2021 Alfa Romeo 4C — Spider
The 2021 Alfa Romeo 4C Spider shipped with 4 different factory tire sizes, depending on the wheel package it left the factory with (this can also reflect a staggered front/rear setup). Check your tire sidewall or door placard to confirm which one applies to your vehicle.
This trim shipped with more than one tire size (staggered fitment, front/rear, or optional wheel package). Confirm which one matches your vehicle by checking your tire sidewall or door placard.
205/45R17 (Front)
| Section width | 205 mm |
|---|---|
| Aspect ratio (sidewall height) | 45% (92.3 mm) |
| Rim diameter | 17" |
| Overall tire diameter | ~24.3" |
| Revolutions per mile | ~831 |
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235/40R18 (Rear)
| Section width | 235 mm |
|---|---|
| Aspect ratio (sidewall height) | 40% (94 mm) |
| Rim diameter | 18" |
| Overall tire diameter | ~25.4" |
| Revolutions per mile | ~794 |
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205/40R18 (Front)
| Section width | 205 mm |
|---|---|
| Aspect ratio (sidewall height) | 40% (82 mm) |
| Rim diameter | 18" |
| Overall tire diameter | ~24.5" |
| Revolutions per mile | ~825 |
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235/35R19 (Rear)
| Section width | 235 mm |
|---|---|
| Aspect ratio (sidewall height) | 35% (82.3 mm) |
| Rim diameter | 19" |
| Overall tire diameter | ~25.5" |
| Revolutions per mile | ~792 |
Compare prices at:
What this size means for your Alfa Romeo 4C
On the 2021 Alfa Romeo 4C Spider, the factory 205/45R17 measures about 24.3″ in overall diameter with a 92.3 mm (3.6″) sidewall, and completes roughly 831 revolutions per mile. Its 45-series aspect ratio gives a low-profile sidewall tuned for sharper handling, common on sport trims and larger-wheel packages. In tire terms it is a passenger (P-metric / Euro-metric) size.
This is a staggered setup: the front axle runs 205/45R17 and the rear runs 235/40R18. The two sizes are not interchangeable, so order each for its correct axle and don't rotate front-to-rear.
Alfa Romeo 4C tire sizes by year
- 2020 Alfa Romeo 4C 205/45R17 (Front) / 235/40R18 (Rear) / 205/40R18 (Front) / 235/35R19 (Rear)
- 2019 Alfa Romeo 4C 205/45R17 (Front) / 235/40R18 (Rear) / 205/40R18 (Front) / 235/35R19 (Rear)
- 2018 Alfa Romeo 4C 205/45R17 (Front) / 235/40R18 (Rear) / 205/40R18 (Front) / 235/35R19 (Rear)
- 2017 Alfa Romeo 4C 205/45R17 (Front) / 235/40R18 (Rear) / 205/40R18 (Front) / 235/35R19 (Rear)
- 2016 Alfa Romeo 4C 205/45R17 (Front) / 235/40R18 (Rear) / 205/40R18 (Front) / 235/35R19 (Rear)
- 2015 Alfa Romeo 4C 205/45R17 (Front) / 235/40R18 (Rear) / 205/40R18 (Front) / 235/35R19 (Rear)
How to read a tire size
A tire size like 225/45R17 breaks down into three parts:
the first number is the section width in millimeters
(the tire's width from sidewall to sidewall), the second is the
aspect ratio — the sidewall's height as a percentage of
that width — and the number after the "R" is the rim
diameter in inches. A letter prefix (P or LT) indicates
Passenger or Light Truck construction; its absence usually means
Euro-metric sizing.
Some trucks and off-road tires instead use "flotation" sizing, like
37X12.50R17 — here the numbers are the tire's overall
diameter and width in inches directly, with the rim diameter last.
Always verify against the tire information placard on your driver's-side door jamb or your owner's manual before purchasing — tire size can vary by factory option package even within the same trim.