The American Trucking Associations’ Technology & Maintenance Council surveyed 51 fleets late last year to get a snapshot of low-rolling-resistance tire and retread use. The vast majority of the respondents were linehaul and regional operators running Class 7-8 vehicles, split about 50/50 between less than or more than 500 trucks.
Peggy Fisher, president of Tire Stamp and regular contributor to TMC’s S.2 Tire & Wheel Study Group, shared the survey’s findings.
The percentage of fleets opting to retread shows a distinct preference for giving non-fuel-efficient tires a second life, but not low-rolling resistance tires or wide-base single tires. Also, the trend is to retread most tires twice or more, but to retread wide-base tires only once.
When using retreads on drive axles, the mileages fleets reported varied from single to tandem axles, but the interesting result shows low-rolling-resistance tires and wide-base tires outlived the non-fuel-efficient tires by significant margins in some cases. (Don’t put too much stock in the actual mileage figures in the accompanying chart; it’s the trend that’s worth a second look. Fisher told us the mileage figures presented in these graphs are “gross estimates” based on averages.)
Perhaps the most interesting result comes from the trailer position. Retreaded low-rolling-resistance and wide-base tires outlived standard tires by 20,000 miles or more. What’s more, survey data not shown on the graph compared mileages from the trailer position recorded with original tires, and except for standard tires, retreads lasted longer than new tires (Standard: 173,684; LRR: 169,828; wide base: 166,667).
The survey didn’t address the question of “why,” but Fisher has some theories.
“As to why LRR tires outlived standard tire retreads, perhaps it is due to more diligent maintenance or improvements in the raw materials used in tread rubber that reduce rolling resistance while providing good tire mileage,” she guesses. “I’d like to think that fleets that are fuel efficient would also have slightly better tire maintenance although I have no data to support that.”
Maintenance is keyPhoto: Jim Park
While it would probably be a combination of all the factors Fisher mentions, none of them would get you very far without solid maintenance. For fleets actively retreading, that includes a casing preservation strategy — one that begins with quality casings.
A good Tier 1 or 2 casing can be retreaded multiple times. Multiple retreads extend casing life and cost recovery on the initial purchase cost.
As with all tires, inflation management is vital in preserving casing integrity. Tires allowed to run under-inflated or overloaded can suffer internal damage that often can be spotted only during the retreader’s intake inspection using a shearography machine.
“Tire related failures can be proactively avoided with a tire pressure monitoring program or automatic tire inflation system,” notes Paul Crehan, director of product marketing with Michelin Truck Tires. “Those tools will not only prevent or reduce the frequency of on-road failures, they help protect the fleet’s tire and casing assets.”
An important part of any tire maintenance program is the decision on what tread depth to pull the tire, whether new or retreaded. Maximizing miles out of a tread demands leaving the tire in service as long as possible, but running the treads down too thin increases the likelihood of casing damage due to penetrations or stone drilling.
Considering the up-front cost of wide-single tires, leaving an extra 32nd of an inch of rubber on the casing is a bit of insurance against casing damage. While only Goodyear offers an internal puncture repair technology, Duraseal, other sealants have proven relatively effective in reducing pressure-loss-related tire failures.
And of course following proper repair procedures will help ensure the casing retains its retreading value. Improperly repaired tires will likely be rejected by the retreader.
While TMC’s tire survey results are interesting in that they show better mileage for retreads than new tires in several instances, the why remains a mystery. Ever since SmartWay decided to include retreaded tires on its list of verified tires, the number of LRR retreads has been growing. Perhaps as that number grows, additional evidence of what smart fleets already know will surface: retreads work.