DOT Code Decoder
Find the factory and age of almost any DOT-marked tyre, then what that age actually means for it. DOT codes appear on almost every tyre made for the global market (mandatory for US sale, and near-universal everywhere else): works whether your tyre was made in China, Japan, Germany, USA, Korea, Thailand, or anywhere else. And for 16 factories we've cracked the internal coding using our own 1,600+ tyre scan archive. For those plants, this decoder identifies the size and tread pattern from the code alone. No other DOT tool can do that.
🌐 Change language (13 available)
The decoder runs entirely in your browser. Your DOT code is never sent to us or to anyone else, and nothing you type here is stored on a server. The whole plant database is built into this page.
2 to 4 characters
e.g. 1V, 1HK, NDHF
up to 12 characters, spaces are fine
e.g. HFFC, or 1RYHK 2HJ. Leave blank if unsure
3 or 4 digits
e.g. 427 or 1622
⚠️ Confused by similar-looking letters? (I, O, Q, S)
Letter I is excluded from DOT codes. If you see I, it's likely the number 1.
Letter O is excluded. Read it as zero.
Letter Q is excluded. Read it as zero.
Letter S is valid in plant codes but easily confused with 5. Check carefully.
📍 Where to Find Your DOT Code
The DOT code is moulded into the sidewall of most tyres you will find in New Zealand, because so many are built for international markets. It is not a legal requirement here though. NZTA accepts tyres certified under several regimes, so an ECE E-marked tyre carrying no DOT code is entirely legal, and you read its date differently. Our certification marks guide covers those. Here is what to look for on a tyre that does carry a DOT code:
The full DOT code sits on the outboard sidewall near the rim. It always starts with the letters DOT, followed by a 2-4 character plant code, internal manufacturer codes for size and construction, and ends with a 4-digit date (week + year).
What Each Part Means
Most decoders stop at the plant and the date. For the factories whose internal coding we have cracked, every segment resolves. This is a tyre from our own inspection archive:
1HK plant: Shandong XinghongyuanB9 size: 205/55R16AC brand: an Anchee-branded production run at that plantU4 pattern: Titan ACF011326 date: week 13 of 2026Five segments, five answers, from the code alone. Paste 1HK B9ACU4 1326 into the decoder above to see it run.
Only the last 4 digits matter for age. Enter them above to calculate your tyre's exact age.
Check Outer Sidewall First
Asymmetric tyres: Full DOT code with date is always on the outboard (outside) sidewall, you can see it without removing the wheel.
Symmetric/Directional Tyres
May have date code on either side. The partial DOT (no date) often appears on both sides, but complete code with date is usually only on one.
Find Last 4 Digits
The date code is the last 4 digits (e.g., 2419 = week 24, 2019). If you only see 3 digits, see our decade guide below.
Worn or Damaged?
Fill in only the boxes you can read. The plant code alone tells you who made it; the date code alone tells you how old it is.
📸 Real DOT Codes From Our Workshop
Every photo below was taken during our tyre inspections. We have personally inspected 1,601 tyres across 131 brands from 26 countries, capturing over 41,000 original photographs. These are not stock images.
Same Factory, Different Brands
One of the most revealing things DOT codes show is that brands you think are competitors often come from the exact same factory. Here is the proof from our inspections.
Plant 1V. Bridgestone Thailand
Firestone is a Bridgestone sub-brand. Supercat and Dayton are budget labels made on the same production lines.
Plant 1AJ. Shandong New Continent, China
Two different brand names. One factory. Both start with 1AJ.
Plant BC. PT Hankook Tire Indonesia
Laufenn is Hankook's budget line. Both carry the BC plant code, proving they come from the same Indonesian factory.
Plant KE. Jinyu Tire, Shandong, China
Three brand names (Blacklion, Evergreen, Jinyu) all trace back to the same factory in Shandong province.
Where New Zealand's Tyres Actually Come From
Because we record the country of manufacture on every inspection, we can answer a question most people only guess at. This is not import data or brand marketing. It is where the tyres physically coming off cars in our workshop were built, read off the sidewall one at a time.
| Country | Share | Count | |
|---|---|---|---|
| China | 53.2% | 777 tyres | |
| Thailand | 13.2% | 193 tyres | |
| Japan | 9.1% | 133 tyres | |
| Indonesia | 6.2% | 91 tyres | |
| Korea | 5.4% | 79 tyres | |
| Taiwan | 3.1% | 45 tyres | |
| Vietnam | 2.0% | 29 tyres | |
| USA | 1.3% | 19 tyres | |
| New Zealand | 1.0% | 15 tyres | |
| Cambodia | 0.7% | 10 tyres |
Country recorded on 1,460 of 1,601 inspected tyres, so 91.2% coverage. 26 countries in total, 16 of which appear fewer than ten times each.
