Most modern cars no longer come with a traditional full-size spare wheel. Instead, you may find a temporary space-saver wheel, a tyre sealant and compressor kit, or run-flat tyres.
Each puncture solution has different speed, distance and safety restrictions. A space-saver or repaired tyre is only intended to help you reach a safe place or tyre centre; it should not be treated as a permanent replacement.
This guide explains the differences between space-saver spare wheels, tyre repair kits and run-flat tyres, including how far you can drive, the usual maximum speed and what UK drivers need to know about tyre safety and MOT rules.
Spare wheel alternatives: quick comparison
| Option | Usual maximum speed | Typical distance | Permanent solution? |
|---|---|---|---|
| Space-saver spare wheel | Usually 50mph | Usually up to 50 miles | No |
| Tyre sealant and inflator kit | Follow the kit and vehicle instructions | Only as far as necessary to reach help | No |
| Run-flat tyre | Commonly up to 50mph after pressure loss | Commonly up to 50 miles | No |
| Full-size spare wheel | Normal road limits if correctly matched and inflated | Replace or repair the damaged tyre promptly | Temporary replacement |
Important: The commonly quoted 50mph and 50-mile limits are general guidelines for many temporary spare wheels and run-flat tyres. Your vehicle manufacturer may specify a lower speed, shorter distance or additional restrictions.
Run-flat tyres explained
Why don’t many modern cars have spare wheels?
Full-size spare wheels were once standard equipment, but they are now much less common. Vehicle manufacturers have increasingly replaced them with lighter and more compact alternatives.
Common reasons include:
- Reducing the vehicle’s weight
- Improving fuel economy or electric driving range
- Creating more boot or battery space
- Reducing manufacturing costs
- Making room for additional vehicle technology
As a result, opening the boot after a puncture may reveal a narrow temporary wheel, a bottle of tyre sealant and a compressor, or no puncture equipment at all.
What are the main spare wheel alternatives?
Most cars without a full-size spare wheel use one of the following three solutions:
- Space-saver spare wheel: a narrow temporary wheel designed for emergency use.
- Tyre sealant and inflator kit: liquid sealant and a compressor that may temporarily seal a small puncture.
- Run-flat tyres: tyres with reinforced construction that can support the vehicle for a limited distance after losing pressure.
How do I know what puncture equipment my car has?
Before taking a long journey, check what equipment is supplied with your vehicle. Do not wait until you are stranded at the roadside.
- Lift the boot floor and look for a wheel, sealant bottle or compressor.
- Check storage compartments at the side of the boot.
- Read the puncture or tyre section of the vehicle handbook.
- Check the tyre sidewalls for run-flat markings such as RF, RFT, ROF, SSR or manufacturer-specific wording.
- Make sure any tyre repair sealant has not passed its expiry date.
- Check whether your breakdown cover includes puncture recovery.
Tyre markings differ between brands, so confirm the tyre type with the vehicle handbook, tyre manufacturer or a qualified tyre specialist if you are unsure.
Space-saver spare wheels
A space-saver is a narrow temporary wheel intended to help you reach a garage or another safe location. It is smaller and lighter than a conventional wheel and is not designed for normal daily driving or long journeys.
How fast can you drive on a space-saver wheel?
Most space-saver wheels have a maximum speed of 50mph or 80km/h. The limit is normally printed on the wheel or shown on a warning label.
This is an upper limit, not a target. Reduce your speed further in wet weather, on bends or where road conditions are poor. A space-saver provides less grip than a standard tyre and can affect braking, steering and cornering.
How far can you drive on a space-saver?
A commonly recommended maximum is around 50 miles, but this is not a universal rule. Some vehicles have different restrictions, so check the warning label and your vehicle handbook.
Only drive as far as necessary to have the original tyre repaired or replaced. Do not continue a holiday journey or daily commute on a temporary spare simply because you have not yet reached the maximum distance.
Can you use more than one space-saver wheel?
No. You should not fit more than one temporary space-saver wheel to a vehicle at the same time.
Some manufacturers also specify which axle the space-saver may be fitted to. For example, the handbook may instruct you to move an undamaged rear wheel to the front before fitting the temporary wheel to the rear. This can be necessary because of braking, steering, transmission or wheel-clearance requirements.
