real psi for tire

**redfoxmavson29** · March 9th, 2012 10:42 PM

sir ano po tamang tire pressure ng honda civic ek.sa akin pinapalagay ko 30 front at 32 rear,nababasa ko kasi ung uba masmataas psi sa front kaysa sa rear.ano po ba talaga ang tama

**niky** · March 9th, 2012 11:12 PM

Follow whatever the door sticker says. Contrawise, you can increase pressure to increase fuel economy (35-40 psi is fine), but try to keep the ratio front-to-rear the same as the door sticker. If the door sticker says front higher, keep the front higher. If it says rear higher, keep the rear higher.

Not all cars are designed to run higher front pressures. But, as far as I can recall, the Civic uses higher front pressures.

**redfoxmavson29** · March 12th, 2012 05:09 PM

Originally Posted by niky

Follow whatever the door sticker says. Contrawise, you can increase pressure to increase fuel economy (35-40 psi is fine), but try to keep the ratio front-to-rear the same as the door sticker. If the door sticker says front higher, keep the front higher. If it says rear higher, keep the rear higher.

Not all cars are designed to run higher front pressures. But, as far as I can recall, the Civic uses higher front pressures.

sir ung nkalagay po sa sticker 185/65r14 30front 29 rear.sa stock mags.pero ung mags ko 15" ang tire 185/65r15.ano po tamang psi.salamat

**niky** · March 12th, 2012 05:19 PM

You can do 30/29 (f/r), or you can increase slightly to increase fuel economy... 35/33 or even higher... then lower it down to a more comfortable level if it's too stiff for you.

**OTEP** · March 12th, 2012 05:20 PM

The tire pressure is measured per volume.

So even if you put in a bigger tire, you can maintain it at the prescribed pressure posted on the door jamb since you are measuring pressure for every square inch of rubber and not the tire as a whole.

**jick.cejoco** · March 12th, 2012 09:14 PM

if you change your tire size or your tire profile or your load range, the pressure requirements changes too. as the pressure requirement changes, the tire footprint should be at optimum. i have searched the internet and some textbooks, i still haven't found the formula as to how much to increase or decrease the tire pressure for any given car for any given tire aside from the standard equipment tire size with the factory recommended tire pressure. the first priority is not on the looks or the comfort level but on [I]safety[I]. so far, the best way is to try different pressures not on the road but in the shop where there is no traffic and the risks are very low. my procedure is not at all very high tech but very highly common sense. by using tire imprint or footprint, you can determine the best pressure by experimentation even when the car is not moving. to do this process, you will need carbon paper and printer paper. these two are run over or the car lowered to the carbon paper/printer paper pair to make an imprint. the pressure can be raised or lowered until the imprint shows full contact of the tread from tread shoulder to the center tread and to the opposite tread shoulder. this is a fool proof procedure since you are determining the pressure required for the GVW of the specific car with the specific tire size or profile or load range other than the factory recommended tire size.

**gearhead000** · March 13th, 2012 02:44 AM

one other quick way is to put chalk marks between tread shoulders. i haven't tried this yet though as i've just bought some white chalks from NB yesterday. i plan to do the testing on our office building's parking area as the floor there is quite smooth and level. will report back on the results later.

tire psi had been quite subjective already, with some preferring their tires softer for a more comfortable ride, while others may prefer it harder for better fuel economy. correct tire pressure though can be determined objectively as outlined by jick.cejoco above, (or hopefully, by the chalk method i'll get to try later). the objective is to inflate your tires for optimum tire contact patch for more even treadwear and better grip. overinflate, and you wear down the center of the tire. underinflated, it is the shoulders that gets worn faster.

**niky** · March 13th, 2012 03:07 PM

With modern construction radial ply tires, you really won't see significant center rib wear until you're up into nasty hard pressures... in the 40 psi to 40 psi plus region... as long as the tire is your typical square-sided radial.

There are economy nuts who inflate up to max sidewall pressure (for this size of tire, usually 45-50 psi) and report no extra wear on the center rib. Of course, since these guys also drive extra slow and hardly ever use the brakes, this may not translate well to use by us regular human beings...

Bias-plies like vans use are another matter entirely.