Worth saying clearly, because the number invites the wrong conclusion. "Made in China" is a fact about a factory address, not a verdict on a tyre. Every plant in that 53% is registered with NHTSA and building to the same DOT standard as anywhere else, and several of them also produce for the premium brands further up this page. What the country tells you is where to look next, not whether to worry. The plant code is the part that actually identifies who built it.
Counts as at August 2026, from our published inspection dataset.
DOT Codes From Around the World
Why the numbers on this page differ slightly. We have inspected 1,601 tyres. Of those, 1,585 had a date code we could read, which is the figure behind every age statistic here, and 1,460 had a country of manufacture recorded, which is the figure behind the origin table below. Different questions, different denominators. We quote each one against the number it was actually measured from.
Every tyre below came through our workshop and every photograph is ours. One example per country, 25 countries, sorted alphabetically. The first characters of the DOT code are what tell you where a tyre was actually built, whatever the badge on the sidewall says.
All photos taken by Taylor Houghton at our workshop. Factory data verified against NHTSA registrations. Based on 1,601 inspections across 131 brands from 26 countries. For more inspection data, see our Tread Gallery.
📅 Pre-2000 DOT Codes. Diamond Tells the Decade
Before 2000, DOT date codes were only 3 digits (e.g. 438). The third digit was the year, but on its own, "438" could mean 1948, 1958, 1968, 1978, or 1988. To resolve the 1990s, manufacturers added a small diamond/triangle symbol (▲) after the date. No diamond = pre-1990. Diamond = 1990s.
We have ten pre-2000 tyres in the inspection archive, every one photographed. Three of them carry a legible triangle, which is rarer than it sounds: the marker is shallow and tends to wear away before the digits do. The oldest is from 1980, which makes it 46 years old.
Not every factory put the date at the end. On tyres from plant V0, the New Zealand Dunlop plant of the South Pacific Tyres era, the date sits in the middle of the code, not at the end:
V0 073 x870 = week 7, 1983
V0 146 x816 = week 14, 1986
The proof is in the tail: the 1980 tyre and the 1983 tyre both end x870, three years apart, so that group cannot be a date. It is a mould code. Feed any of these into the decoder above and it now reads them correctly, because we taught it this plant specifically.
Real Examples From Our Workshop
Post-2000 Reference (For Comparison)
From 2000 onwards, all DOT codes use a clear 4-digit date (week + year). No more diamonds, no more guessing decades. This makes age determination unambiguous from 2000 to 2099.
⚠️ Quick Rule
3 digits = pre-2000 = replace immediately. Don't waste time decoding, any 3-digit code means the tyre is at least 25 years old and unsafe at any speed.
Decade Identification. Quick Reference
| Era | Format | Diamond? | Example | Verdict |
|---|---|---|---|---|
| 1970s-80s | 3 digits |
No |
438 = wk43, 1988 (or 1978) |
⛔ Replace |
| 1990s | 3 digits ▲ |
Yes (sometimes faded) |
247▲ = wk24, 199? |
⛔ Replace |
| 2000s | 4 digits |
N/A |
4402 = wk44, 2002 |
⛔ Replace (24+ yrs) |
| 2016+ | 4 digits |
N/A |
2425 = wk24, 2025 |
✓ Use the calculator |
📜 History of the DOT Code. With Examples
The DOT code exists because of tragedies. Here's how it came to be on every tyre, with examples of what codes looked like at each stage:
Week 24, year ending in 7 → Could be 1977, 1987, or even 1997!
Week 24, 199? The ▲ means 1990s, but is it 1993 or 1997?
Week 24, year 2000. Clear! Works until 2099.
Week 24, year 2025. This tyre is brand new!
Is DOT Required on Every Tyre?
| Tyre Type | DOT Required? | Max Recommended Age | Notes |
|---|---|---|---|
| 🚗 Passenger Car | ✓ Yes | 10 years | Standard recommendation worldwide |
| 🏍️ Motorcycle | ✓ Yes | 5-7 years | Higher stress, more critical, many riders replace at 5 years |
| 🚐 Caravan/Motorhome | ✓ Yes | 5-7 years | Often sits unused + UV exposure = ages faster than driven tyres |
| 🚛 Truck/18-Wheeler | ✓ Yes | 7-10 years | Retreading complicates age assessment. Check casing age. |
| 🚜 Agricultural/OTR | Usually | Varies | Enforcement varies. Many have DOT, some don't. |
| 🚲 Bicycle | ✗ No | N/A (no standard) | Premium brands sometimes include date codes. Rubber still degrades. |
| ✈️ Aircraft | ✗ Different System | Cycles, not years | FAA/CASA uses takeoff/landing cycles, not calendar age. |
| 🏎️ Racing Slicks | Sometimes | Varies by compound | Marked "NOT FOR HIGHWAY USE", competition rules apply instead. |
🔬 Why Tyres Age (The Science)
Tyres don't just wear out from driving, they degrade chemically over time, even sitting unused in a garage. Here's what happens:
🌡️ Oxidation
Rubber reacts with oxygen in the air. Over years, this breaks down the polymer chains that give rubber its flexibility. The tyre becomes brittle and hard.
