The law says 1.6mm, and then it says more
The instrument is the Road Traffic (Motor Vehicles, Construction and Use) Rules, rule 109, titled "Condition and maintenance of tyres." It is drafted as a prohibition. No person shall use, or cause or permit to be used, a vehicle on a road if any of a list of conditions applies.
Here is the tread limb, in full:
"the tread pattern (excluding any tie-bar) of the tyre does not have a depth of at least 1.6 millimetres throughout at least 75% of the breadth of the tread and round the entire outer circumference of the tyre." Road Traffic (Motor Vehicles, Construction and Use) Rules, rule 109(1)(f)
Read the qualifiers, because they are the part that gets left out of every summary.
- Throughout at least 75% of the breadth of the tread. Not the deepest groove. Not an average. Three quarters of the width of the tyre has to make the number.
- Round the entire outer circumference. Not where you happened to look. One worn band anywhere around the tyre is enough.
- Excluding any tie-bar. The small raised connectors between tread blocks do not count as tread for this purpose.
So a tyre that measures 2mm in the middle and 1.2mm across the outer shoulder is not a borderline tyre. It is an offence, because that worn band is inside the 75%. This is exactly the wear pattern a car with alignment out of specification produces, and it is exactly the one drivers miss, because the part of the tyre you can see from outside the car is the part that still looks fine.
The five other ways a tyre becomes illegal
Tread depth is one limb of rule 109(1). There are five more, and any one of them on its own makes the tyre an offence.
| Rule | What it prohibits |
|---|---|
| 109(1)(a) | A tyre unsuitable having regard to the use the vehicle is being put to, or to the types of tyres fitted to its other wheels |
| 109(1)(b) | A tyre not inflated so as to make it fit for the use to which the vehicle is being put |
| 109(1)(c) | A break in the fabric, or a cut over 25mm or 10% of the section width, whichever is greater, measured in any direction on the outside and deep enough to reach the body cords |
| 109(1)(d) | Any lump or bulge caused by separation or partial failure of its structure |
| 109(1)(e) | Any portion of the ply or cord structure exposed |
| 109(1)(f) | Tread below 1.6mm across 75% of the breadth, around the entire circumference |
Rule 109(4) separately prohibits using a recut tyre whose fabric has been cut or exposed by the recutting process. And rule 109(5) puts a standing duty on the owner. Tyres must at all times be maintained so as to "be fit for the use to which the vehicle or trailer is being put" and "be free from any defect which might in any way cause damage to the surface of the road or danger to persons on or in the vehicle or trailer or to other persons using the road."
Note that mismatched tyres and under-inflation are in the list. Two of the six limbs have nothing to do with how worn the tyre is.
What it costs you
We are going to be careful here, because a lot of what circulates on this is wrong.
Rule 109 does not itself prescribe a penalty. The chain runs to section 131 of the Road Traffic Act 1961, which makes it an offence to contravene the Act or the rules, and provides that where no special penalty is prescribed a person is liable on conviction to a fine not exceeding $1,000 or imprisonment for up to 3 months or both for a first offence, and $2,000 or 6 months or both for a second or subsequent offence.
Those are court imposed maximums on conviction. They are not the everyday composition fine, and you will see the $1,000 figure quoted online as though it is the standard penalty for worn tyres. It is not.
The Traffic Police schedule of composition fines does list one tyre offence directly: using tyres with ply or cord carcass exposed, which carries 3 demerit points and a composition fine of $150 for light vehicles, $200 for heavy vehicles.
For tread below 1.6mm specifically, we could not find a published composition fine figure on any official source, so we are not going to invent one. The honest position is that driving on sub-1.6mm tread is unambiguously an offence under rule 109(1)(f), and the amount you would actually be asked to pay is not something we can quote to you from an official page.
Separately, tyres are part of the LTA periodic inspection. LTA states the inspection covers "the operating condition of the tyres, suspension, shock absorber, wheel bearing, and the alignment of wheels." For private cars, that inspection falls due every two years between three and ten years old, and annually after ten.
1.6mm is the legal floor, not the safe one
The legal minimum tells you where enforcement starts. It does not tell you where grip goes.
