My BMW 320d's run-flat tyre proves its worth on a road trip to Karwar

RFTs are supposed to be capable of being driven about 100km or so on zero pressure. Today I was testing that theory to the limit, in real-world conditions!

BHPian Dr.AD recently shared this with other enthusiasts.

An Eventful Weekend Drive to Karwar (RFT Proves its Worth!)

This weekend, along with a close friend BHPian @praveenbalan (driving his Octavia 1.8 TSi), I did a weekend drive to Karwar. The destination was not important - we just randomly chose something where we got accommodation at a short notice on a major long weekend. The idea was to just enjoy the drive and the monsoon in the coastal area.

It was indeed a beautiful drive that we enjoyed a lot. We got plenty of rain on the way and also in Karwar, and we enjoyed the coastal monsoon. The section of the route between Hubli and Karwar was very scenic (this is one of my favourite roads to drive on). This time, thanks to the heavy rains, this section was even more beautiful with lush green views all around. We absolutely enjoyed driving there!

However, unfortunately, this drive turned out to be an eventful one for me. In short, I had a tyre cut after hitting a nasty surprise pothole, and I lost the entire air pressure instantly. Thankfully, I was running Run Flat Tyres (RFTs), and that saved the day for me. The BMW owners groups (and even many threads on this forum) are full of discussions about whether RFTs are good or bad. I always believed that RFTs were a great safety tool, and thankfully, always chose RFTs over regular tubeless tyres. This weekend my trust in RFTs was proven right! Now after this experience, I am an even stronger believer in the RFTs!

Anyways, more on that a bit later.

We met at a breakfast place in the outskirts of Bangalore to start our weekend drive:

Refuelling just before Hubli:

On the beautiful Hubli-Karwar road (this road was indeed very scenic and we enjoyed our drive there):

Lovely roads, nice rain, and lush green views all around:

However, just after this, this routine weekend drive turned eventful. This road between Hubli and Karwar is very scenic for sure, but at the same time, infested with countless "surprise potholes". In most places, the tarmac is smooth and the road is wide, encouraging one to drive at decent speeds. However, this is all very deceptive. At numerous locations, there are sudden sections with totally broken roads and some massive potholes. One has to constantly be prepared to face such sudden bad patches. It is quite a scary drive due to this.

I managed to avoid most of the potholes and was quite careful in navigating around the potholes and keeping my speeds in check. However, eventually, at one point, there was a massive pothole which was almost invisible due to its location of it with respect to the angle of the road. And almost inevitably, I hit this pothole. I just did not see it at all. I hit this pothole without seeing it or braking at all and was surprised by a loud thud as soon as I hit it. That impact was scary! The moment I hit it and heard the loud thud, I knew this was going to be trouble. Even before I could gather my thoughts, just in about 2 seconds, there was a loud chime from the TPMS system, with a message flashing on my iDrive. I pulled over immediately (and safely) to the side of the road, and saw that TPMS was telling me that I had instantly lost all pressure in my front right tyre. All other wheels had normal running pressure, but the front right tyre pressure was 0.0! All in a matter of two seconds!

I got out of the car to check the tyre, and my worst fears turned out to be true. The tyre had a major cut on the sidewall, and there was no hope of fixing it. The tyre was dead on the spot, and I had lost all air inside.

In all my ownership years of the car, I have been reading about similar tyre blowouts in other BMWs and was part of many discussions about the pros and cons of RFTs in such situations. Luckily, until now I never had this experience and was merely a theoretical participant in such discussions. Finally, this time, it was my turn to have the tyre blowout that I have discussed numerous times in many groups.

In a way, it felt almost inevitable. I have been driving on plenty of bad roads (good roads are anyways rare to find), and plenty of times I have had to hit potholes on the roads. It is just impossible to keep driving on such roads weekend after weekend and not hit the potholes. Therefore, I had this feeling of inevitability about this incident. I felt it was just a matter of time. And unfortunately, today was that time.

After accepting the inevitability of this event in a philosophical way, my instant next thought was that I had two things in my favour: One, I was running on RFTs, and two, I had a spare tyre (although not a full-size, but instead a space saver or "donut") in my trunk.

Even the iDrive message (it was a nice and elaborate message telling me what to do - unfortunately I forgot to take a photo of that message) said that for vehicles equipped with Run Flat Tyres, "you may continue your journey with speeds less than 80km/h". It was a bit funny to see exactly 0.0 psi as the pressure value for a front right tyre in the TPMS, but this message about continuing the journey was encouraging. This is where I realized how valuable RFTs are in real life!

