guido4475
Not a Member
I totally agree with you.Absolutely correct.
Take Care...(of your tires...)
- Thread starter moose
- Start date
I totally agree with you.Absolutely correct.
guido4475
Not a Member
About 10 years ago, a freind and I had the same trucks.We ordered them identical, except the color.When it came time to put tires o our trucks, we got them the same day,at the same place, Jackson Tire in Jackson, Ga by the Flying J.He went with bridgestone 726's for drives, I went with Dynatrack, a Jap tire for about 1/2 the cost. the only difference was the name on the side, as far as cosmetics go. tread depth, design, everything was the same as the bridgestones.we both balance even our drives and put centimatics on them as well, and are anal about tire pressure.What I am getting at, is that we both got 375,000 out of our tires.Top of the line, with the top of the line price, and cheap,with a cheap price.When it comes to steer tires, I will run a top brand tire there, and make sure it is a 16-ply tire.There is so much difference between a 14 and 16-ply in the front.not only the weight carrying capacity, but how much better it handles as well.Cost is not that much more, either.
DougTravels
Not a Member
I have seen some trucks running Kumho tires. I am pretty sure I pronounce it wrong but that is one strange name!
Hey Turtle, if you are running nitrogen, do you boost your cold pressure to compensate for the lack of heat build? If so how much?
The one irrefutable piece of advice from Wellarmed if checking your tires very regularly. While you have your head down there to check the pressures you also have your eyes open to see other potential problems. A good looky lou will save you a buck or two.
Cooooom hoe Doug......Coooooom hoe.
The one irrefutable piece of advice from Wellarmed if checking your tires very regularly. While you have your head down there to check the pressures you also have your eyes open to see other potential problems. A good looky lou will save you a buck or two.
Cooooom hoe Doug......Coooooom hoe.
No. Whether nitrogen or regular air, the recommended cold tire pressure (ambient air temperature) is still the one to go by, since that affects the load rating of the tire. As the temperature of the tire increases with driving, it is quite impossible to know the correct tire pressure at a given increased temperature without knowing the exact temperature inside the tire and the exact load weight on that tire. That's why the cold tire pressure always works, as long as the tires are not overloaded.
The max pressure on the sidewall is not necessarily the same as the recommended pressure by the vehicle manufacturer. In the case of the Sprinter, Dailmer recommends 55psi Front and 80psi Rear, so in this case the recommended and the maximum are the same for the Rear tires. They recommend 55 Front because of a smoother ride and better handling at high speeds (above 65MPH) and, as it turns out, more even tread wear.
The Sprinter has a GVWR of 8550, but a max rating of 3860 Front and 5360 Rear. LRE tires have a load rating of 2680 at 80psi. So a pair on the rear has a max load rating of 5360, same as the Sprinter. So, the max cold tire pressure of 80psi on the rear works, whatever the cold tire temperature may be. Manufacturers also recommend checking the pressure in the cool of the morning before the day's heat sets in, since inflating them in the mid day heat will have too much of a negative effect while driving at night.
If you fill the tires in upstate NY where it's 60 degrees, and then take a load to Laredo where it's 100, you need to let the tires cool down to the 100 degree ambient temperature and check the cold tire pressure. Tires will increase or decrease about 1 psi for every 10 degrees of ambient air at the cold tire pressure. So 80psi in New York may be 84 or 85 psi in Laredo. But that's with regular air. Nitrogen will increase or decrease about 1/4 of that, so 80 in NY might be 81 or so in Laredo, not really enough to worry about unless I'm loaded heavy.
I just run the max as stated on the tire. That way I'm always covered for the max load rating for the tire, also the empty weight of the vehicle is within the load range for the tire. In temperature extremes I won't compensate, other than to run the max cold tire pressure for wherever I am. But with Nitrogen, I've found it to always be within a pound or two of the local ambient cold tire pressures.
The first set I ran 55 front, 80 on rear, as per the owner's manual. Second set I ran 80 all around, which gave a slightly more bumpy of a ride, but I'm getting the same miles out of these as I did the first set, even with the added weight of the shelves and the junk on them that wasn't there on the first set. I'm due for a new set any day now, and I'll probably go back to 55/80. There has been slightly more tread wear on the front tires at 80psi than there was at 55psi, mostly around the inner and outer edges. Normally that indicates underinflated tires, but in the case of the Sprinter, the handling characteristics are slightly changed by the higher pressure. It causes the tires to spend more time on the inner or outer edges while steering and turning, whereas 55 psi would keep the tire more fully flush with the road.