An AutoBild wet braking test, reported by Continental, ran a VW Golf on 225/45 R17 tyres and measured stopping distance on a wet surface from 80 km/h:
| Tread depth | Wet stopping distance from 80 km/h |
|---|---|
| New tyre | 25.8 m |
| 3 mm | 31.0 m |
| 1.6 mm, the legal minimum | 36.2 m |
Ten and a half metres between a new tyre and a legal one, from a speed below Singapore's default 50 km/h limit by a comfortable margin. That is roughly two and a half car lengths of difference, arriving at the exact moment you need it least.
The crash data points the same way. NHTSA's study of tyre related factors in the pre-crash phase found that of tyres with tread between 0 and 2/32 of an inch, which is the 1.6mm region, about 26% were on vehicles that experienced tyre problems in the pre-crash phase, against 8% for tyres in the 3/32 to 4/32 range. That is US crash scene data from 2005 to 2007, not a Singapore figure, but the shape of it is not in question.
It matters here more than it does in a dry country. The Meteorological Service Singapore puts our long term mean annual rainfall at 2,113.3mm across an average of 171 rain days a year. Wet grip is not an edge case on this island. It is most of the year.
1.6mm is the point at which the tyre becomes an offence, not the point at which it becomes worse. Performance has been falling the whole way down. If you are near the line, you have already spent the margin.
How to check your own tread in about a minute
You do not need a workshop for the first pass.
Find the wear bars
Every tyre has treadwear indicators moulded into the bottom of the main grooves. NHTSA describes them as raised sections spaced intermittently in the tread grooves, and the rule is simple: when the indicator sits level with the surrounding tread, the tyre is done. In the United States, federal standard FMVSS 139 requires these indicators precisely so tread depth can be judged visually at the 1.6mm point.
Manufacturers mark where the indicators are with a symbol on the sidewall, and the symbol varies by brand. Michelin, for instance, uses the Michelin Man figure to mark the position on its tyres.
Check across the width, not just the middle
This is where rule 109's 75% qualifier does its work. Check the inner shoulder, the centre and the outer shoulder, and do it at three or four points around the tyre. Turn the steering to full lock to get a proper look at the inner edge of the front tyres, which is where alignment wear usually shows up first and where you will never see it otherwise.
Use a gauge if you want a number
A tread depth gauge costs a few dollars and removes the argument. The coin test you will see on American sites uses a US penny, which is not much use here.
If any point across 75% of the width is at or near 1.6mm anywhere around the tyre, it is a replacement, not a monitoring item.
Tyre age, and the numbers people get wrong
Two things get confused here constantly, so let us separate them.
How to read the date
The last four digits of the DOT Tire Identification Number on the sidewall give the week and year of manufacture. NHTSA's example: "3197" means the 31st week of 1997. A tyre stamped 2224 was built in the 22nd week of 2024.
What the age guidance actually is
This is where the folklore starts. There is no Singapore law setting a maximum tyre age. We looked. Rule 109 regulates tread depth and condition, not age, and no LTA or Statutes Online source imposes an expiry. Anyone telling you tyres are illegal here after five or six years is repeating something they read.
What does exist is manufacturer guidance, and it should be attributed as such. Michelin recommends that tyres be thoroughly inspected at least once a year by a trained professional after five years of service, and replaced ten years after the date of manufacture regardless of remaining tread or apparent condition. Bridgestone gives materially the same guidance: replace tyres more than ten years old, including the spare, and have them inspected after five years.
The US Tire Manufacturers Association adds the caveat that is usually left off, and it is the honest one:
"Accurately predicting the actual serviceable life of any specific tire based on simple calendar age alone is not possible." US Tire Manufacturers Association
So: the date code tells you the age, the age tells you when to start inspecting, and the inspection tells you whether the tyre is finished. Age is a prompt, not a verdict. That said, a set that has spent ten years on a car in this climate is worth a proper look regardless of how much tread is left, and a spare that has never touched the road is exactly the tyre nobody ever checks.
The number on the sidewall is not your number
This one is worth the thirty seconds it takes to fix, because it is genuinely common.
NHTSA states it plainly. The maximum permissible inflation pressure moulded into the sidewall is "the greatest amount of air pressure that should ever be put in the tire under normal driving conditions." It is not the recommended pressure. The vehicle manufacturer determines the correct pressure, not the tyre manufacturer.
Your number is on the tyre information placard, which sits on the driver's door edge or door post, sometimes on the glovebox door or inside the boot lid, and it is repeated in the owner's manual.
