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Originally Posted by awais_shahid
So we all have long known large rims and runflats are not kind to alloy wheels. It doesn't help that the quality of BMW wheels are generally pretty shit (I had 3 cracked alloys replaced on my e92 coupe).
The trouble is there's absolutely no give in the side wall of the tyre, thus all the force is distributed to the rim ultimately leading to it buckling or failing.
So there I am driving along a main road in Manchester, and I drive over a dropped drainage grid in the middle of the road at around 30-35mph...thud felt like my tyre had exploded! It caused the wheel to deform with a flat edge.
You'd think I would have learnt my lesson, but 2 days later I was driving along the same road and completely forgot about the grid....thud...again!
Needless to say the rim is completely f*cked now and I took it to the dealer who simply said warranty won't touch it and I'll need to claim from the local council. I think it is poor wheel quality which has led to it failing so badly, has anybody else had a similar issue?
Fortunately I found a 2015 refurbished wheel on ebay for £260 delivered!
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From a wheel engineering perspective, those are actually very impressive safe failures. I'm surprised the first impact didn't cause the bead seal to leak and that the car was driven after the first bend. The issues with RFT's transferring excessive loads to the rim was resolved many years ago. The tires are now designed to flex initially at the shoulder under normal loads and at the max load, the bead is allowed to compress onwards and remain seated courtesy of the implementation of EH2+ Bead Contours and and strengthened J Rim Flange specs.
One thing that stands out though are the excessive balance weights. Just from the ones I can count, it's there's at least 50% more above the maximum allowed on the entire wheel installed on the outboard side alone. Was it previously repaired or already compromised to begin with?