Tender Spring Upgrade vs. Dual-Rate Spring Kit

Tender Spring Upgrade vs. Dual-Rate Spring Kit

Off-roaders upgrade their UTV’s suspension for a variety of reasons, whether it be to gain back ride height after adding accessories, replacing sagging, worn out springs, or to upgrade to the highest-performance, race-winning setup.

Polaris RZR Turbo S

If you own a Polaris RZR XP1000, RZR XP Turbo, RZR Turbo S or RZR Pro XP, chances are you have a shock with an upper tender spring. These vehicles come with a dual-spring setup with an upper spring that is very soft and most often completely collapsed at normal ride height. These collapsed upper springs are most often referred to as a tender spring and their primary purpose is to provide tension on the spring pack when the shock extends. Under normal load, this spring was designed to be fully collapsed. 

Polaris RZR XP1000 Tender Spring

The lower spring, or "Ride Spring" as labeled above, is designed to do all of the work in this system, with the upper tender spring solely being used to fill the gap.

Polaris RZR XP1000 Tender Spring

E.g., the Polaris RZR XP 1000 comes with tender springs stock from the factory, as shown above. 

New tender springs are a popular upgrade amongst some of the Polaris RZR community –– in part due to their affordability –– yet leave much to be desired compared to a true Dual-Rate Spring Kit. While upgraded tender springs can result in marginally improved ride quality and ride height, the system also has limitations. While indeed a dual spring system, the design lacks a crossover ring, and therefore uses a combined spring rate as opposed to a true dual rate system. Put simply, a dual-spring does not guarantee a dual-rate.

Dual-Rate Spring Kit

A system that utilizes a tender spring will have a combined spring rate. While one can purchase an aftermarket tender spring with a higher spring rate than that which came stock to gain ride height back after adding accessories, it will not be a true dual-rate setup. Its spring rate will be linear, and will not change since it does not have a crossover ring.

While a more premium quality product than many tender spring upgrades on the market, the Dual-Rate Spring Kit from Shock Therapy provides substantive benefits. True to its name, a dual-rate system allows for two different spring rates — likewise, the suspension system can more effectively respond to a variety of terrain. Thus, a dual-rate spring kit can provide plush and smooth ride quality throughout small bumps, chop, and chatter, while still providing more resistance against the large forces of jump landings and bottoming out.

Tender Spring Upgrade

Left: Tender Spring;   Right: Dual-Rate Spring Kit 

The design of the system –– specifically the arrangement and location of the crossover ring –– allows us to fine-tune its performance to meet the terrains and riding style of each customer at hand. As the springs compress you can control when the system gets stiffer with the location of the cross over ring, where the heavier spring rate of the lower spring engages. By changing this engagement location, we can bring the stiffer spring rate in at the perfect time –– keeping your UTV plush when you want it and stiffer when you ramp up the speeds and terrain. 

Polaris RZR Pro XP

If you have a Polaris RZR XP1000, RZR XP Turbo, RZR Turbo S or RZR Pro XP that came with an upper tender spring, our dual-rate spring kit is far superior to a tender spring upgrade or tender spring swap.

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