A slow leak is a different problem away from home
In town a tire that loses a few pounds a week is an annoyance somebody tops up. On a vehicle that leaves on a long leg, the same leak is the thing that puts it on the shoulder a long way from anywhere.
The arithmetic is simple and it is why this matters more on a corridor fleet. A leak that costs a couple of pounds a day is invisible over a short trip. Over several days away, on a tire nobody is checking, it takes a tire from correct to seriously under-inflated, and an under-inflated tire at highway speed in summer heat is the failure mode that ends casings.
Which means a slow leak is not a small problem on these vehicles. It is a tire failure with a delay built in.
The wheel is usually the leak
The national wheel refurbishing page explains why a leak that outlives a new tire is almost always the sealing surface on the wheel rather than the tire.
What is worth adding here is the valve, which in a dry dusty climate wears at the seal and is a common and cheap cause of exactly this kind of slow loss.
Find them deliberately
A leak this slow will not be found by looking. It is found by checking pressures cold, against the specification, and noticing which positions are consistently a little low.
That is a record rather than an observation: the same position, a little low, repeatedly. One reading tells you nothing, and three tell you where to look.
For a fleet, that is worth building into the pre-departure check rather than leaving to whoever notices.
About this store
The Fernley store runs sixteen services, offers tire and wheel balancing at the same address, and is managed by John Jangula.
See the national wheel refurbishing page for all 42 locations.