Truck Topics
Making a Wheel Decision
By Jeff Jensen, Editor
Dec 26, 2007 - 8:35:00 AM

Wheel selection is really a matter of knowing what’s available, and knowing what you need from your equipment.

Polished aluminum wheels look great.  They're also lighter, stronger, and some contend that you'll get a better ride with them.  But, hold on there! 

The reason why the industry-standard wheel spec for North American trucks calls for steel wheels is simple - they're about three times cheaper than aluminum wheels.
 
Steel wheels come standard on seven of the eight heavy-duty truck makes, with the exception of a few higher-end models, says a marketing and product management director for Accuride, manufacturers of both steel and aluminum wheels.

But, price doesn't seem to be a problem with 40 to 50 percent of truck buyers who choose aluminum.  And there are four main reasons why fleets and owner-operators make the decision for aluminum: weight savings, aesthetics, ride comfort, and resale value.

Weight
Accuride says the standard Accuride steel wheel weighs 76 or 78 lb, depending on whether it's a five- or two-handhole wheel, whereas a similar Accuride aluminum wheel weighs 47 lb and has 10 handholes.

This means a weight savings of about 30 lb. per wheel or a total of 300 lbs. for a tractor-trailer combination.  For a weight-sensitive application like bulk hauling, that translates to 300 lbs. of additional cargo, but for the typical expedited freight application, where very few loads max out the truck, the weight savings are negligible.

Good looks
Then, of course, there's the aesthetics. Polished aluminum truck wheels just look good, which is important to many owner-operators as well as image-conscious fleets.

Some trucking fleets say they outfit their trucks with aluminum wheels as a driver-retention measure, just because drivers like the look.

However, there is the price of additional effort to keep things looking nice.  With steel wheels, you just wash 'em off. With aluminum, you have to polish them or pay one of those guys in the truck stop to do it for you.

Smooth ride
Some experts say because aluminum wheels are a one-piece forging, they’re more true than steel assemblies, so vibration is kept to a minimum. They’re lighter, so there’s less unsprung weight.
 
Others contend that this may be true in a controlled test environment where you might see less flex with an aluminum wheel, but in the real world it won't make any difference.

Aluminum wheel supporters point to the products' superior strength. In crush testing conducted by Alcoa, a steel disc wheel buckled two inches with 30,000 pounds of pressure.  It took 30,000 pounds to do that to an Alcoa aluminum wheel.

Anti-corrosion qualities
For those owner-operators who run through the colder parts of the country where salt and magnesium- and calcium-chloride compounds are used, it should be noted that aluminum resists corrosion better than steel, another plus in the aluminum wheel column.

Value
Representatives from both Accuride and Alcoa say that many aluminum wheel buyers will recoup at least 50 percent of the aluminum upcharge when they go to trade their truck in.
 
They state that market research suggests that the resale value of a truck goes up substantially when fitted with aluminum wheels.

Keeping them shiny
Rock salt works well on pavement and can be fairly easily washed from vehicles to protect them.  But the more efficient ice-melters are more corrosive and cling tenaciously to metal. Wheels are literally closer to salt sprays than anything else on the truck, so they need extra defensive measures to protect them.

Aluminum can be dulled by salt sprays and acid baths at commercial washing facilities.  As a result, many owners clean and wax them often.  If neglected, aluminum takes on a whitish film that doesn't wash off but can be removed by laborious polishing.

Special finishes - called Accu-Shield by Accuride and Dura-Bright by Alcoa - keep the wheels shiny. The makers say their special wheels can be cleaned with soap and water, and never need polish or wax.
     
Alcoa says its Dura-Bright is the result of a chemical-thermal processing that toughens aluminum surfaces. The process can be applied to polished and non-polished wheels, but about 90% of Dura-Bright sales are to folks who spec polished wheels, Alcoa says.

Expect to pay $75 to $80 per wheel for the special surfacing (by comparison, factory polishing costs $30 to $50 a wheel, on pricing by vehicle builders). The finishing is done at factory and can't be applied to existing wheels unless they're removed from a rig and sent in - not always practical.

A note of caution
Spec’ing wheels requires only a few choices. Load capacity and offset are determined by vehicle OEMs, and departing from original values is not recommended.

Insufficient load capacity poses an obvious safety hazard, but the danger of incorrect offset is less obvious. Offset is the distance between the axial center of the wheel and the mounting pad.

Wheels with incorrect offset put unusual loads on wheel bearings, causing rapid wear and possible bearing failure and wheel loss.

Alcoa Wheel Products: North America
Accuride Corporation