Cotay
Member
We just returned from fetching our travel trailer in California to bring back to North Idaho. Before departing we had routine maintenance performed on both the Expedition EL 4wd (has factory HD tow package) and trailer. Tires (2 year old Nitto Dura Grappler 275/55R20 XL 117S with 40K miles on them) were inspected by a mechanic the day before we departed and inflated cold to 44 psi (front) and 48 psi (rear) and all four had plenty of tread.
Until now the Dura Grapplers have been the best tires we've used for towing with the Expedition and they exhibited very little mush or sway when properly inflated. About 100 miles from home the right rear passenger tire blew at 60 mph. I have no doubt this was a defective tire but I'm not sure it's even worth a warranty claim. The three remaining tires are all still in very good condition. When we got home I checked and found that others have had similar issues with these tires so I'm looking to replace all four tires now.
I narrowed my choice down to two Cooper tires. The Discoverer HTP 275/55R20 XL 117T (in stock locally) and the Cooper AT3 XLT 275/55R20 120/117S E1 (ordered for delivery on Monday). The difference in price isn't a factor here so I went ahead and asked them to order the AT3 XLT. These E rated LT tires may be overkill but my wife wanted them for the slightly better winter driving traction. Discount Tire assured me that the stock factory Ford 20" rims are capable of 80 psi.
So my questions really are, are the stock Ford 20" rims really capable of running a E rated tire at 80 psi (not that I'll ever do this) and what psi should these be set at for everyday driving and for towing? I've looked for load index figures for an E tire inflated to less than max psi but I simply cannot find it. Or should I just stick to the XL tires?
Until now the Dura Grapplers have been the best tires we've used for towing with the Expedition and they exhibited very little mush or sway when properly inflated. About 100 miles from home the right rear passenger tire blew at 60 mph. I have no doubt this was a defective tire but I'm not sure it's even worth a warranty claim. The three remaining tires are all still in very good condition. When we got home I checked and found that others have had similar issues with these tires so I'm looking to replace all four tires now.
I narrowed my choice down to two Cooper tires. The Discoverer HTP 275/55R20 XL 117T (in stock locally) and the Cooper AT3 XLT 275/55R20 120/117S E1 (ordered for delivery on Monday). The difference in price isn't a factor here so I went ahead and asked them to order the AT3 XLT. These E rated LT tires may be overkill but my wife wanted them for the slightly better winter driving traction. Discount Tire assured me that the stock factory Ford 20" rims are capable of 80 psi.
So my questions really are, are the stock Ford 20" rims really capable of running a E rated tire at 80 psi (not that I'll ever do this) and what psi should these be set at for everyday driving and for towing? I've looked for load index figures for an E tire inflated to less than max psi but I simply cannot find it. Or should I just stick to the XL tires?