Japanese wheel and tyre talk often turns on one question: does the wheel or tyre stick out past the fender? In Japan this is written into the vehicle safety standards, and the wording is short. This guide sets out what the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) text says on its own pages, what a Japanese consumer-car site and a Honda Access recall-style notice add, and where the sources disagree. The translations are ours. Where a point rests on one secondary article, we say so.
The Short Version
- The rule names rotating parts, not wheel sizes. Article 18 of the Road Transport Vehicle Safety Standards requires the body shape not to have sharp projections or protruding rotating parts that could endanger other traffic, and leaves the details to a notice.
- The notice sets a zone. With the car pointing straight ahead, the tyre, wheel and wheel cap in the area between the vertical plane through the axle centre and planes angled 30° forward and 50° rearward must not stick out sideways past the body directly above them, such as the fender.
- The text we read gives no millimetre figure. It does include a proviso that sidewall lettering, symbols, protective bands and ribs on certain tyres are treated as not protruding. A “10 mm” figure appears in several news and magazine articles, but we did not find it in the notice, and the articles do not agree on what it covers.
- Wheels are treated more strictly wherever the sources mention them. The articles that discuss wheels describe the 2017 change as a tyre matter, and the notice itself separately lists sharp projections on wheels, wheel nuts and caps, and spinner-type decorations as failures.
What the Safety Standards Say
The table lists only what we read on MLIT’s own PDF pages. The version dates are the ones printed in each file’s header.
| Source | What it says (our translation) |
|---|---|
| Safety Standards, Article 18 (version dated 2022.6.22) | Paragraph 1, item 2: the body shape and the shape of the car must meet a notice’s standards so that there are no sharp projections, no protruding rotating parts and the like that could endanger other traffic. Large and small special vehicles are excluded. |
| Detailed notice, Article 22, paragraph 2, item 4 (version dated 2023.9.22) | Restates the requirement: the shape of the car must not have sharp projections or protruding rotating parts that could endanger other traffic. |
| Same notice, paragraph 3, item 1 | With the car in a straight-ahead position, rotating parts of the running gear (tyres, wheels and steps, wheel caps and the like) lying between the vertical plane through the axle centre and two planes through the axle centre, 30° forward and 50° rearward, must not protrude outward beyond the body (fender and the like) directly above them. |
| Same item, tyre proviso | For tyres on cars used mainly for carrying passengers (the list of excluded types includes cars seating 10 or more, motorcycles, three-wheelers and towed vehicles) that comply with UN Regulation No. 30, rules 3 (except 3.2) and 6, protrusion of sidewall lettering, symbols, protective bands and ribs is treated as not protruding. |
| Same notice, paragraph 4, item 3 | For passenger cars seating fewer than 10, wheels, wheel nuts, hub caps and wheel caps that have a sharp projection beyond the outermost edge of the rim fail the standard. |
| Same notice, paragraph 4, item 6 | Spinners, wing nuts and similar propeller-shaped decorations attached to a wheel fail the standard. |
Paragraph 4 opens with an exception for cars covered by paragraph 2, item 1 of the same article. We did not map which cars that exception covers, so we do not claim the paragraph applies to every car.
How to Picture the 30° and 50° Zone
The zone is measured from the axle centre, not the whole wheel arch. Looking at the car from the side, imagine a vertical line through the centre of the wheel. The notice checks the area from a line leaning 30° towards the front of the car to a line leaning 50° towards the rear. Within that wedge, the tyre, the wheel face and the cap must stay inside the line of the body above. The notice text does not say what happens outside the wedge, and we did not find a source that does.
