I'm on the road, need input!!

[mwiener2]

I'm at a hotel for the night in IL on my way to CO from PA.

I put the tires at 42/40 cold before I left and the car unloaded. The car is now LOADED!!!

about 400 something miles in i noticed the front left tire looked low. It read 36psi hot. The other three were around 38-39 hot.


Where'd my air go?

I pumped them back up to 42/40 hot.


Stopped at a walmart and bought a $10 cig lighter powered air pump and a plug set just in case.

Spent about 10 min trying to decide if the goo was worth the extra insurance of not getting stranded. But that goo really makes a mess later on.


Anybody got any ideas?

[Nutter]

Use the goo and you'll need to get a new tire after you use it. 42/40 seems realy high even if its loaded. Are they stock wheels and tires ? I would say 36psi even hot would be plenty. How did you test the pressure ? Do you have a good gauge ?

Bottom line is make sure your spare has enough air in it and keep the pressures even on each axle, check the front left often.

John

ps. If the others where 38-39 hot then something may be wrong with your gauge, if they where 42- 40 cold they would go up when hot not down. ?

[mwiener2]

Toyo T1R - Max infl is 44psi 245/45-18 on a 18x8 OZ rim

I want them almost filled to max to get every bit of MPG out of them. Also with the extra weight the stiffer tire is safer at speed.

[bosco]

why so high on tire pressure just do what the factory recommends. get to a tire shop in the am and check your tires for leaks. bosco

[toshiba2.5]

where in IL are you?

[mwiener2]

why so high on tire pressure just do what the factory recommends. get to a tire shop in the am and check your tires for leaks. bosco


32/30 is the recomended pressure for the stock RE92's (which kill bunnies) and not the best pressure for other tires that you may put on your car.

I've found that 40/38 works best for daily driving with the T1R's


I would just go to a tire shop, but where am I gonna find on that's open on Sunday Memorial Day weekend?

[mwiener2]

where in IL are you?


Effingham.. i think. I'm kinda tired.

[Nutter]

Toyo T1R - Max infl is 44psi 245/45-18 on a 18x8 OZ rim

I want them almost filled to max to get every bit of MPG out of them. Also with the extra weight the stiffer tire is safer at speed.

The Max infl pressure is a safty WARNING not a recomend inflation pressure. You should stay as close to the recomended pressure for your car. You will wear the tires more in the center with high pressure. Also you will gain mpg but not much more at 42/40 compaired to 36/36 all that will happen is they will wear out faster and unevenly.

John

[mwiener2]

i'm 1mm off the wear bar. I'm not too concerned with that.

My big concern is why am I losing pressure....in all 4....when they're hot

[Vimy101]

^ If your car is loaded down, you should reduce pressure. Running high pressure with a heavy load stresses the tires. One reason the placard inflation seems so low is that the OEM is figuring worst case scenarios. i.e. A fully loaded vehicle hitting a pot hole at 75mph causing massive tire failure if pressure is too high. You need to have some flex in the tire when running heavy.

[bosco]

^ If your car is loaded down, you should reduce pressure. Running high pressure with a heavy load stresses the tires. One reason the placard inflation seems so low is that the OEM is figuring worst case scenarios. i.e. A fully loaded vehicle hitting a pot hole at 75mph causing massive tire failure if pressure is too high. You need to have some flex in the tire when running heavy.

:confused: then why does the manual say to increase a few pounds when loaded? btw are you loaded now? :lol: bosco

[mwiener2]

That is true, but also if you don't up the pressure the tire gets squished and has the same effect as being underinflated. It's gets hot and wears on the outsides.

The placard pressure is for stock tires assuming 4 passengers.


If you look at the placard for a MB or an Audi (I'm sure BMW is the same) it has a normal pressure and a loaded pressure (usually depicted by a picture of 5 people and luggage)


I'm not here to argue what the correct pressure should be. As long as you are between the placard pressure and the max pressure you are fine.

I'm trying to figure out why I'm losing pressure. I was expecting to see around 46-47 after 400 miles non-stop. If it were just the one tire, great, it's got a leak. But all 4 to read lower than the cold pressure when they are hot?????

[Vimy101]

:confused: then why does the manual say to increase a few pounds when loaded? btw are you loaded now? :lol: bosco

On my way. :redface: :)

You can add a few pounds to keep them "round" but approaching max. cold inflation under heavy load is stressing the tires by decreasing their ability to absorb the tremendous shock loading they incur. Think balloons.

