In short. Curb rash (kerb damage, in British English) is the scraping of a wheel's outer rim edge against a kerb. Most of it is cosmetic: if the scrape stays in the paint, or goes no deeper than about 1 mm into the metal near the outer edge (the limit set by German and European wheel refurbishment texts), a DIY kit can fill and paint it on a painted wheel, and a refurbisher can make it disappear. Three things move it out of kit territory: depth beyond that millimetre, a diamond-cut, polished or chrome face, and any bend, crack or chunk missing where the tyre seals, which is a job for a wheel specialist, or for a new wheel. Prevention comes in two forms: tyres with a moulded rim protector rib, and add-on rings fitted between tyre and rim. Both take light scrapes, not hard impacts.
Is it cosmetic or structural? Judge the depth first
Before you buy anything, clean the wheel and look at the damage in good light. Run a fingernail across it.
- Scuffed paint or lacquer, metal smooth underneath. Cosmetic. A kit or a touch-up does the job.
- A gouge you can feel, with raised burrs, on the outer lip. Still cosmetic in most cases, if it is shallow. This is where the 1 mm figure below matters.
- A flat spot, a ripple in the rim edge, a vibration at speed, or a tyre that loses air. Not curb rash anymore: the rim may be bent. See our guide to alloy wheel repair, which covers straightening and welding.
- A crack, or metal missing where the tyre bead sits. Stop driving on it and have it inspected before you go back on the road.
Check the tyre too: a kerb strike can also cut the sidewall. The MOT manual fails a tyre with a cut deep enough to reach the ply or cords (major), and a lump, bulge or tear caused by separation of its structure is dangerous (GOV.UK, MOT inspection manual, 5.2.3). Our guide to sidewall bulges explains what to look for.
How deep is "about 1 mm"? The two texts that give a number
Only two documents we read put a figure on cosmetic depth. Germany's federal guideline on refurbishing light-alloy wheels, published on 5 December 2022, allows damage into the base metal of "at most 10 per cent of the cross-section (rim flange width), and in no case more than 1 mm" (our translation), and adds that on a narrow flange under 11 mm wide the remaining wall must not drop below 10 mm. It allows that depth only within 50 mm (2 in) of the outer rim edge; further in, only the paint may be redone (KÜS note reproducing the guideline, in German). The wheel makers' association EUWA lists, among repairs it does not allow on the outer rim edge, "removing material more than 1.0 mm" or leaving a "reworked thickness below than 10 mm" (EUWA ES 1.07, June 2020, table 1).
Put side by side, the two rules give the same answer. This table is our arithmetic, applying both to a few flange widths:
| Rim flange width | 10 % of width | Most that can go before the 10 mm minimum wall | Deepest cosmetic damage the rules allow |
|---|---|---|---|
| 10.0 mm | 1.0 mm | 0 mm to remove | None: refurbishing would thin the wall below 10 mm |
| 10.5 mm | 1.05 mm | 0.5 mm to remove | 0.5 mm |
| 11 mm | 1.1 mm | Rule does not apply | 1 mm (the cap) |
| 13 mm | 1.3 mm | Rule does not apply | 1 mm (the cap) |
The guideline is German, not British, American or Australian law, and you cannot measure a flange to a tenth of a millimetre on the car. Read it as an order of magnitude. Our rule of thumb, not a measurement: a scrape that only catches a fingernail is usually within it; a groove you can sink the edge of a coin into deserves a wheel specialist's look.
What a DIY kit can do, finish by finish
A curb rash kit is filler, abrasive paper and paint. Permatex's data sheet for its wheel restoration kit (revised January 2009) is one of the few that sets out the whole procedure: wash and dry the wheel, sand raised edges with 220-grit paper, fill, leave the filler to dry for at least four hours, test it with a fingernail, sand with 220 and then 320 grit, mask the areas that must not be painted, and spray two light coats and one medium coat within an hour, ten minutes apart. The paint is dry to the touch in an hour and fully dry after 24 hours, and the paint should go on between 60 and 92 °F (16 to 33 °C) with humidity under 60 per cent. The same sheet says the kit is "not for use on" wheels that are "badly damaged, cracked, bent or excessively rusted", and "not recommended for use on chrome wheels" (Permatex data sheet).
