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Old 06-25-2019, 10:28 PM   #11
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Cool Re: For Anyone Who Owns a Digital Tire Gauge

Originally Posted by shorod View Post
I would expect the gauge to be consistent, it just might be consistently high by as much as 1psi or consistently low by as much as 1psi. I would not expect it to read high 1 reading and then low on the next though.

Regarding lower full scale capability, yes, you interpreted my comment correctly. For a gauge that can read up to 100 psi, 0.5% full scale would be 0.5 psi. For one that has a 60 psi full scale, 0.5% would be 0.3 psi.


Thanks! I know it's just tire pressure, set & forget, come back in a month, but, it's my F-18- I mean, Hyundai! And I just want things as evenly set as possible.

By the way shorod, there's a set of calculations out there that I learned, that returns a set of front and rear cold pressures even more exact than the ones listed on a car's b-pillar load sticker:

It involves knowing the max load and inflation pressure of the original tires, and the front and rear GAWR(gross axle weight rating).

IE: The load sticker on my 2015 Hyundai recommend 33psi cold, front and rear.

Plugging the information about my car and the tires in, and the formula returns 35psi front and 32 rear - to account for the front weight bias in a typical front wheel drive econo-sedan. The car really sticks to the road in turns, smoother ride, and 1-2mpg better highway mileage. Same for my wife's 2004 Toyota:

Recommended: 30psi all around. Calculated: 32psi front, 29 rear. She says she presses the gas less, and the brakes more! Fuel economy improved too.

For a friend's 2005 Legacy GT sedan however, the calculated pressures made ZERO sense: 48psi front, 49 rear! WT... ?! Sound more like TRUCK pressures, ehh?

Actual recommended pressures on that Subaru's sticker: 35psi front, 33rear. I think she will stick with those! lol

It's tires are 45-series 17" wagon wheels, vs my Hyundai's - 65-series normal tires. That might explain why I got the wonky figures on the Subaru.

Ordinarily, most vehicles I've done it for are predictable: They add 1-2psi for the heavier GAWR axle, and reduce 1-2psi for the lighter axle.
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