QuestionQUESTION: I have a 2004 Harley Davidson Superduty which came with 275/65 18's on it. I want to know if I can put 285/50 (yes, 50) 18's on it and if I can go with a Load Range D instead of E? I know it will sacrifice the handling but I'd like to improve the ride a little, if possible.
ANSWER: Melissa,
Your tires have the letters "LT" in front of them. That means they are different than "P" type tires.
I could not find any 285/50R18's that were "LT" type tires - so they can not be Load Range D's. If you have found such an animal, I would appreciate a link.
Plus Tire Guides doesn't list any 2004 Ford F-250's with 18" tires. They do, however, have this size listed on a several versions of 2005 Ford F-250's and F-350's - and it lists the inflation pressures as .... well ....... there is a complicated lis of possible pressures - but all in the 60 psi to 80 psi range. The rim they list is 8" wide.
My understanding of the way the load carrying characteristics of tires works says that even if the 285/50R18 is an "LT", a Load Range D would have less load carrying capacity - and that increases the risk of a load related tire failure, which sometimes has tragic consequences.
Beside a 285/50r18 requires a minimum of an 8 1/2" wide rim.
So you need to check your vehicle's placard to make sure this all lines up. The placard on a Ford is on the drivers doorpost.
---------- FOLLOW-UP ----------
QUESTION: I'm not sure about the load rating b/c I don't know how to read tires, but someone told me they thought it was load rating "d" for the 285/50r18's I was looking at. But, that's irrelevant if the rims aren't wide enough for 50's (which I thought might be the case). These rims only came on 2004 Ford Superduty Harley Davidson series trucks. 2005 and up have 20's and 22's on them. This is the only one with 18's. Thanks for the info. I'll be going with 285/55r18; don't know about the load rating yet. I'm sick of riding in a log wagon. :-(
AnswerMelissa,
Have you checked the vehicle's placard? What does it say was the original tire size and inflation pressure?
This is important because of the "LT" issue I mentioned. The tire size you quoted - 285/55R18 - is also a "P" type tire, so we run into the same load carrying capacity issue and the same risk of tire failure.
It's obvious that you need technical help with this selction process and the advice you have been given up to this point, is not sound.
But I suspect you are thinking that changing tires is going to change this truck into a plush riding car - and nothing could be further from the truth. It's a truck and you will only change the ride quality a little bit. In other words, it will still be a log wagon.
