Case study
A field trial of TreadReader was recently conducted with three major UK 3PLs. The largest study showed that across a fleet of 50 tractor units (300 tyres) a total of 53 tyres (18%) were replaced prematurely with remaining tread depths ranging from 9mm to 4mm. Moreover some 58% of tractors (29) had their tyres checked just once and 16% (8) not at all in a 3 month period.
| Tread depth at replacement |
10mm | 9mm | 8mm | 7mm | 6mm | 5mm | 4mm | 3mm | 2mm | 1mm | 0mm |
| Month 1 | 0 | 0 | 1 | 5 | 0 | 0 | 9 | 0 | 0 | 0 | 0 |
| Month 2 | 0 | 0 | 0 | 1 | 1 | 2 | 10 | 5 | 0 | 0 | 0 |
| Month 3 | 0 | 0 | 1 | 3 | 2 | 2 | 16 | 6 | 2 | 0 | 0 |
| Total | 0 | 0 | 2 | 9 | 3 | 4 | 35 | 11 | 2 | 0 | 0 |
Tread depth as a function of time were measured using TreadReader and manual measurements using a manual depth gauge. These were compared with manual depth gauge measurements recorded by the contracted tyre service / ppk provider. Data was recorded for tractor unit steer tyres (A1 and A2) and drive tyres (B1, B2, B3 and B4). A typical data set for a left steer tyre (A1) is shown below. Throughout the three month duration of the trial tread depth measurements from TreadReader on each tyre and for each tread groove demonstrated finite and measureable wear (shown in blue). Trends were less clear using our own manual depth gauge in all tread grooves (shown in yellow). However, data provided by the existing tyre service provider using a typical commercial manual depth gauge is only accurate to 1mm and often showed no trend at all (shown in red).
Average tread depth measurements from TreadReader were recorded with tractor mileages to generate tyre wear rates. A typical set of results for one tractor is shown below for steer tyres (A1 and A2) and drive tyres (B1, B2, B3 and B4).
The observed wear rates of 7,000km per 1mm tread for steer tyres and 7,600km per 1mm tread for drive tyres are in good agreement with theoretical savings based on a 10% lifetime extension giving an additional 2mm tread depth and 13,000 vehicle km at 1.2% improved fuel efficiency. These data may be used to quantify the wasted mileage associated with premature tyre removal for the fleet of 50 tractors. This is tabulated below based on a minimum tread depth of 3mm but excluding the early replacement of tyres due to damage or recutting.
| Month | Vehicles checked | Wasted steer tyre km | Wasted drive tyre km | Wasted steer tyre £ | Wasted drive tyre £ | Total waste £ |
| Month 1 | 48% | 70,760 | 197,704 | 3,559 | 9,944 | 13,503 |
| Month 2 | 20% | 49,532 | 45,624 | 2,491 | 2,295 | 4,786 |
| Month 3 | 40% | 205,204 | 0 | 10,321 | 0 | 10,321 |
| Quarter | 325,496 | 243,328 | 16,371 | 12,239 | 28,610 | |
| Annualised | 1,302,000 | 973,312 | 65,484 | 48,956 | 114,440 |
Premature replacement resulted in more than 500,000 km of wasted mileage for steer and drive tyres during the three month study or >2 million wasted km annualized. Therefore:
| Savings per tractor unit per additional km on worn tyres | = £ 676/13,000 = £ 0.05 /km |
| Total fuel and tyre savings by eliminating wasted km | = 2,275,000 x 0.05 = £114,000 |
It is worth noting that tyres on 58% of the 50 tractor fleet were only checked by the existing tyre service provider once and 16% not checked at all during the three month trial and therefore wastage may be considerably higher.
The waste in fuel and tyre costs described above is due to the premature replacement of tyres based on a minimum tread depth limit of 3mm. Further savings may be expected if improved tyre management and more accurate and frequent tyre inspection with TreadReader allow a reduction in the minimum tread depth limit from 3mm to 2mm. Savings for the 50 tractor fleet in this study would therefore be:
| Steer tyre saving | 7,000 km x £0.05 /km x 100 tyres = £ 35,000 |
| Drive tyre saving | 7,600 km x £0.05 /km x 200 tyres = £ 76,000 |
| Total saving | = £111,000 |
Conclusions
1) TreadReader can improve tyre management by preventing premature tyre removal and ensuring tyres do not wear below their minimum tread depth.
2) Preventing premature tyre replacement can save a minimum of £114,000 pa in fuel and tyre costs for the 50 tractors studied based on a 3mm minimum tread depth limit.
3) Improved tyre management can generate further fuel and tyre savings of £111,000 pa for these 50 tractors by reducing the minimum tread depth from 3mm to 2mm.
4) Total fuel and tyre savings for the fleet of 50 tractor unit amounts to £225,000 pa which equates to £4,500 per tractor per year. This is more than three times the theoretical saving.
5) Potential CO2 savings of 1.83 tonnes per vehicle per year is conservative based on trial data.
