Mountain Bike Reviews Forum banner
1 - 5 of 5 Posts

·
Registered
Joined
·
24 Posts
Discussion Starter · #1 ·
hi guys im pretty new here.

Today i picked up an 05 stinky as basically my first bike. Its been years since i rode bikes and when i did there was no disc brakes, full suspension, etc.

I also picked up a shock pump today (made by beto?) anyways, the front fork is a marzocchi drop off triple. How do these work? Is there a coil spring in them, according to the manual my understanding is there is a coil in only 1 side. Im supposed to be riding with 42-52psi positive air pressure in the right leg and 0-15psi on the left.

I guess im just confused i thought they were as simple as a shock absorber like on a car. Is there some kind of oil in there too? As for the rear shock and spring its a 450lbs/per " coil and fox dhx 3.0. But i want start talking how that all works yet.

i pump air into the forks as the instruction say i should, look at the pressure guage and when i unscrew the hose i lose all my air out of the forks????? I thought maybee it was just out of the pump hose but when i reattached it it said 0. So im driving on 0 psi on front fork and 0 psi on rear shock,

heres some pics, anyone got any links on how to learn my bike? bleeding brakes, adjusting derailers, suspension etc
 

Attachments

·
Registered
Joined
·
6,762 Posts
Okay I'll give this a shot....kinda long though..

cobra said:
hi guys im pretty new here.

Today i picked up an 05 stinky as basically my first bike. Its been years since i rode bikes and when i did there was no disc brakes, full suspension, etc.

I also picked up a shock pump today (made by beto?) anyways, the front fork is a marzocchi drop off triple. How do these work? Is there a coil spring in them, according to the manual my understanding is there is a coil in only 1 side. Im supposed to be riding with 42-52psi positive air pressure in the right leg and 0-15psi on the left.

I guess im just confused i thought they were as simple as a shock absorber like on a car. Is there some kind of oil in there too? As for the rear shock and spring its a 450lbs/per " coil and fox dhx 3.0. But i want start talking how that all works yet.

i pump air into the forks as the instruction say i should, look at the pressure guage and when i unscrew the hose i lose all my air out of the forks????? I thought maybee it was just out of the pump hose but when i reattached it it said 0. So im driving on 0 psi on front fork and 0 psi on rear shock,

heres some pics, anyone got any links on how to learn my bike? bleeding brakes, adjusting derailers, suspension etc
The Drop Off tripple really is a simple fork. It uses one coil spring in one leg with air preload, and air preload only in the other leg. There is no separate air chamber in either leg. If you were to open up the left leg all you would see looking down into the stantion tube is the surface of the oil way down in the fork leg. You cannot compress a liquid so the surface of the oil makes for a perfect "air piston" or bottom for an air chamber. Yes there is oil in both legs as the fork uses dual SSV dampers (one per side), I don't recall if the dampers in that model fork are adjustable or not so we won't go there. As for the problem that you are having with the shock pump, it could be one of two things. First get a valve stem wrench and check the valves in the caps of the fork. If they are not seated all the way in the they will allow air to escape as the air chuck on the pump will disengage before the valve is closed. Next check the pump. Does the air chuck have a pin inside of it that engages the the pin inside the air valve on the fork? If not then you have an older style pump that simply uses air pressure to compress the valve. In other words as you pump the handle the pressure of the incoming air pushes the valve open and then pushes the air through. Then the valve snaps closed again. This could be why you are getting a zero reading when you reconect the pump. The only time the guage reads is when it is pumped, the valve in the fork stays open a fraction of a second after the air passes and allows back pressure into the pump before is closes allowing the gauge to read what is in the fork. So when you release the air chuck from the fork all you are loosing is the air in the pump. Anyway I would check the simple way by pumping up the right side to 50 psi, removing the pump and then pressing down on the valve with a pen or small screw driver to see if any air comes out. If it does, guess what, your not loosing all your air, you just have a pump that doesn't compress the valve mehcnically. Your just not able to check the pressure with you shock pump with out pumping it up a couple of times first because the air chuck on the pump doesn't compress the valve stem and allow air into the pump gauge when it is attached.

All that being said, I would highly recommend that you get a low pressure shock pump for your fork! Zocch uses a high volume/low pressure set up. As little as a 2 psi difference in pressure can make quite a large difference in the way the fork reacts and feels. something that reads no more that 100 to 200 psi in 2 psi increments would be best.

