With diesel having recently done an about face, and fuel efficiency always a hot topic, are low-rolling-resistance tires worth the additional cost? Manufacturers would say that the initial cost is made up for in the long run through fuel savings, but can that be proven?
Some also point to the fact that you may get fewer miles out of low-rolling-resistance tires. In fact, according to a survey done by the American Trucking Associations’ (ATA) Technology & Maintenance Council, perceptions about LRR tires may not match up with reality.
A total of 51 fleets participated in the survey, with the majority of them being linehaul and regional operators. Almost 85 percent of the respondents indicated they are using LRR tires, and of that number 63 percent reported more than half their fleet running the tires.
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Contradictory Data
LRR tires typically cost about 15 percent more than regular tires and their tread life is reduced by about 30 percent. The generally accepted 3 to 4 percent fuel savings by using them is thought to offset the higher price and lower life span.
Surprisingly, the survey showed that in all cases except trailers, LRR tires last longer than standard varieties. So the assumption that they don’t last is long looks like it may be misplaced.
At the same time, fleet managers reported that their fuel savings did not actually offset the cost of the tire. One possible explanation for this discrepancy can be found in another area of the data set.
The Numbers Game
The study revealed that only trailer tires were reported as getting less mileage. One reason for this could be that trailer tires are often the worst maintained tires in the fleet. There is a direct correlation between how well the tires are maintained and how long they last.
Although the numbers came in a little low, they did show that LRR tires outperformed their standard counterparts by almost 10 percent. The survey broke out single and tandem drive axles on standard, LRR and wide-based tires.
On single drive axles, the wide-based tires last longer than the other varieties by a – pun intended – wide margin. For tandem axles, the margin was much slimmer. These results show the mileage shortcoming for LRR tires in the single-drive axle group, but this shouldn’t come as much of a surprise.
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Trailer tires may be where people are getting the perception that LRR tires can’t cut it. Standard tires outlived LRR tires by 4,000 miles on average. They beat out wide-based single tires by almost 7,000 miles. Whether or not trailer maintenance is the cause remains to be seen.
Are Fleets Checking?
A 2002 study showed that, on average, only 44 percent of a fleet’s tires are within plus or minus 5 of their psi target. Even if that number has improved by ten or twenty percent in the intervening years, then it’s no surprise that fleets aren’t seeing the payoff in fuel economy and tread mileage.
Over 29 percent of fleets still don’t know what their average fuel economy is. Although this is a relatively easy thing to measure, many fleets still are not up-to-date on the numbers. Oddly, measuring tread life is a much more labor-intensive process, so how some fleets are deciphering that and not fuel economy is not obvious.
The survey asked fleets to indicate fuel improvement levels for LRR tires, and that number came in around 1.9%. The next question asked if the fuel savings met their expectations. Of that group a third said yes, slightly less than half of the group said no, and another third said they weren’t sure.
The Case for Better Monitoring
When asked whether fuel savings paid for lost tread rubber, only 40 percent of the group surveyed said yes, with the other 60 percent saying no. It’s hard to understand how that could be the case when LRR tires ran more miles than regular ones.
Going by trailer performance, that might be the case, but in all wheel positions, fleets may be doing better than they think. LRR tires have the potential to save fleets money in the long run, so it’s important to be very careful about how performance is monitored.
By using application-to-application and model-to-model comparisons, fleets can get accurate numbers on how effective LRR tires are. There may be a lot of fleets leaving money on the table simply because the perception is that LRR tires don’t last as long, when this clearly is not the case.