UPDATE on my 19 Inch BMW Wheel Cracks

[Mr. ///M3 RD]

Some of you have seen my post(s) and pictures. Some have asked to be kept up-to-date on the outcome. Here then FYI is the UPDATE on my 19 Inch BMW Wheel Cracks

A) Model & Year of my car: 2009 sDRIVE Z4 35i
B) When it happened: August 10, 2010
C) Why it might have happened: I have a hunch, more about this later.
D) My mileage at the time: Approx. 18,000 KM ~ 11,180 Miles
E) My Wheel Type & Tire Sizes: Front 225/35/R19 Rear 255/30R19
F) Was it covered by warranty? Driver Side NO, Passenger Side YES
G) Was it covered by insurance? No

Remarks:

It happened in Idaho on a US road trip. I was given 2 choices by a BMW dealer in the US 1) to order a new wheel and claim warranty in Canada. Or call Roadside Assistance and have them toe me to the nearest Canadian BMW dealer (I was told that warranty policies are different in the US and Canada! Something I think BMW drivers should be aware of on both side of the border). I opted for option 1 above. During the change out the next day of the cracked wheel we found the other rear wheel also had 2 cracks (hairline cracks at that time). I decided to drive home the rest of the way (another 3,000 KM ~ 1,864 Miles). I made it home okay.

Update as of this day;

BMW will NOT warrant the driver side wheel, the verdict is the wheel has a bend. BMW will replace the passenger side rear wheel having two hairline cracks under warranty. I strongly believe that if I had standard tires I would have not been stuck with the cost of $666- plus hotel and expenses to replace a badly cracked wheel on the driver side. I will write to BMW and let my feelings be known. I think my next car might be a Audi or Mercedes for sure. Can you tell that I am pissed off, yes I am.

References:

While waiting for the overnight delivery of the replacement wheel I Googled “Cracked 19 Inch BMW Wheels” It made for some interesting reading. Why not check it out on Google for yourself.

My Tips & Cautions to others would be …

If you have 19” wheels with RFT be very aware of potholes and other ripples in the road. I also recommend as long as you have RFT on your car to be extra careful taking the sharp curves on the on and off ramps to and from express ways. I know that my RFT will be history as soon as my tread wear is at the minimum. RFT and 19 inch wheels are just not made for one another.

(Photos of my cracked Driver Side Rear Wheel can be seen when viewing my Garage below Page 2 Photos)

If you like to read more about UK Watchdog ------> Then have a look here ... very interesting

Some more Comments 305 in all about Cracked BMW Wheels ----> Right here ... if you have the time to read them all

[billwr]

Thanks for posting this in such good detail.

I had a strikingly similar experience with my 35i with 19" wheels and RFT's. Passenger side front and rear wheels both had cracks. You could pretty much copy/paste the rest of your info as my post.

BMW covered one of the two - I paid for the other. You REALLY have to be very careful when it comes to potholes. Even minor ones are a hazard to this tire/wheel combination. When it comes time to replace my tires, I'll be considering non-RFT's.

[Mr. ///M3 RD]

Originally Posted by billwr

Thanks for posting this in such good detail.

I had a strikingly similar experience with my 35i with 19" wheels and RFT's. Passenger side front and rear wheels both had cracks. You could pretty much copy/paste the rest of your info as my post.

BMW covered one of the two - I paid for the other. You REALLY have to be very careful when it comes to potholes. Even minor ones are a hazard to this tire/wheel combination. When it comes time to replace my tires, I'll be considering non-RFT's.

Bill,

I posted it in this detail (here as well as in 3 other forums, including the German one) so that others might benefit form it as well. I cannot wait until I can toss out the RFT what a joke that is. My M3 had 19 inch wheels with regular Michelin Tires, never in 4 years did I have a problem. I think the wheels will be fine with the regular tires.

I know what potholes can do and I do drive very carefully. BMW declared the wheel bend, I am not surprised with a crack like this that the wheel is no longer round. I don't expect it to pass the TIR (total indicator reading) check set by BMW. What a joke this is.

I hope we get some dialog going on this subject ... I truly think someone screwed up here and it is certainly not the BMW driver. Most of us are very careful drivers.

Thanks for your post.

[Silver-Bolt]

Rolf,
I have to agree with you. RFT's in a 30 profile coupled with cast wheels is a bad idea. At least with a forged wheel they are far more likely to retain their shape and more important, not crack. A forged wheel have far more memory than a cast wheel. If the hit is hard enough to deform it the likelyhood of a crack is very small. The RFT's transmit too much of the impact directly to the wheel. Those sidewalls are not forgiving at all.

