Coil spring rate adjustment for MTB suspension.
Sprindex is an innovative new system for coil spring MTB shocks that allows the rider to adjust and fine tune spring rate without the need to change the coil. Coil shocks are widely regarded as superior to air shocks for rear MTB suspension, but have always lacked the adjustability of their air shock counterparts. Until now.
Sprindex is a shock upgrade available in 3 different spring sizes (to suit different shock lengths and riding styles) and completely replaces the existing coil spring. The Sprindex adjuster sits within the spring with spring rate adjusted by a simple tool-free twist of the dial. Importantly, this adjustment doesn’t change the length of the spring and does not change preload and sag. Spring rate is identified by a printed number on the spring making adjustment simple and intuitive. The product is compatible with the majority of coil shocks from all the leading suspension manufacturers.
Sprindex is born from the riding and engineering expertise of Carl Windfordner Richie Schley, Frank Hermansen, Andrew Herrick who were fed up of the limited adjustability of coil shocks, impeding the performance benefits of coil spring suspension.
2pure are delighted to bring the brand to the UK market, helping drive forward technical developments in mounting biking, a sport at the very heart of 2pure.
Yes. Besides having an adjustable spring rate, Sprindex is also progressive. Sprindex is specifically designed to have a progressive spring rate for the last 20% of stroke for big hit support and for bikes with a linear linkage design. For more detail, go to "how it works / progressive" at the top of the page.
Yes, and in most cases, more so. Sprindex coils were designed to handle the stress at the highest adjusted spring rate. To achieve this, we used the highest tensile spring steel available. When adjusted to its maximum spring rate, Sprindex will last as long as any quality shock spring. When adjusted below it's highest maximum spring rate, Sprindex will last even longer.
The included Performance Adapters allow Sprindex to fit nearly all mountain bike shocks. The Sprindex coil is designed to fit the largest diameter shocks (Rockshox) without an Adapter and to fit all the other shocks with an Adapter. The difference diameter between the smallest shocks (Fox) and the largest is small, but it is important to use the proper Adapter to remove unnecessary play. The Adapters are made of slippery Delrin to allow small twisting movement of the coil ends, which adds performance. That is why we recommend using the included Performance Washer for Rockshox when no size Adapter is required.
Start by following your shock brand's recommended SAG amount and adjust your Sprindex rate as needed. This is only a starting point. Then slide your rubber bottom-out bumper over so that during your ride, you can look to see how far the bumper has moved. If the bumper is not moving as far as possible, then adjust your Sprindex spring rate lower, move the bumper again, and ride more. Ideally, you should get near full shock travel during your ride without bottoming out.