How does a space-saver affect handling?
A temporary spare is narrower than your normal tyres and may have a different tread pattern and pressure requirement. This can reduce grip and make the vehicle feel less stable.
- Increase the distance between you and the vehicle ahead.
- Brake, steer and accelerate gently.
- Take bends more slowly.
- Avoid heavy loads where possible.
- Do not tow a trailer unless the vehicle manufacturer permits it.
- Follow any restrictions shown on the wheel.
Check the spare wheel’s pressure
Space-saver wheels often require a much higher air pressure than standard tyres. Check the correct pressure in your handbook and include the spare wheel in your regular tyre-pressure checks.
A temporary wheel that has been stored for years may be underinflated, damaged or too old to use safely. Check its condition before long journeys.
Tyre sealant and inflator kits
Many cars now include an emergency tyre repair kit containing a bottle of liquid sealant and a small electric compressor. The kit may temporarily seal a small puncture in the main tread area and reinflate the tyre without removing the wheel.
How does a tyre sealant kit work?
The sealant is injected through the tyre valve while the compressor restores pressure. As the wheel rotates, the liquid spreads around the inside of the tyre and may seal a small hole.
The exact process differs between kits. Some have a separate sealant bottle and compressor, while others combine both parts into one unit. Always follow the supplied instructions rather than relying on general advice.
When should you not use tyre sealant?
An emergency repair kit will not work in every puncture situation. Do not use the kit unless the manufacturer’s instructions say it is suitable.
- The tyre’s sidewall is cut, split or punctured.
- The tyre has suffered a blowout or major tear.
- The wheel rim is cracked, bent or otherwise damaged.
- The tyre has come away from the wheel rim.
- The vehicle has been driven with the tyre flat for an extended period.
- The puncture is larger than the maximum stated by the kit manufacturer.
- More than one tyre is damaged.
- The sealant has expired.
TyreSafe advises that some temporary repair kits are unsuitable for punctures larger than 4mm or damage outside the main tread area. However, the precise limit depends on the repair kit, tyre and vehicle, so always follow the instructions provided with your car.
What should you do after using tyre sealant?
- Follow the kit’s instructions for inflation and initial driving.
- Drive only the specified short distance at the recommended speed.
- Stop somewhere safe and recheck the tyre pressure.
- Stop driving if the tyre is losing pressure or the TPMS warning remains illuminated.
- Take the vehicle to a qualified tyre professional as soon as possible.
- Tell the tyre fitter that sealant has been used.
Sealant is a temporary emergency measure, not a permanent puncture repair. A tyre professional must inspect the tyre to determine whether it can be repaired safely or needs to be replaced.
Does tyre sealant ruin the tyre or TPMS sensor?
It depends on the sealant, the tyre and the extent of the damage. Some water-based sealants can be cleaned out, while others may make repair more difficult. Sealant can also contaminate certain tyre-pressure monitoring components.
Always tell the tyre technician which product was used. They can inspect the tyre, wheel and TPMS sensor before deciding whether a repair is possible.
Check the expiry date
Emergency tyre sealant has a limited shelf life. Check the expiry date as part of your regular vehicle maintenance and replace the bottle when required. An expired kit may not seal or inflate the tyre successfully when you need it.
Run-flat tyres
Run-flat tyres have reinforced construction that can support the vehicle for a limited distance after a loss of air pressure. This can allow you to leave a dangerous location and reach a tyre centre without changing the wheel at the roadside.
How do run-flat tyres work?
Most run-flat tyres use reinforced sidewalls that temporarily support the vehicle when pressure is lost. Other designs may use an internal support system.
Although the tyre may continue to hold its shape, it has still suffered a loss of pressure. Continuing to drive generates heat and can damage the internal structure, which is why strict speed and distance limits apply.
How far can you drive on a run-flat tyre?
Many run-flat tyres allow travel for up to 50 miles at a maximum of 50mph after losing pressure. However, this varies between tyre and vehicle manufacturers and may be reduced by vehicle load, tyre damage, speed, temperature and road conditions.
Check the handbook and tyre manufacturer’s instructions. Travel only as far as necessary to reach a safe place or tyre specialist.