The filler is never what runs out. That kit holds 0.34 fl oz of filler, which is 10.06 ml. A groove 3 mm wide and 1 mm deep takes 3 mm³ per millimetre of length, so one tube fills about 3.35 m of it. The outer edge of an 18-inch rim is roughly 1.55 m round (our assumption: 457 mm nominal diameter plus about 17.5 mm of flange height on each side). One tube fills that groove twice round the wheel. If a repair seems to need more filler than a kit holds, the damage is deeper than any of the texts above treat as cosmetic.
| Finish | What a kit can do | What it cannot do | Who does it properly |
|---|---|---|---|
| Painted (silver, grey, black, any solid colour) under clear lacquer | Fill, sand, paint and lacquer a scuff on the lip; the match is the hard part, so test the colour first | Hide the repair completely on a large, flat, visible area | A refurbisher, by local repair or a full repaint |
| Powder-coated | Fill and paint over a small scuff | Match the thickness and texture of the powder; the German guideline caps paint work at 100 °C and does not allow powder coatings cured above it | A refurbisher; see powder coating vs painting |
| Diamond-cut (bright machined face, clear lacquer) | Seal the exposed metal so it does not corrode until the wheel is repaired | Reproduce a machined face: paint will never look machined | A lathe re-cut, which removes metal; Germany does not allow machining other than local grinding, and EUWA lists re-machining of a spoke face as not allowed; see diamond-cut wheels |
| Polished or bare aluminium | Sand and polish a light scrape by hand | Fill a gouge invisibly: filler shows under a polish | A polisher |
| Chrome (plated) | Nothing, according to the kit sheet above | Plate over a scrape | A plating shop, or a replacement wheel |
Three points matter more than the order of the steps (our reading of the procedures we read): sand only inside the damaged area, to remove as little metal as possible; mask the tyre and the valve; and keep paint off the faces the German guideline says are never painted: the hub contact face, bolt holes, centre bore, valve seat and tyre bead seats, where paint can let the tyre slip on the rim.
If you take the wheel off, the jack only lifts the car: put it on axle stands, and tighten the nuts to the car maker's torque when the wheel goes back on.
When it is a job for a professional
Go to a wheel specialist, not a kit, when:
- the gouge is deeper than the millimetre above, or more than 50 mm (2 in) in from the outer edge;
- the face is diamond-cut, polished or chrome;
- there is a flat spot, a ripple or a vibration, which points to a bent rim;
- metal is missing next to the tyre edge, where the bead seals: in our reading, a sharp edge there can cut the tyre or stop it seating, so have it inspected before you go back on the road;
- there is a crack anywhere, or the tyre is damaged.
The rules for professionals vary by place. In British Columbia, the weld repair regulation allows cosmetic work freely: "Cosmetic weld repair is allowed on the entire wheel", described as repair of "surface nicks and gouges which do not affect the structural integrity of the wheel" (section 10(2)). Structural weld repair is limited to the lips, flanges, bead seats and wheel wells, and every repaired wheel is stamped beside the valve hole with a severity rating from 0, "a minor cosmetic repair", to 9, straightening combined with welding (section 13) (B.C. Reg. 5/97, consolidated to 13 October 2026). In Germany, a refurbished wheel may not be refurbished a second time. EUWA says that visual reconditioning by an outside company transfers the full liability from the wheel maker to that company or to whoever ordered the work, and that it can be done only once. If the wheel is under a maker's warranty, ask before anyone touches it.
