Shock Pump

Just bought shock pump for my front air forks. When I pump air to desired level, the air disappears when I disconnect pump. What am I doing wrong.
 

Mtl_Biker

Active Member
Just bought shock pump for my front air forks. When I pump air to desired level, the air disappears when I disconnect pump. What am I doing wrong.
Are you SURE the air is disappearing from the SHOCK? Whenever you disconnect a pump, whether it's a shock pump or a tire pump, you will hear a rushing of air as you disconnect the pump. It's really the remaining air in the pump body.

Having said that, most of our tires these days use Schrader valves (where you unscrew the little locking piece to fill or measure) while shocks use the Presta valve like most cars. The shock pump screws onto the Presta valve so if you screw it on (or unscrew it) slowly, yes, you will be loosing air from the shock. The trick is to really screw/unscrew quickly. Maybe put a couple of pounds more air than you want to end up with. It's not going to make any difference.
 
Thx for input. Worked thru all your suggestions which I had applied. I got rid of my Schrader valves cause I have a hate relationship with them. Some shock pumps have a non return on them but this one does not. Will go to local guru at bike shop for help.
 

Mtl_Biker

Active Member
Thx for input. Worked thru all your suggestions which I had applied. I got rid of my Schrader valves cause I have a hate relationship with them. Some shock pumps have a non return on them but this one does not. Will go to local guru at bike shop for help.
You changed the valves on your tires from Presta to Schrader? (By changing the tubes?). Why did you do that? By all accounts, Presta valves on bike tires are better, and I've been using them without problem for 20+ years.
 
I found them to be a pure hassle when topping up tires. They were too fussy. I much prefer the straight valve cap e.g. schrader. Yes they changed the tubes.
 
I also stopped in to my cycle shop and got my forks topped up with their superior shock pump. The one I got from MEC a large sports co op was inferior and most of the air would escape when topping up, even when used by bike techs. Its goin back.
 

Over50

Well-Known Member
One of my bikes came with a shock pump that was apparently crappy. It would release a lot of air as you describe but also the pressure readings were way off. I didn't realize until I had it in my LBS and their pump was reading something totally different. I tossed it out and bought this one (which has worked very well):

Lezyne digital shock drive:

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gorse

Member
All shock pumps release air from the hose on disconnection. If you screw the pump back on you'll find you'll have "lost" ~10psi (depending on pump) as the shock pressurizes the hose/pump. You've haven't actually lost much if anything from the shock, on disconnection
 
I think not all. Some of them have a little clip on the end to fasten the hose while it fills. You release the clip when filled and no air comes out. I have tried 3 different pumps and they all have let most of the air escape when unscrewing. Bummer! Even my bike tech had to do mine 3 times before he was quick enough to retain air. Such a simple little task but so annoying. Found one highly rated in USA with no air loss for 30 bucks. By the time it gets to me in Cdn monopoly money it was over $60.00 with all costs in. I appreciate all the input though.
 

Amazer98

Member
Having said that, most of our tires these days use Schrader valves (where you unscrew the little locking piece to fill or measure) while shocks use the Presta valve like most cars.
FWIW, I think you confused the valves-- the skinnier one that you see on road bikes are Presta, and the more robust ones you see on wider tires (and cars) are Schrader. Easy to mix up the two!
 

Mtl_Biker

Active Member
FWIW, I think you confused the valves-- the skinnier one that you see on road bikes are Presta, and the more robust ones you see on wider tires (and cars) are Schrader. Easy to mix up the two!
Yup! Slip of the tongue there. Of course I got them backwards. Thanks for the catch.