuring accuracy of each damper pump at 80, 150 and 200 psi. We repeated the test three times with two identical pumps. The average values were then calculated.

Analogue pressure gauges difficult to read

Because the analogue pressure gauges on the shock pump are often difficult to read, we mainly looked for outliers here. It is also not possible to accurately depict the series dispersion with just two test models. However, we were able to clearly demonstrate the pressure equalisation of the pumps when unscrewing them. Next, we counted the required strokes up to a pressure of 150 psi and used this to determine the pump volume in psi per stroke.

In practice Handling, readability of the pressure gauge and the required manual force were checked and documented by several test persons. We also checked how well the valve heads can be fitted to the different suspension forks and shocks and whether they can also reach shocks that sit unfavourably in the frame.

Measured values at a glance

Valuation at a glance

Pressure loss: myth or truth?

The myth that suspension forks or shocks lose a little air when the pump is unscrewed still persists among bikers. We can disprove this myth with our test! In our tests, not a single shock pump lost pressure when the valve head was unscrewed - regardless of whether the model in question had a decoupling screw or not. On the contrary: incorrect operation of pumps with decoupling can even lead to the air pressure just set escaping again when unscrewing, if you forget to activate the decoupling.

However, when the pump is screwed onto the valve, the air pressure drops with every pump because air escapes from the air chamber into the hose. Incidentally, the pressure loss protection was only developed by the manufacturers because of this myth. However, decoupling does have one advantage: If the connection between the pump head and valve is disconnected, it is possible to check whether the correct SAG has been set, even with the pump screwed on. This does not work with shock pumps with a standard pump head.

The most important details