I know that the factory spec is 32 PSI for blazers, or at least mine. But when I pump them up to 32 they still seem a bit low to me. The entire tire is touching the ground and seems to be bulging more then it should. Would it be bad to increase this to say 40 PSI?

 

I've always run 32 in front and 30 in back inevery vehicle I've driven. Some looklower than other But like the ride

 

check the sidewall of the tire. all tires run under different psi. my front tires p235 75/r15 goodyear silent armors require 40psi and my rears p235 75/r15 goodyear at/s require 50psi. and there is a noticable difference when they are under the required psi.

 

The tires (whatever brand) should be inflated to the recomended pressure on the tire placard. Keep in mind that this is a "cold" pressure recomendation. When a tire heats up it's pressure increases...generally you should figure 1 PSI increase with every 10 degrees F increase. Keep in mind the coldest temperature that the tire will be. For example this morning it was in the teens here soifI was going toset the pressure after the tires have been warmed up and the surface temp of the tire is 60 degrees I would set it at 37 PSI. That way in the morning when the tire is cold (say 15 degrees F) it will have sufficient pressure of about 32-33 PSI.

 

The sidewall of the tire is not the recommended tire pressure, but the max pressure. So for the crappy Uniroyal tires on my Bravada, their max pressure is 32psi, exactly what the tire sticker on the driver's door. They look underinflated even with 36psi in them.

How the tire looks at the recommended pressure is all based on the construction of the tire. If you have a 'LT' (light truck) tire, the tire will probably look like its inflated correctly all the way down to 25psi due to its heavier construction. A 'P' (passenger) rated tire may never look like it's fully 'up' with a heavier vehicle on top of it. Also, a 75 series tire may squash more than a 70 series due to the increased sidewall.