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Puncture repairs to Run-Flat tyres
Reading: Puncture repairs to Run-Flat tyres
(Minor tyre repair to the BSAU 159 standard)
The position regarding puncture repairs to run-flat tyres is muddled. Originally most tyre manufacturers stated that their run-flat tyres should not be repaired under any circumstances. The reasoning behind this was that when a run-flat tyre is punctured the weight of the car is supported by the specially strengthened sidewalls. These are designed to carry the weight of the car and withstand speeds of up to 50 mph for a limited distance. However the exact nature of the damage, the speed at which it occurred and the distance subsequently driven are all factors that would effect the internal integrity of the tyre and it’s subsequent safe use of the tyre following a repair. As these “known unknowns” represent a serious safety issue the policy was that repairs were prohibited.
Michelin were the first manufacturer to modify this directive and now most other leading tyre state that their run-flat tyres can be repaired as long as there is no visible internal damage and no more than one repair per tyre is executed. As some Michelin run-flat tyres carry a sidewall notice prohibiting repairs the company state that this should still be complied with. Consequently most run-flat tyres can be repaired, to BSAU 159 specification as long as the sidewall markings do not contradict that advice. Michelin have published their run-flat tyres directive in a question and answer form. This is as follows:-
Why may Michelin ZP be repaired?
We have examined many ZP tyres after they have been punctured in order to establish a position on reparability. This statement is the result of considerable study to ensure that ZP tyres may be repaired safely.
New Michelin ZP tyre lines, such as PRIMACY HP ZP, are repairable once and once only following the same rules as standard car tyres such as Michelin PRIMACY HP. Michelin have prepared this statement which dealers should follow when dealing with the repair of ZP tyres. However, it is the dealer’s responsibility to decide whether an individual tyre is repairable or not.
What about existing ZP versions of tyre lines such as Pilot Primacy, Pilot Sport PS2, PILOT Alpin PA2?
Existing ZP tyres from tyre lines such as PILOT SPORT PS2 / PILOT PRIMACY / PILOT ALPIN PA2 are still considered NON-REPAIRABLE when, “Do not reuse or repair the tires after a low or zero pressure operation” or equivalent is written on the sidewall.
Pirelli on the other hand adopt a completely different approach and state that their run-flat tyres should not be repaired under any circumstances. Their directive is as follows:-
After low pressure warning is shown, the condition of the remaining tyres and the TPMS should be immediately checked by a specialised dealer. (Such as etyres)
A tyre should always be changed and not repaired after a loss of pressure, as it is not always possible to establish the time and conditions under which the tyre has been used with insufficient inflation pressure.
Damaged Run-Flat tyres, or Run Flat tyres that have experienced a loss of pressure should be immediately replaced with another Run-Flat tyre of identical size and service description (Load Index and Speed Code). Pirelli recommends that a tyre of a different type, or which contains a different load index or speed code, should never be mounted on the same vehicle.
After a loss of pressure, the rims should be inspected to ensure they haven’t been damaged. Damaged or deformed rims should always be replaced prior to mounting a new Run-Flat tyre.
etyres’ position on the reparability of run-flat tyres is that we will comply with the official policy of the manufacturer concerned. We will therefore carry out minor repairs to Michelin but not to other brands. If the position of other manufacturers changes will comply with whatever recommendations they may make.
Tags: michelin zp, puncture repairs, run-on-flat
This entry was posted on Friday, October 20th, 2006 at 1:51 pm and is filed under Michelin. You can follow any responses to this entry through the RSS 2.0 feed.
Update: Feb 2010. Since we wrote this report, it appears that things have improved with regard to run flat tyre repairs. Both Bridgestone and Michelin have stated that their RFT's can be repaired if the tyre is not damaged, just like a standard tyre.
The problem you have now is finding a place that is equipped to do the job. Here are links for both Bridgestone and Michelin, where they make a statement about RFT repairs.
Run Flat Tyre Repair - Safe?
If you buy a brand new BMW or Audi the salesman might have used the Run Flat Tyres (RFT) as a selling point. It has to be said that there are many benefits in running a car on run flat tyres. What they won't tell you is that if you have a small puncture, instead of a £15 or £20 repair bill you could be looking at a bill for £200 to buy a new tyre. The fact is that in the UK at least tyre fitters will not repair a run flat tyre. What makes things worse is if you suffered a puncture with a conventional tyre that could not be repaired the bill could be just half that at £100. So you're paying almost twice as much for the RFT and if you happen to run over the tiniest of nails you'll need to buy a whole new tyre.
