225/45R17 vs 235/35R19
235/35R19 has an overall diameter of 647.1 mm (25.48") compared with 634.3 mm (24.97") for 225/45R17, a difference of +12.8 mm (+2.02 %). The sidewall changes by -19.0 mm, section width by +10 mm and ride height by +6.4 mm. Using the ETRTO rolling circumference, 225/45R17 turns 517 times per kilometre and 235/35R19 turns 507 times. With 235/35R19 fitted to a car calibrated for 225/45R17, an indicated 100 km/h is a true 102 km/h, and the odometer records 98 km for every 100 km driven. This is close to the commonly quoted 3 % tolerance, so check clearance and local rules.
Full comparison
| Measurement | 225/45R17 | 235/35R19 | Difference |
|---|---|---|---|
| Section width | 225 mm | 235 mm | +10 mm |
| Sidewall height | 101.3 mm | 82.3 mm | -19.0 mm |
| Rim diameter | 17" | 19" | +2.0" |
| Overall diameter | 634.3 mm (24.97") | 647.1 mm (25.48") | +12.8 mm (+2.02 %) |
| Static circumference | 1993 mm | 2033 mm | +40 mm |
| Rolling circumference (ETRTO) | 1935 mm | 1974 mm | +39 mm |
| Revs per km | 517 | 507 | -10 |
| Ride height | +6.4 mm | ||
| Inch equivalent | 25×8.9R17 | 25.5×9.3R19 | |
| Approved rim widths (approx.) | 7″–8.5″ | 8″–9.5″ |
Speedometer error
| Speedo reads | 40 | 50 | 60 | 80 | 100 | 110 |
|---|---|---|---|---|---|---|
| Actual speed (km/h) | 40.8 | 51.0 | 61.2 | 81.6 | 102.0 | 112.2 |
| Error (km/h) | +0.8 | +1.0 | +1.2 | +1.6 | +2.0 | +2.2 |
Assumes the speedo was accurate on 225/45R17. Odometer records 98.0 km for every 100 km actually driven.
- The 235/35R19 is 12.8 mm (2.02 %) larger in diameter, so your speedo will read low and your odometer will under-record distance.
- Section width changes by +10 mm. Check guard, strut and inner-arch clearance and that the rim width is within the approved range for the new tyre.
- Rim diameter changes from 17" to 19", so new wheels are required.
Is 235/35R19 legal in Australia? Within limits, verify speedo
| Overall diameter (VSB 14 LS 4.2.4) Diameter change of +12.8 mm is within the +15 mm / -26 mm allowance for a passenger car (MA/MB) (measured against the largest size the manufacturer designates for the model). | OK |
| Speedometer (ADR 18/03) A larger tyre makes the speedo read lower: at an indicated 100 km/h you would be doing 102.0 km/h. ADR 18 requires the speedo never to read below true speed, but factory speedos typically over-read by 2-6 %, so a 2.0 % increase is usually absorbed. Verify with a GPS speed app after fitting. | Verify |
| Load index (tyre placard / ADR 42) Enter the placard load index and the replacement tyre load index to check. | ? |
| Speed rating (tyre placard / ADR 42) Enter the placard speed rating and the replacement tyre speed rating to check. | ? |
Frequently asked
Can I fit 235/35R19 instead of 225/45R17?
Overall diameter changes by +12.8 mm (+2.02 %). That is close to the 3 % rule of thumb; it may fit, but check guard, strut and brake clearance and your local rules. In Australia VSB 14 allows up to +15 mm for passenger cars and +50 mm for 4WDs/goods vehicles without certification.
How much will my speedo be out with 235/35R19?
Your speedo will read low by about 2.02 %. At an indicated 100 km/h you would actually be travelling 102 km/h, and at 110 km/h about 112.2 km/h.
What is the rolling circumference of 235/35R19?
Static circumference is 2033 mm; the ETRTO rolling circumference under load is about 1974 mm, which is 507 revolutions per kilometre.
235/35R19 in inches
235/35R19 is approximately 25.5×9.3R19: 25.5" tall, 9.3" wide, on a 19" rim, with a 3.2" sidewall.
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