TireFitLab

Safety and legal checks

Safety and legal checks

Tread, damage, seasonal and inspection topics where the safest next step matters.

FAQ

Safety and legal checks
Tread, damage, seasonal and inspection topics where the safest next step matters.
What should I verify before using this information?
Use TireFitLab values as a sizing reference, then verify the vehicle handbook, tire placard, rim compatibility, load rating, and physical clearance before fitting.
Tire tread depth guide How deep should tire tread be? Legal minimums (1.6 mm / 2/32"), the penny and quarter test, and a depth-to-action chart from new to unsafe. Tyre wear indicators guide How tyre wear indicators work: where to find TWI markers, what they look like, measuring tread depth with a gauge or coin, 1.6 mm legal limit, 4 mm winter safety threshold, and when to replace. Summer vs all-season vs winter tires What is the difference between summer, all-season and winter tyres? Temperature thresholds, compound chemistry, legal requirements and when to swap. Winter driving tyre tips How to prepare your tyres for winter: winter vs all-season vs summer in cold weather, cold-pressure drop, stopping distance data, snow chain rules, and ice driving technique. Winter tyre laws by country Country-by-country legal requirements for winter tyres: which countries mandate winter tyres by law, exact seasonal dates or conditions, minimum tread depth for winter use, qualifying tyre markings (3PMSF vs M+S), and fines for non-compliance. MOT and roadworthiness tyre requirements Tyre requirements for MOT (UK), HU/TÜV (Germany), contrôle technique (France), ITV (Spain), revisione (Italy), APK (Netherlands), and EU roadworthiness inspections: tread depth limits, sidewall condition, mixing rules, speed/load rating, TPMS, and spare tyre rules. Run-flat tyre guide What are run-flat tyres? How they work, when you can drive on a flat, speed/distance limits, repair rules, and whether to replace all four at once. Aquaplaning guide What is aquaplaning (hydroplaning)? Why it happens, speed and tread-depth thresholds, how to prevent it, and the correct response when your car starts to hydroplane. Tyre hydroplaning speed: at what speed do tyres aquaplane, and how tread depth and pressure affect it Tyre hydroplaning speed guide: what aquaplaning is (the tyre rides on a water film rather than the road surface — steering, braking, and traction are lost), the critical speed formula V ≈ 9.0 × √P km/h (where P is inflation pressure in bar) for new tyres, how tread depth affects aquaplaning speed (at 1.6 mm tread the critical speed is approximately 70–80 km/h vs 110–120 km/h for a new tyre), why wider tyres have a lower critical aquaplaning speed than narrower tyres of the same load and pressure (more tread surface to drain per unit time), practical avoidance steps (reduce speed in heavy rain, check tread depth, maintain correct pressure, avoid standing water), and how to recover from an aquaplaning event. Tyre sidewall damage guide Tyre sidewall damage explained: bulges, cracks, cuts, and scrapes — which are safe, which require immediate replacement, and how to tell the difference. Tyre puncture repair guide Can you repair a nail in a tyre? Plug vs patch vs plug-patch, the repairable zone rule, what size object can be repaired, speed limits after repair, and when to replace instead. Tyre delamination: belt separation, tread chunking, and when to scrap Tyre delamination guide: the difference between tread separation, belt separation, and sidewall delamination, what causes each type (age, heat, impact, manufacturing defect, improper repair, overloading), how to inspect for early signs, and when a tyre must be scrapped rather than repaired. Tyre bead damage: causes, fitting damage, and why bead faults are unrepairable Tyre bead damage guide: what the bead is and how it seals against the rim, causes of bead wire failure (kerb mounting, fitting machine misuse, corroded rim bead seat, running flat), how to identify bead damage, why bead damage cannot be repaired, and how to prevent fitting damage during tyre changes. Tyre blowout: causes, warning signs, and what to do when one happens Tyre blowout guide: what causes a tyre to blow out (under-inflation, overloading, heat buildup, belt failure, bead failure, impact damage), warning signs before a blowout, exactly how to handle a vehicle during a blowout at speed, and systematic prevention checklist. Tyre overloading: what happens when you exceed the load rating, and how to avoid it Tyre overloading guide: what the load index number means (load index 91 = 615 kg per tyre, 4 × 615 = 2,460 kg total), how overloading causes heat buildup in the carcass (heat is the primary tyre failure mechanism), at what point overloading becomes dangerous (sustained overload of 10%+ significantly reduces tyre life and failure threshold), which situations most commonly lead to overloading (passenger cars with maximum occupancy and full boot, vans and MPVs, caravans and trailers, rooftop cargo), and what the law says about tyre load ratings. Tyre heat buildup: why tyres get hot, how hot is too hot, and how to manage tyre temperature Tyre heat buildup guide: why tyres generate heat (hysteresis — rubber compound absorbs and releases mechanical energy as heat with each flex cycle, friction between tread and road surface, internal air compression), how much pressure rises when a tyre heats up (typically 0.2–0.4 bar rise from cold to operating temperature), why you should never deflate a hot tyre to the cold pressure specification, the DOT temperature grade (A = highest heat resistance, B = intermediate, C = minimum acceptable), what operating temperatures are normal (60–80°C tread surface) vs dangerous (above 100–120°C internal carcass), and how overloading, under-inflation, and high speed combine to cause dangerous heat levels. Tyre inspection checklist Monthly tyre safety checklist for tread depth, pressure, sidewall damage, age, valves and uneven wear, with signs that need professional inspection. Are used tyres safe? A buyer's guide Used tyre safety guide: 9-point inspection checklist before buying second-hand tyres, risks of hidden damage (internal cord damage, prior repairs, DOT age), when used tyres are acceptable, what to avoid, and how to identify a safe vs unsafe used tyre.

More tools

Seasonal check

Planning a long summer drive?

Use the budget and running-cost tools before a trip, especially if the current tyres are worn or the replacement size changes diameter.

Estimate tyre budget
Last reviewed: 2026-06-28
What changed
  • Added pillar pages for the existing guide bundle taxonomy.