What inspections say about a scraped wheel
None of the inspection texts we read names curb rash. They name what curb rash can turn into.
| Where | Text and date | What it says about a damaged wheel |
|---|---|---|
| Great Britain | MOT inspection manual, 5.2.2, updated 14 October 2026 | "Any fracture or welding defect on a wheel": dangerous. "A wheel badly distorted": major. A cosmetic scrape is not a listed defect |
| United States (Pennsylvania, as an example: inspection rules are set state by state) | 67 Pa. Code § 175.80(e)(1)(xiii), amended with effect from 26 October 2013 | Rejection if "part of the wheel is bent, cracked, welded or damaged so as to affect safe operation of vehicle" |
| Australia (Queensland, as an example: each state has its own manual) | Queensland Light Vehicle Inspection Manual, effective 7 July 2026, section 7 | Reason for rejection if wheels or rims "are cracked, corroded, bent, buckled, have pieces of casting missing, show signs of welding (as a repair), or are otherwise damaged" |
| Canada (British Columbia) | B.C. Reg. 5/97, current to 13 October 2026 | Sets how a licensed facility may weld and straighten aluminium wheels; a wheel judged beyond repair is stamped "UNSAFE" |
Sources: MOT manual; 67 Pa. Code § 175.80; Queensland manual; B.C. Reg. 5/97.
The Queensland wording is the broadest: "corroded" and "otherwise damaged" are reasons for rejection on their own. We do not know how examiners there treat a purely cosmetic scuff, and the manual gives no depth. Before a Queensland safety inspection, a scraped wheel is worth repairing or asking the examiner about.
What curb rash repair costs
Prices are not regulated anywhere we looked, and independent figures are scarce. The only one we could read is British and five years old: in a survey of 2,000 drivers commissioned by a carmaker, reported on 16 October 2021, the average repair price was £67.50 per wheel, and 56 per cent of the drivers with damaged alloys said the damage came from a kerb (Motoring Research). We found no independent figure for the United States, Australia or Canada; of the three US pages ranking first for "curb rash repair" that we read on 16 October 2026, one gives a range per wheel and names no source for it, and the other two give no price.
What moves a quote, from the documents above:
- Depth: a lacquer scuff, a filled gouge, or a weld.
- Finish: a painted lip is the cheapest case; a diamond-cut face needs a lathe; chrome needs plating or a new wheel.
- Local or whole wheel: a spot repair on the lip, or a strip and full refinish, which involves taking the tyre off.
- What is included: tyre removal and refitting, a new valve (the German guideline recommends one after painting), the pressure sensor if there is one, and a rebalance.
Ask for each item to be named in the quote, per wheel. Whether an insurance product pays for it is a separate question, covered in our guide to tire and wheel protection.
Prevention: rim protector ribs and add-on rings
The rib moulded into the tyre
Many low-profile tyres have a raised band of rubber just above the bead that stands proud of the rim edge. Continental marks it "FR" on the sidewall, for Flange Rib or Rim Protector, and describes it as "an extra rubber bulge at the bead" that acts as a shield for alloy wheels against kerbs (our translation of Continental France, in French). Michelin's version on its van tyres, called Curbgard, is a set of protruding "keystone-shaped features on the sidewall" that provide "additional rubber for protection against curb scrubbing" (Michelin Canada). Other makers use other codes; the tyre's data sheet or your fitter will say whether a given size has one.
Why it matters more on big wheels. The taller the sidewall, the more rubber stands between the rim and the kerb. This table is our arithmetic (sidewall height = width × aspect ratio; overall diameter = rim diameter + two sidewalls), and you can repeat it for any size with our tyre size calculator:
| Tyre size | Sidewall height | Overall diameter | Share of the radius that is rubber |
|---|---|---|---|
| 205/55 R16 | 112.8 mm | 631.9 mm | 35.7 % |
| 225/45 R18 | 101.3 mm | 659.7 mm | 30.7 % |
| 235/35 R19 | 82.3 mm | 647.1 mm | 25.4 % |
| 255/30 R20 | 76.5 mm | 661.0 mm | 23.1 % |
Sidewall height is not the same thing as how far the tyre bulges beyond the rim edge, and none of the tyre makers' pages we read publishes that figure. The trade-offs of a short sidewall go beyond kerbs; see our guide to low-profile tires. Onyx Forged does not recommend a size or an offset: the sizes your car can take are in its handbook and on its tyre placard.