[Mr. ///M3 RD]

Originally Posted by Silver-Bolt

Rolf,
I have to agree with you. RFT's in a 30 profile coupled with cast wheels is a bad idea. At least with a forged wheel they are far more likely to retain their shape and more important, not crack. A forged wheel have far more memory than a cast wheel. If the hit is hard enough to deform it the likelyhood of a crack is very small. The RFT's transmit too much of the impact directly to the wheel. Those sidewalls are not forgiving at all.

Right on ... you got it

Yes exactly that is my feeling. When you think about it. You steer into corners with your steering wheel and the front rims therefore see a lot less stress then the rear wheels. Once I get my wheel back from the dealer I will take additional photos that will show (black markings on the inner rim outside diameter) these marking made by the tire sidewall are stress marks in my opinion. As I said think about it the front wheels are guided into the curve and the rears are just following along. In my opinion the RFT are the culprit here .... someone screwed up (they just don't want to admit it) and believe me it is not the BMW driver. Most of us are very careful drivers.

What I ask is the difference between the cracked wheel and the one having 2 hairline cracks? The driver side was just more advanced and did crack open letting air escape triggering the low air pressure alarm. Also for the entire 18,000 KM I was the only one in the car for 15,000 KM on my road trip earlier this month I had a passenger for 3,000 KM. Starting to make sense yes any way high stress is my story and I am sticking with it.

Thanks for your post.

[Memphis1]

i just have to ask,

what's "texing"??

btw, change your profile, because if you have the 35i, you have the DCT tranny, not a "steptronic with paddles"

[Mr. ///M3 RD]

Originally Posted by Memphis1

i just have to ask,

what's "texing"??

btw, change your profile, because if you have the 35i, you have the DCT tranny, not a "steptronic with paddles"

Okay so you found a typo ... hands you a medal ...

I do have paddles see ---> This Photo here

BTW I never ever look at spelling when I read this or other forums ... I do speak and write 4 languages Memphis, how about you? Thanks for pointing it out has been corrected.

[H-Doc]

Rolf,

I don't think Memphis was doubting that you had paddles- he was pointing out that the 35i automatic is the ultracool DCT, not the steptronic "slushbox" (as some refer to it) found on the 30i. He just wanted you to give your car its due...

Nobody is getting on your case for this, or any spelling errors... try not to take out your frustrations regarding BMWs classless handling of your wheel problem on poor Memphis- he was just trying to make a joke.

We're all BMW brethren here, after all...

[Mr. ///M3 RD]

Originally Posted by H-Doc

Rolf,

I don't think Memphis was doubting that you had paddles- he was pointing out that the 35i automatic is the ultracool DCT, not the steptronic "slushbox" (as some refer to it) found on the 30i. He just wanted you to give your car its due...

Nobody is getting on your case for this, or any spelling errors... try not to take out your frustrations regarding BMWs classless handling of your wheel problem on poor Memphis- he was just trying to make a joke.

We're all BMW brethren here, after all...

Thanks for the clarification Sorry Memphis forgive me

[Alext]

If you change the tires to a different brand it may invalidate the BMW rim and tire insurance no?

Also do we know of any 'M' or BMW performance 19 inch wheels affected like the 326M and 313?

[Dr Stig 2]

Originally Posted by Alext

If you change the tires to a different brand it may invalidate the BMW rim and tire insurance no?

Also do we know of any 'M' or BMW performance 19 inch wheels affected like the 326M and 313?

Good questions... need to ask them myself...

[teagueAMX]

Originally Posted by Alext

Also do we know of any 'M' or BMW performance 19 inch wheels affected like the 326M and 313?

As to your second question, I don't think it makes much difference which 19" wheel it is, although I do believe forged wheels will fare better than a cast wheel.

1) Rolf's wheel has a lot of spokes on the spoke side of the rim, so it's not a weakness of the number or type of spokes because,

2) You note from Rolf's (and others) the wheels are cracking on the inside edge of the rim where there are no spokes.

3) The other critical factor is the camber angle of the rear wheel. From what I can tell so far, it's as much as 2.5 degrees on a BMW (unloaded). Loaded, that would be greater. Compare a honda (not a performance car, I know) it's a much smaller setting of 1 degree.

