Is it possible for a 700x 25c tire to appear hard and inflated with only 30 psi of pressure ?

A 700 x 25 tire will look inflated at 30 psi but it won't be very hard. If you are having trouble getting past 60 psi your pump may not be designed for high pressure tires. High pressure pumps have very narrow barrels while pumps for low pressure have wider barrels. A lower pressure pump will inflate tires quickly but you have to push very hard to attain high pressure

For a 700x 25c tire you need a high pressure pump rated to at least 160 psi. Most bike pumps are for comfort and mountain bike tires and anything over 60 psi is hard to reach. A high pressure pump has a smaller barrel so it takes less effort to reach 100 - 120 psi.

Get one with a gauge.

no 30 psi would sag to the ground if you weigh over 75 lbs

gauge may be wrong

or pump is really for mtb and you are not looking for bulge when seated

a tire with 5 psi will ''appear'' inflated

but it won;t feel the least bit hard

and when you sit down, the thing will sag to the floor

wle

Get a BETTER PUMP!!! 700 x 25c tires can go up to 120 psi - maybe more. 30 psi is waaaaaay to low.

http://pedros.com/products/tools/wheel-and-tire/pr...

Most 700 x 25c road bike tires have a MINIMUM air pressure around 80 - 90 psi.