Bridgestone to Good Year. Iffy handling...

enuff_zed said:
Nictrix said:
strugglinauthor said:
Ok, I had a long chat with a very helpful guy in Goodyear's technical team and I have an answer. I wasn't aware that BMW approved tyres are 'star marked'. Now whether this means that all Bridgestone RE05s are star marked or you specifically have to ask for them to be, I've no idea. Anyway, the Goodyears I fitted are not star marked. What this all means is that within the international standards on tyre construction a small margin of tolerance is allowed on tyre sizes and we're talking a few mm here. With star marked tyres the sizes are exact. The guy said that the software in all but the very newest BMWs can get upset when the tyre is not star marked and so, presumably, could be fractionally smaller or larger. As far as the software is concerned the tyres are not travelling at the correct speed and so it detects a skid situation.

The only solution, which is what I kinda expected, is to switch back to a star marked tyre or, to be safe, a Bridgestone RE05. The guy agreed that matching the fronts with the rear Goodyears should help to fool the software. He said that if other Z4 owners have done this successfully then I'm likely to be OK, but he couldn't guarantee it.

So there you go. Looks like I'll have to go with Plan B and switch the rears back to Bridgestone.

If anyone would like to buy some Eagle F1s with a about 100 miles on them then let me know! :D
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This is more of an issue with 4 wheel drive cars with staggered tyre fitments as the transfer boxes struggle to cope with different tyre diameters and can prematurely knacker the box. The tyres being star marked mean that the tolerances in the diameters are smaller.
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That's interesting. My daily 335d X-drive may be susceptible to this then, but as 90% of the time most of the drive is to the rear wheels, surely they would wear faster and then the mismatch in diameters should cause an issue? All sounds a bit 'smoke and mirrors' to me, but then I'm no car mechanic :?
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Yip exactly. I have an X6 and when you start reading about it it can worry you a bit. A set of tyres for the X6 is pretty much £900+.
The transfer box can tolerate small differences in the rolling diameter between the front and rear tyres which would cater for some tyre wear but rumours say any more than 2-3mm difference in tread on star marked tyres can also lead to problems.
If you have a car under BMWs warranty and use non star marked tyres they will apparently knock back any warranty claims for the drive train.
Its obviously a known issue to them but outside of BMW people will advise to fit 4 tyres at the same time to limit the possibility of transfer box problems. Rear diff problems I think is another issue something to do with diff wind up.
Theres a member on the Xdrivers forum that rebuilds transfer boxes and as far as he has said its almost a wear and tear item.
 
Star marking ? This sounds a little preposterous. Who would ever know anyway ( as has been shown here).
My Audi has 4 wheel drive and the transfer box operates within limits if with a 5mm difference in tread depth between front and rear (but needs closer tolerance across the same axle). That’s about the difference between a new and fully worn tyre. That would make sense to cater for just about the most extreme case of normal, legal, consumer use.
Manufacturers would be mad to start imposing such ridiculously tight tolerances on a generally unknowing public surely.
 
strugglinauthor said:
Ok, I had a long chat with a very helpful guy in Goodyear's technical team and I have an answer. I wasn't aware that BMW approved tyres are 'star marked'. Now whether this means that all Bridgestone RE05s are star marked or you specifically have to ask for them to be, I've no idea. Anyway, the Goodyears I fitted are not star marked. What this all means is that within the international standards on tyre construction a small margin of tolerance is allowed on tyre sizes and we're talking a few mm here. With star marked tyres the sizes are exact. The guy said that the software in all but the very newest BMWs can get upset when the tyre is not star marked and so, presumably, could be fractionally smaller or larger. As far as the software is concerned the tyres are not travelling at the correct speed and so it detects a skid situation.

The only solution, which is what I kinda expected, is to switch back to a star marked tyre or, to be safe, a Bridgestone RE05. The guy agreed that matching the fronts with the rear Goodyears should help to fool the software. He said that if other Z4 owners have done this successfully then I'm likely to be OK, but he couldn't guarantee it.

So there you go. Looks like I'll have to go with Plan B and switch the rears back to Bridgestone.

If anyone would like to buy some Eagle F1s with a about 100 miles on them then let me know! :D
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Sounds like tosh to me....but I am no expert.

I put Uniroyal Rainsports (not star marked?) on my Zed last year and changed the tyre profile from standard to give a better profile (i.e. more cushion) on my 19 inch wheels.

I have not experienced anything like what you have experienced, so in my opinion the tyre diameter has nothing to do with it.

Also, what about those that have changed the size of wheel rims - this presumably would also upset the "software" if that was the issue?

Anyway, as I say, I am no expert but can only go on what I have experienced.
 
