I too have great difficulty inflating tyres with my pump - the kind you have a T-handle to enable use of 2 hands whilst securing the pump firmly with your foot/feet. I simple dread having to add more air and am exhausted by the end of the task. Just as well there are only two tyres to pump! I too have difficulty attaching the pump onto the valve and also can hear hissing when the pump is attached. Pumping difficulty increases by the time I reach 70 lb and I struggle to get the remaining 20 or so lb in, and then I have to rush to remove the pump from the valve as it's still hissing. There's no way I could use the little hand pumps that fit ever so nicely on to my bike frame - it's there, but I would guess it would be near on impossible to get 90 lb + into a tyre.