Open Tire Pressure Discussion
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Joined: Feb 2011
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From: San diego
If you look at the numbers, 40 is too low even for an empty F150 with most LR E tires. Especially at the front. Most LR E tires have a limit of between 3000 and 3600lbs. At 40 they are limited to half or less of that weight. An empty 2011 scab is going to run around 5500lbs empty, no passengers. With the biggest amount of that weight in the front. Those tires would be overloaded with 40 psi.
Personally I have run LR E tires at 50 with no problems with wear, and if carrying a load, I did not have to worry about adding air just to do it.
Also the recommendations by NHTSA is that TPM system would alert if the pressure drops to 46psi for a LR E with a max of 80.
http://www.nhtsa.gov/cars/rules/ruli...ule.html?name=
As for the Trail Grapplers, LR E 35", they have a max of 65 rather than 80. 35 is not as bad as the other suggestion, but is still too low. Discount had them about right, although they would have been better at 45 when loaded.
The 295/70R18 has a very high rating for a LR E (4080 at 80psi). You can run them at 40 and be good for even a loaded truck. ASlthough if towing, you may want to run them slightly higher (45) for sidewall support.
Each and every tire is different. You have to look at the numbers for each one to determine what the should be run at.
Personally I have run LR E tires at 50 with no problems with wear, and if carrying a load, I did not have to worry about adding air just to do it.
Also the recommendations by NHTSA is that TPM system would alert if the pressure drops to 46psi for a LR E with a max of 80.
http://www.nhtsa.gov/cars/rules/ruli...ule.html?name=
As for the Trail Grapplers, LR E 35", they have a max of 65 rather than 80. 35 is not as bad as the other suggestion, but is still too low. Discount had them about right, although they would have been better at 45 when loaded.
The 295/70R18 has a very high rating for a LR E (4080 at 80psi). You can run them at 40 and be good for even a loaded truck. ASlthough if towing, you may want to run them slightly higher (45) for sidewall support.
Each and every tire is different. You have to look at the numbers for each one to determine what the should be run at.
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From: Calgary, Alberta
One other quick reference question regarding 295/70/18 Nitto Trail Graps.
At which tire pressure would you notice over inflation and/or under inflation wear pattern, when (if it matters) the tires are mounted on a '10 screw FX4
At which tire pressure would you notice over inflation and/or under inflation wear pattern, when (if it matters) the tires are mounted on a '10 screw FX4
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From: Mount Airy,MD
The problem with underinflated is that even before wear is evident, you may damage the tires. Where with overinflated, the worst that will happen is excessive wear (except when over the the tires max).
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From: Calgary, Alberta
Well, these 295/70/18 Nitto Trail Graps are going on my factory FX4 18's. They are a 7.5"wheel, the minimum on Nitto's site. Would that help any wear vs pressure assumptions?
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From: Mount Airy,MD
The fact that it is one of the recommended widths does help. Still, make sure they are properly inflated. I would start at 40 and go from there. I would not go any lower than about 37-38. Just remember that they are close to a mud terrain tire with an open tread (less rubber on the road in the footprint that other tires). Even properly inflated, they may wear quicker than something like the Terra Grappler.
Last edited by kingfish51; Apr 28, 2011 at 06:46 PM.
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From: Maine
Another suggestion I would give is to pick up an inexpensive tread depth gauge, take an initial reading across the tread and keep an eye on wear in the middle and the the outer side of the tread, then adjust pressure accordingly
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From: Maine
Mr Kingfish...quick question to avoid this old man lots of searching (just lazy tonight)
LT275X70X18 Nitto Dura grappler highway terrain on 9" XD wheel...what would be a good pressure (starting) on an 07 FX4 Daily Driver no load or towing mostly ??
LT275X70X18 Nitto Dura grappler highway terrain on 9" XD wheel...what would be a good pressure (starting) on an 07 FX4 Daily Driver no load or towing mostly ??
Last edited by sam1947; Apr 28, 2011 at 08:45 PM.
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From: Mount Airy,MD
Looking at the specs, that tires recommended widths are 7-8.5". So in your case you may even want to go slightly higher than what is needed. I would start at 50 and see how they wear. Might be a slightly rougher ride, but to get better wear, you may need to go higher.