Check your rental cars' tire pressures!!!!

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Stanley Rockafeller

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Went on a short trip this week to get out of town. Picked up a cheap Corolla to take the trip to save wear and tear on the e30.

Upon picking up the car I noticed the ride was a little too hard so when i got home I checked the pressures while the car was sitting in the shade (temp was cool that day)

Pressures read an even 40 PSI on all 4 tires! I quickly dropped the pressures down to 35 to save myself a blowout while on the highway. Obvioucly the previous renter did this to save money on gas, but 40 PSI is just CRAZY!
 
It's more common to see under inflated tires here on rental cars, or most cars in general, than over inflated. I suppose over inflated would run cooler, and although the wear pattern won't be even, so long as you don't exceed the maximum cold tire pressure on the sidewall you should be safe as far as blowouts are concerned. What size tires are these? Are they mounted on 15 or 16 inch wheels?
 
I find that the tire pressures on Rental cars are usually quite low...I have been glad to have the new GM TPMS to be able to check...I used to carry a small digital gauge with me because the car often didn't feel right.(note: I travel a lot, rent about 40x per year...).
 
Originally Posted By: Stanley Rockafeller
to save myself a blowout while on the highway.

How do you figure? 40 PSI is nowhere close to causing a blowout problem.

If anything, a blow out is more likely to happen from under-inflation.
 
I run all three of my cars at 40 PSIG. It makes the tires wear longer and keeps the sidewalls stiffer over the Michigan potholes. An average rim replacement for Nissans are around $500 a piece.
 
I agree - I always check the tire pressure and fluids on rental vehicles.

Did you happen to notice what the Toyota recommended tire pressure was? On my wife's Camry it is 29 psi but I usually run about 32. I would agree that 40 is a little high.

When I bought the Trailblazer I test drove it the vehicle had about 6 miles on it. I drove it for about 7 or 8 miles, went inside with the wife, sign the papers, wrote the check and then waited for them to "detail" it.
On the drive home the thing rode like a tank and it felt like I was driving on ice. I checked the tires and they all were at about 50 - 52 psi. I changed it back to the factory recommended 30 front, 35 rear and it rode and handled nice.

Funny those engineers at GM seem to know more then the "lot boys" at the Chevrolet dealership.
smile.gif
 
I rented a Cobalt one time. Noticed it was overdue for an oil change so I decided to check the level. Didn't even register on the dipstick. I added 3 quarts!!!

I really didn't want the engine blowing up on my watch.
 
Originally Posted By: oldmaninsc
I agree - I always check the tire pressure and fluids on rental vehicles.

Did you happen to notice what the Toyota recommended tire pressure was? On my wife's Camry it is 29 psi but I usually run about 32. I would agree that 40 is a little high.



It's 30, that's why I was a little alarmed to see the pressure so high
 
Tire blowouts occur independent of a tread separation, and in such cases the cause is entirely different than the factors which initiate a tread separation event. The most common cause of a blowout is low air pressure, which causes the tire to sag and allows for the buildup of heat within the tire. Ultimately, the sidewalls which are not reinforced by steel belts will burst and allow for the dramatic expulsion of air and pressure.

Most tires are rated at 40-50 psi dependant on the load the recommended and the engineered limit are completely different. Auto makers generally spec the air pressure dependant on axle load that same tire may fit other vehicles and have a much higher tire pressure also high speed driving most car makers in europe recommend adding 3-4 psi
 
I run my tires at 40 psi most of the time. No problems. Less rolling resistance means less heat generated from friction.
 
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How new was the car you rented? Manufacturers and dealers often over inflate tires so they don't develop flat spots while sitting for long stretches on cargo ships or in dealer lots. Often times this is overlooked by the dealership staff that preps the car for the buyer.

Also, how much did you drive it before checking them?
 
Should also check the tire pressure when you buy a car. Especially when it has run flats.

Got the Z4 home, checked the pressure, and instead of 36 rear 33 front, they were all at 20.
 
Originally Posted By: sicko
How new was the car you rented? Manufacturers and dealers often over inflate tires so they don't develop flat spots while sitting for long stretches on cargo ships or in dealer lots. Often times this is overlooked by the dealership staff that preps the car for the buyer.

Also, how much did you drive it before checking them?


I waited till i got home since the car seemed to kinda bounce a little too much over bumps.

After reading this thread I've started, I'm starting to think i shoudl run all my vehicles at least at 35 PSI
 
Originally Posted By: Bottom_Feeder
40 psi is on the high side but safe and hardly 'CRAZY!'.


+1.

In fact, if the reading was after a little driving, 40 psi could be just normal.
 
Originally Posted By: Stanley Rockafeller
Originally Posted By: sicko
Also, how much did you drive it before checking them?


I waited till i got home since the car seemed to kinda bounce a little too much over bumps.


Then 40 psi is very normal.
 
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All the new Mazdas we get from Japan, well got for the time being, came with at least 50psi in the tires. The ones built in Ohio were maybe 35-40. Its part of the Pre Delivery Inspection to set the tire pressure. I remember a new RX8 had about 90psi in the tires. I had a cheapy stick pressure gauge that launched the white stick about a few stalls down from the pressure.
 
40psi wouldn't worry me, especially if the tires are rated to 44. Keep in mind, the sidewall rating is generally max cold pressure, with plenty of safety margin for heat. The one time I took the Jeep to a track, I ran my 44psi rated tires at 46psi front, 40 rear (set cold, and done to keep the sidewalls stiff enough). No issues on the 1.5 hour highway drive there or back, or when beating on it at the track.

Keep in mind, more pressure means less sidewall flex, so less heat buildup. Unless you're well over the max sidewall pressure, you're not at risk of a blowout.
 
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