☀️ UV Degradation
Sunlight accelerates aging significantly. Tyres stored outdoors or in sunny climates (Hawke's Bay, Nelson) age faster than those in shaded garages.
🌡️ Heat Cycling
Repeated heating and cooling (daily driving, seasonal changes) stresses the rubber compound, causing micro-cracks to form and propagate.
💨 Ozone Attack
Ozone in the atmosphere attacks rubber, causing characteristic "crazing", fine surface cracks visible on sidewalls of aged tyres.
What We Actually Measure On Aged Tyres
The chemistry above is well established. What is harder to find is real inspection data showing how fast it shows up on the road. Here is ours: every tyre through our workshop with a readable DOT date, sorted by how old it was on the day we inspected it, and whether it had visible cracking or perishing.
Read the middle of that table, not the ends. The rate roughly doubles between the 6 to 7 band and the 8 to 9 band, and it is that step, rather than the 10-year mark everyone quotes, that shows up most clearly in our data. It is also why we recommend 8 years for coastal vehicles rather than the generic 10.
Sample: 1,585 tyres with a readable manufacture date, inspected at our Te Puke workshop. Full method and dataset in our published workshop report. Each tyre counted once, however many defects it had. Sidewall-specific cracking rises over the same range, from 0.8% on tyres under 4 years to 18.6% on tyres over 16.
What Happens to Old Tyres?
- Reduced grip: Hardened rubber can't conform to road surface, less contact = less traction
- Longer braking: Peer-reviewed research confirms friction coefficient decreases with age, with measurably longer stopping distances on aged tyres (MDPI 2023, peer-reviewed study). Try our braking distance calculator to see what age does to your specific car.
- Sidewall weakness: Cracks allow air loss and can lead to sudden blowouts at speed
- Tread separation: Degraded bonds between rubber layers can cause catastrophic failure
- Unpredictable handling: Aged tyres respond inconsistently, especially in emergency manoeuvres
Does Weight or Use Matter?
Common myth: "My tyres have low mileage, so they're fine."
Reality: Time degrades rubber regardless of use. A spare tyre sitting in your boot for 10 years is just as old as one driven 100,000 km. UV exposure and oxidation are the primary aging factors, not mileage or weight.
🏎️ When Old Tyres Are Actually Wanted
Yes, some people prefer aged tyres! Here's the legitimate use case:
Drift & Track Practice
Racers and drifters often seek tyres that are 1-3 years old (not ancient, just "seasoned") because:
- Reduced grip = easier to initiate and control slides
- Predictable breakaway = more consistent lap times during practice
- Cost-effective = why destroy expensive fresh tyres learning?
- Hardened compound = lasts longer in abuse conditions
⚠️ Important: This is for controlled environments only (closed tracks, private property). Old tyres are never appropriate for road use or high-speed competition. Sidewall integrity still matters, check for cracks.
🏷️ Special Markings & OE Codes
Beyond the DOT code, many tyres have special markings indicating they were developed for specific vehicle manufacturers:
Original Equipment (OE) Markings
Pro tip: OE tyres shouldn't be mixed with non-OE versions of the same model. The compounds are different, which can affect handling balance.
The markings on this page are only part of what is moulded into a tyre. Two companion guides cover the rest:
- How to find your tyre size, if you are trying to work out what the numbers on the sidewall actually mean.
- Tyre certification marks guide, for E-marks, 3PMSF, M+S, UTQG and the country and compliance stamps, with close-up photos of each.
- Load rating guide and speed rating guide, for the two numbers and the letter that sit right after the size.
- UTQG grades explained, for the treadwear, traction and temperature numbers.
- Tread pattern guide, since the decoder above names the pattern for 16 factories without explaining what a pattern actually changes.
Run-Flat Indicators
Run-flat tyres have reinforced sidewalls allowing limited driving after puncture. Look for these codes:
Different manufacturers use different codes. All mean the same thing: self-supporting technology.
