Pumpin air shocks, help.

[liltommy]

First, this is my first air shock. Bought a pump a few days ago and played with the positvie pressure ( on top of the fork). It seemed to work fine although I noticed I'd lose about 10lbs of pressure taking it off. No problem, I just overinflated by 10.

Today I'm playing with the negative pressure (bottom of shock). I can't get the pump off without losing "all" pressure. I'm using a "wrenchforce" pump which I'd never heard of but the guy who sold it to me said it was by Trek.

Am I doing something wrong :confused: or is this pump a piece of garbage. When I picked the bike up I saw them adjust both chambers and they didnt have a problem. When I attached the pump initially the lower chamber still had 150# in it but now its zero.

Any advice please
LT.

[Dirt]

What kind of shock is it?

I've got a fox shock and fox pump and haven't had any trouble. I can loan you my pump if you want to try it out.

We're supposed to get a ton of rain tomorrow, so we probably won't ride on Tuesday. I'll be in Maryland on Tuesday afternoon, I we could meet up and drop it off if you like.

Drop me an e-mail (PedroGringo@yahoo.com).

If you have your bike with you, We could just try it out and see if it works. I may even have a spare fox pump around that you could have if it is the right one. I'll dig through my tool box tonight.

Peter

[esfand]

I just saw an ad for this part that you add on to shock pumps. The part effectively stops you from losing pressure when removing the pump from the shock.

I'll post back if I remember where I saw the ad. Might be worth trying.

good luck.

[liltommy]

Its a Reba Race for the 29er. I think I'll stop by the LBS tomowrow and see what brand of pump they have and take the bike with me. I'll open the pump up there in the store and make sure I can make it work.

I'm just thinking here, but a part you'd put on the pump would have to act in 1 direction only. Thats Ok, but wouldnt that render the the built in guage on the pump useless? If you find the link where you saw it put it up please. I'm curious now.

LT

[cjled]

Most of the time shocks\forks 'lose' pressure when you reconnect the pump to check the pressure, because the air has to fill the volume of the pump hose. I bought a pump from Performance that allows you to secure the head over the valve and then secure an insert that opens the valve seperately. It removes the same way, and makes it easier to maintain an accurate pressure. It was a Hurricane model, around $20

[bigbadbrad]

Yo Lil'T-- welcome to the wonderful world of air shocks! I just entered it myself, w/a new Trek Fuel w/a Fox air shock in the rear & a Manitou Black Super Air up front.

First time out I experienced same difficulties; fortunately for me, Rick (MORE member, aka wrtaylo) was a kind soul w/a good shock pump-- in fact, his was a Wrench Force; found it to be a good tool, unless yours is malfunctioning.

Here's a few tips he gave me, which really helped. You'll need to try it/tweak it a few times initially.

He suggested screwing the pump on until it just engages the valve, to make for easier removal. Once engaged, pump it up (I suggest here cueing Elvis Costello's "Pump it up...until you can feel it".. :D ) to desired pressure.

RE Desired Pressure: I had read in my manual "about half of rider weight", but he recommended higher, about 50%-75% more. (For example, I weigh about 200 --OK, more like 205-210-- so I was thinking ~100-105 PSI. More like 150-175 PSI worked for me). Also, given that you can lose pressure while removing pump, I'd go ~10 lbs. higher accordingly.

While preparing to remove pump, he suggested pulling up on it, keeping tension on the hose line, before unscrewing the valve/hose connection. This way, plus the earlier step of the pump being just barely engaged w/the valve, facilitates minimal air loss; as soon as the pump disengages, since you've pulling up on it, it releases quickly. You should only hear a very brief (1-3 seconds) "hiss" when disconnecting pump. With my fork, I was trying to use my shock pump (less than ideal), and was getting like a 10 second hiss, which released virtually all the air.

Good luck.
--Brad

[liltommy]

Took the bike and pump to the LBS. They couldn't figure it out either. They got the same results. We tried the things Brad mentioned. Nothing worked.

I bought another pump from them and tried it there. Everythings cool.

I'd like to mention how cool the guys at the Bike Doc in Waldorf were. They took back the pump I'd gotten from the Crofton store and let me exchange it there in Waldorf, saving me the hassle of going north.

See yall
LT
(I noticed theres another tommy on the forum, so this is to avoid confusion.

[esfand]

Here is the part I mentioned earlier:


http://risseracing.com/Products/Misc/Acu-fill.jpg

The left piece threads onto the pump. The piece on the right goes on the shock valve.


http://risseracing.com/Products/Misc/acu-fill.html