The Ultimate Guide to Tyre Sidewall Markings, OE Codes, Load Ratings & EV Tyres

Modern tyres contain far more information than most drivers realise. Every marking stamped into the tyre sidewall serves a purpose — from identifying load capacity and speed ratings through to manufacturer approvals for BMW, Porsche and Tesla vehicles.

Understanding tyre sidewall markings is essential when replacing tyres, upgrading wheels, diagnosing uneven wear or selecting the correct tyre for EVs, 4WDs and performance vehicles. Choosing the wrong specification can negatively affect handling, safety, braking performance, fuel economy and warranty compliance.

This comprehensive guide explains everything you need to know about tyre markings, OE manufacturer codes, runflat technology, EV tyres and acoustic tyre systems.

Tyre Sidewall Markings 

Every tyre sidewall contains a series of letters, numbers and symbols that identify its size, construction and performance capabilities.

Example:

275/45R20 110Y

Here is what each section means:

Additional sidewall information may include:

• Manufacturing date
• Maximum inflation pressure
• Treadwear rating
• Wet grip rating
• OE manufacturer approvals
• Runflat symbols
• EV-specific markings
• Acoustic foam indicators

These markings help ensure the tyre is compatible with the vehicle’s suspension geometry, weight distribution and intended driving conditions.

Tyre Load Ratings

A tyre load rating, also called a load index, identifies the maximum weight a tyre can safely support when inflated correctly.

For example:

• 110 Load Index = 1060kg per tyre
• 121 Load Index = 1450kg per tyre

Load ratings are especially important for:

• 4WDs
• Touring vehicles
• Utes carrying constant loads
• Vehicles towing caravans or trailers
• Electric vehicles due to heavier battery weight

Using tyres with an insufficient load rating can lead to:

• Excessive heat build-up
• Premature tyre failure
• Reduced handling stability
• Insurance or roadworthy compliance issues

Always meet or exceed the manufacturer’s recommended load index.

Tyre Speed Ratings

The speed rating indicates the maximum speed capability of the tyre under load.

Higher speed-rated tyres often feature:

• Stronger internal construction
• Enhanced heat resistance
• Improved cornering stability
• Better high-speed braking performance

Performance SUVs, European vehicles and EVs commonly use W or Y-rated tyres due to their increased weight and torque output.

OE Manufacturer Codes

OE stands for Original Equipment.

Many premium vehicle manufacturers work directly with tyre manufacturers to create tyres specifically tuned for their vehicles. These tyres receive unique OE approval markings on the sidewall.

OE-specific tyres may include:

• Modified tread compounds
• Reinforced sidewalls
• Reduced road noise
• Vehicle-specific handling characteristics
• EV load optimisation
• Custom wet-weather performance tuning

Brands like BMW, Porsche, Tesla, Mercedes-Benz and Audi all use manufacturer-approved tyre specifications.

Premium manufacturers such as Pirelli Tyres produce dedicated OE tyre versions engineered specifically for individual vehicle platforms.

BMW Star Markings

BMW-approved tyres feature a small star symbol (*) on the tyre sidewall.

These star-marked tyres are developed alongside BMW engineers to suit:

• BMW suspension tuning
• Steering feel
• Weight distribution
• Stability control calibration
• Runflat compatibility

BMW recommends replacing tyres with matching star-marked versions to maintain factory handling and performance characteristics.

Porsche N Ratings

Porsche-approved tyres use an N marking system:

• N0
• N1
• N2
• N3

The number represents revised generations of approved tyre development.

Porsche N-rated tyres undergo extensive testing for:

• High-speed stability
• Braking performance
• Wet grip
• Steering precision
• Track capability

Using non-N-rated tyres on certain Porsche models may affect warranty coverage and vehicle dynamics.

Tesla Tyre Markings

Tesla vehicles often use tyres with the following identifiers:

• T0
• T1
• TO
• Elect marking
• Acoustic technology symbols

Tesla-specific tyres are engineered to manage:

• Instant EV torque
• Increased vehicle weight
• Reduced rolling resistance
• Cabin noise reduction
• Battery efficiency

Many Tesla tyres also incorporate acoustic foam technology to minimise road noise due to the absence of engine sound masking.

Runflat Tyres

Runflat tyres are designed to support the vehicle temporarily after a puncture or complete pressure loss.

Common runflat markings include:

• RFT
• SSR
• ROF
• ZP

Benefits of runflat tyres:

• Ability to continue driving after puncture
• Improved safety during sudden pressure loss
• No immediate roadside tyre change required

However, runflat tyres may also:

• Produce a firmer ride
• Cost more than standard tyres
• Require specialised repair assessment

Many BMW and European vehicles are factory-equipped with runflat systems.

EV Tyres

Electric vehicles place unique demands on tyres due to:

• Higher overall vehicle weight
• Instant torque delivery
• Increased rolling resistance sensitivity
• Reduced cabin noise

EV-specific tyres are engineered with:

• Stronger load construction
• Low rolling resistance compounds
• Noise-reducing tread designs
• Reinforced sidewalls
• Enhanced durability

Without EV-specific construction, tyres may wear significantly faster on electric vehicles.

Modern EV tyres help improve:

• Driving range
• Cabin comfort
• Wet-weather traction
• Regenerative braking stability

Acoustic Tyres

Acoustic tyres contain internal polyurethane foam bonded to the inner tyre cavity.

This technology reduces cabin noise caused by tyre resonance and road vibration.

Common acoustic tyre markings include:

• PNCS (Pirelli Noise Cancelling System)
• ContiSilent
• Acoustic
• SilentDrive

Acoustic tyres are especially common on:

• Luxury vehicles
• EVs
• Performance SUVs

Benefits include:

• Reduced road noise
• Improved driving comfort
• Lower cabin vibration
• Enhanced highway refinement

Uneven Tyre Wear

Uneven tyre wear often indicates underlying mechanical or inflation issues.

Common wear patterns include:

Inner Edge Wear

Usually caused by:

• Incorrect wheel alignment
• Excessive negative camber
• Suspension geometry changes after lifting

Outer Edge Wear

Often linked to:

• Underinflation
• Aggressive cornering
• Suspension roll

Centre Wear

Typically caused by:

• Overinflation

Cupping or Scalloping

May indicate:

• Worn shock absorbers
• Suspension imbalance
• Wheel imbalance

Regular wheel alignments, tyre rotations and suspension inspections help maximise tyre life and maintain safe handling.

Tyre Symbols & Sidewall Codes

Additional sidewall markings may include:

Tyres also display a manufacturing date code.

Example:

DOT XXXX 2425

This means the tyre was manufactured in:

• Week 24
• Year 2025

Tyre age matters because rubber compounds naturally degrade over time, even if tread depth remains acceptable.

Tyre sidewall markings provide critical information that directly affects vehicle safety, handling, ride comfort and performance. Whether you drive a 4WD, EV, luxury SUV or performance vehicle, understanding tyre load ratings, speed ratings, OE markings and specialised technologies helps ensure you select the correct tyre for your application.

From BMW star-marked tyres and Porsche N ratings through to Tesla acoustic EV tyres, modern tyre engineering has become highly vehicle-specific. Choosing the right tyre is no longer just about size — it is about matching the tyre’s construction and performance characteristics to the demands of the vehicle itself.

For drivers upgrading suspension, fitting larger wheels or building touring vehicles, understanding tyre sidewall information is essential for maintaining reliability, safety and long-term performance.