gyozadude

My theory? Valve stem insertion. Most likely, cruiser tires are using schrader valves. The insertion of the pump head onto the valve is important for proper tire pressure readings. Probably the rear tire has a center valve tip that is a hair more proud than the front, so the pump head center pin will depress it properly and give you good pressure readings. Most likely, the front is more depressed and you don't get good depression. If the pumping gets very hard and hits like 80 to 100 psi with little air going in, then the center pin on the valve isn't depressed at all. If it's slightly depressed, then air goes in slowly, but the valve shuts on backstrokes slightly even if there is a check valve in your pump. Situations vary.

Simply solution: put the chuck on deeply and securely over a schrader valve. Also, write the manufacturers and demand a metal center pin for schrader pump heads. The plastic ones supplied by most manufacturers pretty much guarantees that after a few uses, 80% of the newbies will put it on wrong because it wears in the pump head and now you really gotta mount the head over the valve good. And the secondary problem is if you mount it deeply enough, you now risk scraping knuckles on the spokes when detaching, and/or wiggling the valve stem too much and causing a flat due to tube damage at the valve stem base. I get better performance from an old Kmart metal barrel pump with old-school pump head for most schrader applications (my Dad bought it in the day - has leather washers in it and still works - go figure). Newer pumps are all disappointing. But that's more reason to ride presta valves, I guess. Still, something so simple as $0.15 could solve many problems (for newbies). But again, if you don't care about newbies pumping tires, well, not a problem. :-)