Stuck in Idaho due to RFT Failure & Wheel Crack

[BOGONY]

I reluctantly purchased BMW tire insurance when I got the car. It was the best investment that I made on the car. It covers tires and wheels for 40,000 miles.
I already had three tires replced at no cost.
Talk to your dealer when you get home to see if it is available

[HerrK]

Originally Posted by BOGONY

I reluctantly purchased BMW tire insurance when I got the car. It was the best investment that I made on the car. It covers tires and wheels for 40,000 miles.
I already had three tires replced at no cost.
Talk to your dealer when you get home to see if it is available

I purchased the same BMW rim/tire insurance. With the 19" low profile RFT's and 296's I can guess that 1 replacement rim/tire will payback the cost. So far only 2K miles on the car - but I will for sure be keeping an eye on the inner tire wear.

If I see any hint of inner tire wear like Rolf experienced I will be making a trip to bring it to the attention of the dealer/service dept. They will not convince me it is normal. This is not a race car.

[tranquility]

Originally Posted by Dr Stig 2

18" rims and 35/40 profile tyres will hive you literally an extra 1/2" of compression in the tyre before you damage the rims above and beyond that of the 30/35 profile on the 19" wheels.

Statistically you will therefore survive more jolts from potholes - but the bigger / deeper ones hit at higher speeds will still ruin just about any wheel.

Ya, that's what I figured when I was test driving and I think I dinged the 19"s on the pavement hitting a rough patch. Scary sound. That made me run to the 18"s.

Originally Posted by siscobmw

I have 3 friends with 2 z4 and 19", a friend with 23i and 18" and some friend of the bmw club with e92 and 19"...now we learned that 19" equipped cars have this bad tire wear.
maybe cause 19" wheels are wider than 18s.....that half an inch more at rear could be the culprit....

I thought for the Z4 that the factory 18"s and 19"s only differ in profile, not in width?

[Dr Stig 2]

Originally Posted by tranquility

I thought for the Z4 that the factory 18"s and 19"s only differ in profile, not in width?

The tread width is the same on both.
The rim width is one size wider on the 19" (8.5J on the 18", 9J on the 19")

What this means is the tyre will have the same contact surface, and the outside tyre wall curvature is matched better.
If you look closely you will not that the tyres curve in from the rims significantly to where they touch the road.
With the larger rims you need to start slightly wider at the rim in order to get the same curvature into the road.

ANyone have access to an 18" and 19" rear wheel to take a photo? (at scale so we can side by side or overlap them?)
I'll try to draw it for you...

[mcbeee]

As the proud owner of a zed with 19" rims and factory tires and 13000kms on them I wait with bated breath for the end result of this tale.

Do I fear driving to Los Angeles, then to Arizona and then back or do I just say "WTF" let's go?

[teagueAMX]

Originally Posted by mcbeee

As the proud owner of a zed with 19" rims and factory tires and 13000kms on them I wait with bated breath for the end result of this tale.

Do I fear driving to Los Angeles, then to Arizona and then back or do I just say "WTF" let's go?

It depends, One question I've had in my mind for Rolf is if the crack went across the rim, or was in line with the bead.

If the crack went perpendicular to the rim, then Rolf inadvertently struck a good sized pothole and it's likely the small fracture progressed from there.

If on the other hand, it suffered a crack in line with the bead, then that's possibly a cumulative stress fracture. In that case the beating on the long drive had it's affect.

The third possibility is that it was a factory defect.

We know that 19" wheel are more prone to damage than smaller diameter wheels. Regardless, you should consider getting wheel/tire insurance and then say WTF, I'm hitting the road Mack!

[tranquility]

Originally Posted by Dr Stig 2

The tread width is the same on both.
The rim width is one size wider on the 19" (8.5J on the 18", 9J on the 19")

What this means is the tyre will have the same contact surface, and the outside tyre wall curvature is matched better.
If you look closely you will not that the tyres curve in from the rims significantly to where they touch the road.
With the larger rims you need to start slightly wider at the rim in order to get the same curvature into the road.

ANyone have access to an 18" and 19" rear wheel to take a photo? (at scale so we can side by side or overlap them?)
I'll try to draw it for you...

Thx for your explanation; which size did you mean matches the tire wall curvature better?

[Dr Stig 2]

Originally Posted by tranquility

Thx for your explanation; which size did you mean matches the tire wall curvature better?

The standard sizes...
for the 8.5Jx18": 255/35R18
for the 9Jx19": 255/30R19

They match eachother in sidewall curvature, when you start them from different widths and inner diametres...
I only drew one tyre on the image, but imagine that there are two tyres superimposed, each one starting at the respective rim lip.
As the 19" tyre is a lower profile, it has less distance to curve over before it touches the road, so it has to start out from a wider starting position...

