Ford E450 Tire Size

Hi Jim,

I'm running the OEM shocks. That, too, is an issue. Even 20 kph (12 mph) on a washboard road is a bone jarring experience.

There are manual air bags on the rear. All they seem to do is increase ground clearance (but not enough). I've tried them at 20, 30, 40, 50, 60, and 70 psi.

PT what shocks are you running? The Ford shocks are too lightly loaded up front and to heavily loaded in the back to give a good ride on a class C loaded near the limits. Those Michelins are great tires. But I bet they have a lot less softening of the ride through sidewall flex today than they did new.

Jim

Hi harold,

I plan on larger width rims. I run 14,000 pounds fully loaded (full gas tank, full water tank, two persons, rack on back and food.)

I want to have a "cushion" above the 14,500 pounds the chassis is rated at. I want to have slightly greater ground clearance. I want to have a gentler ride.

There are, with the current 225 75R16 tires zero sway or handling issues.

My existing Michelin tires are from Jan 2004, and I have 100,000 kilometers (60,000 miles) on them. There are no wear issues on the tires, and plenty of tread. The RV was 5 years old with 7000 kilometers on it when I purchased it, in Feb of 2009. I drive it about 1600 kilometers (1000 miles) per month on average.

The rear duals are run at 80 psi and the front at 65 psi.

pianotuna wrote:
Hi,

What I was asking was that a 225 and 245--of the same load rating (E), will the 245 carry more weight. I.E. have greater carrying capacity?

Here are the ratings for the goodyear tires. It would also depend on whether the rims will accept the wider tire.
Duals;
225= 2470@80 psi
245= 2778@80 psi
Siungle;
225= 2680@80 psi
245= 3042@80 psi

I had lunch a few weeks back with a good friend who was talking of taking off his dull wheels on a class c and putting on wide singles to save mpg. I said Tom why save money, you will never give but pennies on the dollar back, you are rich, and you only drive 3000 miles per year now. You have had to much coffee today.

Don,

Below is a link to a 16 inch (I believe you stated you were staying with 16 inch rims?) chart of the superb Goodyear G947 all steel tire that at least shows maximum (all values @ 80psi) loading carrying capacity versus tire size for Load Range E. However you probably want a chart that shows load carrying capacity of 16 inch LR E tires at different pressures(?):

http://www.goodyear.com/cfmx/web/truck/line.cfm?prodline=160026

Regarding your desire to reduce pressures with a larger tire so you can maybe get a softer ride ... keep in mind that a larger Load Range E tire is probably getting it's additional load carrying capacity at a given pressure via stiffer sidewalls. Hence, your ride may remain just as stiff even with slightly lower running pressures because a given carrying capacity is going to require the same overall tire stiffness - from air pressure and sidewall strength in combination with each other.


gmctoyman,

As you are probably well aware, the "physics" of 19.5 inch rims - assuming a given, or close, overall tire diameter - means that the larger rims require tires of less-tall sidewalls and this means stiffer sidewalls because there is less sidewall rubber to flex up and down. Aren't 19.5 inch tires with a given pressure in them going to provide a stiffer ride because of the less forgiving sidewalls?

I realize that the big "pro" for less-tall sidewalls for a given overall tire diameter is that you get less squirm (that's why racing cars use them), but boy .... in my case my E450 is stiff enough riding as it is ... without going to lower profile tires on it.

However FWIW, I am running larger diameter Load Range E 16 inch tires on it to provide increased offroad clearance, which makes my ride slightly softer (because of taller sidewalls to flex) at the same 80 psi pressure in the duals that I was running with the stock tires.

All load range E tires are 10 ply and have the same load carrying capacity no matter the tread width or sectional width. It is an industry standard for rating load capacity. It does not matter whether the size is 16.5 or 22.5, the load capacity is the same if both are rated E.

Hi,

I do plan to change the rims and to increase the "spacers" between the rear duals.

HiTech wrote:
Tires with the same Load Range (E) can have a different Load Index. It is more likely to find a higher weight rating on wider tire in the same Load Range I believe.

Jim

Agreed, but I believe one would have to change out the rims also to accommodate a larger width tire such as the super singles.
All rims that I am aware of have a maximum tire width and maximum pressure rating. Exceeding either of these would be flirting with disaster.

Tires with the same Load Range (E) can have a different Load Index. It is more likely to find a higher weight rating on wider tire in the same Load Range I believe.

Jim