[dhanushs]

Originally Posted by GTO

Is it safe to assume that the stronger sidewall of a runflat tyre makes it more suitable to bad roads?

I'd say, yes.

Or is it that a firmer sidewall will flex lesser and bulge easier?

The bulge always happens only when you go through a pothole hard enough for the rim to take the hit. Flexing sidewalls doesnt cause bulges.

I'd say, you do risk sidewall damages with a low profile tubeless tyre, when compared to the runflats.

But, on the practical side, with right air pressure and some sensible driving the advantages of a good tubeless tyre far outweigh those of runflats.

[autobahnjpr]

GTO,
I feel it has more to do with the make of tyre than whether it is tubeless or Run Flat.
However, i have no experience of Run Flat tyres so below is just my opinion.

I replaced regular tubeless tyres on my DZire and third gen City and both times i have replaced Bridgestone with Continental. Just go to any tyreshop and press the two tyres side by side with your hands. Bridestone is too soft and just depress which means they are more prone to wear, tear and shear. If the tyre gets hit by a pot hole the tyre has higher chances of getting damaged. Whereas Continental tyres do not depess upon being pressed which means they are tougher and can stand wear and tear better specially on our indian roads. Also the sidewall of Continental are at least twice tough as compared to tyres of other brands.

[hyaksha]

I used to have the 2013 F30 328i until recently and now have a 530d. My run-flat experience has been very different so far in these two cars.

The 328i (stock Goodyear ROF 225/45 R18) had numerous bulges and sidewall cuts (almost always thanks to Bangalore's potholes). A year or so back, I went through 7 tires.

The 530d (stock 275/40 R18 rear and 245/45 R18 front) seems... different and more resilient - a couple of scenarios where the 328i's RFTs would have certainly developed a bulge.

Not sure what has changed? (perhaps its a newer compound in the 530d?)

[Jaggu]

Originally Posted by hyaksha

The 530d (stock 275/40 R18 rear and 245/45 R18 front) seems... different and more resilient - a couple of scenarios where the 328i's RFTs would have certainly developed a bulge.

Not sure what has changed? (perhaps its a newer compound in the 530d?)

Sidewall profile went up with the 5 series and i feel that is making a huge difference with the run flat tyres. Maybe should take a poll of people with 5 series and tyre issue, maybe the 3 series with lower profile is not able to take care of the the indian potholes :P

[IRS]

I have no experience of run flats.

However, we have faced problems of 'side bulging' with lower profile tubeless ones.

What I believe is, for our road conditions it is better to have a stiffer sidewall than anything else.

The rest is for you to read.

[sidhu_hs]

I don't have any suggestions but I'll leave some points for you to ponder before taking a call.

• Necessary disclaimer that I don't have much experience of driving any of the luxury brands.
  
  
• Some people have raised the issue of tyre profile being 45 or 'x' as the reason for sidewall cuts and damages, but I think it has more to do with sidewall height which is a function of both section width and profile. 225/45 results in about 101 mm of sidewall height while 245/45 will be about 110 mm with the same 45 profile.
  
  
• I presently drive an Elite i20 which has covered about 25000 kms, about 90% of which is highway driving. Now, 530d has 245/45(F) and 275/40(R) setup which translates to about 110 mm of sidewall height. The new breed of cars such as Verna, Elite i20, Ciaz, Baleno, Abarth Punto to name a few use 195/55 setup which translates to about 107 mm of sidewall height! Which is lesser than the mighty BMW.
  
  
• Now, Maruti and Hyundai would never use such a tyre setup without extensive testing for any damages on Indian highways. Also the present generation Verna has had 195/55 setup since 2011 and I am guessing from the fact they introduced this setup on Elite i20 that not many problems were reported about it.
  
  
• For those crying out loud by now, I understand that BMW is far more heftier and powerful than any of the vehicles I am citing above. But, again load ratings of the tyres chosen take care of the weight difference aspect. 195/55 setup usually has a load rating of about 87 (545 kg/tyre @ max press of 50 psi) while I am guessing BMW setup will have a load rating of 99 (775 kg) or 100 (800 kg).
  
  
• Another aspect that BMW is far more powerful and hence will be usually travelling at much higher speeds is taken care of by the speed rating. Now, 195/55 setup is usually H (210 km/h) or V (240 km/h) rated while I am guessing BMW will be W (270 km/h) or most probably Y (300 km/h) rated. Now, this means that the tyre can travel at those speeds and not take potholes at those speeds! And their lies the rub, I think. If one hits a sharp pothole at speed, I think both RFT or tubeless are going to get squished. And, a BMW is more likely to hit the same pothole at a higher speed.
  
  
• So, GTO if you decide to go the tubeless route, I would suggest you look at XL or extra load tyres. Just google Extra Load Tyres.
  
