How to fix it
Work through these in order, the most common causes come first.
Why Covers Crack
Th in material: budget covers use polycarbonate at 1mm or less.
This provides adequate protection in temperate climates but becomes brittle at temperatures below 25F.
UV degradation: polycarbonate without UV stabilizers becomes brittle over 1-2 years in high-sun environments.
The material yellows visibly before it cracks, yellowing is an early warning.
Acrylic instead of polycarbonate: acrylic (PMMA) looks similar to polycarbonate but is substantially more brittle.
How to Replace Without the Same Problem Recurring
Remove the cracked cover, unscrew the plate, remove the cover, and reinstall the plate.
Select a replacement with: polycarbonate material specified, UV-resistant or UV-stabilized coating, minimum 2mm thickness, and temperature rating to -20F or lower.
Inspect the mounting screws when the plate is off, replace any rusted screws with stainless steel to prevent the next removal from being difficult.
Install the new cover and hand-tighten the screws only, overtightening creates stress cracks at the screw holes.
Screw Hole Cracking
A separate common failure mode: cracks radiating from the screw holes.
This is caused by overtightening.
License plate screws are decorative-load fasteners, the plate needs to be held in place, not torqued.
Hand-tight plus a quarter-turn is sufficient.
Use nylon or rubber washers if the cover has th in material around the mounting holes.
Our picks
Products we recommend
As an Amazon Associate I earn from qualifying purchases. Picks are based on manufacturer specs, independent reviews and owner reports.
Best OverallPilot Automotive
UV-resistant material prevents yellowing that makes plates unreadable in strong sunlight states
- UV-resistant polycarbonate construction
- Universal fit for standard US license plates
- Stainless steel screws included
- Snap-in installation
✓ Pros
- UV-resistant material prevents yellowing that makes plates unreadable in strong sunlight states
- Thick polycarbonate resists cracking from winter temperature fluctuations
- Legal in all 50 states, clear cover does not obstruct the plate in any way
✕ Cons
- Condensation can form inside the cover in high-humidity climates
Aootf
Flexible silicone frames that won't rust or rattle, with drainage holes.
✓ Pros
- Rust-proof and rattle-free
- Drainage holes
- Slim edges keep stickers visible
- Two frames included
✕ Cons
- Pla in matte look
- Can collect dust
- Check your state's frame rules
Aootf
Mirror-polished stainless frames with screw caps and anti-rattle pads.
✓ Pros
- Polished stainless look
- Screw caps included
- Anti-rattle pads
- Two frames
✕ Cons
- Shows water spots
- Can scratch
- Edges must not cover state or stickers
FAQ
Common questions
Why do license plate covers crack in winter?
Most cracking occurs from thermal contraction in cold temperatures combined with physical stress from vibration. Th in polycarbonate (under 2mm) becomes brittle at temperatures below 20F. Road vibration at highway speeds creates micro-stress in the brittle material. The combination causes corner cracks that spread across the cover. UV degradation from sun exposure accelerates brittleness, covers in high-sun states crack faster even if they crack at a less extreme temperature.
What material doesn't crack in cold weather?
High-impact polycarbonate rated to -40F does not crack in typical winter conditions. Check the product specification for temperature range. Avoid covers labeled only as 'clear plastic' or 'acrylic', acrylic is significantly more brittle than polycarbonate and typically fails after one harsh winter.
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