HighlandPete

Fronts wearing like that! The second picture is the worst/sharpest shape I've seen on the shoulder, worse than any rear tyre, so surely we must be talking low pressure and running the sidewalls, more than a camber issue. Or... is the car a lowered/modified example with much more negative camber? HighlandPete

Particularly for Tony... Are you aware that Bridgestone are said to have made a modification to the tyres, to help the inner wear problem? What I'm reading.... The new tyre designation on the sidewall is Bridgestone RFT 050A YZ HighlandPete

Have you thought, if they were not run-flats they probably wouldn't be worn like this. BTW, is the second picture the inside of the other rear tyre? If so, notice the cracking in the tread grooves, not a good sign. Have these tyres been run at lowish pressure and also overheated? HighlandPete

But surely he is kicking up a fuss, now he knows what is wrong? I just can't believe we still have that sort of incompetence these days.... bet they say all of their guys are trained.... HighlandPete

I've read a couple of these 'blow out' cases on the forums and in both instances the run-flat tyres were shreaded. Now gets me thinking, was the run-flat a blessing or was it the cause? Was the tyre (or more than one) running at low pressure for quite a while and (TPMS didn't trigger) contribute to a fatigued tyre, so it popped. One such account the tyre was photographed and it did look to me that the tyre was probably ruined before it blew out. There are reports of many run-flats that only go a handful of miles, after the warning bong, before they disintegrate, so does again make me wonder if the pressures were low and contributed to the final failure. No substitute for checking pressures very regularly. HighlandPete

I've read a couple of these 'blow out' cases on the forums and in both instances the run-flat tyres were shreaded. Now gets me thinking was the run-flat a blessing or was it the cause? Was the tyre (or more than one) running at low pressure for quite a while (TPMS didn't therefore trigger) and contribute to a fatigued tyre, so it popped. One such account the tyre was photographed and it did look to me that the tyre was probably ruined before it blew out. There are reports of many run-flats that only go a handful of miles, after the warning, before they disintegrate, so does again make me wonder if the pressures were low and contributed to the final failure. No substitute for checking pressures very regularly. HighlandPete

See what you mean. I'm aware that many folks are replacing a 'pair' of tyres... to non run-flats, which goes against the clear recommendations from TIC/Tyresafe and everything I've read from the tyre manufacturers. Even BMW AUC's have left the forecourt with mixed (RF/non RF) tyres. Other users don't know what they have on their cars, so I'm sure the insurance companies could have a field day in the event of accidents, where they may note a mixture of tyres, or undeclared changes. HighlandPete

Obviously need to notify the insurance company. Most who have been through this have the same experience. They just want assurance the tyres are to the same/correct load and speed rating and note the change. Not normally a cost penalty either for a same size change. HighlandPete

Inspiration for the Tweel? Probably perform as well as a run-flat, at least they look to have a decent spring rate. HighlandPete

Why buy new rims if the old ones are not cracked? Fit non run-flat tyres to the BMW OEM rims. (There is nothing to cut away). I understand that even some BMW franchised garages do it, to satisfy customer complaints. HighlandPete

It is a shame that a lot of what is written above, as good as it sounds, doesn't exactly work in the real world. I'm a BMW user of many years and the run-flat experience has almost cost BMW a loyal customer. The only way I've continued with my BMW is by removing the run-flats and driving on non run-flat tyres. Now I have a BMW that drives as I expect it to. The other option was to trade the car and move to another marque. I still believe the run-flats should be an option, there should still be the capability to have a spare wheel in the wheel well, for both run-flat and non run-flat fitment. HighlandPete

From the posts and picture, 35k miles and 5 sets of tyres... extreme wear. Simple questions... not specific to this car, but typical of some cars out there. How on earth is a car set up like that, was it ever inside the build parameters, needing adjustment kits to put it right? Or what is going on? What's the experience? HighlandPete

Sorry if you have discussed this before, I've had a search but not found a discussion. What's the opinion on having a re-alignment when fitting new tyres? Obviously if the old tyres have strange wear patterns, but if there is even wear, I personally leave alone. Many shops want to check and adjust toe at any opportunity, to me that is the last thing I want touched unless there is a valid and clearly understood reason to do so. Also would you normally touch toe settings without a full alignment? For example if there was some nearside front outer scrub at the end of a tyre's useful life. To me, I want the rear given the all clear and running true, before the front is adjusted. I do appreciate a lot will depend on the tyre history and whether the owner has been looking after the tyres, like regular and accurate pressure checks and observing wear over their life. HighlandPete

No excuse for that what so ever, it frightens me that drivers can go about like that, while we are also on the road. Now there's a driver who, if spouting on about how one car is better than another, or handles better, etc., you'd not take seriously. HighlandPete