  And I think Karan's Michelin Super Sports were XL tyres and he didn't report any problems. Or at least have the front tyres as XL and the rear ones as SL (standard load).

Please excuse the lengthy flourish of my armchair intellectual indulgence!

[coolboy007]

Originally Posted by sidhu_hs

Now, 530d has 245/45(F) and 275/40(R) setup which translates to about 110 mm of sidewall height. The new breed of cars such as Verna, Elite i20, Ciaz, Baleno, Abarth Punto to name a few use 195/55 setup which translates to about 107 mm of sidewall height! Which is lesser than the

The Baleno/i20 etc may have a low sidewall height but you are disregarding the fact that the cars mentioned by you run on 16 inch wheels and BMW/Merc offerings run on 18 inch or even 19 inch which is why they have issues with tyre failures.

Merc relaunched the new A class with 16 inch alloys because customers complained of harsh ride and tyre/alloy damage. 16 inch is fine in our country, even 17 if you are a little careful but any thing over 17 and you do need to have a keen eye on potholes.

The Jetta/Octavia comes with 205/55 R16 which has a sidewall height of 112mm, how many times have we read of tyre issues, all thanks to 16 inch alloys and a much more compliant suspension compared to a BMW.

If the suspension does not absorb a pothole, alloy/tyre has to, as simple as that.

[Strella]

Originally Posted by hyaksha

I used to have the 2013 F30 328i until recently and now have a 530d. My run-flat experience has been very different so far in these two cars.

The 328i (stock Goodyear ROF 225/45 R18) had numerous bulges and sidewall cuts (almost always thanks to Bangalore's potholes). A year or so back, I went through 7 tires.

The 530d (stock 275/40 R18 rear and 245/45 R18 front) seems... different and more resilient - a couple of scenarios where the 328i's RFTs would have certainly developed a bulge.

Not sure what has changed? (perhaps its a newer compound in the 530d?)

Hello hyaksha, slightly digressing from the subject. But couldn't resist .

Since You have been fortunate enough to have had the 328 and now the 530d, could you kindly give us your insight into the driving pleasure of the former vis a vis the latter.

Many thanks.

[sinhsha]

After 3 years and 40K Km I think fear about RunFlat is kind of paranoia.
On varied surface, never faced an issue.
Yes my tyre is little high profile (225/55R16) in 320d but some roads I have traveled are far from the roads these tyres were designed for and not necessarily at pussyfooting speed.
For long drives I carry the spacesaver and for punctures repair is pretty easy and can be done through DIY way.
What RUNFLATs provides can't be ignored though. Like stretching the time and distance after which you have to fix it and that's really a boon sometimes in some parts of the country especially with family on board.

[dhawcash]

I'd prefer a tyre with a stiff side wall anyday- runflat or not - if you consider surprises on the road.

Lets compare the sidewall stiffness to suspension stiffness. If a car with soft springs hit a bump at speed, the spring will compress fully owing to its softness, and hit the bump stop. Although the initial shock will be okayish, a lot of remaining energy which was beyond the spring's absorbtion capacity gets transfered to the chassi as the suspension runs out of travel and you get a nice shock load braking havoc with the chassi and your spine.
A stiff spring, on the other hand, will ride stiffer, but in the above mentioned scenario, wont bottom out and the magnitude of overall forces at chassis suspension mounts would be lower.
Thats the reason cars with stiff suspension tend to ride better at higher speeds.

Did you notice any signs of bending on your alloy rim perimeter? ( check the insides- the side more prone to bending ) Ill guess not. If you hit a sudden pothole at speed with a soft sidewall, the side wall will deform and transfer the forces directly to the metal rim, and bend it.

And the advantages of a tubeless might go for a toss in this situation as i experienced once.
Hitting a sharp edged pothole at speed , i got immidiate pressure loss. On closer inspection, the sidewall had a nice little cut, where it got pinched between the rim and the road. The rim had a nice dent too. Yes the a539s have had too many bulges over the months i used them. What causes a tyre bulge? Broken fibres . How do they break? By getting pinched. In my case the pinch was so severe, it cut through rubber. Which was much higher profile in a much lighter car compared to your 5.
Car in this case was an esteem shod with yokohama a539s on factory fitted aura alloy rims.( not the best in the world, but not poorly made stuff either)
To give you another perspective, jk tyre tornados have a good survival rate in the rallying scene owing to stiffer side walls. Gypsys running on geolanders or other softer sidewall tyres tend to have a lot of bent rims compared to tornados. The bent rims are even rarer on rides using rally tyres ( advan a035)( super stiff sidewall- you cant tell if the tyre has air or not in a parked car- that stiff) do note, im not saying stiffer sidewalls will eliminate rim damage, but will definitely reduce the chances/extent of rim damage.
I might sound stupid comparing bmw parts to lowly esteems and gypsys, but the same laws of physics apply in every car.