Z4Sparky said:
strugglinauthor said:
Ok, I had a long chat with a very helpful guy in Goodyear's technical team and I have an answer. I wasn't aware that BMW approved tyres are 'star marked'. Now whether this means that all Bridgestone RE05s are star marked or you specifically have to ask for them to be, I've no idea. Anyway, the Goodyears I fitted are not star marked. What this all means is that within the international standards on tyre construction a small margin of tolerance is allowed on tyre sizes and we're talking a few mm here. With star marked tyres the sizes are exact. The guy said that the software in all but the very newest BMWs can get upset when the tyre is not star marked and so, presumably, could be fractionally smaller or larger. As far as the software is concerned the tyres are not travelling at the correct speed and so it detects a skid situation.

The only solution, which is what I kinda expected, is to switch back to a star marked tyre or, to be safe, a Bridgestone RE05. The guy agreed that matching the fronts with the rear Goodyears should help to fool the software. He said that if other Z4 owners have done this successfully then I'm likely to be OK, but he couldn't guarantee it.

So there you go. Looks like I'll have to go with Plan B and switch the rears back to Bridgestone.

If anyone would like to buy some Eagle F1s with a about 100 miles on them then let me know! :D
Click to expand...

Sounds like tosh to me....but I am no expert.

I put Uniroyal Rainsports (not star marked?) on my Zed last year and changed the tyre profile from standard to give a better profile (i.e. more cushion) on my 19 inch wheels.

I have not experienced anything like what you have experienced, so in my opinion the tyre diameter has nothing to do with it.

Also, what about those that have changed the size of wheel rims - this presumably would also upset the "software" if that was the issue?

Anyway, as I say, I am no expert but can only go on what I have experienced.
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All valid points and I've had similar thoughts. To be fair to the guy he wasn't saying never put anything on that isn't star marked otherwise you're definitely going to have a problem. Instead he looked into the issue I was having on my car and suggested a likely cause. I guess the lesson (for me) is that if you stray away from what a manufacturer recommends then it doesn't mean you're guaranteed to have a problem, but you increase the likelihood.
 
liffy99 said:
Star marking ? This sounds a little preposterous. Who would ever know anyway ( as has been shown here).
My Audi has 4 wheel drive and the transfer box operates within limits if with a 5mm difference in tread depth between front and rear (but needs closer tolerance across the same axle). That’s about the difference between a new and fully worn tyre. That would make sense to cater for just about the most extreme case of normal, legal, consumer use.
Manufacturers would be mad to start imposing such ridiculously tight tolerances on a generally unknowing public surely.
Click to expand...

Yep, I had the same thoughts. I went back to the tyre dealer today and while chatting I said that in the many years of owning the car I've neither asked for star marked tyres before nor even known what it meant :( .

My take-away from this is that you live'n' learn. I suspect there are scores of other things to do with the car that I'll only know about when something plays up. One example I can think of is screenwash. When I first bought the car almost immediately the screen washers gummed up. I later learned that BMWs prefer certain brands of screenwash. So I switched to BMW's own and have never had a problem since. That said, like the tyres, there are probably plenty of owners who'll say that's hogwash and they've used Halford's own brand for years without any problems :wink: .
 
Okay ama put my 2 pence coin in. Ive had the bridgestone potenza on my e89 runflat, kept it for a year and literally did the jump to non runflat. I was looking at reviews, and i didnt want to splash out a heap amount but i also didnt want some crappy odd tyre on my zed. Anyways after a few consideration and probably a week or two researching i came across two options khumo’s or toyo proxies. Went up on the sizing according to mr.wilks and honestly best decision I've made after purchasing the z4 hands down. The difference is night and day, comfort and everything! I cant stress it enough.

I think personally before you jump back onto the bridgestone runflats, ask around if you could test drive a forum members z4 with non runflats and then make your decision. Also the star mark maybe something may not be something I'm just saying newer bmw’s are staying unless youve got an aftermarket or replica alloy on your zed, dont think star marked tyres going to make a huge difference. When i test drove the new z4 and the 3 series i took multiple pictures just zoomed into the tyre and no star mark. But hey each to their own correct aslong as you love your zed
 
strugglinauthor said:
Ok, I had a long chat with a very helpful guy in Goodyear's technical team and I have an answer. I wasn't aware that BMW approved tyres are 'star marked'. Now whether this means that all Bridgestone RE05s are star marked or you specifically have to ask for them to be, I've no idea. Anyway, the Goodyears I fitted are not star marked. What this all means is that within the international standards on tyre construction a small margin of tolerance is allowed on tyre sizes and we're talking a few mm here. With star marked tyres the sizes are exact. The guy said that the software in all but the very newest BMWs can get upset when the tyre is not star marked and so, presumably, could be fractionally smaller or larger. As far as the software is concerned the tyres are not travelling at the correct speed and so it detects a skid situation.

