A coil spring inherently puts significantly more pressure on one side of the spring perch than the other because of its shape. This uneven force also varies throughout the range of compression. This puts lateral force on the shock shaft which is less than ideal. 

Lateral force on the shock shaft causes the damper to not operate quite as smoothly as it would otherwise. This has a negative impact both on handling and on ride quality to some extent. It also reduces shock life by putting strain on the main seal which can cause the shock to weep more oil.

The Hyperco hydraulic spring perch rocks back and forth as the coil spring compresses which evens out the force exerted on the lower perch. While this does not completely eliminate all unwanted lateral force, it greatly reduces it.

We sell quite a lot of these. It’s a great upgrade if it’s within your budget. It’s an easy upgrade to add to existing coilovers, and we pre-build Cygnus Performance, Ohlins, Fortune Auto, Penske and MCS coilovers with Hyperco hydraulic spring perches when customers opt for this optional upgrade.

We highly suggest running our coilover covers in conjunction with these. Over time dust can get into the hydraulic perch. Eventually it will stop moving, and you will have to rebuild it. Running our Cygnus Performance coilover covers with the hydraulic perches will significantly extend rebuild intervals.