Why Tyre Decals Can Turn Brown — And How to Prevent It

If your tyre decals turn brown or develop patches, it’s not because the material has failed. The cause is tyre chemistry, not product quality. While it shows most on white decals, all colours can be affected.

Our decals use a tough, multi-layer 1 mm rubber built to last. But even the best construction can’t completely block certain chemicals that tyres release. Here’s what’s going on.

What causes tyre browning?

The main cause is blooming — when protective chemicals in the tyre migrate to the surface and react with oxygen. One of the most common is 6PPD, an antiozonant added to stop UV and ozone damage.

When tyres heat up on the road or in sunlight, these compounds move out of the rubber and oxidise, leaving a brown film on the sidewall. This is normal and doesn’t harm the tyre, but it can stain decals if they’re fitted too soon.

How blooming affects decals

If decals are applied while the tyre is still in its high-bloom phase, these chemicals can move through the adhesive layer and into the surface of the decal. The result is a surface-level stain that permanently changes the look.

It’s most obvious on white decals, but coloured ones are affected too. Once browning appears, it can’t be removed without damaging the decal.

Why hot climates make it worse

Heat speeds up chemical movement inside the tyre. In hotter weather or on cars parked in direct sunlight blooming happens faster and more aggressively. UV light also accelerates oxidation at the surface, making stains appear sooner and more noticeably.

Why we recommend 1,000 miles before fitting

New tyres release the most surface compounds in the first 1,000 miles. To reduce browning risk, either:

  • Drive 1,000 miles before fitting decals, or

  • Leave tyres in warm sunlight for several days before installation.

This allows the tyre surface to stabilise, making bloom transfer far less likely. Decals fitted after this period often last years without browning, even in summer conditions.

Why browning can reveal tyre lettering patterns

Some customers notice faint outlines of the tyre’s raised lettering showing through when browning occurs. This happens because decals stretch over the surface raised areas press tighter and transfer chemicals differently from flat areas, leaving a visible pattern over time.

What to do if browning happens

If it does occur, the best fix is to mask it with a Uni Paint Marker PX-30. This won’t remove the chemicals but will restore a clean, fresh look.