Workshop Comparison Tools & Reference
Compare tyre sizes, speedometer variance, and vehicle pressure guidance.
Workshop Technical Tools & Fitment Intelligence
Precision tyre size comparison, speedometer calibration, South African vehicle pressure charts, and strategic R82 market insights.
Side-by-Side Tyre Size & Speedometer Comparator
Calculate overall rolling diameter difference, ride height variation, and speedometer error percentage before fitting new tyres or mag rims.
Popular Presets:
Tyre 1: Current / Stock Size
OEM
195/65 R15
Tyre 2: New / Target Upgrade
UPGRADE
205/55 R16
Overall Diameter
634 mm
632 mm
-2 mm (-0.3%)
Sidewall Height
127 mm
113 mm
-14 mm (-11.0%)
Circumference
1993 mm
1985 mm
-8 mm (-0.4%)
Ride Height Change
-1.0 mm
Ground clearance adjustment
Revolutions / km
502
504
Revolutions per 1,000m
⏱️ Speedometer Calibration Shift Table
When speedo displays Indicated, your True GPS speed will be:
| Indicated Speed | 60 km/h (Town) | 80 km/h (R82 Main) | 100 km/h (Highway) | 120 km/h (N1 Cruise) |
|---|---|---|---|---|
| Actual True Speed: | 59.8 km/h | 79.7 km/h | 99.7 km/h | 119.6 km/h |
South African Vehicle Tyre Pressure & Fitment Reference
Official manufacturer inflation pressures (PSI & Bar), required ply ratings, and payload recommendations for popular South African passenger and commercial vehicles.
Strategic Market Intelligence Report
Analyze price-per-inch curves, high-velocity taxi SKUs, and margin opportunities along R82.