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Puncture: repair or replace a flat tyre

Sure, there is nothing as unpleasant for a driver than to find a flat tyre when they are about to drive off for a holiday, or even to have to pull off because of a puncture when driving flat-out on the motorways. But we should consider ourselves lucky compared to what people had to face in the 1950's. From then on, tyre tech has evolved so much that even entry level, standard tyres guarantee some level of resistance, let alone Tubeless or Runflats.

On this page, you can find out about:

Different puncture types.

Foreign body :The introduction of debris into the tread may will to a pressure loss of varying speed.

Incorrect pressure : Contrary to widespread ideas about tyres, underinflation is more risky than overinflation.That is because driving with under inflated tyres may inflict heavy damage on the tyre internal structure and increase rolling resistance. The risks of puncture is then increased and hard to diagnose.

How should I deal with a puncture?.

This is not an article about wheel replacement,Instead, we will try and give you the most useful info about the behaviour you should adopt..

Often, it is quite tempting to pull over as soon as you feel the first vibrations in the steering wheel, or when the steering becomes hard to control. What you might not know however, is that it would be safer to slightly accelerate in order to regain traction BEFORE you pull over.

Please beware: Driving on a flat tyre will ruin it in no time.

The use of puncture spray and/or spare wheel

Puncture spray

You may repair a Tubeless tyre temporarily using puncture spray if the damage is limited. The spray contains foam that will fill in the breach left by the debris..

Before anything else, you will need to spot the exact location of the puncture and remove any debris from the tread before you inject the content of the spray through the valve. Moderate driving speed after such repair is strongly recommended..

The spare wheel

In case the previous attempts have failed, you can resort to the spare wheel. If you want to be able to rely on your spare wheel, please make sure you check pressure regularly. .

In order to change a wheel, the first step consists in setting the brake and a gear to ensure the car won't move during the operation..

Start by loosening the bolts, lift the car with your jack and finish loosening the bolts to remove wheel.Place the spare wheel and start tightenining the bolts. Once the car is back on the ground, apply torque to the bolts to make sure the wheel is secured..

The spare wheel should not be considered like a normal wheel, and speed limits of 50miles/h should be respected. Never use a spare wheel on a permanent basis.

How to make sure a tyre is properly repaired?

Unless you are equipped with a tubeless tyre repair kit and you actually know how to use it, a visit to the repair shop seems to be the best option.

Some garages with no second thoughts might try to service your car, charging insane amounts of money,so beware!

This is what you should mind when it comes to tyre repair :

  • The damage caused by the object is assessed and under control
  • The innerlinner seal is repaired and airtight
  • The path the object used to get into the tyre is filled..

In order to evaluate the extent of the damage, it's is important to take the tyre off the wheel. Indeed, damage that seem repairable from outside may reveal to be non repairable when viewed from the inside..

Only using a plug might not be enough because it doesn't guarantee air won't keep leaking off the tyre. Finally, only using a patch is not enough as air moisture might still be able to reach the steel belts and damage them..

Once punctured, the innerliner must be cleaned, buffed, cemented, patched and coated to assure its ability to retain air has been restored..

The Runflat technology

These are tyres originally designed by Michelin (PAX) that are now present in all the main brands.. They feature reinforced rubber on the sidewalls, making them so rigid as to bear the weight of the vehicle, even in case of a puncture.. Even in case of a puncture, driving remains possible at a limited speed of 50miles/h. The Runflat tyres are indicated by white markings on the sidewall that depend on the manufacturers : ZP, SSR, ROF, EMT, RFT et BSR.

What errors to avoid when changing tyres

Can you replace Runflats by standard tyres ?

Definitiely, yes. However, please mind the following elements:

  • You must be equipped with a puncture kit and a spare wheel.
  • If your vehicle has been customized for driving on Runflats, using standard tyres might influence balancing negatively (read our article on unsprung masses for more details).

Can you replace standard tyres by runflats? ?

No, this is not possible because:

  • You have to be equipped with a pressure monitoring system (tpms) because of the self-sustaining sidewalls.
  • Runflats being heavier than standard tyres, they would affect the car's performance negatively..
  • Runflats should always be mounted on runflat wheels (on the right in the picture) with deeper angles to prevent the tyre from getting loose in case of a puncture..

Can I only replace the tyre with the puncture ?

On the same axle, you are legally compelled to have two tyres of similar wear and size, as well as tread pattern. In practice, that means that most of the time, you'll have to replace two tyres at the same time, even if only one is damaged..

When it comes to four wheel drives, it is preferable to replace all four wheels in order to prevent mechanical problems related to the antiskid system. . You may replace only one tyre if the remaining three tyres are , for all practical purposes, new.