Choosing the right size plate for your bike
Bike plates come in a lot of sizes, and only some of them are road legal. The size is not really a style choice on a legal plate. It follows from the character measurements.
Why 9in by 7in is the standard
A road-legal bike plate has to fit characters that are 64mm tall and 44mm wide, on two lines, with 10mm between characters, 30mm between the age identifier and the random letters, 13mm between the lines, and margins of at least 11mm all round.
Add that up and you land at roughly 229mm by 178mm, which is 9in by 7in. That is why it is the standard motorcycle size: it is the smallest plate the measurements will actually fit into.
When a smaller plate stops being legal
Anything smaller than the standard size cannot hold compliant characters, so it is a show plate by definition. Small plates look purposeful on a naked bike or a custom build, and plenty of people run them off-road or at shows. Just be clear that a 7in by 5in plate is not a legal plate, whatever font is on it.
This is the most common misunderstanding we deal with. Customers order a small plate expecting it to be road legal because the registration is correct. The registration being correct is not the test. The character measurements and the markings are.
By type of bike
Naked and classic. The standard 9in by 7in usually mounts cleanly on the original bracket. Nothing to think about.
Scooters. Bodywork often sets the space, and the mounting area can be shallower than it looks. Measure before you order, particularly the depth available behind the plate for fixings.
Adventure and touring. Usually plenty of room, but panniers and top boxes can shadow the plate at an angle. An obscured registration is an offence even if the plate itself is perfect, so check it is visible with the luggage on.
Custom and chopper. This is where people most often end up with a show plate by accident. If the bike is road-ridden, you still need a compliant plate in a compliant size, however much it fights the lines of the build.
Enduro and motocross. Competition machines are a different case, and plates for off-road use are not held to road standards. If the bike is road registered though, the road rules apply.
Fitting
Sticky pads are easier and avoid drilling, which also avoids the risk of a fixing bolt sitting where it changes the look of a character. Screws are fine too. Either way, use the old plate as a drilling guide rather than measuring from scratch. Our bike plate fitting guide walks through both methods.
If in doubt
Choose the legal plate option in the builder and pick the standard motorcycle size. That combination is compliant, and you can spend your attention on borders and badges instead of worrying about the measurements.