As to why the OP is losing pressure, who knows? Leaky bead seals?

[Andyjo]

Heading to CO aye? watch out for Nebraska, last time i drove through there, omaha ate my windshield :icon_evil
also, if you're loaded up, and you hit a pothole, air can leak out the bead, no matter how good it is, think about hitting a curb real hard dead on the tire, your instantaneous pressure jumps up, and most of the time a little air will force itself out the bead. I've had it happen in my old impreza, offroading a little too fast... and in my OBXT in denver, hit a nasty pot hole, lost a good 5 psi in that tire.
ALSO, watch out for michigan, that state likes to eat wheel studs :rolleyes:
oh yeah, and those 'fix-a-flat's' work pretty well if you're stuck in the middle of nowhere.

[rao]

42/40 :lol:

[Xenonk]

i run 42/38 on my car.. but didnt you say you are running 18? that actually sounds right for 18 anyways (actually I run about 45/42 hot for 18" tire sizes).

What kind of tire gauge are you using???

check your tire for a nail, that could be a small one on there. Get a bottle of fix-a-flat. i never leave the house to do a long drive like without having a spare to go with it at least. I think you'll be ok, just keep going.. if you really need to get a tire patched up, do it now while you got some day light at a local NTB, because tomorrow most stores will be closed and you wont be able to get that tire patched up. Good luck.

[brett s]

^ If your car is loaded down, you should reduce pressure. Running high pressure with a heavy load stresses the tires. One reason the placard inflation seems so low is that the OEM is figuring worst case scenarios. i.e. A fully loaded vehicle hitting a pot hole at 75mph causing massive tire failure if pressure is too high. You need to have some flex in the tire when running heavy.

Bad advice, absolutely incorrect - higher (up to the max cold limit) is better for heavy loading. The tire will run cooler, it's the heat that'll kill it quick when running at pressures too low for the load...

The low OEM pressure recommendations are more about ride comfort than anything else, and are totally meaningless when using different tires anyways.

[rao]

Since you always carry dry ice with you - just put some of that on the tires and then take a cold reading and see what's happening :lol:

[mwiener2]

i run 42/38 on my car.. but didnt you say you are running 18? that actually sounds right for 18 anyways (actually I run about 45/42 hot for 18" tire sizes).

What kind of tire gauge are you using???

check your tire for a nail, that could be a small one on there. Get a bottle of fix-a-flat. i never leave the house to do a long drive like without having a spare to go with it at least. I think you'll be ok, just keep going.. if you really need to get a tire patched up, do it now while you got some day light at a local NTB, because tomorrow most stores will be closed and you wont be able to get that tire patched up. Good luck.

I'm using two guages. I had an electric one, but it leaked out a ton of air each time I tried to get a good reading. Then I switched to the classic one where the little stick pops out and you read the number.

I think I'm gonna go 38/38 cold now that the car has had time to sit overnight. That is assuming there is any air left and the tire doesn't have a hole in it. I'm also assuming the reason for making the rear 2 psi less than the front is that since the engine sits right over the front wheels, the extra psi makes the tire as round as the rears which have less directly over them.

Since I'm loaded to the maxe, the rears probly have more weight on them then the rear.

The other reason I want the tire pressure really high is I'm driving through alot of really heavy thunder squalls. The Higher pressure means a stiffer tire which is more resistant to hydroplanning.




And to everyone freaing out about the high pressure, you should go look at what a semi truck has in it's tires. 100-120psi or more

[praedet]

Since you are running a heavy load, I would do the matched 38/38. That is what I ran when I had 600 lbs. in the back going from OH to CA. Don't worry about the folks saying factory specs or that running high will kill your tires. The tires probably just lost some due to the heat expanding them a little. Not a major concern, just check them every morning before you start out :D

[Vimy101]

Bad advice, absolutely incorrect - higher (up to the max cold limit) is better for heavy loading. The tire will run cooler, it's the heat that'll kill it quick when running at pressures too low for the load...

The low OEM pressure recommendations are more about ride comfort than anything else, and are totally meaningless when using different tires anyways.

Keeping the tires round is the object of the game. Max cold inflation is the point up to which maximum load can "safely" be carried. Tire OEMs are very cagey when describing this limit due, undoubtedly, to liability concerns.

[rao]

And to everyone freaing out about the high pressure, you should go look at what a semi truck has in it's tires. 100-120psi or more

Do you have semi-truck wheels and tires on your car?

