Duals have to match, or one tire carries the load
Some heavy equipment runs dual tires: two tires side by side on each end of an axle, sharing the load between them. The arrangement assumes the two are sharing equally, and that assumption depends on them being the same size where it matters, which is the diameter under load.
When they are not, the larger tire carries more than its share. It stands taller, so it meets the ground first and takes the weight, while its partner does less work. The overloaded tire runs hotter and wears faster, and the lighter-loaded one can scrub. Both end up with shorter lives than a matched pair.
Mismatches creep in quietly. A single replacement tire goes on next to a worn one. Two tires of the same nominal size but different makes or tread patterns sit side by side. One tire of the pair runs at a lower pressure than the other, which shrinks its working diameter just as surely as wear does.
Keeping pairs matched
Replace in pairs where possible, or pair a new tire with a partner close to it in tread depth.
Measure, do not assume. A tape around the tread, or a tread depth check on both, shows whether a pair is close enough to share properly.
Keep the pressures equal. Both tires of a dual, checked at the same time and set to the same pressure.
Record which tires are paired. When one comes off, the record shows what it was running with and why.
The same thinking applies across an axle: tires that differ significantly from one side to the other put uneven loads into the machine as well as into the tires.
Fitting, repairs and supply
Large tires and their rims are dangerous to work on, and fitting is a job for trained hands with the right equipment. Repairs, change-outs and supply are all handled here. A site wanting this managed as a program is mining fleet services, and the rims are wheel refurbishing. The national OTR services page covers the full scope.
This is the Commercial & Consumer listing; the Phoenix city page explains the others.
Other stores nearby
Casa Grande and Tucson also offer OTR services.
About this store
The Phoenix store carries all nine Purcell tire categories and is managed by Patrick Taylor.
See the national OTR services page for all 41 locations.