Aluminum vs. Steel
CALGARY, Alta. – Aluminum wheels are not new – they’ve been available in the trucking industry for more than 50 years.
But they have become more popular in recent years, despite the fact they cost three to four times the amount of traditional steel wheels.
So why are more fleets and owner/operators shelling out the extra money for aluminum wheels?
There are a number of reasons, says Mark Holtz, Alcoa’s marketing manager for commercial vehicle wheels. The biggest advantage of aluminum over steel is that the wheels weigh a lot less: about 30 lbs less each.
“The primary motive originally was weight savings,” Holtz explains, noting a truck’s weight can be reduced by 300 lbs and a truck/trailer combination can be reduced by more than 500 lbs by replacing steel wheels with aluminum.
“Aluminum started out very much utilitarian initially with a weight-saving goal,” says Holtz. But there are other advantages to aluminum, he adds. For instance, aluminum wheels have proven to be tougher than their heavier counterparts.
“What we have found, particularly in the mining and logging industries was that aluminum wheels came into favour because they’re actually more durable,” Holtz says. “People have the perception that steel is stronger than aluminum but aluminum wheels are designed to take advantage of the strength to weight ratio. Aluminum wheels are thicker in the mounting areas, the disc and the rim but because we take advantage of the strength to weight ratio…we put the metal where you need it.”
As a result of the strength of aluminum wheels, they are even becoming a common spec’ in heavy-duty vocational applications including logging, mining and oilfield.
“A lot of our customers in off-road applications in the Canadian market would use aluminum wheels because they are very heavily loaded on unimproved roads and it’s a pretty demanding test for both steel and aluminum, but aluminum typically outlasts steel,” says Holtz.
Holtz notes a problem called “rim flange wear” – a condition frequently used as an argument to deter off-highway customers from using aluminum wheels. The condition occurs when the heavy loads cause the tires to wear away the edges of the rim flanges on aluminum wheels and often occurred in logging and mining applications.
To address the problem, Alcoa introduced the Dura-Flange wheel – a wheel that has added protection for the top of the wheel flange. It has been particularly popular among chip and petroleum haulers, Holtz says.
“We’ve sold a lot of those wheels in the Canadian market and we see that continuing to grow. The bulk of our testing was done with fleets operating in Canada,” he adds.
Linehaul operators continue to spec’ aluminum wheels for weight savings benefits but some are also reporting an increase in tire life.
“Because the wheel is a single piece of metal…it’s very uniform and you get very little vibration input into the suspension so it’s a smooth ride for the drivers and it cuts down on tire wear,” says Holtz.
Larry Taylor, vice-president of sales and marketing with Accuride, says he feels proper wheel balancing has more to do with tire wear and overall ride quality.
While he agrees aluminum wheels are “truer,” he adds: “What we find is that with today’s tires and today’s steel or aluminum wheels really the balancing of your tires and the matching of your tire to your wheel has more to do with the overall smoothness of it.”
Another benefit of running aluminum wheels is the overall appearance of the vehicle.
A highly-polished aluminum wheel can enhance the aesthetics of the truck which in turn helps improve a company’s image and can even help attract and retain drivers. Taylor says many fleets are using shiny aluminum wheels to lure drivers to their company.
Fleets spec’ing aluminum primarily for aesthetic reasons can minimize the cost increase by replacing the outside wheels only. While they won’t achieve the entire weight-savings potential, they will still reduce their vehicle’s weight somewhat while improving the appearance of their equipment.
Taylor says Accuride also offers lightweight steel wheels that can reduce the weight by about 10-12 lbs. compared to traditional steel wheels, without the dramatic cost increase. Mixing and matching wheels of different types and weights is usually fine, but it’s best to discuss the different options with an expert.
“We sit down with the fleet customer and see what he’s really interested in (before making recommendations),” says Taylor.
The beauty of aluminum wheels is that it’s possible to keep them looking bright and shiny without a lot of maintenance.
Alcoa’s Dura-Bright wheel features a special wheel treatment that protects the appearance of the wheel and eliminates the need for polishing. All that’s required is an occasional washing with soap and water.
“It’s for those customers that want to avoid all the maintenance and like the shiny look and would like to keep it that way without spending time polishing,” Holtz says.
Accuride’s ACCU-SHIELD also features a protective layer over the aluminum which provides a virtually maintenance-free shine. Although aluminum wheels are subject to some oxidation, they tend to be very corrosion-resistant, even to road salt and sand applied to Canadian highways during the winter.
Some corrosion will ultimately occur where there’s friction between surfaces, however, and Accuride suggests using a wheel guard which is placed between the mounting surfaces protecting the wheel.
“It also makes it easier for maintenance when you go to change the tires,” Taylor says.
Given the numerous advantages of aluminum wheels, it’s not surprising more than 50 per cent of new truck wheels (and 40 per cent of the truck and trailer market) are now aluminum – despite the up to 400 per cent price increase.
A generous payback can be realized due to the increased payload, resale value and by eliminating refurbishing costs.
“Eventually after a couple of years you have to take steel wheels off and have them refurbished or repainted,” points out Taylor.
Still, some carriers continue to use steel wheels because there are instances when the investment simply wouldn’t be wise, admits Holtz.
“If they’re not running great distances and they’re not fully scaled-out they’ll typically stick with steel wheels,” he says.
“They just can’t take advantage of some of the benefits of aluminum wheels just because they’re not running the miles and they’re not carrying the loads that would justify the additional expense.”
For those that do make the switch from steel to aluminum, there are a couple of key safety considerations to keep in mind.
Holtz warns that aluminum wheels should never be welded. The heat could impact the metal properties of the wheel and could compromise its safety characteristics.
“You certainly don’t want to subject it to excessive heat or try to repair a wheel,” agrees Taylor.
Aluminum wheels should also never be painted, Holtz says.
It’s generally not necessary to paint them in the first place and adding outside materials to the wheel’s surface can also affect the performance of the wheel/hub interface and the clamping load that the lug nuts provide.
Talk to a sales rep before applying any foreign substance to the surface of an aluminum wheel.
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Simple question when changing from steel to aluminum on our limo freightliner should we chance out all six wheels ??? the tire shop we are going through says we should leave the steel wheel on the inside of the duals…. what is your thought on this
Great article – would like to know more if available about fatigue testing results in 19.5 and 22.5 steel vs alumni. There has to be a lot more micro vibration at the end of these steel bolts. That have now grown out 3 to 3.5 inches. Seems like when we try to develop accessory for a steel wheel it takes much more retention force to keep it in place than with an aluminum wheel even the best one Alcoa