[bosco]

this thread rocks! so much potential. :lol: another thing is your car so loaded the rear end is sagging? btw comparing truck tires with passenger tires is apples to oranges. bosco

[Andyjo]

I'm gonna put truck tires on my OBXT and see what happens :spin:
oh... and well.. i guess the 24 lug conversion may be an issues too :lol:

[SeeeeeYa]

Tire gauge? Are you using the same one you always use?

I am runing 40front, 38rear hot now, cold that measured 38f 36r yesterday in my new RE960s. For the last year I ran 40f 38r cold in my Pirelli PZero M&Ss and they all wore out evenly to the bars. I have almost always used 5psi over whatever the door sticker said. Better handling, better gas mileage, and a little better pothole protection for the rims.

Obviously, outside temps make all the difference. I use an AccuGauge dial tire pressure gauge. When travelling I always have two with me because history has had one go bad. I'm a perfectionist about tire pressures, checking and adjusting all the time. Once I had one of my tires be flat and found it out within a couple of blocks. Upset, I filled it up and it NEVER varied again!! All I could guess is that someone let the air out while at the mall as a prank.

In your case all I can think of is a) elevation change, b) temperature change, c) gauge issue.... assuming you use the same gauge all the time and that you yourself filled them to the pressures you reference. Whatever, stop and check them at every opportunity, especially every gas stop. Inspect the tires minutely for objects that a vandal may have placed beneath them to puncture them. If it remains a one tire problem and you have to press on.... goop it up and deal with that later. Stranded is no good.

Good luck.

[KA81]

RE92's kill bunnies

[mwiener2]

Once I had one of my tires be flat and found it out within a couple of blocks. Upset, I filled it up and it NEVER varied again!! All I could guess is that someone let the air out while at the mall as a prank.

In your case all I can think of is a) elevation change, b) temperature change, c) gauge issue.... assuming you use the same gauge all the time and that you yourself filled them to the pressures you reference.



That's why I went and got locking valve stem caps with a subaru logo on them;)


That's why I was freaking out, I filled them, I used the same guage, Tire temp and ambient temp went up... but pressure was down, altitude was within a few hundred feet.



Today everything was fine. Adjusted the pressure when I woke up(40/40), it was fairly close to what it should have been. When I checked it out after a tank of gas, it was what I expected (46/46) then it stayed that way for the rest of today's driving. :spin: :spin:



BTW Kansas sucks. BORING!!!!

[SeeeeeYa]

That's why I went and got locking valve stem caps with a subaru logo on them;)

Super glad all is going ok!

I didn't even know that a locking valve stem cap existed. When I find them I will put them on.

Looking forward to hearing you're safe and sound at trip's end.

[red beast]

could be your tire pressure sensor are leaking around the little rubber seal.



when i first put a set in on the jdm rims they leaked slowly.

i got a socket and tightened them up a little over a week and they held air..



BE CAREFUL if you tighten them up. the collars are plastic and will break if "wrenched"



the valve stem cap are also required for the sensors to prevent some leakage.

[mwiener2]

I don' have tpms



Arrived in Dever!

[Andyjo]

Arrived in Dever!
It's a 'fun' drive isn't it? :cool:

[mwiener2]

yeah, I hope to do it again next week!

[Andyjo]

sounds like my spring break this year :rolleyes:
the part i find kind of funny.. it that the drive is just nothing... from the outskirts of denver.... all the way back to the east coast :p
If you take I-80 back, watch out for freaking insane truck drivers! :spin:

[mwiener2]

AAA wanted me to take 80. I was like hell no, that's too far north. I kinda wanted to be in the middle of nowhere cause there would be less traffic and less people to worry about.

It wasn't too bad till IL. Then Kansas made IL look like a theme park ride. The east side of CO isn't a winner either.

But interestingly, since I got over 4000 feet, my mpg has shot way way up. I went from middle 18's all through Kansas to 22.5 here in CO. And it keeps going up. I like.

[Andyjo]

we cruised around CO for a good week, and averaged 26 mpg running stage 1 :eek:
and that includes a trip up through estes part & the rocky mtn national park, and a bunch of highway driving down to CO springs and around.

[Vimy101]

^ Things are changing as far as ethanol in fuel but it used to be that once you got off the prairies you started getting 100% gasoline.

[sebberry]

This roadtrip is worthless without pics! :D

[sebberry]

Oops... just found the pics thread :)