Rare & Unusual Markings
- Treadwear/Traction/Temperature (UTQG): US grading system. Treadwear 400 = 4x baseline. Traction AA/A/B/C. Temperature A/B/C.
- M+S or M/S: Mud and Snow, meets basic winter requirements. Common but doesn't guarantee true winter performance.
- 3PMSF (Three Peak Mountain Snowflake): ❄️ The mountain/snowflake symbol means tested for severe winter conditions. Worth knowing what it is and is not: the Prinx recall further up this page covers half a million tyres that carried this symbol without meeting the North American snow test. See also NZ mandatory performance labelling.
- XL or RF: Extra Load / Reinforced, higher load capacity, usually require higher inflation pressure.
- C or LT: Commercial / Light Truck, stronger construction for vans and utes.
- E-mark (E4, E11, etc.): European type approval. See our cert marks guide for closeups.
- Coloured dots: Red dot = high point for matching. Yellow dot = light spot for valve alignment.
🛑 How Tyre Age Affects Your Stopping Distance
Old tyres don't just look worn, they perform worse. As rubber ages, it hardens and loses grip, directly increasing your stopping distance. The relationship has been documented in peer-reviewed research and confirmed in tests by ADAC, Germany's automotive consumer testing organisation.
Normal braking
Annual inspection recommended
Manufacturers say replace
We recorded the manufacture date of 1,585 tyres that came through our workshop, then logged what condition each one was actually in. The average tyre we see is 5.7 years old (median 5.0), and 11.5% are already 10 years or older.
Cracking and perishing tracked almost exactly with age:
- Under 10 years old: 12.6% showed cracking or perishing.
- 10 years or older: 37.9%. Three times the rate.
- The jump happens at 8 years, not 10. Under 8 it is 10.4%, from 8 onwards it is 34.4%.
And the one that should change how you think about a WOF: of the 10-year-old-and-older tyres that still had legal tread depth, 41.5% were already cracking or perishing. Legal tread tells you nothing about whether the rubber has gone.
Based on 1,585 inspected tyres with a readable DOT date, counted as distinct tyres, August 2026. Method and full dataset: our published workshop report.
Our braking distance calculator models this with your specific tyre age, vehicle weight, and road conditions, validated to 0.71% accuracy against measured data.
🚦 Tyre Age Safety Guide
Rubber degrades over time regardless of tread depth or kilometres driven. Here's what different ages mean for your safety on NZ roads:
🚨 Tyre Recall History & Safety Database
Tyre recalls have caused some of the deadliest vehicle safety crises in history. Understanding this history helps you appreciate why checking your tyres matters.
⛔ The Firestone-Ford Crisis (2000). The Recall That Changed Everything
🔍 How It Was Discovered
The crisis unfolded over years, with warnings ignored until tragedy forced action:
- 1996: Personal injury lawyers first aware of accidents, but didn't report to NHTSA fearing it would compromise lawsuits
- 1996: Arizona state government told Firestone their treads were separating in high temperatures. Firestone sent engineers who blamed "customer misuse"
- 1999: Ford quietly replaced tyres in Saudi Arabia, Venezuela, Malaysia, Thailand, but didn't report to US regulators
- February 2000: KHOU-TV Houston investigative reporter Anna Werner broke the story, revealing the pattern of failures
- May 2, 2000: NHTSA finally opened formal investigation after the news coverage
- August 9, 2000: Firestone announced recall, but only after retailers (Sears, Discount Tire) had already stopped selling the tyres
📋 Detailed Timeline
❓ What Went Wrong
Root causes identified:
- Manufacturing defects: Poor adhesion between tread and steel belts at Decatur plant
- Design issues: Tyre ran hotter than Goodyear equivalents, small wedge angle
- Ford's pressure recommendation: 26 PSI (Firestone recommended 30 PSI) to mask Explorer's rollover tendency
- Heat + Speed: 80% of failures in hot states (FL, TX, CA, AZ) at highway speeds
- Tread separation: Belt edge lifted, causing rapid deflation and loss of control
Affected vehicles: Ford Explorer, Ranger, F-150, Mercury Mountaineer, Mazda Navajo
Financial consequences:
- Firestone: $800 million lawsuit settlements
- Ford: $590 million in settlements, 1,600+ cases settled
- Firestone paid Ford $240 million in 2005 to settle claims
- Individual fatality settlements: $4-8 million; paralysis cases: $12-16 million
Historical note: This wasn't Firestone's first major recall. In 1978, they recalled 14.5 million radial tyres at a cost of $100 million (about $387 million today), it nearly bankrupted the company and made them vulnerable to Bridgestone's 1988 acquisition.
