Tire pressure is important!
#62
12-18-2007, 08:36 PM
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Join Date: Jul 2007
Location: San Diego, CA, USA
Posts: 941
Re: Tire pressure is important!
I fill up to 42PSI, which is 10 above the recommended for my car, but still a few under the sidewall max. I think it is a good balance.
#63
12-19-2007, 06:41 PM
Re: Tire pressure is important!
#64
12-20-2007, 06:25 AM
Re: Tire pressure is important!
Has this ever actually happened? Probably not. Sounds like a good show idea for MythBusters. And 50psi when a tire is sidewall rated at 44psi is not grossly different. In fact, 44psi is the rating for a cold, un-loaded tire.
A 44psi cold, un-loaded tire will reach 50psi when hot, and heavily loaded, and this is 100% within the design spec.
"Worry Wort!"
A 44psi cold, un-loaded tire will reach 50psi when hot, and heavily loaded, and this is 100% within the design spec.
"Worry Wort!"
44 - 50 would only occur if the moisture content in the tire was high. Eliminate the moisture content and you will get a smaller range of PSI differences between temperature changes.
#65
12-20-2007, 06:51 AM
Re: Tire pressure is important!
I think what's happen is there has been a number of hypermilers that have increased their tire pressure and dispelled many of the concerns you have asked about. Two years ago, I would have never increased my tire pressure to sidewall max. When we started seeing a decrease in wear and better handling, we determine the tires had a safety benefit with more pressure. I really don't know about going with 60psi being the safest thing, but I have seen an overall benefit at 50psi in my conditions here in FL.
I did have a flat from an object that put a clean hole in my right front tire a few months ago and it leaked down very normal. There was no object left in the tire. I was at a stoplight when someone next to me said my tire was going flat. I pulled over safely with no other damage to the tire or rim. Called my roadside service and the guy showed me the hole and changed my tire. Goodyear repaired the tire and I use it as a spare. There was no blowout problem when the tire was damaged. I wouldn't ever put max pressure in a repaired tire for safety reasons.
I had the front-end adjusted to spec at my first tire rotation at 5,000 miles. Later saw the inside wear and brought it back to Goodyear to check it again. They said it was still at the Ford spec and Escapes had that problem and it was normal. I haven't changed the camber from spec.
At first, I increased the tire pressure for mileage, but I've seen other benefits. About 10 months ago I took a hard left turn at ~70mph. I'm convinced my FEH would have rolled over if my tires had not been so firm. Instead, I was in a controlled slide to the right till I could straighten out on the road.
I'm not so sure the max pressure on the tire is for safety for all conditions. It may be for snow and ice conditions or extreme heat like in a desert where the tire pressure may expand on a 115F road surface. I think I'm fine in my conditions where my average speed on my SGII tank averages is ~22mph.
GaryG
I did have a flat from an object that put a clean hole in my right front tire a few months ago and it leaked down very normal. There was no object left in the tire. I was at a stoplight when someone next to me said my tire was going flat. I pulled over safely with no other damage to the tire or rim. Called my roadside service and the guy showed me the hole and changed my tire. Goodyear repaired the tire and I use it as a spare. There was no blowout problem when the tire was damaged. I wouldn't ever put max pressure in a repaired tire for safety reasons.
I had the front-end adjusted to spec at my first tire rotation at 5,000 miles. Later saw the inside wear and brought it back to Goodyear to check it again. They said it was still at the Ford spec and Escapes had that problem and it was normal. I haven't changed the camber from spec.
At first, I increased the tire pressure for mileage, but I've seen other benefits. About 10 months ago I took a hard left turn at ~70mph. I'm convinced my FEH would have rolled over if my tires had not been so firm. Instead, I was in a controlled slide to the right till I could straighten out on the road.
I'm not so sure the max pressure on the tire is for safety for all conditions. It may be for snow and ice conditions or extreme heat like in a desert where the tire pressure may expand on a 115F road surface. I think I'm fine in my conditions where my average speed on my SGII tank averages is ~22mph.
GaryG
If not for safety then what? Tire manufacturers know their product and probably don't list the actual MAX to be on the conservative side but still, it's there to cover their liability. I think we can all agree on that. You will notice the absence of the word "recommended" on the side of the tire for MAX.
As for higher pressure saving you when you did a hard left turn at ~70mph. I think that at higher speeds, hard turns have little impact in actual direction of the car. Not that I recommend you try this again, but had you been at recommended PSI, you would have slid as well. But their is some luck involved here so I'm not convinced it was the higher PSI that saved you. If you go to an empty lot (not in an SUV for this test, take any car) and get up to 40 miles per hour and do a HARD left (pick one side or the other) followed back to normal position followed by another hard left (at recommended PSI) you will notice that your steering inputs are sort of being ignored. Your tires are essentially sliding but the car is going (sort of) straight, in effect you are braking with your tires. I see race car drivers do this all the time (turning in one direction only, usually in the direction of the corner) to reduce speed as their brakes fade.
#66
12-20-2007, 03:23 PM
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Join Date: Jul 2007
Location: San Diego, CA, USA
Posts: 941
Re: Tire pressure is important!
Saw a Pruis today with Nitrogen filled tires. Here back right tire was nearly flat. I told the owner and she said that she had noticed a decrease in FE.
#68
12-20-2007, 05:57 PM
Re: Tire pressure is important!
John, what is your average tank speed? I didn't say my average speed is 22mph, just when the SG tank averages all my stops and periods of acceleration, that's what it says. Your starting to sound like your friend PMSman.
In the morning, I have to travel across the state at highway speeds and my average speed will be much higher. I'm coming off the effects of ethanol but I'll bet I will average greater than 45mpg in the 400 mile round trip. Now that is a LOL to your mileage and speed if you care to share the truth.
GaryG
In the morning, I have to travel across the state at highway speeds and my average speed will be much higher. I'm coming off the effects of ethanol but I'll bet I will average greater than 45mpg in the 400 mile round trip. Now that is a LOL to your mileage and speed if you care to share the truth.
GaryG
#70
12-20-2007, 06:25 PM
Re: Tire pressure is important!
--------In the morning, I have to travel across the state at highway speeds and my average speed will be much higher. I'm coming off the effects of ethanol but I'll bet I will average greater than 45mpg in the 400 mile round trip. Now that is a LOL to your mileage and speed if you care to share the truth.
GaryG
GaryG
So I'm suffering new car break-in period, lowering ambient temperatures, not so ideal driving conditions in this part of the country, and my wife drives the car 90% of the time.
I'll never be able to achieve the mileage some of you guys get, especially with a AWD and the hills (not mountains) here in KY. Tailgaters, speeders, and agressive drivers will not get anything from Santa this Christmas
