Hi I bought a bike pump for my tires that use presta valves. (tires say "max 135 psi") It cost about 30$ (was 40 retail) after 80 psi, it is difficult to pump air into the tubes (even though I could keep going). Even if the tires feel only halfway flat, and I first hook the pump in, the gauge only reads about 5 psi (even though i'm guessing it has 55 psi) Is this common with floor pumps with pressure gauges? should I buy a tire pressure reader? maybe the presta adapter on the pump is cheap and I should buy a schrader adapter? I strongly suspect the gauge is not accurate.
1 more question: how much will a upgraded rear deraiuler help with smooth shifting, (I am getting some roughness and complaints when I shift into the very top gear) I know the one I have is fairly cheap (this is a road bike) or will the gears wear in after a while (bike is three months old) I clean the moving parts with dry degreaser and lube it with dry lube.