Verified recalls worth knowing (2024-2025)
Every recall below carries an NHTSA campaign number and a link to the public record. Notice how often the DOT date is what decides whether a tyre is affected.
Why we only list these four. A recall is only useful if you can check it yourself. Every entry here has a campaign number you can look up and a public record you can read. Recalls that circulate without one are not on this page, however widely they get repeated.
Search by VIN, tyre brand, or DOT code
🏢 Tyre Brand Corporate Ownership
The tyre industry is dominated by 9 multinational corporations. The "different brand" you're considering may actually be the same company under a different label. Here's the verified corporate family tree (confirmed via each parent's official disclosures):
Plant U2: three famous names, one Sumitomo factory
The corporate tree above is compiled from each parent company's own disclosures. This one we can prove from tyres that came through our workshop. Three tyres, three different brand names on the sidewall, and the same plant code moulded into all three:
Dunlop and Falken are both Sumitomo Rubber Industries brands, so those two sharing a plant is ownership working exactly as the tree above describes. The Goodyear is the interesting one: Goodyear and Sumitomo ran a global alliance for years, and tyres built under it carry the same plant code as their Sumitomo stablemates.
Worth being precise about: this is not the same thing as the contract manufacturing covered further down the page. A shared plant can mean common ownership, a licensing deal, or simply rented capacity. The plant code proves where a tyre was built. It does not, on its own, tell you who owns the brand.
💡 Why this matters: Choosing between Hankook and Laufenn? Same parent company, same R&D, Laufenn just has a simpler design and costs less. Many "Chinese budget brands" trace back to NHTSA-registered facilities meeting the same DOT standards as premium offerings.
🤝 Shared Factories and OEM Partnerships
Same factory does not always mean same company. Two separate businesses can share a plant through contract manufacturing, technology licensing, joint ventures, or distribution agreements. The DOT plant code on a tyre tells you where it was physically made. It does not tell you who designed it, who owns the brand, or who's responsible if something goes wrong.
From our 1,600+ tyre inspections, we've documented 35 plants where multiple "different" brands are physically produced at the same address. Some are corporate sister brands (like Bridgestone and Firestone, both Bridgestone Corp). Others are completely independent companies sharing factory capacity.
Plant KE. Five brand names, one factory
These five sidewalls were photographed in our workshop. Different brands, different owners, different prices. Look at the first two characters of each DOT code.
Plant 022. A name you know and one you probably do not
Kumho is a household name. Zetum is not. Both come off the same line at Nanjing Kumho Tire in China, and the plant code says so.
Common patterns we see in the inspection data
- Plant 1RY (Shandong Hengfeng, China): produces Hifly, Goldway, Constancy. Three separate brand owners, one factory.
- Plant 1AJ (Shandong New Continent, China): produces Comforser, AMP, Unigrip, plus several private-label brands.
- Plant 1V (Bridgestone-affiliated): produces Bridgestone, Dayton, Firestone, plus contracted Supercat production for Australasia.
- Plant KE / 1KE (Evergreen/Jinyu, China): produces Jinyu, Blacklion, Evergreen, MOMO and Road X. Five brand names on five sidewalls, all photographed, all carrying the same plant code. The largest multi-brand plant we have documented.
- Plant 022 (Kumho, South Korea): produces Kumho and Zetum. A name everybody knows and one almost nobody does, off the same line. If you want one example of why the badge on the sidewall is not the whole story, this is it.
- Plant 17B (China): produces Arivo, Fronway, Roadmarch and Rockblade. Four separate brand owners, one factory.
What this means for buyers: if two brands share a plant, the manufacturing process and rubber compounds are likely similar but not necessarily identical. Each brand owner specifies their own compound formulation and quality criteria. A budget brand from a premium plant is not automatically a premium tyre at a budget price. It's a different product made on the same equipment.
Anchee (one of our two house brands) has been manufactured at its own long-standing plant since the 1990s, and since around 2012 has run a design and technology co-operation with Yokohama Rubber Co.: shared designs, compound know-how and materials. Anchee tyres are not made in Yokohama factories, and this is not a corporate ownership relationship. Anchee is its own brand. The partnership is why we trust the product enough to put our name on the importer line.
Predator (our other house brand) is engineered for the US off-road market with a separate manufacturing chain. We're transparent about both arrangements because we'd want any retailer recommending tyres to us to do the same.
📋 What Tyre Manufacturers Officially Say About Age
There are two different official positions on tyre age, depending on who you ask. Tyre manufacturers generally cite a 10-year maximum from the date of manufacture, with annual inspections from year 5. Some vehicle manufacturers (Ford, Mercedes-Benz, Toyota, Nissan) give a more conservative 6-year maximum in their owner's manuals. Both positions are real, both are sourced below.
