to not ruin the asphalt
Many aircraft use nitrogen in their tires
tires is what is used on a car for a wheel.
My van has bad tires at front and better ones at rear, should wheel alignment be performed with bad tires?
Wheels or tires? if tires, 14. If wheels, 7. There are 2 tires per wheel.
HAMMER THE CLOSEST SIZE SOCKET YOU HAVE ONTO THE WHEEL LOCK THEN USE A RATCHET TO REMOVE IT
More than likely your tires are out of balance. Have your tires rotated and balanced. Make sure they check for a bent wheel.
Tires fit onto the wheel rim
Depends on what's wrong with it, what you have available, and what kind of valve it has. Usually wheel barrows use the same kind of valve as on car tires, so if you have a pump or a compressor to inflate your own car tires you can easily inflate the wheel barrow the same way.
15" Use 195/60/15 sized tires.
that is fine, check for rubbing under wheel well.
P235 75/ r15
Yes, you can use 14" or 15" tires/wheels. Just try to keep the overall diameter of the tire/wheel combo as close to the OEM tire/wheel diameter as possible. Otherwise your speedometer will be inaccurate and performance/handling can suffer.