If atmospheric pressure is 14.9 psi and the pressure in the tire is 12 psi does that mean the total pressure is 26.9? what is the actual pressure to hold a tire bead on a rim. The pounds per square inch
...:Handshake say it takes 50 lbs. of air pressure to seat the tire to the rim. then you take and remove the valve stem center. all the tire pressure is removed and the tire is still on the rim. ...so...at rest, 0 lbs. of tire pressure to hold tire on the rim... my thinking...12lbs. is 12lbs... a tire would act as a balloon would, it would expand/contract with a given air pressure as the...atmospheric pressure...changes... it's way to early to be thinking about things like this...
Welcome! In answer to your two questions, The air pressure inside and outside the tire are the same ( 14.9 psi ) before you start to inflate the tire so you won't add the pressures together. Now, if you have 35 psi in your tire and drive up a mountain that is 10,000 ft, the atmospheric pressure will now be 10.1 psi so you will add pressure to your tire at altitude! To keep a bead seated on a rim ( to drive on ) usually takes about 12 psi. This depends on the diameter and width of the rim and the type of tire you're using. When I used to have dune buggies, I'd run 4 - 5 psi on the beach and inflate to 12 psi to drive on pavement. I had tubes in the tires and screws through the rims so that the tires couldn't slip on the rims.
Pressure inside the tire is usually rated as the internal pressure being exerted against the external pressure. So as Simple Man said, as atmospheric pressure drops internal tire pressure increases.
Thanks Thanks for the warm welcome to the site. now time to get out and work on one of our race cars.