The 2017 Change and the “10 mm” Figure
Several Japanese articles describe a change to the inspection standards that took effect on 22 June 2017. They agree on the date and that wheels were not relaxed, but not on the details.
| Source | How it describes the change |
|---|---|
| Norimono News, 9 July 2017 | Before the change, any rotating part (tyre, wheel, wheel nut or centre cap) sticking out in the zone failed. After it, tyre protrusion of less than 10 mm is allowed in the same zone. Applies regardless of manufacture date; tyres only, not wheels. |
| CARPRIME (updated 9 September 2024) | For qualifying passenger cars, a tyre protruding less than 10 mm outward is treated as not protruding. Wheels, caps and bolts must still stay within the body line. |
| Best Car Web (8 March 2023) | Passenger-car tyres may protrude up to 10 mm. Lists vehicles that cannot use it, naming the Toyota HiAce, Honda N-VAN, Suzuki Every and commercial-registered off-roaders as examples. |
| Kuruma no News (3 October 2018) | Says the relaxation concerns sidewall lettering and symbols and protective bands and ribs, where protrusions under 10 mm are treated as not protruding. Stresses that this does not mean any tyre bulge is acceptable. |
The MLIT notice text we read matches the Kuruma no News description in one respect: it names sidewall lettering, symbols, protective bands and ribs. It does not contain a millimetre figure at all. We searched MLIT’s published notice, a 2013 tyre technical annex (marked deleted in 2015) and the 2015 to 2017 press releases we could open, and none of them contained a tyre-protrusion tolerance in millimetres. The 10 mm figure may sit in an inspection-procedure document we did not find. Until that is located, we do not state it as the rule.
A Case From the Wheel Trade: Honda Access, 2003
MLIT’s 29 May 2003 release on a voluntary improvement describes 16-inch aluminium wheels made by Honda Access and fitted by dealers to the Honda Stepwgn, Odyssey and S-MX sold between March 1998 and December 2001, 4,717 sets in total. The product catalogue said fender arch moulding was required with these wheels. Without it, the release says, the wheel design could cause the wheel to stick out of the body, and tyre size variation could do the same, so the cars might not meet the safety standards. Dealers were to check for the moulding and fit it where it was missing. The release gives no dimensions. It is useful mainly as evidence that a wheel maker treated the protrusion standard as a fitment condition, not a styling matter. Our guides to the Honda Stepwgn and Honda Odyssey cover the factory wheel data for two of those models.
What This Means When Shopping
- A wheel does not stick out or stay in on its own. The outer face of the wheel depends on the width and offset together with the car’s body. The same wheel can sit inside the fender on one car and outside it on another. Where a car uses different front and rear sizes, check each end, as in our staggered fitment reference.
- Treat a listing’s inspection wording as the seller’s claim. We did not find a Japanese official definition of the phrases some listings use about passing inspection, so we do not interpret them here.
- Spinner-style and sharp-edged parts are named in the notice. Wing nuts, spinners and propeller-shaped wheel decorations, and projecting edges on wheels, nuts and caps, are listed as failures for the cars the paragraph covers.
- The standard we read is Japan’s. We did not check the rules of any other country or state, and we do not say how another country treats a wheel that sits outside the fender.
What We Could Not Verify
- The 10 mm tolerance. It appears in four secondary articles, but we did not find it in the MLIT notice text, and the articles disagree about whether it concerns the tyre as a whole or only sidewall features.
- The 22 June 2017 effective date. It rests on the secondary articles above. We did not find the MLIT announcement.
- Later amendments. We read Article 18 as dated 2022.6.22 and the notice as dated 2023.9.22. We did not check whether anything changed after those versions.
- Which cars the paragraph 4 exception covers, and how the article’s category of “passenger cars” maps to specific models. The Best Car Web list of excluded models is a single source.
- How a given inspector measures, and whether a particular wheel and tyre on a particular car would pass an inspection in Japan.
- The text of UN Regulation No. 30, which the tyre proviso cites. We did not read it.
- The Honda Access catalogue itself. We know it only through MLIT’s description, and the release gives no dimensions.
- Rules outside Japan.
Looking for a specific set? We specialise in genuine Japanese wheels — RAYS, Volk, Enkei, SSR, WORK, BBS Japan and the rare discontinued sets that never left the country. Tell us the wheel, the fitment, the year — our team searches our networks until we find it.