The answer to this question is not as straight forward as you would like to think. Some tyre manufacturers say you can repair their run flat tyres, though there are guidlines & stipulations to adhere too, while others say you can't repair their tyres.
In this article we answer the following questions:
A repair to a RunFlat Tyre is the same as any tyre being repaired under BSAU159 G.
However in addition to the ‘normal' checks prior to repair, one should check the inside inner liner of the tyre (around the shoulder area). If there is any evidence of ‘creasing', ‘cracking' or deposits of rubber ‘crumb/dust', then a repair should not be carried out as these are signs that the tyre has been running at very low or zero pressure for an extended amount of time, therefore using the RunFlat sidewall component up to/very close to its distance/seed limit. (50 miles @ 50mph).
If there are none of these signs above, then it is generally ok to proceed with the repair.
Do not recommend the repair of any SSR (Self Supporting Run flat) this is because the hard inserts within the tyres sidewall can be damaged if the tyre has been ran on in an under inflated condition. This damage is not noticeable or visible and if a tyre is put back into service this could potentially be extremely dangerous. Although the tyre may have lost little pressure there will be no visible signs if this underinflation has caused the secondary damage mentioned and for that reason we cannot recommend them for repair.
Unless otherwise specified in the car owner's manual, a Goodyear or Dunlop self supporting tyre can be repaired by a qualified tyre professional after a thorough inspection and analysis of the tyre history. In case of doubt the tyre should not be repaired.
The professional repairing the tyre is in any case responsible for his repair work.
Goodyear or Dunlop does not support tyre repairs under following conditions:
• Repairs outside the tread area. • If the tyre sidewall area is damaged inside or outside of the tyre by a sharp object. This damage could have damaged the supporting insert and would thus substantially reduce runflat distance or otherwise reduce the tyre life. • If the tyre has been run at low or zero pressure (with warning alarm active) for a long distance or at too high speed. This can be identified through driver feedback, worn appearance of the external tyre shoulder or upper sidewall. • Innerliner damage or rough appearance. • Any damage that would make a standard tyre unrepairable.
Hankook tyres are repairable as long as the following conditions are met. An improper repair is unsafe and will void the limited warranty. Runflat tyres are not repairable in the following situations; - If the tyre was operated with inflation pressure less than 15 psi (100 kPa). - Abrasion or other damage is present on the exterior tread, sidewall or bead areas. - Abrasion, wrinkling, or separation is present on the tyre interior. - Any condition or damage is present that disqualifies the repair of a conventional tyre.
A Michelin ZP tyre may be repaired once and once only by a tyre professional following the normal rules and procedures for the inspection, preparation and repair of standard tyres. If the object in the tyre is at an angle to the tread of less than 30degs then the tyre is NOT repairable.
ZP tyres which carry sidewall markings indicating that repairs should not be carried out are still considered non-repairable.
Pirelli run flat tyres are not repairable. Pirelli said the reason why their tyres are not repairable is because you cannot see what damage has been done to the tyre construction when it has been driven flat for any distance.
How do I know if my run flat tyre is punctured?
indication you have that your run flat tyre could be punctured is when your
tyre pressure monitoring system (TPMS) light comes on.
Due to the tyres construction run flat tyres are not always easy to see if they are going flat. If your TPMS light has come on take your car to the nearest tyre centre or garage to have the tyre examined. Do not reset the TPMS until the tyre is at the correct pressure as this will give a false reading which could cause an accident due to the tyre pressure being low and the vehicles speed exceeding 50mph.
If I see a nail in the tyre do I leave it or remove it?
If you see a nail in a tyre it is
natural to want to remove it. It is, however, better to leave the nail in the
tyre & take it to a professional tyre repairer to have it inspected.
The reason for doing this is because with a tubeless tyre the only place the air can escape from is where the object has penetrated the tyre so by removing the nail the hole becomes larger and the air escapes quicker.
Even if you test the tyre with soapy water & you don't see bubbles appearing around the area of the object it doesn't mean the tyre hasn't been damaged. The object may have not punctured the tyre but it could have gone down to the steel bracing in the tyre which would allow water to go into the hole and cause the tyres bracing to corrode & subsequently fail.
Are there run flat repair kits?
Repairing a run flat tyre requires a very good knowledge of a tyres construction and knowledge of what can & can't be repaired. Even if there are kits to repair run flat tyres we would recommend you don't use one yourself unless you have been professionally trained to repair a vehicle tyre.
How long does a puncture repair last?
Any repair to a tyre has to last for the lifetime of the tyre.
Puncture repair cost?
The cost of repairing a run flat tyre is usually the same as a standard tyre as the process is exactly the same. Due to the nature of a run flat tyre being more difficult to remove & replace it could, however, increase the cost of the repair.
How far can you drive on a run flat tyre?
It is generally recommended you only drive on a flat run flat tyre for 50 miles at a maximum speed on 50mph
Can you put tyre weld in a run flat tyre?
Tyre weld or tyre sealants are only a
temporary measure to allow you to drive a vehicle far enough to have the tyre
repaired or replaced.
As run flat tyres are designed to be driven when flat there is no reason to use tyre sealants in a run flat tyre.
If you thought using a tyre sealant would help keep the air in the tyre, allowing you to drive further, would be wrong as prolonged running of an under the inflated tyre would cause damage to the tyre.
Add to this, all tyre sealants are designed for use as a temporary measure and would still go down when the wheel is stationary for prolonged periods.
How do I identify run flat tyres?
All tyre manufacturers have writing or a logo on the sidewall of their tyres to indicate the tyre is a run flat tyre.
Below are the markings on the sidewall of the tyre to show you it is a run flat tyre.
Bridgestone – RFT (Run Flat Technology) or DriveGuard
Continental – SSR (Self Supporting Runflat)
Dunlop – DSST (Dunlop Self Supporting Technology)
Goodyear – EMT (Extended Mobility Technology) or ROF (Run On Flat)
Hankook – HRS (Hankook Runflat System)
Michelin – ZP (Zero Pressure)
Pirelli – Run Flat