Before installation make sure that your Sprindex coil is compatible with your shock.  Note:  Yo-Yo instructions at bottom of this page.

Read this entire installation manual prior to installing and using your Sprindex coil. Be sure that the Sprindex stroke is at least as long as your shock rating. It is okay if your shock stroke is less than the Sprindex stroke maximum.

Above: Installation on shocks such as Fox, DVO, X-Fusion, Cane Creek, and Ohlins require 2 Performance Adapters (included).  Determine which of the included Performance Adapters to use (shock brands are identified on back of Performance Adapters).  For Fox shocks, use both their aluminum adapter AND the Sprindex Performance Adapters.

Above: Installation on shocks such as Rockshox do not require any Performance Adapter but we recommend using the Performance Washer Adapter (included).


Coil Direction

The Sprindex coil can be installed in either direction and should be installed in the direction that provides the best adjusting access.  If your entire shock has good access, then install the Sprindex with the Dial away from the piggyback for easiest hand access.

                                        Direction 1 okay

                                        Direction 2 okay


Performance Adapters

Sprindex coils fit a wide variety of shocks, but you must use the included Performance Adapters for most of them.  Our Performance Adapters both improve the fit between the coil and your shock and are made of low friction Delrin to improve shock performance by allowing the spring to twist during high deflection.  Also, the Performance Adapters help prevent the preload ring from self-adjusting due to coil windup.  See bottom of Performance Adapter for direction of which adapter you should use.  For Rockshox, no Performance Adapter is necessary but we recommend you use the Performance Washer for improved shock function.

5 size Performance Adapters are included to fit a wide variety of shocks.

For most shocks such as Fox, DVO, Cane Creek, and X-Fusion, use one Performance Adapter at each end.  Use the Performance Adapter that best centers the coil on the shock at both ends (takes out the most play).

For Rockshox, Performance Adapters are not necessary but we recommend using the included Performance Washer Adapter on the preload ring end to provide a low friction surface for improved shock performance and to increase the coil length if necessary.


Installing Sprindex

Follow your shock maker's instructions for changing coil spring which are typically:

  1. Remove your shock from your frame.
  2. Loosen the preload adjuster until the spring moves freely.
  3. Lift up the coil spring and remove the slotted spring retainer and the spring retainer insert (if any).
  4. Slide the coil spring off the shock body. Depending on your bike model, you may need to remove the shaft eyelet hardware to create enough clearance to remove the coil spring.
  5. Determine which direction (1 or 2) the Sprindex coil should be installed on your shock body that will provide you the best access within your bike frame for twisting the Dial to adjust your spring rate.
  6. Add Performance Adapters or Performance Washer Adapter to your Sprindex depending on shock model.
  7. Slide Sprindex with Performance Adapters or Performance Washer Adapter onto the shock body.
  8. Install slotted spring retainer back on the shock with its recessed side toward the shaft eyelet and its protruding section going into the inside of the Performance Adapter or Performance Washer Adapter.
  9. Tighten the preload adjuster just until the spring no longer moves. Then turn the preload adjuster per your shock manufacturer's recommendation (typically 1 to 2 turns).  In any event, do not preload your Sprindex more than 3 turns.
  10. Check sag and shock setup as detailed per your shock's instructions. Sprindex recommends as a starting point to achieve the recommended sag by adjusting your spring rate rather than adjusting your preload.
  11. Lower spring rate increases sag. Higher spring rate decreases sag.


Adjusting Spring Rate

To adjust the spring rate, hold the coil with one hand and twist the Dial with your other hand or vice versa.  The spring rate value is identified by the printed number on the coil displayed through the Dial opening (for example, 370 lb/in in the picture above).  You can even adjust the spring rate at different points of your ride depending on the trail or conditions.  Preload is not a substitute for a spring that is too weak.

 Shock Adjustments

After installation, all shock adjustments including preload, sag, and other settings based on your shock maker's recommendations.  However, remember that the sag setting is really only a predictor of proper shock setup and that obtaining near full shock travel during your ride is what is most important.  So after setting up your sag, which is a good starting point, go ride and then adjust your Sprindex as needed to obtain near full shock travel on whatever is the most extreme area of your ride, without regard for sag percentage.  Remember to further stiffen your Sprindex for any trails that will likely cause even more shock travel.

For your first ride, position the rubber shock bumper so that you can see how much travel your shock reaches and adjust your spring rate accordingly.  Periodically check the travel of your shock and adjust your spring rate as necessary to provide you your ideal ride.