Why is TPMS essential with run-flat tyres?
A functioning Tyre Pressure Monitoring System is essential because a run-flat tyre may not visibly collapse when pressure is lost. Without a warning, the driver might continue using the tyre beyond its safe operating limit.
Under the current MOT inspection rules, a malfunctioning or obviously inoperative TPMS is a major defect on applicable M1 passenger vehicles first used on or after 1 January 2012.
Can a run-flat tyre be repaired?
Possibly, but only after a professional inspection and subject to the tyre manufacturer’s repair policy. A technician may be unable to establish how far or how fast the tyre was driven while deflated, and the reinforced structure may have suffered hidden damage.
Many damaged run-flat tyres therefore need to be replaced. Do not assume that a small visible nail automatically means the tyre can be repaired.
Can you mix run-flat and standard tyres?
TyreSafe strongly recommends that conventional tyres and self-supporting run-flat tyres are not mixed on the same vehicle. Changing tyre type can affect steering, suspension, ride quality and handling.
Before replacing run-flats with standard tyres, or fitting run-flats to a vehicle that did not originally have them, seek advice from the vehicle manufacturer and a qualified tyre specialist.
Advantages and disadvantages of run-flat tyres
| Advantages | Disadvantages |
|---|---|
| May let you reach safety after losing pressure | Often more expensive than standard tyres |
| No immediate roadside wheel change may be required | Ride can feel firmer on some vehicles |
| Can free up boot space | Repair may not be possible after driving deflated |
| Vehicle may remain more stable after some punctures | Replacement sizes may not be available at every tyre centre |
Do electric cars have spare wheels?
Many electric cars do not include a full-size spare wheel. Manufacturers may use the space for battery components, luggage storage or other equipment, while reducing weight can help improve vehicle efficiency and driving range.
An electric vehicle may instead have:
- A temporary tyre repair kit
- Run-flat tyres
- A self-sealing tyre
- Optional roadside assistance
- An optional space-saver wheel available separately
EVs can be heavier than equivalent petrol or diesel cars, so any replacement tyre must have the correct size, load rating and specification. Do not fit a generic spare wheel unless it is approved for the vehicle.
What should you do if you get a puncture on a motorway?
Do not attempt to change a wheel or use a tyre repair kit next to moving motorway traffic.
- Leave the motorway at the next exit or pull into a service area if possible.
- If you cannot leave, move left into an emergency area, lay-by or hard shoulder where available.
- Stop as far to the left as possible and switch on your hazard warning lights.
- If it is safe, leave the vehicle using the doors furthest from traffic.
- Wait behind a safety barrier and stay away from moving traffic.
- Contact a breakdown recovery provider.
- If you are stopped in a live lane and cannot safely leave the vehicle, keep your seat belt on, switch on your hazard lights and call 999.
National Highways specifically advises drivers not to attempt repairs on a motorway. Do not place a warning triangle on the motorway carriageway.
When should you call breakdown assistance?
Call for professional help when:
- You cannot stop somewhere safely.
- The puncture happened on a motorway or fast main road.
- The tyre has sidewall damage or has blown out.
- The wheel rim is damaged.
- Two or more tyres are affected.
- The sealant kit does not restore pressure.
- You do not have the correct wheel-changing equipment.
- You are unsure how to use the supplied equipment.
- You cannot loosen the wheel bolts safely.
- The vehicle is on soft, unstable or sloping ground.
Are temporary spare wheels legal in the UK?
Temporary spare wheels can be used legally for emergency purposes when they are suitable for the vehicle, in roadworthy condition and used in accordance with the manufacturer’s restrictions.
The commonly displayed 50mph restriction must be followed. Driving faster than the tyre or wheel’s permitted limit could make the vehicle unsafe and may lead to enforcement action.
UK tyre rules continue to apply when a temporary wheel is fitted. For most cars, the legal minimum tread depth is 1.6mm across the central three-quarters of the tyre’s breadth and around its entire circumference.
Drivers found using an illegal tyre can receive a fine of up to £2,500 and three penalty points per tyre. This penalty relates to tyres that are illegal or unroadworthy; correctly using a suitable temporary spare is not automatically an offence.
Will a car pass its MOT with a space-saver fitted?
