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245/40R19 upsize, downsize & alternatives

Every safe alternative tire size for 245/40R19 within the ETRTO ±3% overall-diameter tolerance. Grouped by upgrade intent. Speedometer impact and catalog availability shown for each.

By Mark Bishop · Last verified 2026-05-17 · What does 245/40R19 mean?

Plus-1 (next rim size up)

Plus-1 keeps overall diameter constant while bumping rim diameter by one inch and dropping aspect ratio by ten points. The standard daily-driver upgrade — sharper steering response, mild ride penalty, modest tire-cost premium.

SizeOD (mm)True @ 60 mphVerdictIn catalog
245/35R20 680 0.13% 60.08 mph Safe
215/40R20 680 0.21% 60.12 mph Safe
275/30R20 673 -0.83% 59.50 mph Safe
235/35R20 673 -0.90% 59.46 mph Safe Yes
255/35R20 687 1.16% 60.70 mph Within tolerance
225/40R20 688 1.39% 60.83 mph Within tolerance
265/30R20 667 -1.71% 58.97 mph Within tolerance Yes
225/35R20 666 -1.93% 58.84 mph Within tolerance
265/35R20 694 2.20% 61.32 mph Within tolerance Yes
235/40R20 696 2.56% 61.54 mph Within tolerance
255/30R20 661 -2.59% 58.44 mph Within tolerance Yes
215/35R20 659 -2.96% 58.22 mph Within tolerance

Plus-2 (two rim sizes up)

Plus-2 lifts rim diameter by two inches with a twenty-point aspect drop. Noticeable ride penalty, higher pothole risk, and a meaningful tire-cost premium. Suitable for performance trims and aesthetic upgrades.

SizeOD (mm)True @ 60 mphVerdictIn catalog
245/30R21 680 0.27% 60.16 mph Safe
235/30R21 674 -0.62% 59.63 mph Safe
215/35R21 684 0.78% 60.47 mph Safe
275/25R21 671 -1.13% 59.32 mph Within tolerance
255/30R21 686 1.15% 60.69 mph Within tolerance
225/30R21 668 -1.50% 59.10 mph Within tolerance
225/35R21 691 1.81% 61.09 mph Within tolerance
265/25R21 666 -1.87% 58.88 mph Within tolerance
265/30R21 692 2.03% 61.22 mph Within tolerance
215/30R21 662 -2.39% 58.57 mph Within tolerance
255/25R21 661 -2.61% 58.44 mph Within tolerance
235/35R21 698 2.84% 61.71 mph Within tolerance
275/30R21 698 2.92% 61.75 mph Within tolerance

Same rim, wider footprint

Same rim diameter as your OEM, just a wider footprint. Increases grip and footprint contact at the cost of fuel economy and steering effort. Confirm fender clearance at full lock before purchase.

SizeOD (mm)True @ 60 mphVerdictIn catalog
275/35R19 675 -0.52% 59.69 mph Safe Yes
255/40R19 687 1.18% 60.71 mph Within tolerance Yes
265/35R19 668 -1.55% 59.07 mph Within tolerance Yes
265/40R19 695 2.36% 61.41 mph Within tolerance
255/35R19 661 -2.58% 58.45 mph Within tolerance Yes

Winter / narrower contact

Narrower than OEM, aspect ratio raised to preserve overall diameter. Higher contact pressure improves snow and slush bite — the Nokian-style rule of one width step down for winter on the same overall diameter.

SizeOD (mm)True @ 60 mphVerdictIn catalog
215/45R19 676 -0.37% 59.78 mph Safe
225/50R18 682 0.53% 60.32 mph Safe
215/50R18 672 -0.94% 59.43 mph Safe
225/45R19 685 0.96% 60.57 mph Safe
235/40R19 671 -1.18% 59.29 mph Within tolerance Yes
235/45R18 669 -1.46% 59.12 mph Within tolerance Yes
235/50R18 692 2.00% 61.20 mph Within tolerance
215/55R18 694 2.23% 61.34 mph Within tolerance
235/45R19 694 2.28% 61.37 mph Within tolerance
225/40R19 663 -2.36% 58.59 mph Within tolerance
225/45R18 660 -2.79% 58.33 mph Within tolerance Yes
215/50R19 698 2.80% 61.68 mph Within tolerance

Other geometric alternatives

Geometrically valid alternatives that don't fit a named category. Often combinations of rim and aspect change that happen to land in tolerance.

SizeOD (mm)True @ 60 mphVerdictIn catalog
225/55R17 679 0.10% 60.06 mph Safe Yes
275/45R17 679 0.10% 60.06 mph Safe
245/45R18 678 -0.13% 59.92 mph Safe Yes
275/40R18 677 -0.21% 59.88 mph Safe
245/50R17 677 -0.27% 59.84 mph Safe
255/45R18 687 1.19% 60.72 mph Within tolerance
255/50R17 687 1.21% 60.73 mph Within tolerance
265/45R17 670 -1.22% 59.27 mph Within tolerance
265/40R18 669 -1.39% 59.17 mph Within tolerance
215/55R17 668 -1.52% 59.09 mph Within tolerance Yes
215/60R17 690 1.65% 60.99 mph Within tolerance Yes
235/55R17 690 1.72% 61.03 mph Within tolerance Yes
235/50R17 667 -1.74% 58.96 mph Within tolerance
265/45R18 696 2.52% 61.51 mph Within tolerance
255/45R17 661 -2.55% 58.47 mph Within tolerance
255/40R18 661 -2.56% 58.46 mph Within tolerance Yes
265/50R17 697 2.68% 61.61 mph Within tolerance

Try another alternative

Type any size below — we will compute its overall-diameter delta against 245/40R19 and verdict using the same ±3% rule.

