The Dreaded Cracked Alloys

[Smartbear]

So at the risk of being thick (ok, I am thick), how do you tell if the wheel is cracked, and is it dangerous?

My suspicions would be loss of air pressure and yes, could be dangerous, but is it an obvious thing, i.e. quick loss of air, or a gradual thing and only really noticeable when looking?

I have the original M-Sport 18" wheels...I know its mainly 19's that are at risk, but do 18's get it also....we have some really bad potholes down here.

when they took my wheels off today, the cracks were on the inner rim, one was worse that the other, but very visible, I had no issue with losing air, I understand that is what will happen when the crack goes right through the rim,
There has been a few issues with 18`s doing it, but is mainly 19`s that suffer, I also have the run flats that I got with the car, that probably have 6mm of tread left, the first thing they said, was that the see very few for repair with non run flats, I was going to change them all when the rears need replacement, now im thinking I might change them all earlier

It’s still not a complete fix, I changed my tyres to non runflats & they still cracked again within a year-on our crummy roads they seem susceptible to it
Rob

[andyfanshawe]

So at the risk of being thick (ok, I am thick), how do you tell if the wheel is cracked, and is it dangerous?

My suspicions would be loss of air pressure and yes, could be dangerous, but is it an obvious thing, i.e. quick loss of air, or a gradual thing and only really noticeable when looking?

I have the original M-Sport 18" wheels...I know its mainly 19's that are at risk, but do 18's get it also....we have some really bad potholes down here.

Here was my cracked wheel.

Gradual loss of pressure. 3 or 4 psi per day.

Andy.

[ihadablackdog]

Thanks all, I understand it a bit better now.

[ronk]

Has anybody heard of aftermarket alloys cracking?

[eff1guy]

I was going to change them all when the rears need replacement, now im thinking I might change them all earlier

Get them changed, you won't regret it and step up the rear profile to 35 as per Mr W's and others recommendations. I wish I'd changed mine as soon as I got the car but like you was reluctant because of the remaining tread. Mine failed MOT in December with 2 cracked rears even though they were apparently checked by the same dealership during service and health check at the end of October
Between service and MOT I had covered 67 miles and I know for definite I hadn't hit a pothole let alone 2! Apparently I had also gained a buckled front wheel. I too had warranty but it was a NO and their offer was new rear wheels at £615 each and £550 for the front, I kicked up a fuss and they had it back for a runout test which it passed. They then offered 50% contribution which I still wasn't happy with. Eventually, managed to get 2 rears for £550 (£275 each) and they also fitted and balanced my new tyres for free although I had to sign a disclaimer because of the incorrect tyre type and incorrect profile on the rears.
Immediately took it to a local indy for a four wheel alignment and to get the buckle checked out, which they couldn't find. Alignment adjustments done and I haven't looked back since, so much more comfortable and enjoyable to drive

It’s still not a complete fix, I changed my tyres to non runflats & they still cracked again within a year-on our crummy roads they seem susceptible to it
Rob

Rob, did they crack again in a new spot or did the welds fail?

[Smartbear]

Hi, my wheel cracked in a new place & the existing weld was intact.
You did better than me with the new wheel discount, I was offered 10% off! The uk seems to fare much worse than other countries for this issue, I think our appalling roads are a large factor
Rob

[ronk]

...... I think our appalling roads are a large factor
Rob

In France and Germany Ive seen signs warning of poor road surfaces ahead - these poor road surfaces are often better than our normal potholed excuse for roads.

If Euro can do it, why can’t we?

[RustyZ4]

...... I think our appalling roads are a large factor
Rob

In France and Germany Ive seen signs warning of poor road surfaces ahead - these poor road surfaces are often better than our normal potholed excuse for roads.

If Euro can do it, why can’t we?

You ought to drive in some parts of Italy, make our roads look smooth

[pbr67_zed]

Just collected my car after it went in for a brake fluid change and a complementary "health check". They found a crack in one of my (19" 296) rears. No issues with losing air yet. Car was from an independent dealer, so no chance of a warranty covering the wheels.

Tiny, tiny, silver lining - the (non-BMW) garage couldn't get their equipment to reset the brake fluid service indicator, so gave me the fluid change for free! Might cover the cost of welding the wheel I suppose

[ronk]

I have a suspicion that these cracks are not due to mechanical damgage and are due to internal manufacturing stress ?

[Smartbear]

I have a suspicion that these cracks are not due to mechanical damgage and are due to internal manufacturing stress ?

It’s strange how most of the instances are to wheels fitted with runflats though Ron, they must be contributing to the failures?
Rob

[Busterboo]

It’s strange how most of the instances are to wheels fitted with runflats though Ron, they must be contributing to the failures?
Rob

Are the runflat tyres so hard that they crack the wheel, Rob?

[Smartbear]

It’s strange how most of the instances are to wheels fitted with runflats though Ron, they must be contributing to the failures?
Rob

Are the runflat tyres so hard that they crack the wheel, Rob?

I think that they don’t help an already fragile wheel survive in arduous conditions, it’s not just one thing but a combination of elements, just my opinion of course as I’m not a scientist
Rob

[Busterboo]

Do you think runflats allow wheels to touch the ground? The edges of potholes, for example?

(Were there signs on your cracked wheels that they'd touched the ground?)

[dario]

The simple fact in my opinion is that the wheels are manufactured weak. the load imposed on the inner edge is high given that the outer edge is supported by the spokes etc.

when mine turned up with 2 cracked wheels on the rear and it was going to cost me £1,100 to replace them....... to replace them again in the future i thought "I SHOULD COCO".

I bit the bullet and purchased some real wheels from a real wheel manufacturer.

my thread with the BBS wheel replacement viewtopic.php?f=23&t=95023