Lower Runt Setup & Installation Guide

You will need 10 mm shaft clamps to install.

You will need to remove the Butter cup assembly and the stock gold tower / piston / spacer from your assembly. (The Lower Runt is not compatible with the Butter cup assembly)

1. You can start the reassembly with installing the main piston  with Quad rings and back up rings on the top of the shaft and the supplied foot stud its 4mm longer than the stock one or butter cup assembly. (This keeps fork travel consistent while changing the relationship between the main piston quad ring and the transfer port in the upper leg.)

2. Next, there are 3 qty 1mm thick shims that adjust the preload.

1 shim Approx. 5-6 LBS Lighter to average weight riders

2 shims Approx. 8-10 lbs. Average to Heavy Riders

3 shims Approx. 10-12 lbs. Heavy Riders and or Heavy Bikes

You may try adding a shim if your running a heavier front wheel (DH casing / Inserts) and or have a longer bike

Preload increases the poppy-ness without having to increase air pressures. Surprisingly, it actually makes the fork more supple with the proper amount. 

3. After the shims are the coil,  perches, and o-rings.  The 2 thick o-rings (size 204) go on both sides of the coil assembly.  The thinner o-ring goes inside the coil on the shaft. You will have to slide it in between the coil as you're putting it on the shaft.  

It’s important to get them in the correct place; the spacing will affect the preload if not put in the correct spots. The thinner one inside the coil gives the assembly a soft top-out. 

4. The main body goes on next.

5. Next inside the body is an o-ring (Size 205 50DU) that cushions the IFP. It is a softer durometer than the other o-rings and fits loosely on the shaft.  After that is the IFP put a thin coat of slick honey on the inside of the body before you put the IFP in. The negative volume spacers go next.

3 Negative spacers = Least amount of Negative air heavy riders / heavy bikes

2 Negative spacers = Most riders average to heavy

1 Negative spacer = Most riders average to light

0 Negative spacers = Very light riders (may increase piston noise as spacers help cushion piston)

When you install them into the main body it’s a little tricky to keep them from going in crooked and dislodging the o-ring. We want a tight fit to keep the spacers from floating around freely and the o-ring helps cushion the IFP.   The o-ring side goes against the IFP. Lastly, install the retaining ring to hold everything inside the body. 

6. When you install the assembly into your fork, put 2 cc of 0wt motor oil in the negative air chamber (between the Gold main piston and Lower Runt Body). Then use the stock snap ring to hold the assembly in place in the fork uppers.