Before You Ride

Make sure that your shock is ready to ride

  1. Clean the outside of your shock with mild soap and water and wipe dry with a soft rag.
    • Do not use any solvents or de-greasers as these products can damage the shock's exterior finish.
    • Do not use a high pressure washer or spray water directly at the seal/shock body junction.
  2. Inspect the exterior of your shock. The shock should not be used if any of the exterior parts appear to be damaged
    • Contact your local bike shop or your shock brand directly for further inspection or repair.
  3. Make sure that your quick-release levers (or thru-axles) are properly adjusted and tightened.
  4. Check your headset adjustment. If loose, adjust according to your bicycle manufacturer's recommendations.
  5. Check that all brake cables or hoses are properly fastened.
  6. Test the proper operation of your front and rear brakes on level ground.
  7. Adjust your Sprindex to provide the sag that is recommended by your shock or bike brand.  This is a good starting point.
  8. Do not ride any extreme trails until you have had a chance to adjust your Sprindex to an optimal level for you.  If your Sprindex cannot be adjusted to your optimal level, you should replace it with a Sprindex that has a spring rate range better suited to you and your bike.

WARNING: Check for clearance before riding.  If you are installing your shock on a bike for which the shock was not original equipment, follow the steps below to ensure proper clearance before riding.

Remove the coil spring from your shock.

  1. Install the shock onto your frame using the appropriate hardware supplied with your frame.
  2. Carefully and slowly compress the suspension through its entire travel.
  3. Check that no part of your shock contacts any portion of your frame or linkage as it cycles through its travel.
  4. Remove the shock from your frame, reinstall the Sprindex, and reinstall your shock. Check that the spring does not contact any portion of your frame or linkage.
  5. Set sag as described in your shock brand's instructions except adjusting your spring rate will also affect sag.

WARNING: Rear shock setup and configuration varies greatly between different bicycle manufacturers. Be sure to refer to the owner's manual for your bicycle. Sprindex products should be installed by a qualified bicycle service technician.  Improperly installed shocks can fail, causing the rider to lose control, resulting in SERIOUS INJURY OR DEATH.

WARNING: All shock mounting hardware will have some inherent level of axial float which is required to achieve smooth performance. This is normal and is not a safety or performance concern. If your shock mounting hardware exhibits what you believe to be excessive float or makes noise, please contact your shock brand for assistance. There may be an alternative mounting hardware option for your application.

WARNING: Unless your shock brand advises differently, tighten the preload adjuster just until the spring no longer moves, then preload no more than 2 full turns. Preloading the spring more than 2 full turns may cause the spring to coil bind when the shock is bottomed out. This can cause damage to the shock which could lead to a loss of control resulting in SERIOUS INJURY OR DEATH.

WARNING: Shocks should be serviced by a qualified bicycle service technician. If you have any doubt whether or not you can properly service your shock, then DO NOT attempt it. Improperly serviced products can fail, causing the rider to lose control resulting in SERIOUS INJURY OR DEATH.

WARNING: Whether too stiff or too soft, the wrong spring rate can cause your shock to perform poorly, causing the rider to lose control resulting SERIOUS INJURY OR DEATH. Adjust your shock per your shock brand's recommendations.


                   Installation and using the Yo-Yo Stroke Gauge

Most people riding coil shocks do not achieve full stroke travel, which greatly affects performance.  Stroke travel is typically hard to measure with coil shocks.  By using this Yo-Yo Gauge, measuring your stroke travel is easy to see and allows you to fine tune your Sprindex to the optimal setting.  The Yo-Yo is meant to be used temporarily during rides in order to dial in your Sprindex spring rate.

Step 1.  Remove spring.  Install shock without spring.


Step 2:  Install Velcro.  Ideally, install Velcro on or near shock Eyes or in locations that move about the same distance as the shock Eyes.


Step 3:  Install Yo-Yo by pushing the centers of Velcro together.  Slide stroke Bead towards Reel.


Step 4:  Fully compress shock.  Note that this includes compressing the rubber Bumper.


Step 5:  Fully extend shock.  Mark string near stroke Bead with Sharpie pen (shown here marked in red).


Step 6:  Install Sprindex per instructions at the top of this page.  To reset, slide stroke Bead towards Reel after every Sprindex rate adjustment.


As shown, more stroke is available.  If this was after your biggest drop, adjust Sprindex rate lower in order to be able to use more shock stroke.


 As shown, full shock stroke was achieved or possibly bottomed out.  It is usually best to achieve slightly less than 100% full stroke to be sure you did not bottom out completely.  Adjust Sprindex rate higher, especially if you expect to hit the ground harder.


Alternative installation.  With some bikes, it is impossible to install the Tab and Reel in locations near the shock Eyes.  In those cases, install Tab and Reel in locations that move approximately the same stroke distance as the shock stroke.  Be sure to determine full stroke by following steps 3-5.

The Yo-Yo can also be used to determine SAG percentage.  But remember that SAG is only based on rider weight and body position.  SAG is a starting point but does not consider riding style, how aggressive you ride trails, etc.  A much better measure of desireable spring rate is how much shock stroke is used during your ride.