Direct quotes from each tyre manufacturer (linked to source)
Vehicle manufacturers take a more conservative position
Several car manufacturers recommend replacing tyres at 6 years regardless of tread depth or apparent condition, citing concerns about heat exposure during driving accelerating rubber chemistry breakdown. The most commonly cited examples in published research are Ford, Mercedes-Benz, Toyota, and Nissan, all of whom include 6-year language in owner's manuals. References for this discrepancy include the Edmunds analysis of conflicting tyre age positions and the Safety Research and Strategies Inc. industry summary. The British Rubber Manufacturers Association (BRMA) advises that unused tyres over 6 years should not be put into service and all tyres should be replaced 10 years from manufacture.
💡 The honest summary: If you want to follow the manufacturer of your tyre, replace at 10 years maximum. If you want to follow the manufacturer of your car, replace at 6 years. Annual inspection from year 5 is the only point both groups agree on. NZ has no legal age limit, so the responsibility is on the driver.
🔬 ISO 17025 Accreditation
ISO/IEC 17025 is an accreditation for testing laboratories, not a marking on the tyre itself. When a tyre is validated through an ISO 17025-accredited lab, the facility doing the testing is independently audited for technical competence and validity of results.
Brands we sell whose testing runs through ISO 17025-accredited labs: Hankook, Laufenn, Anchee (via its Yokohama technology co-operation), Predator, Bridgestone (manufacturer testing). Reference: ISO 17025 official standard at ISO.org and background on Wikipedia.
🌏 NZ-Specific Environmental Factors
New Zealand has unique conditions that accelerate tyre aging beyond what manufacturers' generic 10-year recommendations assume:
🌊 Coastal Salt Air
98% of NZ's population lives within 60km of the coast. Salt accelerates rubber and steel belt corrosion. Tauranga, Auckland, Wellington, coastal aging happens noticeably faster.
🛣️ Road Surface Quality
NZ's chip seal roads are abrasive, they extract a tyre's expected lifespan faster than smooth asphalt. Provincial routes especially.
☀️ UV Index
NZ has one of the highest UV indices in the world due to the ozone hole and clear air. Hawke's Bay, Nelson, and Marlborough see 40% more UV damage than equivalent latitudes overseas.
🌡️ Temperature Cycling
Cold mornings (5°C) to hot afternoons (28°C) is normal in summer. This thermal cycling stresses rubber compounds, especially in temperate regions like Canterbury.
🇳🇿 Tyre Dispatch's NZ-Adjusted Age Recommendations
Based on 1,600+ inspections in NZ conditions, we recommend:
- Coastal vehicles: Replace at 8 years max (vs 10-year manufacturer rec)
- Inland vehicles: Manufacturer's 10-year rec is appropriate
- Caravans/motorhomes (any region): Replace at 6 years: they sit unused, exposed to UV
- Spare tyres: Replace at 5 years: even in the boot, they oxidise
- Hawke's Bay/Nelson/Marlborough: Subtract 1-2 years from manufacturer recs due to UV
🛣️ NZ's Most Dangerous Roads. Why Tyre Age Matters Here
If you regularly drive any of these routes, your tyre condition is the difference between getting home safely and becoming a statistic. Aged tyres compound the risks of already-dangerous roads.
🚨 Reality check: On these roads, a tyre with degraded grip from age can be the difference between recovering from a slip and crashing. Aged tyres can add 25% or more to wet stopping distance. At 100 km/h that can mean 10-15 extra metres. Use our braking distance calculator to see exactly what your tyres can do.
⛽ Tyre Age & Fuel Economy. The Hidden Cost
Aged tyres cost you money even before they fail. Here's how:
Rolling Resistance Basics
Roughly 4-7% of your fuel is consumed overcoming rolling resistance. Compound aging and wear shift it slightly in both directions. Tyre pressure matters far more than age here.
The Numbers
Honestly: age's direct fuel penalty is small and disputed. Hardened rubber can even lower rolling resistance slightly. Age's real cost is grip and safety, not economy. Don't keep an old tyre for fuel reasons.
Pressure Matters More
Underinflation by 7 PSI (common!) reduces fuel economy by 2-3%. Check your pressures monthly, it's free and it works.
Counter-Intuitive Finding
Worn-but-not-old tyres often have better fuel economy than new ones (less tread mass to flex). The trade-off is grip, which is exactly where old tyres fail you.