NHTSA advises checking pressure at least once a month, because tyres lose air naturally over time and can lose it suddenly after a pothole or a kerb strike. Its crash data found that when tyres are under-inflated by 25% or more, they are around three times as likely to be cited as a critical event in the pre-crash phase.
Check them cold, before the car has been driven far, since heat raises the reading.
Uneven wear is telling you about something else
A tyre wearing unevenly is a symptom. Replacing it without finding the cause buys you a new tyre that will wear out the same way.
Michelin's own guidance on reading wear patterns:
| Where it is worn | Usual cause |
|---|---|
| Centre of the tread | Over-inflation |
| Both outer edges | Under-inflation |
| One side only | Incorrect alignment or camber geometry, or suspension components in poor condition such as bushes or dampers |
That last row is the one that costs money if it is ignored, because the tyre is the cheapest thing in the chain. One sided wear on a car that has been over a few kerbs is usually geometry. One sided wear plus a knock over bumps is usually geometry and a worn component, and putting new tyres on without addressing it is throwing away the tyres you just bought.
What can be repaired and what cannot
There is an industry standard for this, and it is stricter than what a lot of people expect.
The US Tire Manufacturers Association sets out the limits:
- Repairs are limited to the tread area only.
- The puncture injury cannot be greater than 1/4 inch, about 6mm, in diameter.
- Repairs must not be made where damage extends into the shoulder or belt edge area.
- A plug alone is not an acceptable repair.
- Outside-in repairs, and repairs done with the tyre still on the wheel, must never be performed.
NHTSA says the same in fewer words. Punctures through the tread can be repaired if they are not too large. Punctures to the sidewall should not be repaired. And the tyre must be removed from the rim so it can be properly inspected before it is plugged and patched.
That last point is the one that matters most and is skipped most often. You cannot see the inside of a tyre without taking it off the wheel, and the inside is where you find out whether the tyre was driven on flat and has already started to break up internally.
Two conditions are never repairs. A lump or bulge in the sidewall means an internal structural failure, which Michelin states requires immediate replacement, and which rule 109(1)(d) makes an offence in its own right. Exposed ply or cord is the same, under 109(1)(e).
Alignment and balancing are not the same job
People use these interchangeably at the counter and they are different work, on different parts, fixing different symptoms. NHTSA's definitions are the cleanest:
Balancing counteracts heavy spots in the wheel and tyre assembly to avoid vibration or shaking when the tyre rotates. Symptom: a vibration that appears at a particular speed and fades above or below it, usually felt in the wheel or the seat.
Alignment adjusts the angles of the wheels relative to the vehicle's frame, which maximises tyre life and keeps the car from veering left or right on a straight, level road. Symptoms: the car drifts on a flat road, the steering wheel is not centred when the car is going straight, or one shoulder of a tyre is wearing faster than the other.
Fitting is the natural moment to do both, since the wheels are already off the car. It is also the cheapest time to catch geometry that would otherwise chew through the new set. We supply and fit tyres, and the fitting, balancing and alignment side is covered on our tyres page. If you would rather just have someone look, bring it in and we will measure the tread across the width and tell you what we find, whether or not you buy tyres from us.
Common questions
What is the legal tyre tread depth in Singapore?
1.6mm, but the full requirement matters. Rule 109(1)(f) of the Road Traffic (Motor Vehicles, Construction and Use) Rules requires a tread pattern depth of at least 1.6mm, excluding any tie-bar, throughout at least 75% of the breadth of the tread and round the entire outer circumference of the tyre. A tyre that makes the number in the centre but not across the shoulder does not comply.
Is there a legal limit on how old a tyre can be in Singapore?
No. Singapore law regulates tread depth and tyre condition, not calendar age. The five year and ten year figures you see quoted are manufacturer guidance, chiefly from Michelin and Bridgestone, who recommend annual professional inspection after five years of service and replacement at ten years from manufacture. The US Tire Manufacturers Association notes that serviceable life cannot be predicted from calendar age alone.
How much is the fine for worn tyres in Singapore?
We are not able to quote you a figure from an official source, and we would rather say so than repeat one. The Traffic Police schedule lists a composition fine for using tyres with ply or cord carcass exposed, at $150 for light vehicles with 3 demerit points, but no published composition fine for insufficient tread depth. Section 131 of the Road Traffic Act sets a maximum on conviction of a fine up to $1,000 or up to 3 months imprisonment for a first offence where no special penalty is prescribed, which is a court maximum rather than a standard penalty.
