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Old 03-16-2008, 02:42 PM   #1
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Continential M & S Tires

I have the above named tires, in size LT275/70R18 Max Load 1650 lbs @ 80 PSI.

Should I be keeping the air pressure at 80 PSI all the time ? I guess I have goofed, as I always check the tires on the Sunny, but seldom check the truck. Guess I assumed (dumb I know) that pressure was checked when serviced.

Now, I really feel stupid saying that I have not been chcecking the air pressure on the truck, I do visually inspect them for defects, irregular tread wear.

Checking all stuff out, as I leave friday morning for an Open Roads Singles Get to Gether, that I am hosting in Walterboro, SC. Lots to check and load since Sunny has been cooped up since Thanksgiving.

Now, I gotta figure out the battery charger and charge the trailer battery (It's in the house)

And I'm getting ready to make a new vinyl cover for the power tongue jack, my old one is about shot (It's about 8 years old)

Also have the laptop turned on, getting updates installed on it.


Sunny #18 2003 F-344SR #8157
Sunny #19 1997 T-2653 #5485
1999 Ford F350XLT DRW Crew Cab, Long bed 7.3 PSD
2002 VW Jetta TDI.. AKA: Kitty's Kruiser
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Old 03-16-2008, 03:58 PM   #2
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My new (to me) Dodge Dually came with 6 Michelin LT235/85R16 tires on it, all aired up to 80 psi. They are load range E , 1650 lbs. at 80 psi. It rode real, real rough, like driving on a washboard.

I did a bunch of checking of pressure charts in the owners manual for the truck and online on the Michelin website.

Anyway, when I was all done, I figured out that for daily driving with little or no load in the truck, I needed to let about 30 psi out of the tires. The truck rides a lot smoother, even with about a half face of firewood (less than 1K lbs.) in the back for some weight in the snowy weather.

If I really need to put the rated load of 4,700 pounds in the bed of the truck, I'll air up to 75 psi or so.


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Old 03-16-2008, 07:24 PM   #3
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Check your driver side door jamb, your glovebox door, or your owner's manual. One of these locations should have the manufacturer information on what tire pressure to run.

If not, give your dealer a call- it will probably be in the 55-65 psi range unloaded, and 75 or so loaded.

Running at 80 psi will give you the capacity to carry 6600 pounds on your axles, so next time you're near a truck scale, stop in... weigh your truck with no trailer, full fuel load. Then hook up, go back, and get a loaded weight. If you bring your original weigh ticket, your re-weigh is usually free. If you ask, they will be able to tell you how far to pull onto the scale to weigh the front and rear truck axles, and then the entire rig.

Use the unloaded weight and the mfg. recommended inflation for around town, then air up using the mfg. inflation ratings when hauling Sunny!

A really good place to find a truck scale if you don't have a truck stop nearby is a waste transfer station or a recycling station. Follow that garbage truck (at a non-stinky distance, of course ).

Some junkyards have them too, but then you are subjecting yourself to scraps of automobiles past getting into your tires....
Kelly & Greg Southeast MA
'04 2500HD Silverado
'05 2380s Solaris Lite, axles flipped
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Old 03-16-2008, 07:49 PM   #4
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Truck was weighed on a certified scale, 3 people in cab, "FULL" fuel , tipped scales at 8,400 lbs, scale accurate to plus or minus 20 pounds. I have never had a chance to get Sunny on a scale. I have a Flying J 11 miles from home, and also the quary that weighed the truck, so one of these days, I might get there.

Thanks for the tire info. OH, man are those 18' inch tires expensive. I am dreading when I need new ones. Have about 48K on mine now. Last price I got was about $182 each,

Sunny #18 2003 F-344SR #8157
Sunny #19 1997 T-2653 #5485
1999 Ford F350XLT DRW Crew Cab, Long bed 7.3 PSD
2002 VW Jetta TDI.. AKA: Kitty's Kruiser
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Old 03-16-2008, 09:07 PM   #5
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Hi Kitty,

I've got Bridgestone Dueler AT Revo's and my Mom has BF Goodrich All Terrain TA's. Both are E Range. I keep all ten at 65 PSI all the time. With Michigan roads, there's no reason not to keep the tires pumped up to get better gas mileage, because the ride sure won't get better when going through all the potholes. In fact, that reminds me, she needs to get those rotated & balanced. The steering wheel was doing the slight left to right movement really quite bad today. She's got about 40600 miles on it right now.

2007 T-286SR Cherry/Granola, #6236, original owner, current mileage: 9467.8 (as of 5/26/19)
1997 T-2653 Blue Denim, #5471
1979 12 1/2' MC, Beige & Avocado, #4639
Past Sunlines: '97 T-2653 #5089, '94 T-2251, '86 T-1550, '94 T-2363, '98 T-270SR
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Old 03-17-2008, 09:03 PM   #6
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On my 2005 F350, same tires as yours, LT275/70R18 Continental

The door jam on mine says 65 psi front and 75 psi rear to achieve a full 11,000# GVWR and full axle ratings.

Around town I air the back down to 65 psi and then leave the front at 65. If I leave the back at 75, that F350 rides real hard empty, I would hate to feel what 80 would do. 80 may make the front bounce bad.

When towing, I go to 75 psi rear, 65 psi front and I have no instabilities in towing my 32 footer 1400# tongue TT with the DC.

Now on by older K2500 Suburban I had LT 245,75R16 E range and I had to run the back at 80psi. But that size tire needed it for the weight and the stiffness on that TV.

I "use" to be able to run the front on the Burb ay 50 psi like the door said for towing and had zero sway issues on the original Steel Tex tires. Then I bought Michelin LTX M/S. Never again on a 130” WB Suburban for towing. I have buddies using LTX on a PU and no problems, but not on a Suburban. I had to take the front to 65psi to stop side wall flexing and towing instability that came with it. And I tried going higher to 70 and 75 but the bounce was to much and made the truck want to wader it bounced so hard.

From that saga I am in tune with effects of tire stiffness and what it can cause in towing instability while use a Reese DC. All tire brands are not created equal regardless of the weight ratings.

The F350 is back to rock solid. The heavier suspension, longer wheel base and the LT275/70R18 Continental work for towing. After may last experience of buying premium tires that I thought where the best, I will stick with what I knows works which is the Continentail on the F350. Or find someone else with a similar load, F350 and using a Reese DC on a 156.2” WB

What you do not want to do is run the tire under pressure for the weight. That is a problem waiting to happen. For towing on your size truck, start with the door jam. If you are getting front end sway from high winds (it actually feels like the back of the truck moves) take the front up to 68 and start experimenting. With only a 26 ft TT (T2499) on 156.2 WB TV like you have, I do not see any issues to even cause to have to go there. It is amazing what long WB does towing stability.

Cushy soft ride and towing stability while using a Reese DC or Equal-I-zer anti sway hitch do not go in the same sentence.

Good Luck


Current Sunlines: 2004 T310SR, 2004 T1950, 2004 T2475, 2007 T2499, 2004 T317SR
Prior Sunlines: 2004 T2499 - Fern Blue
2005 Ford F350 Lariat, 6.8L V10 W/ 4.10 rear axle, CC, Short Bed, SRW. Reese HP trunnion bar hitch W/ HP DC

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