🔍 WOF & NZ Compliance. What Inspectors Actually Check
NZTA's Vehicle Inspection Requirements Manual (VIRM 4.2) defines what fails a Warrant of Fitness. Age is not a direct fail criterion, but the consequences of age usually are.
✓ Tread Depth
Minimum 1.5mm across the central ¾ of the tread, around the entire circumference. Below this = immediate fail. We recommend replacing at 3mm, wet braking distances increase exponentially below 3mm.
✓ Visible Damage
Cuts exposing cord, bulges, lumps, separation, or sidewall damage = fail. Inspectors look for cracking deeper than 2mm. Old tyres often fail here even with legal tread.
✓ Construction Mismatch
Mixing radial and cross-ply on the same axle = automatic fail. Different sizes within axle pair = fail. Speed rating below the vehicle's maximum speed = fail (rare but real).
✓ Load Rating
Tyres must meet or exceed the vehicle manufacturer's specified load index. Caravans, utes and light commercials get checked carefully, under-rated tyres fail.
The Inspector Doesn't Care About DOT Date
VIRM 4.2 contains no clause requiring inspectors to read or fail tyres on DOT date. They check what they can see and measure. This is exactly why DOT awareness matters, you have to advocate for your own safety because the regulatory minimum doesn't.
Manufacturer recommendations (6-10 years depending on brand) routinely exceed what NZ regulation enforces. Use the inspection as a baseline, not a ceiling.
Includes axle compatibility checker for NZ + Australia
🔓 Factories Whose Internal Coding We've Cracked
The middle section of a DOT code is officially "manufacturer use only", and no public database explains it. By scanning 1,600+ tyres and comparing repeat codes, we've reverse-engineered the internal size and pattern coding of 16 factories. Enter a full DOT code from any of these plants and the decoder reads the spec automatically:
| Plant | Factory / brands | What we can read |
|---|---|---|
| 1HK | Shandong Xinghongyuan (Anchee, HiLo, Annaite) | Size, rim digit, tread pattern, brand token |
| 1RY | Shandong Hengfeng (HiFly) | Size, pattern, "HF" brand mark (+ "VT" Vitora contract runs) |
| AD | Vitora plants | Size, "VT" brand mark, pattern initials (SL = Sportlife, CL = Citylife) |
| 1V | Bridgestone Thailand (Bridgestone, Firestone, Dayton, Supercat) | Size, pattern family |
| 2R | Bridgestone-group Indonesia (Supercat, Dayton) | Size, pattern |
| 1KE | Blackhawk, RoadX | Size, pattern (3-char codes) |
| LB | Farroad | Size, pattern |
| JU | ZC Rubber (Goodride, Westlake) | Size, pattern |
| 20 / UY | Maxxis Thailand / Taiwan | Size, pattern |
| BC / T7 | Hankook Indonesia / Korea (Hankook, Laufenn) | Size, pattern |
| KE | Jinyu group (Jinyu, Evergreen, Blacklion) | Size, pattern |
| FD | Yokohama Japan | Size, pattern family |
| 11P | Shandong Haohua (Royalblack) | Size, pattern |
| 1XU | Joyroad / Centara plant | Size, pattern |
This list grows as our inspection archive grows. Every scanned tyre either confirms a factory's coding or reveals a new piece of it. Recall and factory data verified August 2026.
❓ Frequently Asked Questions
Compiled from 1,200+ Trade Me messages, 350+ Google reviews, and direct workshop questions. Tap any question to expand.
📚 References & Sources
Everything claimed on this page is sourced from a verifiable third party or from our own first-party inspection data. Where we say "manufacturers recommend X", "X% of plants do Y", or "this code means Z", here's where the underlying evidence comes from.
Plant code database
- NHTSA Manufacturer Identification Database (publicly available, anyone can access this), vpic.nhtsa.dot.gov/mid. The 1,255 plant codes in our database start from this public source. NHTSA assigns and maintains these codes.
- Tire Business industry coverage of new DOT plant code issuance, 2018 NHTSA expansion to 3-character codes and Modern Tire Dealer industry analysis.
- FOB Business Directory: used to confirm specific plant locations like Maxxis International (Thailand) at codes 20/120 in Rayong Province.
- Taylor Houghton’s own photo-verified entries (200+ plants photo-verified from real tyres + 60+ multi-brand connections documented), every verified plant has an actual photograph in our 41,000+ workshop image library.
Tyre age and replacement recommendations
- Michelin official position, When to replace tyres.
- Yokohama Tire technical bulletin, Tire Life.
- Goodyear tyre age guidance, Goodyear Tire age basics.
- Bridgestone tyre age guidance (follows JATMA), How old tyres are too old.