The only solution, which is what I kinda expected, is to switch back to a star marked tyre or, to be safe, a Bridgestone RE05. The guy agreed that matching the fronts with the rear Goodyears should help to fool the software. He said that if other Z4 owners have done this successfully then I'm likely to be OK, but he couldn't guarantee it.

So there you go. Looks like I'll have to go with Plan B and switch the rears back to Bridgestone.

If anyone would like to buy some Eagle F1s with a about 100 miles on them then let me know! :D
Click to expand...

That's not all bullshit. The star marking is actually a thing. For tyres like the Michelin Pilot Super Sport which come as OEM fitment on the high end BMWs they have a little star marked on the tyre to signify that the tyre is to OEM specification. I was told that there were slight differenced in the construction of the star marked tyres that were a result of feedback from BMW. I don't use OEM wheel widths so it's not possible to get star marked tyres as I have to increase tyre width to maintain correct fitment.

There will be no significant difference between a star marked and non star marked tyre in tyres of identical sizes so what he said about it causing issues with stability control is a little OTT. What he may have been alluding to is making changes to the rolling radius of the tyre. If you change the rolling radius of the rear tyres (by increasing the tyre profile) and don't make the same proportional change to the fronts or vice versa then you will start to impact on the operation of the stability controls. This will cause issues with DSC and ABS (wheel speed is the main variable for those systems), in fact I've seen several threads started by people on E90post about their traction control going crazy after changing tyres which always comes back to incorrect rolling radius.
 
R.E92 said:
strugglinauthor said:
Ok, I had a long chat with a very helpful guy in Goodyear's technical team and I have an answer. I wasn't aware that BMW approved tyres are 'star marked'. Now whether this means that all Bridgestone RE05s are star marked or you specifically have to ask for them to be, I've no idea. Anyway, the Goodyears I fitted are not star marked. What this all means is that within the international standards on tyre construction a small margin of tolerance is allowed on tyre sizes and we're talking a few mm here. With star marked tyres the sizes are exact. The guy said that the software in all but the very newest BMWs can get upset when the tyre is not star marked and so, presumably, could be fractionally smaller or larger. As far as the software is concerned the tyres are not travelling at the correct speed and so it detects a skid situation.

The only solution, which is what I kinda expected, is to switch back to a star marked tyre or, to be safe, a Bridgestone RE05. The guy agreed that matching the fronts with the rear Goodyears should help to fool the software. He said that if other Z4 owners have done this successfully then I'm likely to be OK, but he couldn't guarantee it.

So there you go. Looks like I'll have to go with Plan B and switch the rears back to Bridgestone.

If anyone would like to buy some Eagle F1s with a about 100 miles on them then let me know! :D
Click to expand...

That's not all bullshit. The star marking is actually a thing. For tyres like the Michelin Pilot Super Sport which come as OEM fitment on the high end BMWs they have a little star marked on the tyre to signify that the tyre is to OEM specification. I was told that there were slight differenced in the construction of the star marked tyres that were a result of feedback from BMW. I don't use OEM wheel widths so it's not possible to get star marked tyres as I have to increase tyre width to maintain correct fitment.

There will be no significant difference between a star marked and non star marked tyre in tyres of identical sizes so what he said about it causing issues with stability control is a little OTT. What he may have been alluding to is making changes to the rolling radius of the tyre. If you change the rolling radius of the rear tyres (by increasing the tyre profile) and don't make the same proportional change to the fronts or vice versa then you will start to impact on the operation of the stability controls. This will cause issues with DSC and ABS (wheel speed is the main variable for those systems), in fact I've seen several threads started by people on E90post about their traction control going crazy after changing tyres which always comes back to incorrect rolling radius.
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This would seem logical. After all, there are plenty of people who appear to have changed all four tyres and had no issues. Even the guy at Goodyear said that I'd likely be OK if I switched all four, but he wisely stopped short of guaranteeing it.
 
strugglinauthor said:
This would seem logical. After all, there are plenty of people who appear to have changed all four tyres and had no issues. Even the guy at Goodyear said that I'd likely be OK if I switched all four, but he wisely stopped short of guaranteeing it.
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In your situation I would replace the fronts with matching Goodyears. I've never seen a person get rid of run flat tyres and regret it.
 
R.E92 said:
strugglinauthor said:
This would seem logical. After all, there are plenty of people who appear to have changed all four tyres and had no issues. Even the guy at Goodyear said that I'd likely be OK if I switched all four, but he wisely stopped short of guaranteeing it.
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In your situation I would replace the fronts with matching Goodyears. I've never seen a person get rid of run flat tyres and regret it.
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Funnily enough the Goodyears that I've just had fitted are run flats as I knew enough not to mix construction types. I did consider changing the fronts to matching Goodyear run flats but it would be galling as there's still plenty of miles in the current Bridgestones.
 
