Suspension pumps

A tool that won't inflate tyres

A suspension pump and a tyre pump have nothing in common. The former reaches 300 or 600 PSI — around 20 to 40 bar — with a tiny air volume per stroke; the latter does the opposite. You can't inflate a fork with a tyre pump, and connecting a suspension pump to a tyre won't get you anywhere. It's a dedicated tool, and essential if you have air suspension.

300 or 600 PSI

300 PSI is enough for the vast majority of forks and shocks. The 600 PSI models are for low-volume shocks and heavier riders, who sometimes need more than 300 PSI in the rear shock. Check the pressure recommended by the manufacturer for your weight before choosing.

Fine-tuning the pressure with the bleed valve is the whole point

Setting sag means adjusting the pressure in 5 PSI steps. All these pumps have a bleed valve which releases a tiny amount of air with each press, so you can bring the pressure down to exactly where you want it without disconnecting everything. You'll use this feature more than the pump itself.

What throws off the reading

A fork's air chamber is small. When you screw on the pump, some of the air fills the hose and pump body: the pressure shown is lower than the actual pressure before connection, and a little more escapes when you disconnect it. Good pump heads minimise this loss, and air-loss-prevention adapters are available for the smallest chambers. Either way, the method is the same: connect, pump, adjust, disconnect — and don't reconnect ten times to check, as every connection costs you pressure.

Analogue or digital

The digital shows the pressure to the nearest PSI and is easy to read at a glance, which matters when you want a setting you can reproduce from one ride to the next. Theanalogue never runs out of battery and costs less. Also consider thelong nozzle, needed for some shocks whose valves are recessed within the frame.

To find out more: How to choose a bike pump

See also: Suspension tools · Suspension oil · Pump parts and accessories