- Pirelli tyre information and warnings, General tyre information.
- British Rubber Manufacturers Association recommendation: tyres over 6 years should not be put into service unused, all tyres replaced by 10 years (covered by Safety Research and Strategies industry summary).
- Vehicle manufacturer 6-year position (Ford, Mercedes-Benz, Toyota, Nissan): summarised by Edmunds analysis of conflicting tyre age positions.
Tyre aging chemistry and braking distance research
- Peer-reviewed research on tyre age and braking distance: "The Effect of Tire Age and Anti-Lock Braking System on the Coefficient of Friction and Braking Distance" (MDPI, 2023). Confirms friction coefficient decreases with age, with measurable correlation to longer stopping distances.
- ADAC research (Germany's automotive consumer organisation) on tyre aging effects, referenced via tyre aging science overview.
- NHTSA tyre aging research on temperature, storage, and aging factors, referenced via Edmunds analysis above.
- Our own UBPS braking simulator (validated to 0.71% accuracy against 60+ peer-reviewed sources), tyredispatch.co.nz/pages/braking-simulator.
Brand corporate ownership
- Each parent corporation's official disclosures: Bridgestone, Michelin, Continental, Goodyear, Sumitomo Rubber Industries, Hankook, Yokohama, Kumho, Pirelli. Specific examples: Bridgestone Australia confirms Supercat; Pirelli ChemChina shareholding history.
- List of tire companies reference, Wikipedia overview.
Regulatory framework
- 49 CFR Part 574: US federal regulation requiring DOT tyre identification numbers, the legal basis for the entire DOT code system. eCFR full text.
- NZ Land Transport (Tyres) regulations: NZ has no mandatory tyre age limit. WOF inspection criteria available from NZ Transport Agency Waka Kotahi.
- ISO/IEC 17025: international standard for testing laboratory accreditation. ISO official.
First-party data. Collected by Taylor Houghton
- Every inspection, measurement and photograph in this dataset was recorded personally by Taylor Houghton at the Tyre Dispatch workshop in Te Puke. The dataset is his own work, shared with Tyre Dispatch for use in these guides. If you are citing any figure from this page, cite it as: Houghton, T. (2026). Tyre Dispatch Workshop Inspection Dataset: 1,601 tyres, 41,000+ photographs. Te Puke, New Zealand.
- The full inspection dataset, method and per-tyre breakdown are published in our workshop report on the first 1,500 tyres, alongside the rest of our studies at the tyre research hub. The dataset itself is available for licensing, with a worked sample record here.
- Inspection counts, brand counts, country counts, photo counts, and "Gallery Verified" tags refer to Taylor Houghton’s inspection database, built from physical tyres handled at our workshop. Specific numbers stated on this page reflect counts as of August 2026: 1,601 tyres inspected, 41,000+ workshop photographs, 131 brands, 26 manufacturing countries, 200+ plants photo-verified, 60+ multi-brand factory connections documented.
- 5.0★ Google rating with 350+ verified reviews, visible at our Google Business Profile.
- 100% positive Trade Me feedback over 1,200+ transactions, visible at our Trade Me member profile.
Spot something we've claimed without an obvious source? Email email@tyredispatch.co.nz and we'll either find the citation or correct the claim. We update this page when we find errors.
🛠️ More Tools From Our Workshop
The DOT decoder is one of several free tools we've built for NZ drivers. All are based on the same workshop data, 1,600+ inspections, 41,000+ photos, 340,000+ vehicle fitments.
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Taylor Houghton
Director, Tyre Dispatch NZ · Traction Tyres Ltd
Sole NZ importer of Anchee and Predator tyres
Every photograph used to verify plant codes in this database was taken by Taylor personally at our workshop, across 1,600+ documented tyre inspections. No stock photos, no manufacturer images, no third-party sources. The plant database combines NHTSA's public registration data (publicly available to anyone) with our own photo-verified entries from the workshop floor, including the 60+ multi-brand factory connections we've personally documented from real tyres.
For ML teams and data buyers: every inspection is captured under a standardised protocol: up to 30+ views per tyre, calibrated tread photography with a physical reference block in frame, full sidewall and DOT documentation, defect close-ups, and structured metadata (per-groove measurements to 0.1mm, certifications, factory codes). If you're looking for tyre training data or want to licence the imagery and structured dataset commercially, contact Taylor directly at email@tyredispatch.co.nz.
Plant locations and factory–brand links are our best identification from 1,600+ physical tyre inspections plus public DOT plant-code registries, highly reliable but hand-compiled and not guaranteed to be error-free. If you spot anything wrong, email email@tyredispatch.co.nz and I'll fix it.