What this page tells you

Every alternative listed above falls inside the ±3% overall-diameter tolerance defined by ETRTO 2024 Standards Manual §2.3 — the universal safe-fit threshold that keeps speedometer accuracy (SAE J1349), TPMS calibration (NHTSA FMVSS 138), ABS reference, and AWD viscous-coupling temperature inside their factory programming. Sizes outside that envelope are excluded from this table; if you want to see them anyway, use the compatibility calculator.

245/40R19 has an overall diameter of 678.6 mm (26.72 inches), a sidewall height of 98.0 mm, and turns 755 revolutions per mile. We surface 59 realistic alternatives across the categories above; 17 of them are currently sold in tire models we catalog. The remaining alternatives are geometrically valid but uncommon — they fit a vehicle perfectly but you may need to special-order the tire.

How to read the verdict column

"Safe" means the alternative is within ±1% overall diameter — indistinguishable from OEM in everyday driving, no recalibration recommended. "Within tolerance" means 1–3% — fitable per ETRTO, but you may notice mild speedometer drift and should consider a one-time OBD-II calibration if you drive an AWD or EV. Anything beyond ±3% is excluded from this list per the safe-fit threshold.

Categories explained

Each category corresponds to a different driving-priority trade-off. Plus-1 and Plus-2 trade ride comfort for sharper steering and a more filled-out wheel-fender opening. Wider sizes on the same rim trade fuel economy for grip. Winter narrower sizes increase contact pressure on snow (more downforce per unit of footprint area), which is why every European winter-tire engineering bulletin recommends a one-width-step-down policy for winter. Narrower same-rim sizes trade dry grip for fuel economy. OEM-equivalent sizes are useful when your favorite tire model is no longer made in your exact size — find the under-half-percent OD match here and you have an effective drop-in replacement.

What this page does not cover

Geometry only. Wheel offset, bolt pattern, brake-caliper clearance, fender clearance at full lock, and TPMS sensor compatibility are mechanical fitment constraints that depend on your chassis and wheel choice — those need a vehicle-specific check. Cross-reference your vehicle fitment page for OEM offset and bolt pattern, the wheel manufacturer's fitment guide, or your vehicle owner's manual before purchase.

Vehicles currently using 245/40R19

Sources & methodology

Last verified 2026-05-17 against the standards below.

  1. ETRTO 2024 Standards Manual §2.3 (section width, aspect ratio, overall diameter formula). European Tyre and Rim Technical Organisation, Brussels.
  2. Tire & Rim Association 2025 Yearbook, Table 1-2 (load index → maximum load equivalence). T&RA, Copley OH.
  3. SAE J1349 (Engine Power Test Code / speedometer accuracy reference).
  4. NHTSA FMVSS 138 Tire Pressure Monitoring Systems — rev/mile calibration requirements.
  5. Tire Industry Association Technical Bulletin TB-2019-04 (plus-sizing guidance).
  6. Nokian Tyres "Why winter tyres should be narrower" technical bulletin, 2019.

FAQ

What is the safest alternative tire size for 245/40R19?
The safest alternative is any size listed above as "Safe" verdict — these are within ±1% overall diameter and require no recalibration. The OEM-equivalent category contains the closest matches; the Plus-1 category contains the most commonly used aftermarket upgrade.
Will any of these alternatives change my speedometer reading?
All listed alternatives are within ±3% overall diameter, which falls inside the SAE J1349 ±4% speedometer envelope. Sizes within ±1% (Safe verdict) produce sub-1 mph error at 60 mph indicated. Sizes within 1–3% (Within Tolerance) produce 1–2 mph error at 60 mph — measurable but inside the factory tolerance.
Why are some alternatives marked "In catalog: yes" and others not?
"In catalog" means at least one tire model in our database is sold in that exact size. Sizes without an "In catalog" mark are geometrically valid alternatives — they fit your vehicle — but you may need to special-order the tire from the manufacturer or expand your tire-shopping radius.
Can I mix two of these alternatives across axles?
Don't. Mixing different overall diameters across an axle creates a permanent rev mismatch that the ABS module can read as constant slip, sometimes throwing warning lights, sometimes degrading anti-lock response. On AWD vehicles the viscous coupling absorbs that mismatch as heat. Fit four matching tires (or at minimum, matching tires per axle for staggered setups).
Where do these tolerance rules come from?
The ±3% overall-diameter tolerance is documented in ETRTO 2024 Standards Manual §2.3 and the Tire & Rim Association 2025 Yearbook, and is adopted by every passenger-vehicle OEM tire-fitment guide we have reviewed. The standard derives from the maximum diameter change that preserves speedometer accuracy (SAE J1349), TPMS rev/mile tracking (FMVSS 138), ABS reference (FMVSS 135), and adaptive-transmission shift calibration in one envelope.