Is my tire pressure ok?

when i check my tire pressure in the morning i get a 40lb reading which is ok, but after work the weather warmed up to about 30 degrees and the reading is at 45lbs. should i go by normal temperature driving conditions for pressure or first thing in the morning?

Reply to
bobby F
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First thing in the morning.

Reply to
bearman

Tire pressure on standard passenger/light trucks is always read cold. If you're at Daytona, that's a different story. :) So the answer to your question is "first thing in the morning."

D
Reply to
Dreamer

to add to those who responded...yeah, read it when cold. Now is 40 psi too much? What truck do you have? My 2003 Tacoma 4x4 SR5 TRD off road says 26 psi cold for the front, 29 psi cold for the rear.

Reply to
TacomaDude

I usually go 3-4 lbs over the recommended. Yes I think 40 lbs is way too much. Doesn't it ride awfully rough (I mean more than normal). Try lowering and see if it doesn't ride a tad better. Consumer Reports pans the Tacoma ride (they think it should ride like a Buick) - yours has to be jouncy.

Reply to
Wolfgang

That's too low.

I don't care what the OM says. Factory recommended pressures were arrived at by engineers who want a nice soft ride and by people who sell tires. Whatever is stamped on the sidewall... that's where I run 'em. I've never had a tire wear out in the center before the edges were also gone.

But wear and ride quality aside, the real issue is hydroplaning:

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"Of course the word 'fast' is a relative term. Tread design, tread depth, weight of motorcycle, tire pressure, depth of water and even the consistency of that water - (whether it is highly aerated or not, for example) - all play a part in determining at what speed the tire will begin to hydroplane. It is a pretty safe bet to assume that any speed in excess of 60 MPH is fast enough to support hydroplaning regardless of the other variables. This is not to say that at 55 MPH you are safe, however. (A formula that comes close to predicting the speed at which you will hydroplane, assuming at least .2" of water on the ground, is: 10.27 * Sqrt(tire pressure) which shows that if your tires hold 35 psi, hydroplaning can be expected at 60.76 MPH, while tires with 41 psi of air in them should expect hydroplaning at about

65.75 MPH. Another formula that is somewhat more accurate, though much harder to calculate, is: 7.95 * Sqrt(tire pressure * contact patch width / contact patch length). This formula shows that the wider the contact patch is relative to its length, the higher the speed required to support hydroplaning.) "

--- Rich

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Reply to
Rich Lockyer

Weeeeeeeeeell, it does sound kinda low, but it does depend on what sort of tires he's got, what sort of load he might normally carry, etc, etc. So I wouldn't say *categorically* it's too low, but unless I had a real good

*specific* reason I wouldn't run 'em that low.

My father, who's one of the world's foremost authorities on Things That Go Wrong With Tires (No, really: he's a troubleshooter for a tire company.) claims that the whole Ford Explorer/Firestone tire debacle was mostly caused by some engineer trying to use the tires as part of the suspension system. Manufacturer recommended inflating the tires to pretty much their minimum safe riding pressure to give a softer ride. Since most people check their tire pressure seldom to never, and tires naturally lose air, there were a

*lot* of Ford Explorers running around with underinflated tires that were being asked to do more than tires usually do vis-a-vis absorbing various kinds of movement from a heavy vehicle. Result: abnormally high tire failure rates. Abnormally high tire failure rates on a topheavy vehicle that most people don't know how to drive result in abnormally high rates of death and destruction. D
Reply to
Dreamer

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