TORONTO, Ont. – “Steer tires mounted two weeks ago were found today at 90 psi. A result of pressure set at indoor temps moving to cooler outdoor temps.”
The above tweet was from professional driver Angelo Diplacido, who through his 30-year career as a company driver and owner/operator has become attuned to how ambient temperatures affect tire inflation pressures. Diplacido’s tweet was sent out in early December, when much of Canada was feeling the first icy blasts of winter.
According to Donn Kramer, director of marketing and product innovation with Goodyear, every 10 F drop in temperature results in an air pressure loss of 2 psi. So a properly inflated tire at 50 F (10 C) will lose 6 psi at 20 F (-12 C).
“So the tire is already at 94 psi, and if it wasn’t at the correct inflation pressure to start with, it might be assumable the tire is below 90 psi,” Kramer explained. “Then you have a 1% drop in miles per gallon and anywhere from 9-16% drop in overall mileage if it’s not addressed. It can have a huge impact.”
And that’s just the impact of temperature alone. Unfortunately, few fleets and drivers are adequately maintaining inflation pressures even in ideal weather.
“It doesn’t matter if you’re a big or small fleet, air pressure is the number one thing,” said Stephane Beaudoin, marketing manager, Michelin truck tires.
It would be wrong to assume that large fleets are always better at managing tire inflation pressures than smaller fleets or owner/operators.
“I’ve seen large fleets with poor tire management,” pointed out Robert Loranger, business development manager, central region, with Yokohama. “They sometimes do not realize that (tires) are their second biggest expense after fuel.”
Tire manufacturers have been preaching the importance of maintaining inflation pressures for 100 years, but “It’s still not being given adequate attention,” Kramer contended. Technology such as tire inflation monitoring and management systems have come on-board to help address the issue, but even those systems, when adopted, are not a panacea.
“The reason adoption has not gone further with that technology is, there is no foolproof solution yet that exists,” Kramer said. “There are deficiencies with each one and that has hindered further adoption by fleets, so air pressure is still a major issue.”
Ideally, inflation pressures should be checked – with a tire gauge, not a hammer – at least once a week.
“Air pressure is still the most critical component to maintenance of a tire,” agreed Bert Jones, product marketing manager at Bridgestone Commercial Solutions. “It’s not just keeping it from overheating or blowing out. Air pressure that’s properly maintained increases the life of the casing, so you can retread it. So, you’re preserving your asset and preserving the value of the casing that you paid for when you bought the new tire.”
Perhaps the biggest problem is that too few fleets think of tires as an asset. Certainly, total cost of ownership (TCO) is a concept tire manufacturers often speak of, but how many customers actually evaluate the complete life-cycle cost when selecting a tire?
“One of the issues we see, is some outfits being lured into buying low-priced tires that may not prove to be the best overall choice when the full value of the product is considered,” said Greg Cressman, technical services director with Yokohama. “Early tire removals, driver complaints, lost casing value, fewer retreads and lack of service support from the brand are classic pitfalls of just buying on price.”
Fleets that don’t consider transportation their core competency are among the most likely to buy cheap tires, according to Goodyear’s Kramer.
“Some of the mid-sized fleets, where transportation is not their business – they need trucks to move their goods – they have a tendency on the maintenance side to look at tire price. That affects their budget. What they don’t realize is, they need to manage the tire asset over its life-cycle and in order to do that, they need to partner with a good tire supply vendor,” Kramer said.
Some of the larger fleets have very sophisticated tire management programs – some even have a dedicated tire guy or gal – and conduct extensive evaluations that measure total cost of ownership. However, smaller companies that lack the resources to do their own testing can tap into a reputable vendor and access the same expertise. The truck tire market is highly competitive and the in-the-field support being offered by the biggest suppliers is comprehensive. Consultations, however, should begin even before the first tire is installed, pointed out Michelin’s Beaudoin.
“When purchasing tires from their dealers, fleets need to make sure they tell their dealers what kind of application they’ll be doing,” she said. “If you purchase the wrong tire for the wrong application, you can put all the air you want into your tire – you’re not going to get the performance you’re looking for.”
With fuel economy being a priority for most fleets today, many buyers gravitate to SmartWay-approved products. But it’s important to remember not all SmartWay tires are created equal.
“Keep in mind that SmartWay verification is done by the tire company involved – so it’s self-policing,” warned Cressman.
Achieving SmartWay certification is not an easy process, but tire companies can choose different paths to compliance – and it may involve compromises in other equally important areas.
“It’s not easy to hit the SmartWay target, but sometimes it’s such that you sacrifice all other performance attributes,” Kramer noted of some suppliers.
“One of the problems is that fuel efficiency is very difficult to measure,” added Bridgestone’s Jones. “There are so many factors involved.” However, he said SmartWay, as a whole, has been a good thing for the trucking industry.
“It has had a major impact on the industry and it has required a push in technology that I think has been very successful,” Jones said.
Rolling resistance, which influences a tire’s contribution to fuel economy, is a relatively new concept, he added.
“We as manufacturers are expending great effort to find new and better ways to achieve the performance characteristics that our customers want and need,” Jones said. “Initially, I think there was some compromise (when maximizing fuel economy). You did have to give up something else in order to achieve ultra-low rolling resistance. But we are able to advance technology at a faster rate these days.”
If fuel economy is important – and it usually is – it’s okay to seek out a SmartWay tire, but also ensure the tire’s performance in other areas will be up to expectations, advised Michelin’s Beaudoin.
“Sometimes, you need to sacrifice on mileage to have a SmartWay tire, so you have to be careful about that,” she warned. “They may have a great tire on fuel, but if it only lasts 100,000 miles instead of 500,000 miles, it may not be worth it to you.”
– In Part 2 of this series on tires, our tire experts will offer practical tips on maximizing your tires’ performance and reducing overall cost of ownership.
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