New forged wheels and the MOT: TPMS, condition and fixing

In short. The MOT does not fail a car because its wheels are not the ones it was sold with: the inspection manual says modifications are assessed on their merits (MOT inspection manual, introduction, § 12). On the wheels, the tester looks for cracks, distortion, loose or missing nuts and bolts, fixings that do not suit the wheel, and tyres that rub or are badly seated. On a car first used on or after 1 January 2012, a tyre pressure monitoring system (TPMS) that is "malfunctioning or obviously not working" is a major defect, and a major defect is a fail. That is the check a change of wheels touches most directly: if your car reads a sensor in each wheel, the new set needs sensors too, and whichever system it has must be reset after the change. Tell us about your sensors before machining, in your reply to the email we send after payment.

What the tester checks on the wheels and tyres

Section 5.2 of the MOT inspection manual, which applies in England, Scotland and Wales, contains these lines relevant to a set of new wheels:

None of these lines compares your wheels with the ones the car left the dealer on. On a wide or low fitment, the line to watch is 5.2.3 (f): the manual fails a tyre that is fouling part of the car at the time of the test, but marks left by tyre flex or suspension travel are not a defect on their own.

A major or a dangerous defect means a fail; minor defects and advisories are listed for you to keep an eye on (GOV.UK, MOT test result). With a dangerous defect, the car has to be repaired before you drive it, even if your current MOT has not run out. Driving it anyway can mean a fine of up to £2,500, a driving ban and 3 penalty points (same page).

Does a TPMS fault fail the MOT? What the warning lamp has to show

The check applies to passenger cars (category M1) first used on or after 1 January 2012 (manual, § 5.2.3, TPMS). The tester normally receives the "first used" date with the vehicle's details. When that date is missing or wrong, the manual takes the earlier of the date of first registration and six months after manufacture; for a car first used without being registered in Great Britain, such as an import, it takes the date of manufacture (introduction, § 6).

The tester reads the warning lamp. According to the manual:

• when you switch on the ignition, the lamp will generally light up and then go out;
• if the system has recorded a loss of pressure, the lamp stays on, which does not by itself mean the system is faulty;
• if the system is faulty, the lamp may flash several times and then stay on;
• a message on the dashboard screen is not a defect in its own right, but it helps the tester tell a fault from a low pressure; when that remains unclear, an advisory is added to the result.

So the answer is yes when the lamp shows a fault in the system: that is defect 5.2.3 (h), major, and the car fails. A lamp lit because a tyre is low is not a fail on its own, although a tyre that is obviously under-inflated is recorded as a minor defect (5.2.3 (l)). Before the test, set the tyres to the pressures your car's manufacturer gives, switch on the ignition and watch the lamp: you will see what the tester will see.

This article covers Great Britain only. Northern Ireland has its own test, run by the DVA under its own manual, and there the TPMS lamp is checked on cars first used on or after 1 November 2014 (DVA, Tyres, April 2026).

The cars on our generation pages, against the 2012 date

Each generation page on our website (in French) gives the years of that generation. Set against the British date, the 14 generations we cover fall like this:

Twelve of the 14 start in 2013 or later, so every car of those generations is within the check. For the 997 and the 991, the generation does not settle it; the date your car was first used does. The years in the table are those of our pages, not of your car. A car of the newest generations meets the check at its first MOT, due by the third anniversary of its registration (GOV.UK, when to get an MOT).

New wheels: a sensor in each wheel, or the ABS sensors

Transport Canada describes the two systems in use: one measures the pressure with a sensor mounted in each wheel; the other uses the ABS sensors, since an under-inflated tyre turns slightly faster.

A sensor in each wheel. The new wheels need sensors: the ones from your current wheels, moved across, or new ones. Transport Canada advises making sure the sensors fit the new wheels. The German Road Safety Council (DVR) notes that after a change of wheel and tyre combination on a car with this system, a visit to a workshop may be needed for it to work safely (DVR, 2016).

The ABS sensors. Nothing goes into the wheel, but the system has to be reset after a change of wheel and tyre combination (DVR). Transport Canada adds that a malfunction warning comes on when tyres are changed and the system is not reset.

Transport Canada's advice is to read your owner's handbook to learn about your car's system. In both cases, a set fitted without its sensors, or a system left without its reset, can end up as defect 5.2.3 (h) above.

Before machining: tell us about your sensors

After every paid order, we email you about your car's measurements before anything is machined, and ask you to confirm the car and whether its brakes, suspension and bodywork are original. That email is in French, as are the checkout, the product pages and the Terms and Conditions. You can configure your wheels, with a configurator that is in French too, or start from our monoblock forged wheels.

The email does not ask about tyre pressure sensors, so add them to your reply: say whether your car has a sensor in each wheel, and whether you will move them to the new wheels or fit new ones. Your answers on suspension and bodywork count for the MOT too: a lowered car or wider wheel arches leave a different amount of room around the tyre, and a tyre fouling the car is a major defect.

The sensors, their programming and the fitting are done by your tyre fitter. For that appointment, customer service sends you, on request, the width, diameter and offset of each wheel. The fixings belong to the same appointment. Our wheels are made to your car's specifications, centre bore included, with no spacers or spigot rings (FAQ); the bolts or nuts still have to suit the new wheels, as a wheel and fixings that are not compatible is a major defect.

Our warranty does not cover incorrect fitting, unsuitable wheel bolts or nuts, or tyre pressures outside the car manufacturer's recommendations (Terms and Conditions, article 6.2, in French). A lamp that stays off is no proof that the pressures are right: Transport Canada notes that some systems warn only once a tyre is significantly under-inflated. Check them with a gauge.

A cracked or bent alloy wheel at the MOT

A crack in a wheel comes under 5.2.2 (a), "any fracture or welding defect on a wheel": a dangerous defect. The car fails and has to be repaired before it is driven. A badly distorted wheel is a major defect; one distorted so far that the wheel or tyre is likely to come off is dangerous (5.2.2 (c)).

Our advice for a cracked wheel is to replace it, not to have it welded, heated or straightened.

If it is one of ours, email customer service before any work on it, with a description, photos, your order number and the delivery date; customer service replies within 48 working hours (Terms and Conditions, article 6.3). Every set comes with a 5-year Onyx Forged commercial warranty from the date of delivery, covering manufacturing and material defects and structural failures not caused by abnormal use. Damage from an impact is excluded, and so is any modification, repainting, touch-up or third-party work we have not authorised (article 6.2). This warranty is in addition to your statutory rights.

What a set costs with UK import VAT is set out on our Delivery to Great Britain page. Other questions are answered in the FAQ, or you can write to customer service.

Ordered on the website, a set of Onyx Forged wheels is delivered in 4 to 8 working weeks, shipping included (FAQ).

Sources

• DVSA, MOT inspection manual: cars and passenger vehicles, section 5, § 5.2.1, 5.2.2 and 5.2.3, read on 5 October 2026.
• DVSA, MOT inspection manual, introduction, § 6 and § 12, read on 5 October 2026.
• GOV.UK, Getting an MOT and MOT test result, read on 5 October 2026.
• DVA, Light Vehicle Inspection Manual, Tyres, April 2026.
• Transport Canada, Tire pressure monitors, page modified on 6 August 2021.
• German Road Safety Council (DVR), Tyre pressure monitoring systems, resolution of 24 May 2016.
• Onyx Forged: generation pages (in French), the email sent after payment, FAQ, Terms and Conditions (in French), articles 6.1 to 6.3.

Contains public sector information licensed under the Open Government Licence v3.0.

The Onyx Forged design office.