Can a nail in my tyre be repaired?
It depends where it is and how big it is. The industry standard limits repairs to the tread area, with an injury no larger than about 6mm in diameter, and rules out anything extending into the shoulder or belt edge. A plug on its own is not an acceptable repair, and the tyre has to come off the wheel so the inside can be inspected first. A sidewall puncture is not repairable.
My tyres are wearing on one edge only. Why?
Usually alignment or camber geometry that is out of specification, or suspension components in poor condition such as bushes or dampers, according to Michelin's guidance on wear patterns. Wear across both outer edges points instead to under-inflation, and wear concentrated in the centre points to over-inflation. Worth checking the cause before buying tyres, because the new set will wear the same way.
What pressure should my tyres be at?
The figure on the placard on your driver's door edge or door post, or in the owner's manual, not the number moulded into the tyre sidewall. NHTSA is explicit that the sidewall figure is the maximum permissible pressure rather than the recommended one, and that the vehicle manufacturer determines the correct pressure. Check monthly and check cold.
Key takeaways
- Rule 109(1)(f) requires at least 1.6mm across at least 75% of the tread breadth and round the entire circumference. The qualifiers are the part everyone leaves out.
- Five other conditions in rule 109 make a tyre an offence on their own, including under-inflation, mismatched tyres, bulges and exposed cords.
- There is no legal tyre age limit in Singapore. The five and ten year figures are manufacturer guidance and should be attributed as such.
- Wet stopping distance from 80 km/h in one published test rose from 25.8m on new tyres to 36.2m at the 1.6mm minimum.
- Check across the width and around the circumference, not just the deepest groove in the middle.
- Your pressure is on the door placard. The sidewall number is a maximum, not a recommendation.
- Repairs are tread area only, roughly 6mm maximum, never the sidewall, and never without taking the tyre off the wheel.
Sources
- Singapore Statutes Online, Attorney-General's ChambersRoad Traffic (Motor Vehicles, Construction and Use) Rules, rule 109The operative Singapore instrument on tyre condition, titled Condition and maintenance of tyres. Sets the 1.6mm minimum tread depth with its breadth and circumference qualifiers, and the other prohibited conditions.
- Singapore Statutes Online, Attorney-General's ChambersRoad Traffic Act 1961, section 131Provides the general offence for contravening the Act or the rules, and the maximum penalties on conviction where no special penalty is prescribed.
- Singapore Police Force, Traffic PolicePenalties for Traffic OffencesThe official schedule of composition fines and demerit points, which lists the offence of using tyres with ply or cord carcass exposed.
- Land Transport Authority (Singapore), OneMotoringVehicle InspectionThe official inspection frequency for private cars and the list of items covered, which includes the operating condition of the tyres, suspension, wheel bearings and wheel alignment.
- NHTSA, US Department of TransportationTire Safety: Everything Rides On ItA government consumer standard covering treadwear indicators, how to read the DOT date code, the distinction between placard pressure and sidewall maximum pressure, and the difference between balancing and alignment.
- NHTSA, US Department of TransportationTire-Related Factors in the Pre-Crash PhaseA crash data study quantifying how tyre problems in the pre-crash phase vary with tread depth and with under-inflation, using US crash scene data collected from 2005 to 2007.
- US Tire Manufacturers AssociationTire Repair BasicsThe industry repair standard, limiting repairs to the tread area with a maximum injury size of about 6mm, ruling out shoulder and sidewall repairs, and stating that a plug alone is not acceptable.
- Continental AGAquaplaning press release, reporting an AutoBild wet braking testReports measured wet stopping distances for a VW Golf on 225/45 R17 tyres at new, 3mm and 1.6mm tread depths. The test is AutoBild's and the release does not state water depth or surface.
- MichelinWhen do I need new tyres, and reading tyre wearManufacturer guidance recommending annual professional inspection after five years of service and replacement ten years from date of manufacture, plus guidance on interpreting wear patterns and sidewall bulges.
- Meteorological Service SingaporeClimate of SingaporeOfficial long term climate statistics, including a 1991 to 2020 mean annual rainfall of 2,113.3mm across an average of 171 rain days a year.
