Thoughts on Cracked 296 alloys please

Burgy100 · Post by **Burgy100** » Tue Feb 21, 2017 4:41 pm

Hello people,

Just like to know your thoughts on 296 Alloy Wheels. My 2 year old Z4 had all the wheels changed under warranty through corrosion!! A report came back with one of the rear wheels had a hair line crack in it and was told it was pothole damage. I have never driven it over a pothole to knowledge and as its a firm ride I think I would of felt it. After some googling it appears to be a common problem, which BMW seem to try and wash their hands of it. How do you Z4 owners with 19 inch alloys try and get over this problem? Do you accept it or try and come up with a damage limitation programme or is there something I should be saying to BMW to cover myself in this situation? Thoughts uplifting or painful would be most welcome please.

Steve

jamie_z4 · Post by **jamie_z4** » Tue Feb 21, 2017 4:44 pm

best way to combat it is to fit non runflat tyres. Also to go up a size in sidwall as the Oem sizes are quite frankly rediculous! No give in them whatsoever, might as well have fitted rubber bands!

Get yourself some goodyear 265/30 rear and 235/35 fronts it'll be fine then

Burgy100 · Post by **Burgy100** » Tue Feb 21, 2017 4:51 pm

Thank you Jamie_Z4

jamie_z4 · Post by **jamie_z4** » Tue Feb 21, 2017 4:55 pm

no problem fella.

alex · Post by **alex** » Tue Feb 21, 2017 5:43 pm

jamie_z4 wrote:best way to combat it is to fit non runflat tyres. Also to go up a size in sidwall as the Oem sizes are quite frankly rediculous! No give in them whatsoever, might as well have fitted rubber bands!

Get yourself some goodyear 265/30 rear and 235/35 fronts it'll be fine then

Does upping the tyre width causing any issues? Assume the rolling radius would be slightly larger.....but is that about it?

jamie_z4 · Post by **jamie_z4** » Tue Feb 21, 2017 6:20 pm

It's negligible mate.
My e92 is meant to be on 255 30 rear and I've gone up to a 265 30 rear

GPS reading at 70 was 68 on speedo before and it's 67 now

mr wilks · Post by **mr wilks** » Tue Feb 21, 2017 8:05 pm

jamie_z4 wrote:best way to combat it is to fit non runflat tyres. Also to go up a size in sidwall as the Oem sizes are quite frankly rediculous! No give in them whatsoever, might as well have fitted rubber bands!

Get yourself some goodyear 265/30 rear and 235/35 fronts it'll be fine then

On the 9j 296 rears i.d go 255 35 rears whether Msport or Se with 235 35 or even 225 40 if on Se spec ( more room in arch as not as low as Msport )
The speedo actually reads more accurate on these numbers or did on my own E89 when i went from the OEM staggered 18s of 255 35 18 & 225 40 18 to 255 35 19 & 235 3519

Pretty sure "lowrider" went to the bigger profiles recently on his E89 & a couple of others on forum have also done so

john-e89 · Post by **john-e89** » Tue Feb 21, 2017 8:16 pm

I put non run flat OEM size MPSS on my 19's Burgy, it's now like floating on Mr Whippy's booty. In fact in comfort mode running the door pressures, it's almost too soft, I'm going to try upping the pressures a couple of psi, you wouldn't believe the difference. Do it, you won't look back.

Busterboo · Post by **Busterboo** » Tue Feb 21, 2017 9:04 pm

best way to combat it is to fit non runflat tyres ...

What evidence is there that runflats crack wheels?

Smartbear · Post by **Smartbear** » Tue Feb 21, 2017 9:05 pm

Busterboo wrote:
best way to combat it is to fit non runflat tyres ...
What evidence is there that runflats crack wheels?

He's back!

rob

jamie_z4 · Post by **jamie_z4** » Tue Feb 21, 2017 9:15 pm

Busterboo wrote:
best way to combat it is to fit non runflat tyres ...
What evidence is there that runflats crack wheels?

There is none. It's all made up

Burgy100 · Post by **Burgy100** » Tue Feb 21, 2017 9:39 pm

Looks like this is can o worms for which I apologise, but it does seem the construction of the run flats on 19 inch alloys have so little rubber on the side wall but strengthened so much to stop them collapsing means they are so inflexible a sudden shock transfers all the energy to the alloy and ends up cracking them particularly on the rears! And reading stuff on the internet appears that BMW are fully aware of this!

If you choose non-run flats what do you do when you get a flat please? Park up and wait for help or use the black stuff to pump in the tyre or another unique way.

alex · Post by **alex** » Tue Feb 21, 2017 10:17 pm

john-e89 wrote:I put non run flat OEM size MPSS on my 19's Burgy, it's now like floating on Mr Whippy's booty. In fact in comfort mode running the door pressures, it's almost too soft, I'm going to try upping the pressures a couple of psi, you wouldn't believe the difference. Do it, you won't look back.

Good to know, planning on changing to PS4S soon on my 35is.

john-e89 · Post by **john-e89** » Tue Feb 21, 2017 10:32 pm

Burgy100 wrote:Looks like this is can o worms for which I apologise, but it does seem the construction of the run flats on 19 inch alloys have so little rubber on the side wall but strengthened so much to stop them collapsing means they are so inflexible a sudden shock transfers all the energy to the alloy and ends up cracking them particularly on the rears! And reading stuff on the internet appears that BMW are fully aware of this!

If you choose non-run flats what do you do when you get a flat please? Park up and wait for help or use the black stuff to pump in the tyre or another unique way.

I keep a couple of cans of foam and a 12v compressor in the boot. You can buy kits with everything you need as well.

Burgy100 · Post by **Burgy100** » Tue Feb 21, 2017 10:38 pm

Thanks john-e89 wise words indeed

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