[tranquility]

Originally Posted by Dr Stig 2

The standard sizes...
for the 8.5Jx18": 255/35R18
for the 9Jx19": 255/30R19

They match eachother in sidewall curvature, when you start them from different widths and inner diametres...
I only drew one tyre on the image, but imagine that there are two tyres superimposed, each one starting at the respective rim lip.
As the 19" tyre is a lower profile, it has less distance to curve over before it touches the road, so it has to start out from a wider starting position...

Can you explain in plain 'ol English?

Sorry, I'm not good at this stuff lol.

[Dr Stig 2]

Originally Posted by tranquility

Can you explain in plain 'ol English?

Sorry, I'm not good at this stuff lol.

I'll get drunk, draw some more pictures, and try again later tonight...

[mcbeee]

Well I had a look at my tires (more than the normal cursory glance) last night. At 14000km the wear pattern on the rears is even and they hardly look used at all. I'm surprised. I didnt put depth gauge in but there's lots left.

I keep my pressures up at the 44-46 psi settings as per the door labels. That being said, "Rolf, you need to definitely get the alignment done".

[Mr. ///M3 RD]

Update for you Fellows;

The new rim arrived yesterday morning at BMW and they directed me to a tire shop near there dealership (BMW does not have the equipment to change tires only to check pressure LOL).

Anyway I had the tire shop check all my wheels for cracks and low and behold the passenger side rear now also has cracks. So now I am the owner of five 19" wheels 2 of them being cracked. The one on the passenger side has two what I call hairline cracks. The wheel still holds the pressure so I decided to change the driver side rear and head for home. I am now taking a break at Starbucks and hope the passenger side holds out until I am home. I paid $666- US for the replacement rim (taking it back to my Canadian dealer for warranty).

I have a fairly good idea why my rear wheels have cracked. Keep an eye out for a post I will issue on the subject. If I don't get satisfaction from BMW I will arrange a class action suit against BMW on the tire cracking issue. If you like to find out how many people out there have the same problems then just Google "BMW 19 Inch Wheel Cracks" and read all about it.

I will add some photos in my Idaho Photo Album including the crack in the driver side rear wheel.

Meanwhile I am still 1,500 miles from my house in Eastern Canada, with every mile I hope and pray that the tire pressure alarm does not come on, driving with two bad rear tires and 2 cracks in the rear passenger side wheel. I guess you know what I mean.

Cheers,

Rolf-Dieter

[tranquility]

Oh no, didn't know it would turn out to be that scary. Hope you make it home fine and get things resolved.

[Mr. ///M3 RD]

Originally Posted by HerrK

I purchased the same BMW rim/tire insurance. With the 19" low profile RFT's and 296's I can guess that 1 replacement rim/tire will payback the cost. So far only 2K miles on the car - but I will for sure be keeping an eye on the inner tire wear.

If I see any hint of inner tire wear like Rolf experienced I will be making a trip to bring it to the attention of the dealer/service dept. They will not convince me it is normal. This is not a race car.

I will check out the insurance issue and read the fine print. What does the fine print say about pot hole damage? Will they still give you a new wheel? tire?

just for your reference, my cost was Wheel, $666- Hotel, $105- Wheel Change with tip for the boys $30- Extra expenses meals etc during waiting for wheel delivery $80- .... yes I say $1,000- for the insurance will cover it.

Cheers,

Rolf-Dieter
(keep your fingers crossed that I make it home with the passenger side also having cracks and two bad tires).

[mcbeee]

Rolf, I googled 19" rims problems and WOW !! If you do a class action suit later on let us know....No problems yet but I'll probably need it...

I had 19's on my M3 and never an issue (not RFT's). It must be a design flaw in the 296's....
I called my Service Manager and guess what? He hasn't returned my call.

Drive careful and cheer up, you'll be home soon.

[bill123]

OP, best of luck old chap

[Silver-Bolt]

Safe travels.

[mcbeee]

I'm on the phone right now to my dealer, arranging for the tire and rim insurance.....robbery to say the least.

[Dr Stig 2]

I enjoyed this clip:
http://www.bbc.co.uk/blogs/watchdog/...oy_wheels.html

[richard in NC]

Glad you got the replacement wheel. I'm crossing fingers that you don't have any more issues. And crossing them that I don't discover an issue as every once and a while, I slam into a pot hole.

[Rafale]

Wow, I am so glad to have 18" on both of my cars...

[tranquility]

I'm wondering if it's really the rim's fault there are cracks, since when I test drove a Z4 w/ 19"s, I found that it was very easy to clang the rims on the road...I never heard that noise before and it scared me enough to stop somewhere immediately to check the car...thought I hit something. Anyways, should the focus be on the tires and their (in)ability to *reasonably* prevent the rims from hitting the pavement? I have no idea.