Next comes the set up. The air is what you use to set up the fork. I would say start out with zero air presure on both sides. Put a zip tie around the stansion tube of one leg of the fork between the lower crown and the lower legs. Snug it up so the tie stays put where ever it is moved on the stantion tube. Next slide the tie down so that it is against the seal in the top of the lower leg where the stansion enters the lowers. Now carefuly sit on the sadle in the riding position and then carefully get off the bike so as not to compress the fork. Now measure between the seal in the lower and the zip tie. This is your sag. Your fork has 170mm of travel if I recall correctly. Sag should be set (to start) at between 25 and 35% of total travel for Down Hill or Freeride use. That works out to between 43 and 60mm in your case. If the fork sags between those two increments then your are good to go. If it sags more than 60mm add air in 5 psi increments, meausring after each addition, until you achieve no more than 60mm of sag. Now got ride and test out the feel of the fork. Too mushy, add another 5 psi measure then test again. Keep adding until if feels right to you. Now it's time to adjust the progressiveness of the fork. This is where the air in the coil side comes in. This one is a cut and try. Take er out and rider hard. Does the fork bottom out all the time? Add some air to the coil side, again 5 psi at a time, until it doesn't bottom all the time and when it does bottom it is only on the biggest hits and then only lightly. Again check sag after each addition of pressure. If adding air to the coil side affects the sag then let out some air on the non coil side, the same ammount that you added to the coil side. Best way to start all this is with the manufacturers recommended pressures (the lowest) and go from there. Set up is pretty much cut and try and personal preference.

I know this all sounds daunting and you may already know about sag etc. so I appologize in advance for anything that you already know. But don't be affraid to experiment with the pressure settings, and remember, small changes can make a large difference. It may take a while to get it set just right, but once you do you'll be in business.

As for your brakes and rear shock, both hayes (brakes) have online tech manuals that cover every thing from installation to maintenance (including bleeding), www.hayesbrakes.com, and Fox has a tech manual that covers your rear shock, www.foxracingshox.com.

Anyway, hope that helps you out, and again sorry for the long post and if I got to newbie with my explanations.

Good Dirt
 

·
Registered
Joined
·
24 Posts
Discussion Starter · #3 ·
that was great!

hey man thanks alot for your time and the help,

im just learning, and i have the just about setting sag but havnt done it yet. i was kind of wodering how i was going to set it, but your explanation of the zip tie will work perfect.

As far as the forks go i put 75 psi into one leg then took the chuck off, i used a key on the valve to see if there was air in there or not, it barely made a noise so im assuming the air is not staying in there. The chuck has another little thing that threads onto it that actually pushes the valve open, you can unsrcew the chuck and you can unscrew the other thing ontop of it seperatly. I figured the proper way to use this was to put desired air into fork, then quickly unsrew the pin on top of the shock. but no luck no matter what i try.

heres a few more pics, of the 0-400psi guage, the chuck with an open pin on it, chuck with the pin screwed in all the way, and looking inside the chuck at the adjustable pin. The red part on the chuck twists on and off independantly and adjusts the pin inside the chuck to open or close the valve. it almost seems like the valve isnt closing fast enough.
 

Attachments

·
Registered
Joined
·
6,762 Posts
Hmmm....now that is odd...

cobra said:
hey man thanks alot for your time and the help,

im just learning, and i have the just about setting sag but havnt done it yet. i was kind of wodering how i was going to set it, but your explanation of the zip tie will work perfect.

As far as the forks go i put 75 psi into one leg then took the chuck off, i used a key on the valve to see if there was air in there or not, it barely made a noise so im assuming the air is not staying in there. The chuck has another little thing that threads onto it that actually pushes the valve open, you can unsrcew the chuck and you can unscrew the other thing ontop of it seperatly. I figured the proper way to use this was to put desired air into fork, then quickly unsrew the pin on top of the shock. but no luck no matter what i try.

heres a few more pics, of the 0-400psi guage, the chuck with an open pin on it, chuck with the pin screwed in all the way, and looking inside the chuck at the adjustable pin. The red part on the chuck twists on and off independantly and adjusts the pin inside the chuck to open or close the valve. it almost seems like the valve isnt closing fast enough.
I've never seen one like that. The way you describe using it does seem to me to be the proper way. Screw the air chuck on then adjust the pin. Then back the pin out when you are done and unscrew the whole chuck. But you say that doesn't work. I don't know on this one. The concept on the pump seems like it would work better than the standard fixed pin type that most pumps use. Try this, screw the pin out as far as it will go, then screw the chuck onto the fork valve all the way, then back it off about 1 or 2 truns. Then adjust the pin so that it depresses the valve core and you can add air easily. Then back the red pin out when you are done and see what happens. Sounds as you said like the valve core pin is being compressed too much and not closing before the chuck comes unsealed from the air valve. But deffinately get a valve core wrench and make sure that those vavle cores are fully seated in the valves on the fork. That can also cause the same problem. If all else fails a different pump may be in order. Like I said, I would recommend a low pressure shock pump for your fork. It will make setting the lower pressures that your fork uses easier and much more accurate. I have a Zocch MX Comp that is one side air and one coil and don't have any probs with adding air. I use a low pressure pump with the standard fixed pin air chuck and it works fine. But from experience I know that not all shock pumps are compatable with all shocks and forks. The only thing I can think of are differences in manufacturing tolerances. Anyway keep plugging away and check the above and see what happens. Hope it works out for you because that looks like a nice quality pump to me. Oh and one other thing, don't be affraid to go to your local bike shop and ask for help. They may think of something that neither of us have thought of yet.

Good Dirt
 

·
carpe mañana
Joined
·
7,307 Posts
The pump you have might not be deep enough to actually engage the air valve. I couldn't use this thing on my Fox air fork and went with a stock Marzochi pump (left over from a different fork I used to have). Just get a different pump.

_MK
 
1 - 5 of 5 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top