If i were in your shoes, ill stick with runflats, just for the added assurance that a sudden hit on a pothole wont leave me with a bent rim and a useless tyre. Reliability comes first, Cost and practicality come later.

Back to work so i can get my own bimmer asap and give a more informed input.
The crazy ideas and desires you plant in people's head GTO!

[VeyronSuperSprt]

RFT's are as durable as tubeless tyres for Indian conditions and can take a beating as much as a tubeless tyre can.

The reasons for wanting to change to tubeless would be an evaluation of the other drawbacks of RFT's- no spare, replacing of tyre when punctured (covered under BSI), etc.

The earlier drawbacks of a hard ride have been addressed in the 4G versions that come on the current 5.

So the only real advantage for tubeless tyres are that they score heavily on practicality in Indian conditions in terms of ease of repair and having a stepney at hand.

And that increases your peace of mind.

[zombiedriver]

My personal experience with the Conti RFT's in terms of ride quality has been horrific after crossing about 17000 kms. Having said that i had only 1 puncture in its lifetime of 23000 kms or so. My present Yoko RFT rides a lot quieter and softer but I am concerned about how it will age.

The guys at the tyre shop had a very difficult time getting the Conti's off the rims during tyre change. Infact one of them said it was the longest they had ever taken for any car and he said that is because the rubber was rock hard. So I think the conti RFT's handle the indian roads better in terms of hitting pot holes or sharp bumps but have shorter lifespan with regards to noise and ride quality and if it is lower profile then I would throw my arms up in the air.

While talking to my SA during the last service he made an interesting point when i enquired about fitting tubeless tyres. He said the suspension has been designed keeping RFT's in mind and switching to tubeless tyres would mean the suspension taking a bigger hit,Hence chances of having to work on the suspension. I decided to stick to RFT's after he said that.

Yoko RFT's are a lot softer to ride and are quieter than Conti. Maybe you can try them out.

[Santoshbhat]

Originally Posted by zombiedriver

While talking to my SA during the last service he made an interesting point when i enquired about fitting tubeless tyres. He said the suspension has been designed keeping RFT's in mind and switching to tubeless tyres would mean the suspension taking a bigger hit,Hence chances of having to work on the suspension. I decided to stick to RFT's after he said that.

I will have to disagree with that. Tyres and suspension work together to absorb road imperfections to keep the occupants of the car comfortable. Now if the tyres are rock hard and transfer all the energy to the suspension, the suspension will have to work harder. Lets imagine the car is running on just the metal rims without any rubber. You will destroy the suspension within minutes. That's one reason why its recommended to change tyres when the rubber becomes too hard and gives a harsh ride. By changing to softer rubber you are doing the suspension a favour.

[honeybee]

Do bad roads cause a tyre to bulge? I don't think so.

After using tubeless tyres on 5 different cars from Maruti to Accord, I have yet to see any bulge on any of their tyres. Some of these cars have been on extremely bad roads including the JVLR before it was concreted (?) and places such as Akkalkot which have been without roads for as long as I can remember.

And I have seldom been gentle. I even managed to slightly damage the rim of my Nano's rear right on the Nashik highway one night. But no tyre bulge.

Also MRF offers warranty on tyres only in case of a bulge. If bad roads and harsh driving caused them, MRF would never offer a warranty for the same.

So all evidence points to manufacturing defect as the only source of a tyre bulge. Or if the car was unused and not driven for months together causing tyres to deform.

[Akshay1234]

Originally Posted by zombiedriver

While talking to my SA during the last service he made an interesting point when i enquired about fitting tubeless tyres. He said the suspension has been designed keeping RFT's in mind and switching to tubeless tyres would mean the suspension taking a bigger hit,Hence chances of having to work on the suspension. I decided to stick to RFT's after he said that.

That is completely the opposite of what will happen. Tubeless tyres will absorb more of the impact hence the suspension would take less of a hit.

Originally Posted by honeybee

Do bad roads cause a tyre to bulge? I don't think so.

After using tubeless tyres on 5 different cars from Maruti to Accord, I have yet to see any bulge on any of their tyres. Some of these cars have been on extremely bad roads including the JVLR before it was concreted (?) and places such as Akkalkot which have been without roads for as long as I can remember.

And I have seldom been gentle. I even managed to slightly damage the rim of my Nano's rear right on the Nashik highway one night. But no tyre bulge.

Also MRF offers warranty on tyres only in case of a bulge. If bad roads and harsh driving caused them, MRF would never offer a warranty for the same.

So all evidence points to manufacturing defect as the only source of a tyre bulge. Or if the car was unused and not driven for months together causing tyres to deform.

With regular touring tyres which are in a high profile (based on the cars you named) you will most probably never encounter bulges or bubbles. Its only in lower profile tyres, with a softer compound, which are susceptible to bulges due to the lower sidewall height.