Will the speedometer still be accurate with those tires? Can they go into the computer and modify it for that tire size?

Do you have a half ton? Load Range E would be a little much in my opinion for half ton. I put the Load Range D tires on and it is a much stiffer ride.

 

I put Dick Cepek E range tires on my 1500 and it's smoother and softer than the stock P-series.

Note that I have not inflated them to the tire's maximum pressure rating. The ability of a tire to hold a certain pressure has nothing to do with the requirements of the vehicle. For instance, just because you install a hitch rated for 12,000#, that doesn't mean you must always have 12,000# on it. It merely means it is able to take it when necessary. Likewise with tires, you should always start with the mfr recommended pressures and add pressure within the bounds of the truck and tire's rating only if necessary.

 

The speedo will only be off a mph or 2. In that size they don't offer a D range tire. I do have a 1/2 ton and plan on buying a travel trailer down the road. I would like to go to a 285/65/20 but my wallet says otherwise and i plan on leveling the truck when the money allows but who knows when that will be. So this is my middle ground option.

 

What pressure do you put in your Es? I have 50 PSIs in my KO2 Ds and they are stiff. I am thinking about dropping down to 45 or 40 PSI. Your thoughts?

 

I always ran the FCII D range tires at 40 front / 45 rear on my old Hemi 1500 unless I was airing down for off-road hunting or fishing or I'd air up for towing/hauling or for better fuel mileage on trips. I found running close to max did make about a 2 mpg difference from running in the low - mid 40 psi range.

But it's probably going to always feel a little bit harsh. BFG doesn't put near the technology in their compounds that Mickey Thompson/Dick Cepek does, plus you went from passenger car tires to an actual truck/SUV tire...

 

I run the stock pressure in my Es*.

Again, the pressure you run in your tires should have nothing to do with the tires, but rather with the requirements of the vehicle, load or surface.

Running a higher pressure only ALLOWS you to carry more load on the tires. But say that your truck is able to carry a load on the rear axle of 5000# and FCA says that the tires should have 40 PSI for that ability. Putting on E range tires with 65PSI rating, and inflating them to 65 WILL NOT increase the capacity of the truck. The truck is limited to 5000#. On the other hand, if you put on some passenger car tires rated for 2200# at a maximum of 35PSI will now lower your capacity to 4400# even though the truck itself can take more.

A truck is a complex system made of many parts, and any one of those parts can be the limiting factor. Increasing the ability/performance of any one of the components will not increase the ability/performance unless it was the one that was the limiting factor.

That said, if you are pushing your truck to the limits, AND your tires are rated for a higher than stock required pressure, adding a few extra pounds WHILE in that situation won't hurt, and will make the truck a little more stable. Be sure to never exceed the maximum rating of the tire.

*I only have about 4000 miles on them and am monitoring them for signs of wear due to under- or over-pressure. Differences in sidewall stiffness, tread belt construction, rubber composition, section profile, and who knows what else can cause an aftermarket tire to wear differently than the stock ones.

 

I ran them at 45 PSI and they rode better. I will try 39 PSI this morning.

Anyways I will try the tape test across the tread to make sure that the tread will wear evenly.

Thanks.

 

LOL... You started this thread complaining of soft tires and now it appears you are trying to get your soft tires back...

A word of warning, don't go too low. You don't have the sidewall flex a 17" tire / wheel combo has...

 

I like them softer for everyday driving, but not for towing. The Load Range Ds seem stiffer anyways aired down.

 

Yeah, if you go too low you start to lose sidewall flex and on 20s there isn't much there to start with. Which is why I stated earlier not to go too low.

Well you really can't have it both ways. You could have gone with LT tires in a C range, but 8000# is a pretty good load on a 1500 and you're much better off with a D. You want that stiffer sidewall when you tow. 17" wheel/tires would have given a good bit more sidewall flex for a bit softer ride and still give the higher capacity in a D (not to mention 1000# higher tow rating over 20s) but then you would have had to buy wheels. For the extra towing capacity over a P(assenger) car tire in daily driving, your truck is just gonna feel like a truck instead of a car...