The star marked thing is grasping at straws IMHO. The majority of E85/86 owners are on non-runflats and and non star marked tyres with no issues. I suspect it's another BMW ploy to keep people buying tyres from dealers and the warnings are no more valid than "dont fit non RFT's to BMW RFT rims", many of us have done it, no problems reported.
Re: Rolling radius differences front to back, lets not forget that they wear at vastly different rates easily knocking an extra 2 or 3 mm off the rear during a tyres life (4 -6 mm rolling radius) which is way more than supposed manufacturing differences in unmatched sets etc. Rolling radius differences are only an issue on the same axle on our 2wd Z4's, or on 4wd transmissions. A difference front to rear should be a non-issue or most of us, or we would all be flopping around with lights pinging off!

I think the most likely cause of your dodgy grip and traction light issue is down to differing grip from the tyre sets and tread/sidewall characteristics working badly, perhaps with underlying suspension wear/alignment now being exposed as others mentioned.
 
This sound like the same issue i'm having with my newly brought Z4 35is

I changed my 2 rear tyres to Goodyear non run flats but left the front Bridgestones run flats on the car as they had lots of tread left.
My car feels all over the place at at the rear end anything over 60mph on the motorway. keeping it in a straight line means little adjustments to the steering. If i floor it it just become scary to drive at first. I'm a little more use to it now.

I am having the front tyres changed tomorrow to the same Goodyear non runflats. Fingers crossed this sorts out the issue.
If this does fix my issue it may give you what you need to keep the Goodyear's and remove the Bridgestone's from the front of yours.
 
Strikerxtx said:
This sound like the same issue i'm having with my newly brought Z4 35is

I changed my 2 rear tyres to Goodyear non run flats but left the front Bridgestones run flats on the car as they had lots of tread left.
My car feels all over the place at at the rear end anything over 60mph on the motorway. keeping it in a straight line means little adjustments to the steering. If i floor it it just become scary to drive at first. I'm a little more use to it now.

I am having the front tyres changed tomorrow to the same Goodyear non runflats. Fingers crossed this sorts out the issue.
If this does fix my issue it may give you what you need to keep the Goodyear's and remove the Bridgestone's from the front of yours.
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Thanks for the info :thumbsup: . Your situation is slightly different in that you've mixed run flats and non run flats. I hope moving to all Goodyear non runflats gives you what you need, but unfortunately I cannot do the same without discarding two brand new Goodyear runflats and the Bridgestone fronts, which are only part worn.
 
strugglinauthor said:
... Thanks for the info :thumbsup: . Your situation is slightly different in that you've mixed run flats and non run flats. I hope moving to all Goodyear non runflats gives you what you need, but unfortunately I cannot do the same without discarding two brand new Goodyear runflats and the Bridgestone fronts, which are only part worn.
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Since the only contact we have with the road is four pieces of rubber, each with a contact surface smaller than a sheet of A4, it seems reasonable to maximise the performance they give us.

Compromising that performance in any way, most of all for a few quid, seems unwise, doesn't it?
 
Busterboo said:
strugglinauthor said:
... Thanks for the info :thumbsup: . Your situation is slightly different in that you've mixed run flats and non run flats. I hope moving to all Goodyear non runflats gives you what you need, but unfortunately I cannot do the same without discarding two brand new Goodyear runflats and the Bridgestone fronts, which are only part worn.
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Since the only contact we have with the road is four pieces of rubber, each with a contact surface smaller than a sheet of A4, it seems reasonable to maximise the performance they give us.

Compromising that performance in any way, most of all for a few quid, seems unwise, doesn't it?
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Agreed. But I'm not compromising performance or safety, if that's what you meant? As far as I know I'm no safer on the road with the Goodyears than I am with the Bridgestones. I know a lot of people on here don't favour the Bridgestones but my car has always felt pretty good with them on. Anyway, the plan is to replace the rears with Bridgestones, store the Goodyears (because the fitter won't take them back) and thenn refit them at a later date as I figure the Bridgestones should all wear out at about the same time :)
 
I can confirm I changed to all non runflat Goodyears and the backend is no how it should be.
I have never known a car to dislike different tyres to this extent. I lived on mix match tyres as a young lad. Just getting what ever I could on the cheap to keep my cars on the road.
This is the first car I have experienced that had this problem with the backend on different front and back tyres.

All I had done is different tyres. No other work needed to fix my wobbly backend on my 35is.
 
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