Tender and Helper Springs

Tender springs and helper springs can often be confused or mistaken for one another.  They are placed in the same location but have very different roles within a suspension set up.  Both types of spring must be used with a main spring.

Helper springs are visually short, and manufactured using thin, flat wire.  This spring will sit above or below the main spring using a middle adaptor to hold it in place.  Its primary purpose is to keep the main spring engaged at all times during full suspension travel.  The helper spring will push against the main spring to keep it located on the middle adaptor.  As the damper compresses the helper will also compress to provide a solid base for the main spring without affecting the spring rate or performance.  A helper spring is particularly important where the droop exceeds the open length of the main spring as without one, the main spring may become dislodged.

The role of a tender spring is different as it commonly has a rate of its own.  It is stiffer than a helper and does not always fully compress at ride height.  A tender spring creates a dual rate system alongside the main spring.  One of the advantages of using this style of setup is, that the softer tender spring may give better ride comfort but once the car is loaded and fully compressed the tender spring becomes inactive which allows the main spring rate to take control and increase stiffness.  This in turn provides the vehicle with more stability during situations such as high-speed cornering but can also give you a softer and more compliant feeling through slow speed and traction areas.

Another function of a tender spring can be to slow the impact of a wheel touching down mid corner.  For example, on a front wheel drive vehicle, it is not uncommon for the rear inside wheel to lift off of the floor.  Once this rear wheel touches back onto the ground, it can create a moment of instability in the car.  A tender spring on the rear would allow the rear wheel to touch back down on the ground with a softer rate, which would create less of an impact to the vehicles stability.