Coil spring rate adjust­ment for MTB suspension.

Channel: Cycle
Logo sprindex colour

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.

Spindex adjustable coil spring 01 38cf589


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.