Bridgestone South Africa

Can More Paperwork Actually Save Money?

Although this might seem like a lot of extra paperwork, what you learn from tracking tyre performance is that the lowest priced tyre is not always the least expensive. And, you may be able to change your cost per kilometre (C.P.K) for the better, without changing tyres already used.

What's the benefit of tracking tyre performance?

First, it’s the best way to determine whether you’re getting what you pay for. It’s also the best way to compare different tyre brands and models. A good tyre-tracking program can also help you with tyre selection, and help you control maintenance, repair and retreading costs.

What kinds of things should we track?

Ultimately, what you want to know is your tyre cost per kilometre. People do this in lots of different ways. Some track cost on new tyres only. Some include retreads. Some add in tyre maintenance, repairs, retreading, casing values, and so on. Whether you make it complicated or simple, what you want is a number that represents your cost to keep a given tyre in service for one kilometre.

Calculating The Cost Per Kilometre (C.P.K.)

(Purchase price + VAT + Mounting & Balancing) +
(Repairs + Maintenance Costs + Mounting & Balancing after repairs) +
(Retreading + Mounting after retreading)

(Orig. Kms + 1st R/tread Kms + 2nd R/tread Kms + 3rd R/tread Kms, etc)

You can make your calculations as complex as you like. As long as you’re consistent, you can compare cost per kilometre figures for one tyre to another.

Do we have to track every tyre?

While that would be best, it may not be practical, especially for a large fleet. After all, the cost of tracking is a factor too. It’s difficult to say just exactly how many tyres you should track. As a rule of thumb, we suggest this: keep records on at least 30 vehicles, or 10 percent of the vehicles in your fleet, whichever is greater.

So, if you have 500 tractors, we’d recommend tracking the tyres on 50 of them. If you have only 100 tractors, we’d recommend you track the tyres on at least 30.

What should we measure?

One of the most basic measurements is rate of wear, in “kilometres per millimetre”. This is the number of kilometres the tyre has gone so far, divided by the number of millimetres of tread worn away.

Tyres, like most things on a truck, tend to wear more slowly as they get older. So, if you calculate kilometres per millimetre, at regular intervals, you’ll find that kilometres per millimetre increases with wear.

And, if you multiply kilometres per millimetre. by the number of usable millimetres, you can project the total number of kilometres you might get from the tyre, based on the average wear rate at that point. Remember to deduct your normal removal tread depth from original tread depth when you make this calculation.

Bear in mind that projected mileage, like kilometres per millimetre, tends to increase as the tyre wears.

At any given point in a tyre’s life, you can calculate kilometres per millimetre:

Kilometres per Millimetre Calculations

Kms to date / (Original tread depth – Remaining tread depth)
= Kilometres per Millimetre
Kms per mm X (Original tread depth – Removal tread depth)
= Projected Tyre Kilometerage

Then why calculate it?

Because once you’ve accumulated data for various tyres on your vehicles, this sort of “snapshot” can tell you if a tyre is wearing faster or slower than normal. Or, if a new make or model of tyre is performing better or worse than those you have used in the past. You can also use it to project removal mileage, one of the crucial measures of a tyre’s worth.

The best thing about this kind of record-keeping is that it tells you things early, and throughout the life of the tyre. You don’t have to wait until the tyre is worn out. What you’re looking for is change, or, if you will, not so much irregular wear, as an “irregularity” in wear rates.

What else should be measured?

It’s a very good idea to record inflation pressures along with mileage and remaining tread depth. You may discover that one tyre, for example, is losing air, perhaps at a slow rate. That should be investigated. If all tyres on a vehicle consistently come in low or high, the driver might have a mis-calibrated gauge, or may be deliberately reducing inflation, trying to soften the vehicle’s ride. Of course, you’ll also want to note any maintenance or alignments done, along with the odometer or Hubometer readings.

You can also experiment (within manufacturer’s recommended inflation pressure limits) with the effect of higher or lower inflation pressures on overall tyre wear and irregular wear. As long as you stay above the minimum inflation pressure required, you may find that there’s an optimum inflation for your operation.

How will we know?

At any given time, you want the highest possible kilometres per millimetre. If you have that data and the inflation pressure data, you’ll be able to tell what’s working best for you.

When should this be done?

Chances are, the most convenient time will be during regular vehicle services. In fact, we’d recommend that you check the tyres first. That way, it may be possible to correct a tyre condition while the vehicle is still in the service bay. The other good thing about doing tyre tracking during servicing, is that your data collection will be consistent and regular. As we’ve said all along, consistency is the recipe for regular, even wear.

What can I expect to find out from scrap tyres?

Mostly, which tyres are working – and which aren’t. If a significant number of tyres are scrapped for any other reason than having been simply worn out, there’s probably something you can do to improve future performance.

It is always advisable to record reasons for tyres being scrapped. This will enable you to ascertain reasons for tyre loss, as well as allowing you to formulate an action to reduce the losses, where possible.

Bridgestone South Africa

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