Do not continue using an alloy wheel with a visible or suspected structural crack. Stop the vehicle safely, arrange an assessment and ask about recovery or a suitable replacement wheel. Holding tyre pressure, driving without vibration or having recently passed an MOT does not establish that a cracked wheel is safe.
The immediate decision is how to keep the damaged component out of use. Questions about appearance, cost and matching the rest of the set come after that decision.
Is it a crack or a mark in the finish?
A surface scratch can expose metal without breaking the wheel's structure. A crack is a fracture in the material itself. However, a line in a photograph may not show its depth or extent, and a coating can obscure what is happening underneath.
Treat uncertainty conservatively. Do not scrape, grind, flex or paint over the area to decide whether the line matters. Photograph what is visible while the vehicle is safely parked and have a competent professional inspect it. Tell them if there was an impact, pressure loss or previous repair.
A close-up is useful evidence, but send a wider view as well so the location is clear. A mark near a spoke, bolt hole or rim edge needs to be identified accurately. Avoid presenting an enlarged crop as proof that the rest of the wheel is undamaged.
Why a pressure check cannot approve the wheel
Tyre pressure tells you about inflation at that moment. It does not test the complete wheel structure. A wheel may retain air even though part of it is fractured, so “it has not gone flat” is not a reason to continue driving.
Likewise, the absence of a warning light is not a structural inspection. Do not repeatedly reinflate an assembly with a suspected wheel crack and use it until the next scheduled service. Tell the recovery provider or workshop exactly what you have found so they can plan the appropriate next step.
What the MOT guidance says
In Great Britain, the DVSA MOT inspection manual classifies a wheel fracture or welding defect as a dangerous defect. This is not a cosmetic advisory category.
An earlier MOT pass does not settle the condition today. Damage may have happened since the test, and the test is not a guarantee about every future journey. Do not wait for the next MOT to resolve a suspected crack.
Should a cracked alloy be welded?
Do not assume that the availability of a welding service establishes manufacturer approval. EUWA's wheel safety guidance calls for replacement of wheels with fractures and rejects structural repairs such as welding. Check the current instructions for the actual wheel rather than treating a generic repair advertisement as authority to reuse it.
Manufacturer policies can also depend on construction. OZ's published FAQ distinguishes its approach to modular wheels from repairs to one-piece wheels, which it does not approve. That distinction is a reason to identify the wheel correctly, not permission to repair any wheel assembled from several parts.
A repaired-looking surface or a successful leak test cannot by itself demonstrate that the wheel has regained its original performance. Request the manufacturer's position and follow it. Where replacement is required, keep the damaged wheel out of service.
Plan the next step with the workshop
Tell the workshop that the concern is a suspected crack before arranging transport. Ask whether the vehicle should be recovered and whether a vehicle-approved spare can be used under the handbook's conditions. A temporary spare is not automatically suitable for every car or axle.
The assessment should identify the wheel, the defect's location and the condition of the tyre and relevant adjacent parts. If the problem followed an impact, provide that history even if the tyre still appears normal. Ask for a written finding and photographs before any disposal if those records may be needed for a supplier or insurer.
Keep the discussion specific. A report that names the affected corner and records a fracture is more useful for ordering than a vague instruction to “replace an alloy”. It also prevents a front wheel being confused with a differently specified rear wheel.
Order by specification, not by appearance
Start with the wheel manufacturer, model or part number and the vehicle details. Confirm the diameter, width, offset, bolt pattern, centre bore, load suitability and brake clearance. Check the required mounting hardware and whether the existing tyres can be reused after inspection.
Our PCD, offset and centre-bore guide explains those identification details. A photograph of a matching spoke pattern does not establish that a replacement has the same dimensions or application.
If the exact wheel is discontinued, ask for a coherent replacement plan. Mixing a visually similar but differently specified wheel into the set can create a new fitment problem. Contact Wheel City with the confirmed requirements before selecting from the alloy wheel collection.
Frequently asked questions
Can I drive a short distance on a cracked wheel?
Do not rely on the journey being short. Keep the wheel out of use and ask a recovery provider or qualified workshop how to get the vehicle assessed safely.
Does every visible line mean the wheel is cracked?
No. Some marks are confined to the coating, but a photograph may not establish that. Have a suspected crack inspected rather than testing it by driving or trying to grind the line away.
Is a wheel safe if it has been welded and holds air?
Air retention is not proof of structural suitability. Follow the wheel manufacturer's guidance; a welding service or leak-test result does not override a prohibition on structural repair.
Do all four wheels need replacing?
That depends on the condition of the set and whether an exactly compatible replacement is available. First establish the correct specification and any axle-specific requirements. Do not assume either one-wheel replacement or a complete set is always necessary.