Suspended trikes are those with shock absorbers. Do you need a suspended trike? You’ll easily add $400 at least over a comparable model. Some people really do need suspension, like those with back problems. Other people just like that deluxe ride. After all, comfort is what you are paying for with these trikes anyway. Rear wheel suspension lends the most to comfort, while front wheel suspension adds to control at speed on rough surfaces.
Types of suspension
The shock absorbers on suspended trikes come in three types. Elastomers are the simplest, which is a powerful argument for them. They are just rubber blocks, built in a range of stiffness. They wear out after a few years of use and you replace them. It is easy to carry a spare in case you are triking across the outback. ICE suspension and Catrike front suspension use elastomers.
Coil/oil shocks are the standard from mountain biking. They are adjustable are durable, they they do have compressed oil in them which can leak or become contaminated. AZUB models use coil/oil shocks, or some derivative thereof, standard on their front and rear suspensions.
Lastly, Air shocks use compressed air for dampening. They are the lightest and more tunable of trike suspensions, but they are more of a hassle. You need to pump them up regularly, and if they need service they are more expensive to work on. Catrikes use air shocks standard on their rear suspension, and AZUB uses them as an upgrade.