Tyre Cracking/separation

Had0uken! · 11-08-2017, 03:28 PM

Not the usual 19" alloy wheel cracking question...

What causes the inner tread rubber to crack? Or look like the sidewall is coming away? Reason being I had 2 new Bridgestone Potenza RE050A put on just over a year ago, ditched them for non run flats today and when the 2 front bridge stones were taken off they were circumferential cracks in the sidewall all the way around on both- tyres can't have done more than 10k.

The garage also said they look like they've been run on flat - can't be the case as I put them on brand new, never had any punctures or pressure issues and always ran them at around 40psi. Tbh they said the same about the rears being run flat when they were changed a 6 months ago and they'd never been run flat either - could it be too little tyre pressure? Even though I run 40psi front and 44 rear.

I know alignment needs doing as I'm getting inner tyre wear but could that have caused the cracking?

Pics attached.

11-09-2017, 07:12 AM

Whoa.

Unrelated, but 40+ psi is a $hit ton of pressure.

What is the date code on the tires?

Had0uken! · 11-09-2017, 08:33 AM

Not sure on date code - i'll check that tonight. They were purchased new around a year ago and are BMW * approved - 10k miles on them might even be pushing it, could even be closer to 7-8k. No punctures, no damage or cracked alloys on the front. just the inside rubber cracking.

These were run at 40ish Psi on the front as the door sticker for the E93 convertible says 2.6 bar front for 2 people or 3.0 bar front for full load - so rather than the lowest 38 psi or highest of 44psi i went in the middleish so 40.

I've heard guys running 19s on the MV4's are 33fr 38r psi but the minimum on my door sticker for these tyre sizes are 38fr 41r.

6ixSpd · 11-09-2017, 01:48 PM

E93s need a shit tonne of rear tire PSI for all that weight back there. Keeping them any less results in ridiculously fast inner tire wear and sometimes separation.

Did you routinely stay on top of your tire pressure or just set them once and forgot about it? That sidewall separation and focussed excessive inner wear looks like they were running lower than they should be for quite some time.

The exact same thing happened to my father's E93 335i... No punctures, but it was running lower than minimum PSI for a long time, eventually the sidewall started wearing and cracking, exacerbating the drop in air pressure until one day it just came apart entirely.

juld0zer · 11-12-2017, 04:54 AM

To be honest, I think I've only seen this on E92 and E93 with the 19" wheels. Same scenario - not old tyres, rapid edge wear with heaps of meat left in the middle.

In my opinion it is due to the very low profile, RFT characteristics, cornering loads, front axle behaviour in turns and large diameter. All you have to do is turn the steering wheel full lock and have a look at what happens to the tyre. That's why even at the placard pressures, the edges wear really quick.

11-08-2017, 03:28 PM	#1
Had0uken! Private 21 Rep 68 Posts Drives: BMW 335i E93 Convertible Join Date: Sep 2016 Location: Western Yorkshire iTrader: (1)	Tyre Cracking/separation Not the usual 19" alloy wheel cracking question... What causes the inner tread rubber to crack? Or look like the sidewall is coming away? Reason being I had 2 new Bridgestone Potenza RE050A put on just over a year ago, ditched them for non run flats today and when the 2 front bridge stones were taken off they were circumferential cracks in the sidewall all the way around on both- tyres can't have done more than 10k. The garage also said they look like they've been run on flat - can't be the case as I put them on brand new, never had any punctures or pressure issues and always ran them at around 40psi. Tbh they said the same about the rears being run flat when they were changed a 6 months ago and they'd never been run flat either - could it be too little tyre pressure? Even though I run 40psi front and 44 rear. I know alignment needs doing as I'm getting inner tyre wear but could that have caused the cracking? Pics attached. Attached Images
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11-09-2017, 07:12 AM	#2
FCobra94 Guest 0 Rep n/a Posts Drives:	Whoa. Unrelated, but 40+ psi is a $hit ton of pressure. What is the date code on the tires?
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11-09-2017, 08:33 AM	#3
Had0uken! Private 21 Rep 68 Posts Drives: BMW 335i E93 Convertible Join Date: Sep 2016 Location: Western Yorkshire iTrader: (1)	Not sure on date code - i'll check that tonight. They were purchased new around a year ago and are BMW * approved - 10k miles on them might even be pushing it, could even be closer to 7-8k. No punctures, no damage or cracked alloys on the front. just the inside rubber cracking. These were run at 40ish Psi on the front as the door sticker for the E93 convertible says 2.6 bar front for 2 people or 3.0 bar front for full load - so rather than the lowest 38 psi or highest of 44psi i went in the middleish so 40. I've heard guys running 19s on the MV4's are 33fr 38r psi but the minimum on my door sticker for these tyre sizes are 38fr 41r.
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11-09-2017, 01:48 PM	#4
6ixSpd Save the manuals! 6053 Rep 6,758 Posts Drives: '16 M3, '23 718 Spyder Join Date: Feb 2016 Location: 416 iTrader: (4)	E93s need a shit tonne of rear tire PSI for all that weight back there. Keeping them any less results in ridiculously fast inner tire wear and sometimes separation. Did you routinely stay on top of your tire pressure or just set them once and forgot about it? That sidewall separation and focussed excessive inner wear looks like they were running lower than they should be for quite some time. The exact same thing happened to my father's E93 335i... No punctures, but it was running lower than minimum PSI for a long time, eventually the sidewall started wearing and cracking, exacerbating the drop in air pressure until one day it just came apart entirely. __________________ '16 M3 \| '23 718 Spyder Past: E92 M3, F87 M2, E39 M5, etc
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11-12-2017, 04:54 AM	#5
juld0zer Lieutenant Colonel 480 Rep 1,600 Posts Drives: Prev 135i 7DCT, Now 130i 6sp Join Date: Jul 2016 Location: 2153 iTrader: (0)	To be honest, I think I've only seen this on E92 and E93 with the 19" wheels. Same scenario - not old tyres, rapid edge wear with heaps of meat left in the middle. In my opinion it is due to the very low profile, RFT characteristics, cornering loads, front axle behaviour in turns and large diameter. All you have to do is turn the steering wheel full lock and have a look at what happens to the tyre. That's why even at the placard pressures, the edges wear really quick.
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