Tyre tread is the patterned rubber that touches the road, and in India the legal minimum tread depth is 1.6 mm for cars and other four wheelers and 0.8 mm for two and three wheelers, as set by rule 94 in India's Central Motor Vehicles Rules. Below that, the tyre is not legally in sound condition.
The legal line is the last line, not the safe line. Grooves carry water away from under the tyre. As they get shallow, a wet road on a monsoon evening feels like ice. This guide explains what the tread does, how to measure it, what the small wear bars mean, and how to read uneven wear like a tyre technician. For more tyre basics, start at our tyre size home page.
At a glance
- Car legal minimum1.6 mm tread depth (Central Motor Vehicles Rules, rule 94)
- Two and three wheelers0.8 mm tread depth under the same rule
- Wear indicatorSmall raised bar in the main grooves; tread level with it means replace
- Safer to changeBefore the bars show, especially before the monsoon
- Wear on both edgesUsually running with too little air
- Wear on one edgeUsually wheel alignment out; get it checked
Tyre tread meaning: what the grooves do
The tread is the thick outer layer of rubber with grooves, blocks and thin cuts called sipes. Each part has a job:
- Main grooves running round the tyre channel rain sideways and backwards, away from where rubber meets road.
- Blocks and ribs give grip under braking and in corners.
- Sipes, the thin slits, add biting edges on wet and dusty roads.
- Shoulder blocks at the edges support the tyre in turns.
When the tread is deep, water has somewhere to go. When it is shallow, a thin film of water lifts the tyre off the road. That is aquaplaning, and it happens at lower speeds on a worn tyre than on a new one.
Tyre tread depth rules in India
| Vehicle | Minimum tread depth |
|---|---|
| Cars, SUVs, vans, trucks and buses | 1.6 mm |
| Motorcycles, scooters and three wheelers | 0.8 mm |
This is the non skid depth, measured in the main grooves. The full rule book is published by the road transport ministry. A tyre at the limit is still only just legal. Braking on a wet road gets much longer as tread wears down, so most tyre makers advise changing well before the limit. For a city car that sees monsoon flooding, plan the new set when the grooves look clearly shallow, not when the bars are flush.
Tyre wear indicator: the built-in check
Every car tyre has small raised bars across the bottom of the main grooves. These are the tyre tread wear indicators, often called TWI. On car tyres they stand at the legal 1.6 mm. Two wheeler tyres have similar bars set for their own limit.
To find them, look on the tyre shoulder for a small triangle, the letters TWI or a maker's symbol. Follow that line into the groove and you will see the bar. When the tread surface is level with the bar, the tyre has reached the legal minimum and must be replaced. If the bar is nearly flush anywhere round the tyre, plan to replace it soon. A tyre tread wear indicator close up looks like a small rubber bridge across the groove.
How to check tyre tread depth
- Park on flat ground and turn the steering to one side so you can see the front tread.
- Use a tyre tread depth gauge. Push the base flat on the tread and press the pin into a main groove.
- Read the depth in millimetres.
- Measure the inner groove, the centre and the outer groove.
- Repeat at three places round the tyre.
- Note the lowest reading. That is the number that counts.
A tread depth gauge is cheap and small enough for the glovebox. If you do not have one, look at the wear bars. Any tyre shop will also measure it for you. Check the spare too, since it can age while it sits unused. Our car tyre life guide covers age as well as depth.
Tyre wear patterns and what they mean
Uneven tyre wear is the tyre telling you something is wrong with the car or how it is kept. Here is a tyre wear pattern chart we use at the shop:
| What you see | Likely cause | Fix |
|---|---|---|
| Both edges worn, centre fine | Running with too little air | Fill to door sticker cold pressure, check weekly |
| Centre worn, edges fine | Too much air | Fill to the sticker figure, not the sidewall maximum |
| Tyre one side wear (inner or outer edge) | Camber or toe out of line | Wheel alignment |
| Feathered blocks, sharp on one side | Toe setting off | Wheel alignment |
| Cupped, scalloped patches | Unbalanced wheel or worn shock absorber | Balancing, suspension check |
| One flat patch | Hard braking with a locked wheel | Inspect tyre, replace if deep |
Inner edge wear is the one people miss, because you cannot see it while standing beside the car. Turn the wheel fully and look, or run your hand along the inside. Our wheel alignment guide and wheel balancing guide explain the fixes.
Types of tyre tread pattern
There are four common tyre tread pattern types:
- Symmetric: the same on both halves. Quiet, long lasting, can be fitted either way. Common on hatchbacks and sedans.
- Asymmetric: different inner and outer halves, marked inside and outside on the sidewall. Better wet grip and cornering.
- Directional: V shaped grooves that must roll one way, shown by an arrow. Good at clearing water. These cannot swap sides.
- Block or all terrain: big chunky blocks for mud and loose gravel, seen on off road SUVs and some bikes. Noisier on tar.
The pattern affects which tyre rotation moves are allowed. Directional and asymmetric tyres must be mounted correctly or they lose their wet grip.
Damage you can find while checking the tread
When you look at the tread, also look for:
- Nails, screws or stones stuck in the grooves.
- Cuts that show cord or fabric.
- Bulges, cracks or cuts on the sidewall.
- Uneven bumps that you can feel with your palm.
Exposed cords, a bubble or a slash all make the tyre unsafe. Crawl to the nearest shop at low speed and let the technician decide. Our tyre sidewall damage guide shows which damage can and cannot be repaired.
Making tyre tread last longer
- Hold every tyre at the maker's cold figure. This alone prevents most early wear.
- Get alignment checked after a hard pothole hit or if the steering is off centre.
- Rotate tyres at the interval in the owner's manual.
- Do not overload. A full family car with a roof carrier needs the loaded pressure from the manual. See our tyre pressure guide.
- Avoid hard launches, burnouts and locked wheel stops.
- On two wheelers, a pillion and luggage add load on the rear tyre, so it wears faster than the front.
Tyre wear and tear is normal. A tyre that wears out much faster than expected usually points to one of the causes above.
Questions owners ask
What is the legal minimum tyre tread depth in India?
Rule 94 sets it at 1.6 mm for cars and other motor vehicles, and 0.8 mm for two and three wheelers. It is measured in the main grooves.
What is a tyre wear indicator?
A low rubber bridge moulded across the main groove. When the tread wears down level with it, the tyre is at the legal minimum. A mark on the shoulder shows where the bars are.
Why is my tyre wearing on one side?
Wear on only the inner or outer edge usually means the wheel alignment is off. It can also come from worn suspension parts. Get an alignment check before fitting new tyres, or the new set will wear the same way.
How do I check tyre tread depth without a gauge?
Find the wear indicator bars in the grooves. If the tread is close to level with them, the tyre needs replacing. A tyre shop can measure it exactly in a few seconds.
Does worn tread matter if the tyre has no puncture?
Yes. Shallow grooves cannot clear water, so the tyre grips poorly in rain and takes longer to stop. Many accidents in the monsoon involve tyres that looked fine in dry weather.
Should I replace tyres in pairs?
Change the pair on one axle at the same visit so grip and handling stay even. If only two are new, ask the tyre shop which axle they should go on and follow the owner's manual.