That is a significant difference when you combine a light weight rim, with a hard low profile RFT tire sidewall + the RFT "reinforcing rib" at the point where the sidewall meets the rim "bead". The 2.5 degree narrows the rim height above the ground thereby increasing the possibility of hitting an object such as pothole. IMO the reinforcing rib increases the impact to the wheel.

So to answer your question, the wheel style is not significant as the tire + wheel combination.

--

I've been analyzing this issue for a bit and have developed some CAD drawings to look at it more closely.

The first drawing shows the small amount of clearance there is with a rear wheel 255/30R19 sidewall. The dimension doesn't show very well but it's approximately 1-9/16".

The 2nd drawings shows relative camber angles.

The 3rd one shows a potential pothole impact with a depth as shallow as 1-1/2", not at all uncommon. No direct impact to the wheel is necessary to cause cracking. As you can see by the line 1-1/2" depth line, it intersects right at the bottom of the reinforcing rib.

.

[Alext]

The BMW R&T insurance policy states:
"We will not provide cover for your motor vehicle or your

motorcycle’s tyres and rims if your motor vehicle or your
motorcycle has been modified from the manufacturer’s
original specifications and these modifications
contribute to the damage of your motor vehicle or your

motorcycle’s tyres or rims."

So I guess if you change out the RFT this would count as a modification beyond the OEM specs & they could say a normal tire would contribute to the damage.

[HerrK]

Originally Posted by teagueAMX

The 3rd one shows a potential pothole impact with a depth as shallow as 1-1/2", not at all uncommon. No direct impact to the wheel is necessary to cause cracking. As you can see by the line 1-1/2" depth line, it intersects right at the bottom of the reinforcing rib.

teagueAMX,

Nice CAD drawings. Obviously the 3rd drawing is assuming full deflection of the sidewall at some pressure. Unfortunately I don't think we have enough details of the tire sidewall to assume what dynamic loading is required -vs- pressure to obtain the deflection noted. The sidewall may be stiff enough that a sharp edge impact load is being directly transmitted into the rim without that much deflection. The metalurigical properties of the rim, another unknown, cannot handle the load case. Either way it is a suspension system design issue that should have been addressed prior to release. But since that is not the case those affect by this problem should document any occurance and contact the following. Unfortunately we the Z4 19" wheel user/consumer are a very small portion of BMW's business and they obviously will not address our few complaints. Now if they get heat from the US gov and it is safety related that will be an entirely different threshold of pain.

Take photos, document the situation, and sent it off to the following.

NHTSA Headquarters
1200 New Jersey Avenue, SE
West Building
Washington, DC 20590

Toll-Free: 1-888-327-4236
Hearing Impaired (TTY): 1-800-424-9153

Media inquiries: 202-366-9550



http://www.nhtsa.gov/Contact

[richard in NC]

There is one other factor alluded to but not covered. The style 296 19's are deeply offset, more so than the CAD drawings. The spokes attach to the rim at the outside edge. There is 9 inches of rim inside of the spokes. Combine that with the camber and there is a huge load against the inside edge of the rims.

The bad news is one will need the car on a lift to inspect the rims. Years ago I had deep offset rims go out of round on cause vibration issues but never had any crack.

I did confirm I purchased the tire and rim insurance, so I should be covered if I discover any cracks. Because I know I've hit some potholes quite hard. But they seem to effect the front tires the worst.

PS: I really don't think hard cornering will do that. But potholes, for sure.

[Mr. ///M3 RD]

teagueAMX and HerrK

Thank you both for your input and analysis. Yes a great CAT drawing teagueAMX. Also HerrK thanks for posting the address, I certainly will copy them with my letter and documents I will shortly be dispatching to Germany. Your input is very much appreciated.

In my opinion this is indeed a safety issue and one of the reasons I am voicing the issue here as well as in a few other forums.

I am just so very disappointed, having driven BMW’s for the past 20 years at what I see today as far as wheels and tires are concerned. I ask what joy is it knowing your wheels may crack when you encounter bumps (almost unavoidable with all the road work going on ~ on my way from Portland, OR to Mount Rushmore I encountered miles and miles of roadwork, gravel roads for long stretches).

The “Sales Slogan” at a local BMW Dealership for the Z4 reads …

Whoever said "you can't have it all," obviously never
commanded a Z4. Its lightweight, 3.0-liter 6-cylinder
engine delivers 255-hp with an amazing 30mpg on the
highway, giving you more time to tear up the road between
fill-ups.

I hust like to add … Just don’t order this fine automobile with
19 inch wheels if you do expect more hotel room waiting time
then our proclaimed joy time on the highway.