This should be a good topic and discussion, as so many think big/wide is always better. On the reference to RFTs and the stiff sidewalls having a different influence, will be interested in your observations. One thing to think about, comparing more supple sidewalls to RFTs, is the distortion of a tyre during acceleration, cornering and the impact on the contact patch. I sense from having inked prints under tyres, that the contact patch for a RFT is even shorter in some dynamic situations than normal tyres, as statically it is so. Then pressure setting is more critical as RFT sidewalls can take/transfer more of the load, than a more supple tyre. Good topic. HighlandPete

Move the wheels side-to-side and see if the steering position changes. Wise man... do many tyre shops even bother looking at the markings? Do you have to remount many directional tyres to sort this sort of problem? HighlandPete

Found the weakest point... Is it the subframe, or a replaceable bush housing? HighlandPete

Interesting. I've got a 4 week old 5 series with 19's on. Will be interesting to see how the availability of the M-sport packages are for wheels when colleagues changeover their cars in the next few months. Could be that internal customers will be getting the stocks and externals offered only the 18s until it's resolved. Predict new range of wheel offerings quite soon. It appears it is just on the 3-series that the 19 "rims have been deleted from the options. Also there is a different attitude to replacement, even though BMW are not yet admitting liability. Seems to be confusion at some dealers, some appear more enlightened than others. HighlandPete

Tony, the wheel example you show in the second picture... isn't it a samller diameter? 16" isn't it? Could be a different alloy, than the larger 18/19" rims that typically fail with the cracking. I've seen pictures of the larger wheels that have had impacts, none so far have flat-spotted. They more or less 'shatter' and the grain structure shows they are a harder material, IMO. Fits with the look of stress cracking, which we see on the examples in the Watchdog video. I recorded the Watchdog prog' at the time, so that I could freeze frame on a large screen. The sample with the long irregular fracture, shouts stress/fatigue fracture to me. HighlandPete

Ah, see what you mean, think owners will have to adapt a bit as well, we do have this notion that the manufacturers know what they are doing. The franchised dealers are in between a rock and a hard place when it comes to moving off BMW policy/spec, even if a decent technician knows more needs to be done to get a proper solutuon. Too easy to say "in spec and you need new tyres". Do you get a chance to put your views and experience across to the makers, when you find working solutions? Or do you just sort the individual customer and leave the bigger issues alone? HighlandPete

Not sure BMW haven't failed, not an unblemished start. I've read a couple of road tests on the latest 316d ES and an X1. Both testers commented on the improved ride quality. On examination, as base models, they have normal rubber fitted. Improved dynamics in one stroke! You mention we are the ones who need to adapt. I believe the manufacturers need to take the public with them, not have a botched start and blame the customers, as they seem to be doing. One major problem I have found keeps coming up in discussions and also from your industry, is the way TPMS/TPWS is interpreted by the customer. BTW, I notice BMW have moved to the description, UK: Run Flat Indicator, USA: Flat Tire Monitor. BMW actually published this statement. Tyre maintenance: A general misconception is that one doesn't need to check Runflat tyre pressures since the vehicle is equipped with a Runflat indicator (RPA System). The purpose of this system is however to give advanced warning that one of the tyres is losing tyre pressure by measuring the relative wheel speed of each tyre. If pressures are not checked regularly, Runflat tyres lose pressure like normal tyres without the system picking up any relative difference in wheel speed. Thus the extended running of Runflat tyres in this sort of under-inflated condition will negatively impact the Runflat range should you lose pressure completely. For this reason, BMW recommends that tyre pressures should be checked on a regular basis, i.e. at least twice a month as well as before setting out on any long journey. Very importantly, it should be noted that the RPA system must be initialised whenever the pressures are adjusted. This is a very quick and easy operation that is also clearly described in the owner's manual. It is another reason BMW are blaming customers for the strange/accelerated wear. They know lots of users are not checking tyre pressures and/or wear, believing they will be 'told' when to. I was reading of a run-flat 'blow out' and then saw the pictures, clearly the tyre had been run low for a long time and the walls just gave up and disintegrated. Another had the warning flash up, and in 5-miles at 50mph, the whole tyre fell apart. No one will convince me that tyre was running full pressure, to within a few miles of the failure. Again what a lot don't realise is the pressure differential before the warning is triggered. BMW publish about 30% for the indirect TPWS. Plus how many users know if all tyres are going down, the system is flawed anyway. No wonder the States are using direct TPMS. There will be a need for a lot more education on what run-flats are really about, also how tyre/wheel choice is even more critical if we want decent drives, IMO. 'Minefield' comes to mind... HighlandPete