An MOT tester inspects the tyres fitted to the vehicle’s road wheels at the time of the test. A temporary spare fitted as a road wheel could result in a failure if its size, type, condition, load rating or compatibility does not meet the MOT requirements for that vehicle and axle.
A spare wheel stored in the boot is not generally inspected as a road wheel, although the tester may advise you if they notice that it is defective.
To avoid problems, replace the temporary wheel with the correct standard wheel and tyre before presenting the vehicle for its MOT.
Which puncture solution is best?
| Option | Best suited to | Main limitation |
|---|---|---|
| Full-size spare | Drivers who want the closest replacement for the original wheel | Heavy and takes up boot space |
| Space-saver | Drivers who want a physical emergency wheel without carrying a full-size spare | Strict speed and distance restrictions |
| Sealant kit | Small punctures in the main tread area | Cannot repair blowouts, sidewall damage or many larger punctures |
| Run-flat tyre | Drivers who want to avoid stopping immediately after pressure loss | Higher cost and possible replacement after puncture |
There is no single best solution for every driver. The safest option is the one approved for your vehicle, maintained correctly and used within the manufacturer’s limits.
Tyre checks before a long journey
- Check the pressure of all four tyres when they are cold.
- Check the spare wheel’s pressure where one is supplied.
- Inspect tyres for cuts, cracks, bulges and embedded objects.
- Check tread depth across each tyre.
- Confirm that the tyre repair sealant is in date.
- Make sure the compressor and power cable are present.
- Check that the locking wheel-nut key is in the car.
- Make sure you know where the jack and wheel brace are stored.
- Investigate any TPMS warning before travelling.
- Confirm that your breakdown cover is active.
Spare wheel and puncture FAQs
Yes. A suitable and roadworthy space-saver can be used temporarily in an emergency, provided you follow the vehicle and wheel manufacturer’s restrictions. This commonly means driving no faster than 50mph and replacing it with the correct wheel as soon as possible.
Many space-saver wheels are limited to around 50 miles, but this is not universal. Check the label on the wheel and your vehicle handbook. Only drive as far as necessary to reach a safe place or tyre repair centre.
The usual maximum is 50mph or 80km/h, although some manufacturers specify a lower limit. Follow the restriction printed on the wheel and in the vehicle handbook.
A suitable space-saver is not automatically prohibited on a motorway, but its reduced speed and handling can increase risk. Leave the motorway at the next safe opportunity and arrange a proper repair or replacement. Never change a wheel next to live motorway traffic.
No. You should not use more than one temporary space-saver wheel on a vehicle at the same time.
You may be able to use sealant for a small puncture in the main tread area. It will not normally work on sidewall damage, a blowout, a damaged wheel rim or a tyre that has come away from the rim. Follow the instructions supplied with the kit.
No. Emergency sealant provides a temporary solution only. The tyre must be inspected by a qualified tyre professional as soon as possible.
Yes. Tyre sealant has a limited shelf life. Check the date printed on the bottle and replace it according to the vehicle or kit manufacturer’s instructions.
Many run-flat tyres permit up to 50 miles at no more than 50mph after pressure loss, but limits vary. Check the vehicle handbook and tyre manufacturer’s guidance and travel only as far as necessary.
Sometimes, but only after inspection and subject to the tyre manufacturer’s repair policy. If the tyre has been driven while deflated, hidden structural damage may mean it must be replaced.
It is strongly recommended that self-supporting run-flat tyres are not mixed with conventional tyres on the same vehicle. Consult the vehicle manufacturer and a qualified tyre specialist before changing tyre type.
A temporary spare fitted as a road wheel may cause an MOT failure if it does not meet the applicable requirements for tyre size, type, compatibility, condition or load rating. Replace it with the correct standard wheel and tyre before the test.
Official guidance and useful sources
- GOV.UK: Check your vehicle is safe to drive
- DVSA: MOT inspection rules for wheels, tyres and TPMS
- TyreSafe: Emergency puncture repair kits
- TyreSafe: Run-flat tyre guidance
- National Highways: What to do if you break down
Information checked and updated in July 2026. Manufacturer restrictions vary, so always consult your vehicle handbook and tyre instructions before using a temporary puncture solution.
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