how much additional PSI do you add to your reserve tire?

[ooba99]

Ako, additional 5 psi for my reserve tire.

[Dr.Kamiya]

Hi Sir sirmikel, pareho lang bigat, meron o walang hangin.



Mas OT: Naalala ko tuloy yung trick question: Ano ang mas mabigat, isang kilong bulak o isang kilong asin? Hehehe.

Technically the pressurized tire is heavier, but not by much. At STP (about 14.5psi) air weighs roughly 1.19g/L. Apply pv=nrt to get the mass of air in your tire. The trick question is not applicable here, because basically you're asking "anong mas mabigat, hangin o mas maraming hangin?" You get the point.

I'm sure if you put an inflated tire vs an uninflated tire on a weighing scale the difference will show, but as you can infer from the figure it's probably going to be a 20-30 gram difference at most depending on the size of the tire.

[ptk675]

normally +5psi sa spare tire.

[dfcsantos]

My spare's a small donut-tire, so it's inflated pretty high. About 45-50psi, compared to about 30psi for tires normally on the car.

I read it's a good idea to keep an overinflated spare, and have an air hose. You can use the extra pressure to re-inflate your other tires (or maybe that inflatable toy you keep for the rainy days). When it's time to use the spare, just let the extra air out.

Having an air hose is a good idea. At least you have extra air in case your other tires are under inflated.

[wewoy_romero]

my spare is at 40psi - when i need to use it, i just let some air out para pantay sa current tires ko. matagal rin kasi ang interval when i check the spare (unlike sa current na nakakabit which i check daily) so i overinflate it talaga since umiimpis naman ito gradually.