What about MPG's? Turtle....the rolling resistance between 80 and 55 psi on the front must be considered?
wellarmed
Not a Member
So Turtle,your saying that outside air temp is what affects tire pressure and I'm sure to a point it does but I would think that friction and pavement temp would play a large part. If you leave from,I'm sorry,If I leave from Detroit and my cold tire pressure is 105 and it is 85 degrees and go to El Paso where it may be 100 to 105 degrees and the tire pressure "hot" is usually 115 to 120 (taking in consideration your very anal) give or take a couple degrees. I have three pressure guages,two of them always give the same reading and the other always disagrees,I've nicknamed it Turtle. And as far as caps are concerned you need to take into consideration the condition of the casing and the method used to cap the casing or how many times the casing has been capped. On dump trucks I've sent casings back three times (Only ones that were bought new)If they were bought as caps they were only sent back once sometimes twice on my own judgment which I know you have no faith in. Yeah,you may think I was born yesterday but I can assure you I stayed up all night. A person should give advice based on personal experience and every ones may be different but I will never under stand why you have to anal-ize it.
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DougTravels
Not a Member
HAHA Very Funny!
Yeah, that's why I went with 80psi all around on the second set, because a higher pressure would decrease friction and increase fuel mileage. And it did, slightly. It's hard to know precisely, because I only had about three months on the first set of tires with the extra weight of the shelving and stored tools and junk on them, which caused an MPG hit of about half a mile a gallon or so. I got the new tires and went with 80psi up front to see if there would be any appreciable increase in fuel mileage, and there really wasn't much of one at all, at least to where I could definitively say there was. At times it looked like a few tenths, but at other times there was no difference. With terrain, loads, winds, it's hard to get an accurate accounting over a short period of time. And it was only a few months after getting the new tires that I offloaded a bunch of the tools that I had been carrying with me, so the reduced weight gave me back a lot of what was lost. How much really really due to the reduced weight versus the 80psi on the front isn't all that clear cut.
Excessive treadwear on the inner and outer edges of a tire usually indicate an underinflated condition. That certainly wasn't the case with 80psi on the front tires. But that kind of treadwear pattern can also be caused by worn ball joints, weakened suspension springs, lots of things. I had slightly loose ball joints and had them replaced, and chalked up the treadwear to that. After having discussions with RLENT who also replaced his ball joints, and was also seeing irregular treadwear, he brought up the notion that somehow the added pressure may have altered the handling characteristics of the vehicle. I was skeptical, but based on what I have been told by a few experts, he was spot on about it, at least in the case of a Sprinter that is often loaded heavier in the rear than is the weight on the front tires. Ove the last 3 months or so I've had some conversations with some pretty sharp people at some tire and repair shops, as well as a conversation with an a couple of engineers at Michelin.
This is where a decent history of scale tickets comes on handly, as the scale tickets will show not only the gross weight, but the weight on each axle. The max rating of the Sprinter's front axle is 3680, or 1840 per tire. Most Sprinters ('06 and earlier, anyway) will have a front end in the range of 3000-3500 depending on how heavily loaded you are. Not surprising, the heavier you are loaded in a Sprinter in the rear, the less weight you have on the front axle. Empty, my steer axle usually weighs in at 3380 (YMMV), but with 2500 pounds of cargo, the steer axle drops to 3160 pounds. Spread that weight between the two tires and each tire is supporting a range of 1580-1690 pounds.
Max tire pressure is one thing, but the correct tire pressure depends on the load. These tires have a load rating 2680 at 80psi, but it turns out the correct pressure for 1600-1700 pounds is, in fact, 55 psi. And at 80psi at that weight they are technically overinflated. Of course, I knew that, but wanted to see if the decrease in handling was a problem (it wasn't) and if the decreased rolling resistance would yield better mileage (it did, but only to a small degree).
While 80psi in overinflated, it's not grossly overinflated to the point where excessive wear will show up in the classic down-the-middle of the tire wear. But what it does do is, it causes the tire to ride a little higher on the road, not quite as flush to the road, not as much even downward force onto the road. So, when you have turns and curves, even slight curves, even changing lanes, the front tires both kind of lean over a little bit off the center tread onto the edges, causing increased wear on both inner and outer edges of the tread.
I swapped out the first set of tires at 118,622, and probably could have gone another 10,000-15,000 miles on them. I rotated those every 25,000 miles. The treadwear was dead even all around at 4/32 when I swapped them out.
