OEM Safe
Borderline
Noticeable drift from OEM — drivable, but recalibration is wise.
Fitment comparison
245/45 R19versus245/45 R20
Δ Ø +25.4 mmSpeedo +3.61%Borderline
245/45 R20 stands taller than 245/45 R19 — bigger rolling diameter, slightly more clearance, calmer cruise revs.
Going from 245/45 R19 to 245/45 R20 steps up to a 20-inch rim while trimming sidewall to stay near OEM rolling diameter. This wheel and tire pairing moves rolling diameter well outside the usual OEM tolerance. Indicated speed will drift far enough that recalibration is worth considering. Visually, the bigger wheel fills the arch and gives the car a more aggressive stance. The 3–5% diameter gap puts this in caution territory: doable on many cars, but verify clearance and consider recalibration.
TakeCommon upgrade for sportier handling and a tighter wheel-gap look on the same vehicle.
Quick fitment verdict
245/45 R19 → 245/45 R20 at a glance
Fender Clearance
Likely rubs
Significantly wider/taller — rubbing risk on liners or fender lip is real.
Speedometer Impact
+3.61%
Dash reads 103.6 km/h at a true 100 km/h — visible drift.
Daily Driving
Aggressive
Geometry deviates enough to matter — confirm clearance before daily use.
Side-by-side telemetry
Dimensional read-out
Current
245/45 R19
- Diameter
- 703.1 mm
- Sidewall
- 110.3 mm
- Wheel
- 19″
- Width
- 245 mm
Δ delta
Ø +25.4 mm
SW 0.0 mm
RH +12.7 mm
NewNew
245/45 R20
- Diameter
- 728.5 mm
- Sidewall
- 110.3 mm
- Wheel
- 20″
- Width
- 245 mm
Real-world effects
How this swap actually feels
- Steering response60/100 · Softer turn-in
- Ride comfort60/100 · Firmer ride
- Fuel economy62/100 · Slightly lower drag
- Highway cruising75/100 · Lower cruise revs
- Pothole resistance55/100 · Less wheel protection
Shareable card
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Ride height
Lifted stance
Chassis sits higher — slightly more clearance, wheel-gap visually grows.
New tire lifts the chassis by ~12.7 mm — more clearance, slightly more wheel-gap.
Suspension travel · arch clearance
Wheel gap
Wheel gap visually increases
How the arch-to-tire gap reads from across the parking lot — the visual stance change everyone notices first.
245/45 R19
245/45 R20
Wheel-gap Δ+12.7 mm
Static · unloaded chassis
Fender relationship
Tucked · Flush · Poke
The visual relationship between the tire's outer edge and the fender lip — the lens enthusiasts use to judge a fitment.
Tucked
Inside fender
Flush
Lip-aligned
Poke
Outside fender
Width & offset dependent
Speedometer reality
Dash reads 103.6 km/h
Taller rubber: at a true 100 km/h your dashboard reads optimistically high.
ABS · ESP · cruise control
Setup telemetry
How this setup changes the car
Driver-perspective read-out of the 245/45 R19 → 245/45 R20 swap — steering, comfort, stance and dash behavior in plain enthusiast language.
Steering feel
+0.0 mm sidewallSteering response stays familiar
Sidewall delta is small; the wheel will feel like the OEM setup at the rim.
Ride firmness
45% → 45%Ride quality essentially unchanged
Comfort delta is below the perceivable threshold for most drivers.
Fender relationship
+0 mm widthFender gap reads near-identical
Width delta is too small to change stance — same visual signature as OEM.
Speedometer behavior
+3.61%Noticeable speedo drift
Drift is visible at highway speeds; ABS still works but loses a sliver of precision.
Daily drivability
Ø +25.4 mmAggressive setup — verify before daily use
Geometry deviates enough to matter — check clearance, recalibrate the dash, then re-evaluate.
Direct answer
Is 245/45 R20 OEM-safe?
Borderline. Overall diameter changes by +3.61% versus 245/45 R19. Borderline. Drivable, but speedometer drift becomes noticeable and ABS calibration is affected.
Direct answer
Will 245/45 R20 rub?
Possibly. Width changes by +0 mm and diameter by +25.4 mm. Possible rub at full lock or full suspension compression — verify fender lip and inner strut clearance before committing.
Direct answer
Does the speedometer change?
