Fitment guide

How to Record Wheel and Tire Fitment

A practical wheel and tire fitment documentation guide for recording axle-specific sizes, brands, and notes on a public car build.

• Fitment is easiest to understand when the record separates front and rear details and names the measurement exactly as it appears on the tire or wheel. Document what is on the car; use the record to communicate, not to turn one setup into advice for every chassis.
• Capture the fields people actually compare
• For each axle, record tire width, aspect ratio, wheel diameter, and wheel width when known. Add the tire model and wheel label separately. Staggered setups should show front and rear as distinct rows so a reader never has to guess which size belongs where.
• Keep units and formatting consistent. If offset, spacer, bolt pattern, or clearance notes are known from the owner, include them as notes with their source and date. Leave an unknown field empty rather than filling it with an assumption. A clear unknown protects the next reader from treating missing information as a zero or a standard value.
• Front and rear tire sizes
• Front and rear wheel sizes
• Tire brand and model
• Wheel brand and model
• Known offset or clearance notes
• Describe fitment as recorded evidence
• Fitment depends on chassis, suspension, brakes, alignment, tire construction, and use. A public build can show what one owner runs, but it cannot establish that another car will clear the same hardware. Avoid mechanical advice unless you have verified the exact vehicle and conditions.
• The Hanzo build records 285/35R20 on a 20x9 front and 325/30R20 on a 20x12 rear, with Michelin Pilot Sport Cup2 and Advan Racing GT labels. It is an owner-recorded illustration of axle-specific documentation, not a recommendation. Boo! records square 275/40R18 tires on 18x10 -20 BBS LM wheels, another example of a specific car's evidence.
• Separate front and rear
• Name the exact tire and wheel
• State when a value is owner-reported
• Add the surrounding setup
• A wheel and tire entry becomes more useful beside suspension, brake, and handling modifications. Add a timeline note when the setup changed, and use photos to show stance or tread condition without implying that a photograph proves clearance.
• When a setup is revised, update the current fitment and preserve the old combination in the build history. This keeps the page useful for the present car while retaining the sequence of decisions. Note whether measurements were read from the hardware, a receipt, or an owner memory so readers understand the source.
• Connect fitment to related mods
• Preserve previous combinations
• Record the source of measurements
• Share a fitment record responsibly
• Use a plain note for what is known, what was measured, and what remains unverified. Invite questions through the build context rather than promising that a size will fit someone else's car. Be especially careful with offset and clearance claims because small changes in alignment or suspension can alter the result.
• A useful page lets another enthusiast compare details without copying them blindly. Show the tire sidewall, wheel stamp, and a representative installed photo when possible. Pair those images with text because a photo alone rarely reveals every measurement a reader needs.
• Mark unverified values
• Avoid universal fitment claims
• Pair photos with measurements
• Keep the notation readable
• Choose one format for tire sizes, such as 285/35R20, and use it everywhere. Write wheel dimensions with diameter and width, then put offset and finish in a separate note. Consistency makes staggered and square setups immediately recognizable.
• If a car uses different setups for street and track, record each as a dated stage or clearly named configuration. The current page can show what is installed now while history explains the change. Do not combine two configurations into one row that no longer describes either setup accurately.
• Review before publishing
• Check the sidewalls and wheel markings against the typed values. Confirm that front and rear labels were not swapped and that the current photos show the same configuration. If a value cannot be confirmed, say so and preserve the useful parts of the record.
• Fitment documentation earns trust through careful limits. State the chassis, suspension stage, and date alongside the numbers, then let readers make their own comparison. The page's job is to preserve evidence about this car and this setup.