The second set I swapped out at 117,391, and should have swapped them out 10,000-15,000 miles sooner. I only rotated those twice, at 38,000 and 46,000 miles, which certainly played a part, as the one pair spent about 71,521 miles on the front axle and only 45,820 on the rear. But even the pair that spent the 45,820 on the front and was on the read the rest of the time showed excessive wear on the edges. The increased weight of the shelving and stored junk added to the treadwear, to be sure, but the 80psi on the front also played a large part in them wearing out sooner than they would have otherwise. There was still between 4/32 and 6/32 in some parts of the tread, nearer the center, but at the outer edges it was closer to 2/32, slightly less than that in some places.
In both cases, not bad for 80,000 mile tires and what I got out of them was still on par with what the use of nitrogen would predict.
I got new tires today, Michelin LTX AT/2, and they are inflated to 55/80. Paid $838 for the 4, which included a New Tire Fee of $8, and a Scrap Tire Fee of $12, so the tires themselves were $204.50 each. Got 'em in Delaware where there's no sales tax, tho.
Well, yeah, but more than the outside temperature, it's the temperature of the air inside the tire and of the tire itself that matters. Obviously, pavement friction will cause heat, and air expands when it gets hot, which is why the tire pressure increases as it gets hotter. But that doesn't have anything to do with measuring the tire pressure when it's cold. Manufacturers design tires to be pressurized at the cold tire pressure, to account for the increased pressure due to the heat of driving.
Well, first of all, my anal what, exactly?
Oh, I'm sorry, I think you mean "taking into consideration you're very anal," as in you are, not your. Got it. Funny. That's a good one. It's good to know you're both well armed and mature, not to mention a class act all around.
Second, if you leave Detroit at 105psi and it's 85 degrees, and you drive around michigan for several hours, what's your "hot" pressure then? Does it matter? Whether it's ambient air or air inside the tire, the pressure increases or decreases about 1psi for every 10 degrees. How hot is it inside that tire after driving around for a while?
If you knew not only what it was, but whether it mattered, then you'd have a better idea of what your "hot" pressure should be when in El Paso. But even then it's just a wild guess, because you don't know the cold tire pressure in El Paso, and that's what matters most. Detroit is 581 feet above sea level, El Paso is 3695 feet above sea level, so even if both towns had the same exact temperature, pressure in the tires would be different in each location. For every 1,000 feet in elevation above sea level, atmospheric pressure decreases about a half a pound. As a result, tire pressure goes up an equal amount. A tire gauge that reads accurately at sea level will read about 3 psi too high at an elevation of 6,000 feet. Tire gauges are calibrated for sea level, by the way.
So when you show up in El Paso and it's considerably hotter than it was in Detroit, like 20 degrees hotter, then you're likely about 2psi overinflated from the heat, plus another 1/5 to 2 psi for the altitude, so maybe 4psi too much. If you compensate for then about 4psi, you're overcompensating. That's why it's best to check tire pressure when the tires are cold, whever you are, after they've been sitting for several hours (manufacturers recommend overnight, and then checking them in the morning before the day's temperature heats up).
Like I said, a real class act.
Well of course you do. But that doesn't change the fact that underinflated tires cause increased friction and heat, and that more tire problems are caused by underinflation than anything else.
I don't know what that means.
I anal-ize it rather than accept advice blindly. That's the only way to determine the validity of the advice. And after careful consideration and much anal-izing, I have come to the conclusion that pressurizing my tires based on their "hot" temperature, and running lower pressures when it's hot outside instead of merely decreasing the volume of air inside the tire in order to achieve the correct pressure, is beyond silliness since the cold tire pressure always works no matter where you are. Others are more than free to reach a different conclusion.
and to think I paid $83 for Primwells from Firestone...they are a semi aggressive tread design for wet snow...very good in snow..but loosey for fuel and ride rough...not again...
Keep in mind that what's on the side of the tire is merely the maximum allowable pressure for that tire, not necessarily what is recommended for the vehicle, and that the correct pressure depends on the load that the tire is to support.
They had a nice set of $67 Toyo's that I could have gone with.
In my car&van driving, tire buying life, I've had several sets of Firestones that all gave me problems, one set of Toyos that was a nightmare (and that's being kind), one set of Continentals that were pure crap, one set of BF Goodrich that wasn't too bad, two sets of Bridgestones that were amazingly trouble-free, and several sets of Michelins that I've never had any problems with. What does all this mean to you? Nuuuuuuthin'. I just wanted to toss something else out there that would grate on Wellarmed's aѕѕ a little, 'cause you know, he loves me so.