Pulleds our a valve, and couldn't get any air in the tube

good

Specialized pump on practically brand new specialized tires on a specialized bike and this thing won't get an air tight seal until it's also got a death grip on the valve body threads. So when I unscrew it to get the damn thing off it also unscrews the valve bodies and causes all the air in the tube -- all of it -- to come rushing out because there's no valve body in the thing any more. I'd return this pump for a refund if I could. If it didn't do this I'd give it full marks. I was happy with this pump until it started doing this. But a pump that does this is not a pump anymore.

A hose is the first requirement for me. Check. Next is a valve attachment that seals tigh but doesn’t remove my valve core when I’m done pumping. Check. Finally, for a mtb or gravel tire, you don’t need high pressure, so “low gearing” ie a high volume per stroke is great. I am impatient though, so I will move this too my gravel bike, and try the Big Bore mini pump for my mtb.

Out on Honeymoon Island's Pelican Trail, I had adjusted my fat tires down to 5 PSI for a deep sandy section, and was using my Specialized pump, trying to firm them back up to 8 or 9 PSI for the hard-packed bits. Hundreds of pump strokes later, I had managed to LOWER the pressure down to 4 PSI. Air bled out faster than I could pump it in due to the failure of the nozzle to seal onto the valve stem. I was about to throw this pump away and complain to my bike shop, but searched ""Specialized 30cc bike pump won't seal"", just in case someone else had solved my problem. One or two negative reviews here pointed out that the pump SCREWS SECURELY ONTO YOUR VALVUE STEM. Why didn't I know this? DOH! Testing back at home proved that the valve core stayed in stem. So, I am keeping this little guy! Do not expect speed with a 30cc barrel, but this pump is Solidly Built, fits in my saddle bag, and gets the job done. I might try the MTB version if this one wears out, but I like the short retractable hose on this model, which provides just enough slack to prevent back-and-forth stem movement. The best pump is the one you have with you, and the Air Tool Flex Pump, at 9"" x 1"", travels very easily.