Before You Go Wide

There might be significant advantages in switching from duals to wide singles, but there are a few things to consider before making the jump.

Retrofitting

With tractors, you can probably just buy new wheels and substitute wide singles. On trailers, because of the way wide singles interact with axles, you should consult your trailer OEM to determine whether the type and condition of your trailer axles—and their components—make them suitable for wide singles.

Of course, you'll need new wheels for these tires as well.

Weight savings

Wide singles weigh significantly less than the dual pairs they replace—as much as 35 to 75 pounds.

If you've been using aluminum wheels, the new wheels needed save nearly 24 pounds per wheel end. If you've been using steel wheels, you save over 90 pounds.

So, if you're already on aluminum wheels, you only save about 600 pounds by converting four axles, but if you still use steel wheels, you can save nearly 1,200 pounds by converting to wide singles.

Vocational niches

In our view, wide singles are for fleets that typically "gross out." That includes bulk haulers of all kinds, whether of liquid or dry commodities.

If you haul certain types of produce—fresh lettuce for example—this might help you squeeze in a few more crates. If you haul soft drinks or beer, you could increase the number of cases, yet stay under 80,000 pounds gross.

Here are some estimates of common cargoes and the extra amounts you might be able to carry:

  • 1,200 lb. = (approx.) 200 gallons of gasoline 139 gallons of milk 156 gallons of fuel oil
  • 41 cases of bottled water
  • 61 cases of canned beer

Remember though, if you're already using aluminum wheels, the extra cargo amounts would be about half what's shown here.

Fuel consumption

With wide base radials, you have only one set of sidewalls flexing on each axle end. Switching to wide singles could save from about two percent to five percent on fuel.

However, switching to wide single tires solely as a way to save fuel may not be your best investment. There are fuel-efficient tires for your existing dual assemblies that can provide equal savings, and don't require you to buy new wheels.

Maintenance issues

You may see tire maintenance costs decrease because you'll be handling half as many tires, half as many wheels, etc. You'll have fewer parts to inventory, mount and balance. And, there are half as many inflation pressures to set and maintain.

All wide base radials put the same load that was on a dual pair onto a single tire that is not as wide as the duals were. So, you can expect somewhat faster wear with wide base tires.

Until more fleets adopt them, dealers and truckstops probably aren't going to be as well stocked with wide singles as with conventional tires. The same is true for the special wheels required.

Before switching, consult with your tire suppliers to determine whether replacement tires and wheels will be available along your routes.

Wide singles can often be retreaded, so consult your retreader regarding their capabilities.

Ride and handling

Some drivers report superior ride and handling with wide single tires.

The position of the tires on their axles moves their tread centerlines out a bit from the centerline of a dual pair. That makes the effective "track" of the vehicle a bit wider, for a lower center of gravity, which, together with shorter sidewalls, could provide some improvement in handling and stability.

Some drivers also report that wide single tires ride well in road grooves. They say they don't feel the tires jumping into and out of road ruts the way dual pairs sometimes do.

Summary

To recap, if all you need is improved fuel economy, there are less expensive and easier ways to get the same fuel economy that wide singles offer.

If you can turn weight savings into additional revenue by increasing your payloads, you can probably gain about 600 pounds by switching to wide singles. If you change from steel to aluminum wheels, you can probably double that.

Wide singles can be of value primarily to users whose revenues are determined by weight hauled, like bulk and heavy commodities haulers.

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