It was raining on and off all the time there, and it was drizzling already again. Therefore, instead of trying my DIY skills to change to the space saver under that rain on that forest road, I decided to drive on till I found a tyre shop. After all, that is the whole point of RFTs. Even the iDrive message said the same thing. So why not use the RFTs to their full potential? With that thought, we decided to slowly drive on (never crossing even 60 km/h, forget about 80km/h that the iDrive message said) till we found a tyre shop.

At that point, we were 72km away from Karwar. I did not think we could reach that far. The next big town on our way, about 35km or so further ahead, was Ankola. I thought we would find a proper tyre shop at Ankola. Unfortunately, as it turned out, we did not see any tyre shop at all on the road all the way till we reached Karwar.

It took what felt like forever to reach Karwar at that speed of about 40km/h. The roads were lovely. But there were still too many surprise potholes. I knew the RFT would hold till Karwar if I drive slow and very carefully. RFTs are supposed to be capable of being driven about 100km or so on zero pressure. Today I was testing that theory to the limit, in real-world conditions!

While I was slow and confident, it was funny to see the reactions of other cars passing me. They were looking strangely at this BMW going at such a slow speed and asking everyone else to overtake it on this lovely scenic road. They must have thought I was some new driver. Some of them noticed the flat tyre while passing me, and their reaction was shock and horror. Most people tried to signal to me that my tyre was flat. I just waved at them and gave them a thank you gesture. I continued on looking for a tyre shop.

While I was driving at this slow speed, carefully avoiding all further potholes and manoeuvring the car as carefully and as slowly as possible, my buddy @praveenbalan drove behind me patiently. It was a great moral support to have him behind me in all this drama. It must have been a horribly boring experience for him to drive his lovely Octavia 1.8TSi so slowly on the sections of good roads, but he stayed with me throughout. Thanks a lot to @praveenbalan for being with me through that ordeal!

Finally, we reached Karwar. We asked the locals about a tyre shop (we still did not see any tyre shop on the highway even in Karwar), and they told us of a local shop which also was a Wheel Alignment centre in Karwar. I promptly drove there.

I forgot to click the photos of the tyre immediately when the incident happened. That time, there was a big sidewall cut. However, after driving on for 72 km after that, the sidewall cut increased a lot, and the tyre looked like it was about to disintegrate dramatically.

This is how the tyre looked after 72km of driving on zero pressure, with a sidewall cut to begin with:

A closer look. This also shows (as is theoretically known) that the RFTs can hold for about 100 km or so on zero pressure, but not longer than that. This would have totally disintegrated soon for sure:

This is the wheel alignment centre that I went to. This turned out to be a nice shop. They were well equipped, and the gentleman there was quite knowledgeable:

I asked him to inspect the space saver tyre. Luckily for me, the space saver was in perfect condition (it was never used).

Space saver tyre. This was 135/80/R17 size:

My car with the space saver in the front right position:

I discussed with him the possibility of finding a new tyre in that area. He told me it will be almost impossible to find a tyre in 225/50/R17 size (my stock size) in that area, and my best chance would be to drive to Goa or Hubli and search there. At the same time, he gave me the confidence that if I drive slowly, without crossing 80km/h, I could drive back to Bangalore on the space saver!

The other relevant fact was that all four of my current tyres were very close to the end of life anyways. I had already driven about 38,000 km on this set of four RFTs, and I was going to replace them very soon anyways. That meant that I did not need just one new tyre, but wanted to buy a set of four tyres together.

Given that this was a long weekend, and most tyre shops might be closed anyways, it looked even less probable to be able to find four new RFTs in my stock size (availability of which even in cities like Bangalore is often a problem) that weekend in that area.

Considering all this, and after a discussion with the expert in that tyre shop, I decided to slowly and carefully drive back towards Bangalore on the space saver; to at least reach Hubli and then maybe review the situation. That would be a drive back the next day. For the rest of the day that day, I just decided to stay calm and enjoyed my time there.

A calming and peaceful sunset at Karwar, overlooking Kali river meets the sea, amidst all the tyre drama:

The next morning, we started back and I continued driving very slowly and carefully to Hubli. My plan was to reach Hubli first and then review the situation. If required, I could search for new tyres in Hubli, or even stay there for one more night if required.

Drive from Karwar to Hubli on that space saver was probably the most nervous drive for me in a long time. That is a proper ghat road and again infested with potholes. The one area where space-saver would be very weak would be the cornering abilities. I decided to not even cross 40 km/h in those corners. I continued driving very carefully, staying under 40 km/h through the turns, and staying at about 70km/h in the straights. Theoretically, the space saver tyre has a limit of 80km/h.

