IIRC the brake pad wear recorded on my two services included the mathematical symbol < meaning 'less than' 20% . A main dealership will see enough Jazz ,on OE pads to be able estimate accurately if its obviously somewhere less than 20% and the pads will last for a long time yet.The use of the < symbol rather quoting an exact percentage suggests its normal Honda workshop practice. In reality they might have been for example only 5% last year and still only 15% this year.
They might only spend extra time measuring them accurately if its necessary to prove to a customer that replacement is due now, or soon, or they are an MOT failure. Or they might just change the wear estimate to > x% ( more than x% ) and recommend replacement.
Rear tyres last longer than front tyres. And you can get variations in tread depth depending on how hard you press the gauge against the rubber and which part of the tread you chose to measure. Especially noticeable on digital gauges measuring to the nearest 0.1 mm
. The V pattern treads on my All seasons reduce slightly in depth as they meet the central radial groove. The radial groove and most of the V groove is 8mm when new but for about an inch either side of the centre groove the depth of the V groove starts to taper up to less than 8mm. Probably to aid water expulsion. Thus for the centre 2" of the tread width you will have a 8mm deep radial groove, but only about 6mm in the side grooves. rapidly increasing to 8mm. A measurement in this area would give a false reading. The inclusion of the 8mm groove in this area maintains a legal tread depth across the entire tread width, as equally well as sparsely grooved summer tyres.