Worse for me is no spare in the boot. I'm often away from home, remote parts of the Highlands when there is no support, if I had a major issue. I put a spare wheel in the boot space. I've had most issues, wear, ride quality and poor driving dynamics. I really think the run-flats were not developed enough before letting them loose on the public. It was bad enough trying to select a model, suspension and wheel specification that even worked up here. I took delivery on a warm May day and we went into a good summer in 2006, so didn't get a lot of the strange behaviour until the weather cooled a bit. Then the car's behaviour deteriorated. Soon realised why choosing the car was so hard. We'd test driven several run-flat shod cars through the winter and had no thoughts on temperature being a trigger for much of the bad dynamics. Looking back, One demo 3-series M-sport car was ready to go over the hedge, but the day was very cold, so no wonder the 'Brickstones' were doing their worst. Now of course we have all the wear issues and the cracking rims, I do wonder if BMW wish they hadn't been so fast into the market. I'm very interested in the Bridgestone 3G (3rd generation) tyres, due in the UK soon I believe. I've offered to test a set for Bridgestone, up here in the Highlands, put them through their paces. But another learning curve ahead I imagine. HighlandPete

I totally agree that we are the quinea pigs, have been since the introduction of run-flats. Almost pushed me to move from the marque. But pleased I moved to normal rubber and fitted different dampers, to get the ride quality back to a real BMW feel. The issue with different owners getting different issues, indicates to me something I've believed from early experience trying run-flat shod models, the working parameters are much tighter on the run-flats and show extremes so much more rapidly. I'll give you a couple of examples. I've found that the run-flats take longer to warm up and therefore don't get to a workable pressure on a lot of the trips we do. I documented my findings when I had the wear, takes at least 12 miles to get about 0.2 bar increase when the ambient temperature is around the 8-degree mark. Typically 0.3 bar over a shorter distance, at higher temperatures and in dry conditions. I live in the West Highlands and when the temperature is around 7- 8 degrees, when it rains there is snowfall on the mountains above us. So drive the Glen and get rain, you get 'water cooled' tyres within seconds, the drive quality deteriorates to such a degree, it is like a different car as you drive. We all know the weird characteristics the run-flats give us anyway, once off of smooth hardtop. I still believe a lot of premature wear is down to low tyre pressure, short trips accelerate the strange wear, paricularly on the shoulders, many of us find that this is so. I've always found that BMW placard pressures have been pretty good, but on the run-flats at least an extra 0.2 bar is needed just to make them work and wear more evenly. And that is driving moderately. This is a Conti on the NS front of a 320d. Included a lot of short trips and the owner was watching tyre pressures closely. Owner changed to the same Conti tyre in non run-flat form and no more strange wear. No change of geometry either. Drive an 18" or 19" wheel set hard, I can see why there are severe wear issues. Just can't understand how BMW could have got it so wrong. HighlandPete

Tony Following you... so you reckon tyres pressure is only likely to be a small part of the issue. So looking at my rear tyre, below, you'd say it's defined, or appears as camber wear? At least increasing the pressure did allow it to balance out the wear, to get the tread down reasonably well for a sensible mileage. When you look at my Goodyear F1 GS-D3 in the first post, you wouldn't say camber wear was an issue for that tyre, shows how the same camber settings translate totally different with run-flats. Can you imagine how the poor guy felt with this tyre? Certainly not what I'd expect from the negative camber settings BMW dial in. I set up a solid model this morning, using CAD, trying to get the shapes a tyre will make on contact at 1.5 degrees negative camber. A 255 section tyre at 1.5 degrees has just under 6mm vertical difference side to side. All this accelerated edge wear certainly looks like the RFT constuction. Surely BMW and companies like Bridgestone had this wear show up in development. In the next illustration I do believe the wear rate of the section marked A, is increased due to the sidewall stiffness not allowing a balanced flex. As it wears the degradation of the communication point makes for a weaker structure, which in turn allows an even faster acceleration of wear, and so on. I take it you are not a 'fan' of run-flats. Peter

Thanks for replying. I think we are very much on the same lines, but do you reckon a lot of users are running too low a pressure for how they drive? One reason I say this, is my own experinece with the run-flat fronts. I ended up in discussions with BMW and Bridgstone and I increased the front pressure by 0.2 - 0.3 bar just to try and halt the stepped outer wear and severe 'heel and toe' wear, which came on at an amazing rate. I ended up putting together a paper trying to understand the reasons why, which in some ways has merit for rear wear as well, but do wonder if the lateral forces in cornering deform the tyre in a strange way, more readily than normal rubber. Say turning right, the load transfer and lateral force to the inner NS rear tyre, deforms the shoulder more violently. The front 'stepping' problem illustrates the carcass has a weak crossover from wall to crown. I hope you follow the diagrams, without me supplying all the reasoning. Conventional tyre, inflated to correct pressure Conventional tyre, coping with camber and cornering Run-flat tyre, inflated to correct cold setting pressure Run-flat tyre, only works well with reduced camber Run-flat tyre, low setting pressure, or not reaching working pressure (slower than normal rubber, even worse in the wet) Run-flat tyre, low pressure, or not reaching working presure, NOT coping with camber/cornering demands Run-flat tyre, shows resulting stepped front wear, similar issue could exist for rear inner wear. One stange thing, some users who have changed to normal rubber, say the rear inner wear can be even faster than run-flats. Can't get my head around that from my experience, are we back to tyre pressure being too low? HighlandPete