BMW 3 Series, Run Flat Tyres… BMW have whole heartedly adopted run-flat tyres across their range (except M cars). The benefits of these tyres seem to boil down to a solitary point; that is, if you have a puncture at high speed (say on the motorway), the run-flat tyre will not explode and cause an almighty crash! Oh, I suppose an additional benefit (to BMW, as I’m sure that any cost saving was not passed on to their customers) is they don’t have to provide a spare wheel (not even a space saver). Whereas, back on topic, it is almost impossible for me to enumerate the issues I have with run-flat tyres; they cannot be repaired if you have a puncture, they cause increased road (and therefore cabin) noise, they cause a harder ride, they cause poorer handling (which is why M cars have retained non-run-flat tyres), and now they are a contributing cause to fractured alloy wheel rims! Yes, as the tyre side-wall is so hard (strong) to enable it to be driven when deflated, it transmits more impact to the alloy wheel rim.

For example, when going over a speed bump a bit faster than intended, or perhaps hitting a pot-hole, not only does it give you an even more jarring ride, but it can (in mine and many other people’s cases) fracture the wheel rim! BMW alloy wheels are not cheap to replace – and it must be replaced because it’s a MOT failure to have a cracked wheel rim.Moen Shower Faucet Low Hot Water Pressure To add insult to injury, imagine my mood after being told by a BMW main dealer that I should have gone over to normal tyres years ago when the run-flats, that the car is supplied with, wore out and needed replacing! Lirr Monthly Ticket PolicyThe service manager said, “not only would it have saved money, it would be like having a new car with better handling and a quieter ride!” Tyre Repair Dublin Bank Holiday

Not to mention that I might not now be faced with an expensive bill to replace a fractured wheel… Entry for Wednesday, 11th March 2009 by Pete, filed under Uncategorized.Follow responses through the RSS feed, comments and pings are closed.One of the most annoying things that can happen to any car is when it picks up some kind of vibration. While a vibration is not usually a safety issue unless it becomes very bad, a shaking car can be no fun at all to drive, and can sometimes be screamingly frustrating to diagnose which of the many complex components that govern the car's contact with the road is causing the shake.For a car to run smoothly at speed requires the contact with the road and the transmission of the contact forces to be achieved within very tight tolerances. The majority of vibration problems are caused by the wheels or tires being out of tolerance in some way, usually because of an impact. When I go to diagnose a vibration, I always check the wheels first, then the tires, followed by alignment and suspension.

Alignment and suspension issues will require other articles, so we'll address how to diagnose wheels and tires first. I generally start with a couple of questions for the driver:Do you feel the vibration in the steering wheel or in the seat?The answer can give us an idea of whether the vibration is coming from the front end, which will generally transmit vibration directly to the steering wheel, or from the back end, which will transmit vibration more through the frame of the car and into the seat. This is not always 100% indicative, as there are a number of variables involved in car vibrations. Certain alignment issues in the back end can cause the steering wheel to vibrate as it shakes the car from side to side, for instance.Do you feel the vibration at a certain rate of speed?Many people come to me already saying, “I get this weird shake between X and Y miles per hour.” I am immediately fairly certain that either a wheel is bent or a tire is out of round. A vibration that has a “sweet spot” at a certain speed range is a classic symptom of harmonic modulation caused by a small bend.

A wheel and tire assembly that is out of round will have a specific harmonic frequency as it spins, depending on how many bends, the severity of the bends, tire wear and other factors. As the speed changes, the harmonic changes, or modulates, as well. At certain speed ranges this modulation can reach a frequency that will overwhelm the vibration-dampening capacities of the suspension. That's the point at which you begin to feel a vibration in the car that was previously being damped out.Do you feel a vibration in the brake pedal under hard braking?If under moderate to stiff braking pressure you can feel the brake pedal shake under your foot, this is a good indication that what you have is a warped brake rotor or other brake-related issues. The brake rotor must be either replaced or re-lathed to make it perfectly flat.Reasons to have Run-flat tires on your BMW Let me start first by saying that this a “touchy” subject and it has been debated over and over again. While there are many people …

While there are many people that love the run-flat tires on their BMWs, there are plenty of others that are absolutely against them and consider the normal tires as being a better choice for their cars. The purpose of this article is to show you BMW’s point of view or the reasons behind using run-flat tires on most of their models. So, I will let them tell us the advantages of using them, but I will have an article ready with the cons as well. The following text was published on babybmw.net, an UK fans forum, in response to a customer’s concern. BMW aims to provide our customers with a premium product that provides ultimate safety with optimum performance and it is always a concern to receive feedback of this nature. We chose to include Run-flat technology on our vehicles for the following reasons: It is dangerous to stop on any road to change a tyre, especially on a motorway or at night. There is no need to have to wait for a breakdown service to arrive.

Safety and security of the driver and passenger(s) is maintained. Alloy wheels are difficult to detach from steel hubs. On most cars the spare is under the contents of the boot, and uses boot space. It can be tricky to line up the wheel bolt holes with the hub screw holes and match the thread. The dirty punctured tyre needs to be removed and stored in the boot. Another puncture before the punctured tyre is mended means one is stranded. A driver can continue for 150 miles at 50mph with a punctured Run-flat tyre. All of our vehicles that use Run-flat technology have their suspension and braking components set up to accommodate Run-flat tyres. Should you decide to change to non Run-flats, it may alter the driving and handling characteristics of your vehicle. It is for this reason that this modification is not recommended by BMW as a manufacturer. However, it is possible to have standard tyres fitted. You will additionally need to purchase either a spare wheel with jack and brace set or a mobility kit which can be ordered from the Parts Department of your nearest BMW Approved Dealership.