Sprindex adjustable rate coil springs suppress Achilles healing from coil shocks [Review]

Sprindex adjustable rate coil springs suppress Achilles healing from coil shocks [Review]


The balancing beam between the positives and negatives for coil spring and air ATV shocks can be frustrating even after both lists are compiled. With all the potential benefits on the table, air shocks often win the prize for the simple fact that their spring pressure can easily be adjusted to suit a specific rider and track.

The folks at Sprindex have created a coil spring that eloquently solves this problem by adding an adjustable collar to the base of the spool, allowing riders to change the stiffness of the spring without touching any tools. Glass reinforced plastic adjuster locks or releases a specified amount of spring to create different spring rates. Or, as the company says, the adjuster “changes the number of active coils available for deflection.” Cyclists no longer have to choose between a spring that is too stiff or too soft for their bike and their weight. Springs can be purchased in all popular sizes and weights, with an adjustment range of 50 lbs.

Mounting the Sprindex is as easy as any stock spool. There are a series of adapters to give it a tight fit with a variety of shock bodies, so as long as you have the correct length and stroke it should be as quiet and tight as the spring you are replacing. Once it’s slid into place, you can click the spring rate adjustment to adjust the sag as you want.

This little piece of red plastic helps the Sprindex spring play well with a variety of shocks.

I tested a Sprindex coil with an Öhlins TTX22M damper on a Privateer 161 and a Raaw Madonna. The Madonna has a higher leverage ratio than the 161, requiring a stiffer spring to withstand that force, and with the Sprindex, I can use the same spring for both bikes. The Privateer performs well with the spring clicked at around 455 lbs, and the Madonna likes the full 500 lbs. In particular, it is unique to be able to take the helical shock absorber from one bicycle and mount it on another without exchanging the springs.

Not only can you adjust the Sprindex spring rate between bikes, but you can also adjust the rate much closer than with any other coil for precise rear wheel feel. With 5lb increments of adjustment, riders can adjust their sag and desired support without purchasing steel spring stacks at over $ 50 each. While the Sprindex spring is a bit more expensive at $ 140 (available online), its high-quality functionality is worth the extra part. If you are feeling tired and want to give the rear tire a little more flexibility, lower your hand and click the dial with one hand. So simple. Likewise, if you are riding with a heavy bag, you can add 5 lbs to compensate.

Unlike many coil springs, the Sprindex coil is progressive. The spring increases with additional pressure in the final 20% of stroke to increase downforce. The difference between this and a typical linear reel is immediately noticeable on the track, and the benefits extend beyond bottom support. When you’re racing down a murky chunk of track, that added resistance also bounces with more force than the previous 80% of the spring, providing a good kick to bounce the bike out of deep holes and compressions. This doesn’t make coil shocks feel like air shocks, but it does provide some of the end-of-stroke benefits that air springs are known for.

The blocked part of the spool wire is not the same as the adjustment preload. According to Sprindex, “Preload does not change the stiffness of the spring, but preload changes the force to start moving the shock, and high preload significantly reduces shock performance on small bumps and makes the ride harder. and the traction worse. Spring stiffness is the force required to travel a certain distance while preload adds a fixed force over the entire stroke. Heavy preload can add over 100 lbs (45 kg) of force required to start shock movement, while optimum shock performance comes from the lowest possible starting force. Strong preload means those little bumps won’t even move your suspension. The brand discusses this topic further on its website.

It’s hard to find anything other than praise for this product. It’s a simple solution to a long thought-out conundrum, and the user experience has been overwhelmingly positive. The only problem I can see is that the spring is slightly wider than some stock models and may not fit all bikes. If you own a frame with a shock tunnel, like a Megatower or specialized Enduro, you may want to take a few steps before purchasing.

⭐️ Sprindex adjustable rate coil springs are available for purchase online.

Party Tours

  • Quickly adjust the spring rate for more precise tuning
  • Tool-less, quiet and easy adjustment
  • Fits most modern coil shocks
  • The weight is similar to the original springs

Advantages and disadvantages of the Sprindex adjustable coil spring.


  • A little expensive
  • Only available in black
  • Wide spring may not fit all frames


Wiley C. Thompson

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