Add-on rim rings
The other option is a plastic ring that sits in the gap between the tyre and the rim edge and takes the scrape instead of the metal. We read the fitting instructions of one widely sold ring, AlloyGator. They set out the conditions:
- Not every wheel and tyre suits it. A gauge is pushed into the gap between wheel and tyre; if the wheel edge finishes in the red part, the maker does not recommend fitting.
- The tyre is deflated to fit it, the ring is tapped in with a rubber mallet, the tyre is reinflated to the handbook pressure, and the gap between ring and wheel should be no more than 1 mm.
- Pressure loss can dislodge it: "Substantial loss of pressure could result in the AlloyGator moving or, in extreme cases, coming out from between the wheel and tyre."
- It is not recommended for machine-polished or diamond-cut wheels, because existing flaws in the lacquer may hold moisture and speed up lacquer breakdown.
- Tyre changes take care: the fitter treats the ring as the rim edge, or removes it for tight tyres such as run-flats.
- It is designed for normal driving up to the legal speed limit, not for off-road use (fitting instructions).
What we did not find: any independent test of how much impact a ring or a rib absorbs, any inspection text in the four territories above that mentions add-on rings, and anything in those instructions about tyre pressure sensors. If you fit one yourself, the car goes on axle stands, not just a jack.
Frequently asked questions
Is curb rash just cosmetic?
Usually. It becomes structural when it bends the rim, cracks it, removes metal where the tyre seals, or goes deeper than about 1 mm near the outer edge, the limit in Germany's 2022 refurbishment guideline and in the wheel makers' EUWA standard.
Can I fix curb rash myself?
On a painted wheel, yes, for a scuff or a shallow gouge on the lip: sand, fill, sand, mask, paint and lacquer. One kit's data sheet asks for at least four hours for the filler and 24 hours for the paint to be fully dry. Not on chrome, and not on a bent or cracked wheel.
Do curb rash kits work on diamond-cut wheels?
Only to seal the bare metal. Paint cannot reproduce a machined face; that needs a lathe, which removes metal and which Germany's guideline does not allow beyond local grinding.
How much does curb rash repair cost?
The only independent figure we found is an average of £67.50 per wheel in a British survey reported in October 2021. We found no independent US, Australian or Canadian figure. Ask for a quote that names the finish, the tyre work, the valve and the balance.
Will curb rash fail an MOT or a state inspection?
A cosmetic scrape is not listed in the MOT manual. A fracture or welding defect is dangerous and a badly distorted wheel is major. Pennsylvania rejects a wheel damaged "so as to affect safe operation", and Queensland's manual lists "corroded" and "otherwise damaged" wheels as reasons for rejection.
Do rim protectors work?
Tyre ribs and add-on rings take light scrapes. We found no independent test of how much they absorb in a harder impact. The ring maker whose instructions we read does not recommend its product on diamond-cut or machine-polished wheels.
Are rim protector rings legal?
None of the inspection texts we read for Great Britain, Pennsylvania, Queensland or British Columbia mentions them. Check a ring after any hard impact, as its maker asks.
Should I drive on a wheel with curb rash?
If it is a scrape in the paint, yes. If the tyre loses air, the steering vibrates, or you can see a crack, a bulge or missing metal near the tyre, have it inspected before you go back on the road.
For wheels made to order for your car, designed to JWL/VIA standards, see the Onyx Forged catalogue.
Sources
- Inspection and repair texts: GOV.UK, MOT inspection manual, sections 5.2.2 and 5.2.3; 67 Pa. Code § 175.80; Queensland Light Vehicle Inspection Manual; British Columbia, B.C. Reg. 5/97; German guideline of 5 December 2022, reproduced by KÜS (in German); EUWA ES 1.07.
- Makers: Permatex, Wheel Restoration Kit data sheet; AlloyGator, fitting instructions and care advice; Continental France, FR rim protector (in French); Michelin Canada, Curbgard sidewall protectors.
- Cost: Motoring Research, 16 October 2021.
All pages were read on 16 October 2026.
The Onyx Forged design office.