Why can't Run Flat Tyres be repaired?
The reason behind this, given by the tyre manufacturers is to do with the thickness of the RFT sidewalls. With a conventional tyre when a technician carries out a puncture repair, one of the first things they will do is to check the tyre for damage, especially damage to the sidewall. This damage is easy to spot as it shows up as creases in the sidewall when the tyre is deflated. With the RFT it is impossible to say for sure if the sidewall has been damaged as the sidewall is so much thicker. Therefore they have no option but to replace the tyre.
What about a slow puncture?
The damage to the sidewall could occur if you continued to drive on the flat tyre for more than the recommended distance (approx. 100 miles) or over the maximum speed of 50 mph. However what if you'd not driven the tyre at zero pressure, what if the car had been sat on your driveway for a few days and happened to deflate as a result of a slow puncture. Surely this tyre would be repairable? Despite there being no damage to the sidewall you won't find anyone that will repair this RFT tyre, the fact is they only have your word that the tyre had not been driven on at zero pressure and they could run into liability problems if the repaired tyre failed.
Verdict
So are Run Flat Tyres safe to repair? In theory yes they are, as long as they are not driven on. However as cars running on RFT don't have a spare wheel, unless the tyre went down whilst the vehicle was parked, this would be impractical. In practice you won't find anyone that will repair a RFT because both legally and financially it doesn't make sense for tyre centers to repair Run Flat Tyres.
So what about the future, will tyre manufacturers create a machine to check Run Flat Tyres for damage before repair? I wouldn't hold your breath on that one! The best thing you can do to save some money at least, is to avoid buying from your local tyre center and buy cheap tyres online.
Read this article to see the pros and cons of changing run flat tyres to conventional tyres
Article Keywords: Run Flat Tyre Repair
Update: Feb 2010. Since we wrote this report, it appears that things have improved with regard to run flat tyre repairs. Both Bridgestone and Michelin have stated that their RFT's can be repaired if the tyre is not damaged, just like a standard tyre.
The problem you have now is finding a place that is equipped to do the job. Here are links for both Bridgestone and Michelin, where they make a statement about RFT repairs.
Run Flat Tyre Repair - Safe?
If you buy a brand new BMW or Audi the salesman might have used the Run Flat Tyres (RFT) as a selling point. It has to be said that there are many benefits in running a car on run flat tyres. What they won't tell you is that if you have a small puncture, instead of a £15 or £20 repair bill you could be looking at a bill for £200 to buy a new tyre. The fact is that in the UK at least tyre fitters will not repair a run flat tyre. What makes things worse is if you suffered a puncture with a conventional tyre that could not be repaired the bill could be just half that at £100. So you're paying almost twice as much for the RFT and if you happen to run over the tiniest of nails you'll need to buy a whole new tyre.
Why can't Run Flat Tyres be repaired?
The reason behind this, given by the tyre manufacturers is to do with the thickness of the RFT sidewalls. With a conventional tyre when a technician carries out a puncture repair, one of the first things they will do is to check the tyre for damage, especially damage to the sidewall. This damage is easy to spot as it shows up as creases in the sidewall when the tyre is deflated. With the RFT it is impossible to say for sure if the sidewall has been damaged as the sidewall is so much thicker. Therefore they have no option but to replace the tyre.
What about a slow puncture?
The damage to the sidewall could occur if you continued to drive on the flat tyre for more than the recommended distance (approx. 100 miles) or over the maximum speed of 50 mph. However what if you'd not driven the tyre at zero pressure, what if the car had been sat on your driveway for a few days and happened to deflate as a result of a slow puncture. Surely this tyre would be repairable? Despite there being no damage to the sidewall you won't find anyone that will repair this RFT tyre, the fact is they only have your word that the tyre had not been driven on at zero pressure and they could run into liability problems if the repaired tyre failed.
Verdict
So are Run Flat Tyres safe to repair? In theory yes they are, as long as they are not driven on. However as cars running on RFT don't have a spare wheel, unless the tyre went down whilst the vehicle was parked, this would be impractical. In practice you won't find anyone that will repair a RFT because both legally and financially it doesn't make sense for tyre centers to repair Run Flat Tyres.
So what about the future, will tyre manufacturers create a machine to check Run Flat Tyres for damage before repair? I wouldn't hold your breath on that one! The best thing you can do to save some money at least, is to avoid buying from your local tyre center and buy cheap tyres online.
Read this article to see the pros and cons of changing run flat tyres to conventional tyres
Article Keywords: Run Flat Tyre Repair
Posted Jul 6, 2010 (14 years ago)