Fork Spring Rate Verification
From Unofficial Zero Manual
- Reference
- How to Verify Fork Spring Rate
- Tools
- A tip-tie long enough to wrap around the fork tube.
- Steps
- Add a zip-tie to the the fork tube.
- Make sure it is snug so it stays in the place it was last pushed too.
- Once the zip-tie is on the fork tube, you push it up to rest it against the upper fork.
- Measure bike sag (unloaded)
- Lift the front fork off the ground and measure the gap (zip-tie to fork gap) created by the front weight of the bike.
- Measure rider sag (loaded)
- Now push zip-tie back up the fork, then sit on the bike and raise your feet so all of your weight is carried through the suspension.
- Then carefully dismount and put kickstand down.
- Measure the gap (zip-tie to fork) created by your weight.
- Add this gap measurement to the bike sag measurement, this is the total sag.
- This measurement should be around 25% of the working range of the front suspension.
- Now that is a guideline; it can be higher or lower than 25%.
- It depends on what is happening when you are loading up the suspension (upper end).
- Checking the upper end by using the zip-tie.
- After riding, check the location of the zip-tie: the gap from the fork to the zip-tie.
- Lets say the measurement is 5". Then you would know the total max travel used was 5" + bike sag measurement.
- That total measurement should never equal the total suspension travel amount (6", I think based on your posting).
- If it equal, then you are bottoming out. Increase the preload and see if this keeps you from bottoming out.
- If you use max preload and are still bottoming out, you will need stronger springs.
- If you find you are only using 75% to 80% of the max suspension travel, you can reduce the preload spacer length some or you can live with this.
- If you are only using ~50% or less of the suspension travel, your springs are probably too stiff. You should swap springs to a lower rate spring.