Cave Dweller
21-11-2005, 08:33 AM
I have been toying with the idea for a while to air spring my monster to shave some weight. There is various ways to do this, drilling in air valves into the cap of each leg is one (like zedros shiver), making some volume reducers like in 888's is another, and the other mod is to completely remove one cartridge of the fork and air spring it. The later is what i have done here.
NOTE:- If you do this i accept no responsibility for your actions, infact, don't do this, it will probably wreck your fork.
First step is to remove the entire cartridge, spring and spacers from one leg. This leaves a hole at the bottom. Get a bolt, stick it in there and put the foot nut back on the bottom. The bottom of the fork leg is now plugged and won't allow oil out.
Next, go to your local tire shop and ask for a tubeless car valve, they cost $5. Stick it into the hole in the valve cap that used to let the cartridge/preload/rebound adjsuters through. Fill the leg with 50-70ml's of oil to allow for lubrication.
NOTE:- there will now be nothing holding this leg together as you have removed the cartridge, it will be held together by the other leg and crowns. So, remeber that you need to release the air pressure from the fork before you undo the tripple clamps otherwise you will end up with a stachion rocket :p
Open up the other leg and drain the oil out. You will need to put a heavier spring in to compensate as you will only be running one spring, not two. You will also need to put heavier oil in to help slow down the rebound, stock it is 7.5wt, i mixxed up some 12wt oil and put it in, i set the oil level 10-15mm higher the the marzocchi recommendation to help with bottom out resistance. Put it back together and bobs your uncle, air sprung monster :cool:
Not sure of the air pressure, i am putting in between 15-20 pumps of my bike pump. Seals are holding the air fine, minimal leakage over the week just gone by.
The fork rides almost the same, slightly more harsh over small bumps due to the air pressure, but it doesn't bottom at all, and the rebound is fine, no nasty top out clunks. Biggest difference is the reduced weight, this has saved around 1.5lbs from the fork making it around 8.5lbs, the fork also feels alot more responsive, probably from the reduction in unpsrung mass.
A new and even better modification to my monster is under way which will blow this out of the water. When its done I’ll post it up.
NOTE:- If you do this i accept no responsibility for your actions, infact, don't do this, it will probably wreck your fork.
First step is to remove the entire cartridge, spring and spacers from one leg. This leaves a hole at the bottom. Get a bolt, stick it in there and put the foot nut back on the bottom. The bottom of the fork leg is now plugged and won't allow oil out.
Next, go to your local tire shop and ask for a tubeless car valve, they cost $5. Stick it into the hole in the valve cap that used to let the cartridge/preload/rebound adjsuters through. Fill the leg with 50-70ml's of oil to allow for lubrication.
NOTE:- there will now be nothing holding this leg together as you have removed the cartridge, it will be held together by the other leg and crowns. So, remeber that you need to release the air pressure from the fork before you undo the tripple clamps otherwise you will end up with a stachion rocket :p
Open up the other leg and drain the oil out. You will need to put a heavier spring in to compensate as you will only be running one spring, not two. You will also need to put heavier oil in to help slow down the rebound, stock it is 7.5wt, i mixxed up some 12wt oil and put it in, i set the oil level 10-15mm higher the the marzocchi recommendation to help with bottom out resistance. Put it back together and bobs your uncle, air sprung monster :cool:
Not sure of the air pressure, i am putting in between 15-20 pumps of my bike pump. Seals are holding the air fine, minimal leakage over the week just gone by.
The fork rides almost the same, slightly more harsh over small bumps due to the air pressure, but it doesn't bottom at all, and the rebound is fine, no nasty top out clunks. Biggest difference is the reduced weight, this has saved around 1.5lbs from the fork making it around 8.5lbs, the fork also feels alot more responsive, probably from the reduction in unpsrung mass.
A new and even better modification to my monster is under way which will blow this out of the water. When its done I’ll post it up.