Yes — by +3.61%. Swapping 245/45 R19 for 245/45 R20 changes overall diameter, so at an indicated 100 km/h your true speed becomes 103.6 km/h. That's noticeable drift but usually safe.
Direct answer
Does lower sidewall affect comfort?
Barely. Sidewall changes by +0.0 mm (45% → 45%). Comfort is essentially unchanged.
Current Tire
245/45R19
New Tire
245/45R20
Fitment · Scaled comparison
● Borderline
245/45 R19
Diameter
+25.4 mm
+3.61%
Sidewall
+0.0 mm
Speedometer
103.6 km/h
at true 100
Clearance
Borderline
245/45 R20
Ground line · Scaled comparison
Slight Difference
Within ±5% — usable, recalibration recommended
Diameter change
+25.4 mm
3.61%
Speedometer at 100
103.6 km/h
+3.61% error
Ground clearance
+12.7 mm
ride height delta
Sidewall change
0.0 mm
revs/km: 436.9
Permalink for this comparison:
/compare/245-45-r19-vs-245-45-r20Detailed comparison
| Metric | 245/45 R19 | 245/45 R20 | Difference |
|---|---|---|---|
| Overall diameter | 703.1 mm | 728.5 mm | +25.4 mm (+3.61%) |
| Sidewall height | 110.3 mm | 110.3 mm | 0.0 mm |
| Circumference | 2.209 m | 2.289 m | +79.8 mm |
| Revs / km | 452.7 | 436.9 | -15.8 |
| Ground clearance | reference | +12.7 mm | +12.7 mm |
| Speedometer @ 100 km/h | 100.0 km/h | 103.6 km/h | +3.61 km/h |
Verdict: warning
Between 3% and 5% — noticeable speedometer drift; recalibration may be advisable.
Dimensional comparison
Side-by-sideScaled engineering side-profile of both tires. Width, sidewall and overall diameter are dimensioned so you can see the change at a glance — without parsing the numbers.
Current
245/45 R19- Profile
- 45%
- Circumference
- 2.209 m
New
245/45 R20- Profile
- 45%
- Circumference
- 2.289 m
Side-by-side fitment
GeometryCurrent
245/45 R19- Section width
- 245 mm
- Aspect ratio
- 45%
- Sidewall
- 110.3 mm
- Wheel diameter
- 19″(483 mm)
- Overall diameter
- 703.1 mm(27.68″)
- Circumference
- 2.209 m
- Revs / km
- 452.7
New
245/45 R20- Section width
- 245 mm
- Aspect ratio
- 45%
- Sidewall
- 110.3 mm
- Wheel diameter
- 20″(508 mm)
- Overall diameter
- 728.5 mm(28.68″)
- Circumference
- 2.289 m
- Revs / km
- 436.9
Real-world consequences
Pros / consTaller overall (+25.4 mm)
Rolling diameter- Higher ground clearance and approach angle
- Longer effective gearing — calmer highway revs
- Bigger contact patch lengthwise
- Speedometer reads low by ~3.6%
- Reduced fender, strut and bumpstop clearance
- Slower 0-60, more downshifts under load
+1″ rim upsize
Wheel diameter- OEM+ look, fills the arch better
- Sharper response with matching low-profile rubber
- Bigger brake clearance for upgrades
- Heavier wheel, more unsprung mass
- Harsher ride, more wheel-damage risk
- Tire and wheel cost both go up
How it changes driving feel
Seat-of-the-pantsSteering response
Similar feel
Ride comfort
Comparable
Road noise
Similar cabin noise
Wet / aquaplaning
Comparable wet behavior
Fuel economy
Small MPG penalty likely
Curb / pothole protection
About the same
Fitment risk check
Verify before installSpeedometer drift
~3.6% — borderline; recalibration recommended.
Cluster preview
BorderlineSpeedometer impact
At a true 100 km/h, your dashboard will read 103.6 km/h after switching to 245/45 R20 — a +3.61% offset. Use the speedometer error calculator for any indicated speed, and the speedometer error guide for the full background.
Ground clearance change
The new tire's half-diameter changes ride height by +12.7 mm. Small differences are absorbed by suspension travel, but anything beyond ±10 mm can affect headlight aim, fender clearance and bump-stop margin. See the plus-sizing guide before committing.
Back to
245/45 R19
Back to
245/45 R20
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