Thankfully, that long, slow and careful drive from Karwar to Hubli was uneventful, and we reached Hubli safe and fine.

The space saver holding the fort as we reached Hubli:

After reviewing the situation at Hubli, I felt confident that I can continue driving to Bangalore. I requested @praveenbalan to go ahead at his own speed (no point in holding him back with me on the six-lane highway). After that, I had a long and slow drive on that six-lane highway from Hubli to Bangalore.

This was the first time that the Speed Limiter feature in my car came useful. I set the speed limiter to 80km/h (so that even by mistake I do not exceed this speed), stayed in the leftmost (slow) lane, and continued driving towards Bangalore at speeds just under 80 km/h.

Speed Limiter set to 80 km/h on the return journey:

It was a bit of a funny experience to drive so slowly on this beautiful, straight six-lane highway. The road looked totally different, and it was a totally different experience to drive here without crossing 80 km/h. I understand that even the official speed limit is 100km/h on six-lane highways. I was well below that.

Actually, I enjoyed this experience too. The car felt absolutely stable and almost standstill at 80km/h, even on the space saver! It was a supremely comfortable ride. I could get time to see around. I started enjoying the greenery around me, the clouds in the sky, the beautiful road that I could see for kilometres ahead in front of me, and the lovely weather in general. I even started enjoying the music playing in the car. I had plenty of time to appreciate all these other things and enjoy the slow but peaceful journey. It was a memorable drive for sure.

A side benefit of such a slow drive on the straight highway was that I got phenomenal fuel economy! The numbers I was seeing on the MID were unheard of.

After the first 3 hours of driving from Hubli, I got such crazy FE numbers of more than 28 km/l (and my average speed was still not too bad while not crossing 80km/h at all):

And when I refuelled on the way, I got this astounding range of 1300 km thanks to the super efficient slow drive (notice the TPMS error flashing - this was because the fourth wheel sensor still was recording 0 pressure; I had to drive back with this error flashing throughout the return drive):

Slowly and steadily, eventually, I reached Bangalore fine and safe. The stats for the journey from Hubli to Bangalore showed some unbelievable numbers:

Even before I drove back to Bangalore, I had called my usual tyre shop, Madhus Tyre Center in Wilson Garden Bangalore, and had taken appointments for buying and installing new tyres. Luckily for me, they had my choice of tyres in stock and available for installation the next day itself.

So the very next day, I visited Madhus Tyre Center and got four brand new tyres installed.

I decided to go with the same Michelin Primacy 3 ZP (ZP = Zero Pressure = Run Flat in Michelin speak), which I had a good experience with over the last 38,000km of driving.

If I had any remote thought of switching to non-RFTs (normal tubeless tyres), that totally vanished when I had a first-hand experience of the uselessness of RFTs this weekend. Now there was not even the smallest doubt in my mind that RFTs are worth it, and are indeed a safety tool.

A set of four new tyres that I got at Madhus:

Decided to go with the same Michelin Primacy 3 ZP in my stock size of 225/50/R17:

The car getting new tyres installed at Madhus:

Alignment in progress after the new tyres:

As always, the experience at Madhus was fantastic. It is my go-to place for any and all tyre and wheel-related matters, and this time too, I was impressed by their professional and courteous service. Overall a great experience at Madhus, as always.

So this is how this weekend turned out to be. Overall a great learning experience for me.

My apologies for this long post on a relatively simple matter of a tyre failure. But since RFTs are so often discussed in various threads, I thought it may be useful to give a detailed account of what happened.

Let me summarize the key lessons I learned below:

1. RFTs are a great safety tool. I was already a believer in RFTs, and this experience makes my beliefs even stronger!
2. With RFTs, you can indeed drive for about 80km or so (or maybe 100km at max), even on zero pressure. No need to immediately change the tyres in the middle of the road, under challenging conditions such as rain or in difficult spots. This can be a huge benefit in some situations (and not so much of a big deal in some other situations).
3. However, even with RFTs, a spare tyre (even just a space saver) is a must! What saved the day for me, in reality, was the space saver. Else even if you drive to the next town on RFTs with zero pressure, you would still be stuck in that town because the chances of availability of typical BMW stock-sized tyres in smaller towns are almost zero! A spare tyre (even a space saver) is a must.
4. I will not do any future drives without the space saver tyre in my trunk now.
5. The space saver or the "donut" as we jokingly call it, in spite of all the jokes, is still quite a capable and useful thing. You can actually drive on that, provided you are slow and careful. It does not look so ridiculous when fitted on the car. It can safely and comfortably take you to the nearest big city (or even back to your home city) where you can buy proper new tyres.

Well, that is all from the events of this weekend. Thank you for reading!

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