I just like to add that my wheel with the open crack (driver side rear, nor does the other one having 2 hairline cracks) shows no markings of any contact or deflection whatsoever from road impact (be it a bump or pothole). This leads me to believe that the most likely cause of the crack in the wheel is load and stress related. As many people in England said “the wheel / tire is not fit for purpose”

[Wraith.]

Originally Posted by Alext

If you change the tires to a different brand it may invalidate the BMW rim and tire insurance no?

Also do we know of any 'M' or BMW performance 19 inch wheels affected like the 326M and 313?

I too am waiting to hear the first report of the 326M failing...

[Vintage]

Rolf-Dieter,

Thanks for this post and the information. Based on your experience I ordered a set of new NON-RFT tires, which I had been debating for some time but you pushed me in the right direction. They will be installed on my wife's car this week and I pray that no damage or cracks have yet occurred to her 19" wheels with about 8,000 miles on them.

A review of the new tires will follow once I have a chance to wear them in a bit. Thanks again and if she does get a flat I have gone over the SOS system with her in detail.

[rmorin49]

Now, I am absolutely convinced I made the right decision to swap out my RFTs at delivery and install a set of UHP non-RFTs. They ride better, handle as well, wear better, allow me to drive in all types of weather, cost less and will likely decrease the chance of a cracked wheel.

[Mr. ///M3 RD]

Originally Posted by rmorin49

Now, I am absolutely convinced I made the right decision to swap out my RFTs at delivery and install a set of UHP non-RFTs. They ride better, handle as well, wear better, allow me to drive in all types of weather, cost less and will likely decrease the chance of a cracked wheel.

You certainly did ^5 and

I am sure quite a few here will keep an eye on you how you are holding out on your tires, wear etc. One tip I've learned ... if you travel long distances with the top down and luggage in the trunk, inflate your rear tires about 10% above the recommended.

I've been browsing thru some Roundel Magazines ..... makes for interesting reading ... and why not I have the time after all I am retired

BMW Tire Add … source Roundel Magazine July 2009

Thousands are tested. Only the best are BMW Approved.

Since they’re the only contact between your BMW and the road, your tires have a significant influence on the handling and performance of your BMW. That is why you should demand BMW approved tires, because they’ve met BMW’s standards for safety and handling characteristics. As your complete source for BMW approved tires, your local BMW center offers a broad range of options for your BMW including al-season tires, high-performance tires and winter tires. Our BMW trained technicians take their service and your safety to a new level. To learn more about how tires affect performance, please visit your local dealer or www.bmwusa.com today.

THE RUN-FLATS KILLED THE DEAL … source Roundel Magazine July 2009

In 2008, I was close to purchasing a 335xi; it was BMW’s sale to lose. Given the car’s premium price relative to it’s competitors, though, my requirements were commensurately high. I ultimately bought an Audi A4 instead. Two primary reasons were the 3 Series’ open differential (on a 300-horsepower high performance sedan!) and run-flat tires. Regarding the tires, Audi’s designers and engineers managed to provide full-size tire on a matching alloy wheel, stored under the trunk, while still providing cavernous trunk space. That, by the way, was before the A4 was upsized for 2009. BMW should at least provide the option of regular tires and space below the trunk, to run-flat tires. Then even those customers choosing the run-flat-tire option could still purchase and carry a spare (full size or space-saver) without having to carry it within a trunk having limited space to begin with. Tom S. Oldwick, NJ

[Mr. ///M3 RD]

Originally Posted by VintageBMW

Rolf-Dieter,

Thanks for this post and the information. Based on your experience I ordered a set of new NON-RFT tires, which I had been debating for some time but you pushed me in the right direction. They will be installed on my wife's car this week and I pray that no damage or cracks have yet occurred to her 19" wheels with about 8,000 miles on them.

A review of the new tires will follow once I have a chance to wear them in a bit. Thanks again and if she does get a flat I have gone over the SOS system with her in detail.

My pleasure, in my engineering working life I was also responsible for quite a number of years for Quality Assurance at one of the major US manufactures. You might be able to sense that I am very safety conscious.

I certainly see this issue as a safety issue and I will not go away until BMW reimburses me for the over $1,000- I am now out for one wheel and extra expenses waiting for the new wheel to arrive during my vacation trip.

[Alext]

What percentage of blame can be placed on the RFT though?

I am thinking this is just as much or more a rim manufacturing or DESIGN issue.