Tyres are the only part of a car touching the road and are chosen more often on price than on any published measure.
Size markings
Width, aspect ratio, construction and rim diameter.
Which must match what the vehicle specifies.
Load and speed indices
The maximum weight and speed the tyre is rated for.
Which are legal requirements in many jurisdictions.
The labelling scheme
Fuel efficiency, wet grip and noise ratings.
Which allow direct comparison and are widely ignored.
Age
A four-digit code giving week and year of manufacture.
Which matters because rubber degrades regardless of tread depth.
Wet grip and stopping distance
The difference between rating bands is measurable in metres.
Which is the gap between stopping and not stopping in some situations.
This is the rating most worth paying for.
Rolling resistance
Energy lost as the tyre deforms.
Which affects fuel consumption and electric vehicle range measurably.
Seasonal tyres
Compounds designed for temperature ranges.
Which matters below roughly seven degrees regardless of whether there is snow.
Several countries mandate winter tyres seasonally.
Pressure
Underinflation increases wear, fuel use and blowout risk.
Which makes a monthly check the highest-value maintenance habit available.
Tread depth
Legal minimums are considerably below the point where wet performance falls away.
Load index in practice
A number corresponding to a maximum weight per tyre.
Which matters when carrying loads or towing.
Fitting a lower-rated tyre than specified is both unsafe and typically an insurance issue.
Speed rating
The maximum sustained speed the construction is designed for.
Which relates to heat build-up rather than only to velocity.
Mixing tyres
Different brands or patterns across an axle.
Which produces uneven grip and is prohibited in some jurisdictions.
Storage and age
Tyres degrade in ultraviolet light and over time.
Which is why many manufacturers advise replacement after a number of years regardless of use.
Buying decisions
Wet grip rating first, then rolling resistance, then noise, then price.
Which reverses the order most purchases actually follow.
Why tyres are the wrong place to save money
Every input from the driver reaches the road through four small contact patches.
Which makes tyres the component with the most direct effect on whether an emergency ends well.
Independent testing repeatedly shows large differences in wet stopping distance between budget and premium products.
Reading the sidewall
Size, load index, speed rating, construction and manufacture date.
Which is a two-minute check that most owners have never done.
Rotation and alignment
Even wear and correct geometry.
Which extends tyre life measurably.
Uneven wear patterns indicate alignment or suspension problems worth investigating.
Run-flat and standard
Different construction with different ride characteristics and replacement costs.
Which is worth knowing before a puncture rather than after.
The maintenance habit
Pressure monthly, tread and condition monthly, alignment when wear looks uneven.
All-season tyres
A compromise across temperature ranges.
Which suits mild climates and underperforms both specialists at the extremes.
For much of the temperate world they are a reasonable single-set choice.
Electric vehicle specific tyres
Constructions designed for higher mass and instant torque.
Which also address the additional noise from a quiet drivetrain.
They typically carry higher load ratings and lower rolling resistance.
Where to find test data
Motoring organisations and consumer groups publish independent comparative tests annually.
Which are free and are far more useful than manufacturer claims.
Fitting
Correct balancing, valve replacement and torque settings.
Which are part of the job and occasionally skipped.
Cost against consequence
The difference between budget and premium tyres across a set is real money.
Which is worth weighing against the difference in wet stopping distance measured in independent tests.
For most drivers the mid-range products represent the sensible balance.
The summary
Read the sidewall, prioritise wet grip, check pressures monthly, replace on age as well as tread, and use independent test data rather than marketing.
A general note on sources
Figures in this area come from manufacturer publications, regulator test programmes, insurance claims data and independent consumer testing, and those four sources do not always agree.
Where they conflict, the independent testing and the real-world claims data are usually the more reliable guide, because manufacturer figures are produced under conditions chosen by the manufacturer.
Anything specific to your own vehicle should be checked against its handbook and against a qualified technician familiar with the model, since specifications differ between markets and between production years in ways that general articles cannot capture.
One last practical point
Almost everything above becomes easier if you keep a simple record for your own vehicle: what was done, when, at what mileage and by whom.
It takes a folder and about five minutes a year, and it improves resale value, makes warranty claims straightforward and turns vague worries about condition into questions you can actually answer.
Owners who do this rarely get caught out, and owners who do not almost always wish they had started earlier.