Hi OP - I replaced my cars Bridgestone run flats with Goodyear Eagle F1 ASY5’s which have helped reduce the crashiness and tram lining and increased grip and comfort. I went with 255/35/19 rears as the increased tyre profile (30 standard) provides extra protection of the style 326 alloys and increased comfort. It’s also worth experimenting with tyre pressures, I’m currently running 36 psi rear and 34 psi front and I’ve not noticed any issues with tyres wearing unevenly.
Getting rid of the run flats
- Thread starter Nick7602
- Start date
Pondrew said:This is a CAR forum??tiglon said:
BTW I don't like change, get the old avatar back
I can't even look at your avatar without wondering what kind of budget rubber you've got wrapped around those fancy wheels.
Burkard Bovensiepen must be turning in his grave! Yes, I googled it :rofl:
Pondrew said:Bit extreme to get a couple of worn tyres IMHOtiglon said:
There's your problem, you're only thinking about getting some worn tyres. Think bigger!
Apologies for ruining the thread, hopefully OP filtered out the nonsense and got the useful info he needed!
The rolling radius of the front and back tyres should be within 1.6% according to some BMW documentation, preferably better than 1%.
Later DSC units can cope with different front and rear rolling radius but these weren't fitted to the E89.
The DSC unit doesn't flag an error as a result of this but when its trying to manage an 'issue' for the driver it can throw a 'plausablity' error and disable part of the drivetrain until you restart the car..I found out the hard way where I ran 235/40 17 and 255/40 17 with a 2.6% error.
I got traction control failure messages, drive train errors and plausablity errors when hard launching and spinning the wheels.
Also the run flat warning goes astray..
So best to target front / rear ratios that keep within 1.6% or ideally 1% or better..the factory sizes are almost spot on.
Later DSC units can cope with different front and rear rolling radius but these weren't fitted to the E89.
The DSC unit doesn't flag an error as a result of this but when its trying to manage an 'issue' for the driver it can throw a 'plausablity' error and disable part of the drivetrain until you restart the car..I found out the hard way where I ran 235/40 17 and 255/40 17 with a 2.6% error.
I got traction control failure messages, drive train errors and plausablity errors when hard launching and spinning the wheels.
Also the run flat warning goes astray..
So best to target front / rear ratios that keep within 1.6% or ideally 1% or better..the factory sizes are almost spot on.
I'd agree with what someone said earlier about the MPSS tyres as my MC had them on 19! CSL Reps when I bought it and they had very little grip in cold and damp weather.
I swapped back to OE 18" wheels and went up one profile on the rears from 40 to 45 and have had no DSC issues. I bought Kumho Ecstas based on a thread from a year or more ago and am really pleased with them.
I swapped back to OE 18" wheels and went up one profile on the rears from 40 to 45 and have had no DSC issues. I bought Kumho Ecstas based on a thread from a year or more ago and am really pleased with them.
Nick7602 said:
Why do you want wider tyres, to increase the wall slightly, maybe better protect the rims?
I tend to stick with the std size as it's more important to get a better tyre than increase the width a nominal amount. It won't be massively significant but the wider tyre and overall increase in diameter will very slightly affect the speedo accuracy. Not really enough to worry about but as others have said more important to keep diameter of fronts and rears the same within reason
Not sure if anyone has flagged it up but those 326M wheels are notorious for cracking…the cracks propagate on the inside rim from the inside edge.
Various people opinion various views..some people say when not if and cite multiple failures ,,others claim it’s not an issue, especially if you avoid runflats.
Obviously it’s your call..often the first clue is a gradual loss of tyre pressure.
In that context I’d go for 235/35 19 and 265/30 19 to give a little extra rubber n air..
Tyre wise I’d suggest GY Assy 5 as a good trade off cost vs performance
Others would cite Vredstein as very cost effect but I have no knowledge.
Dunlop Sportmax work well as a premium tyre but not quite in the top 3 which are usually Conti, GY and Michelin.
Bridgestone have come out with some competitive tyres but few reports on Z4.
Michelin PS4 may have an edge , I’m not so sure unless you go for PS4S..I would forget PS4SS for UK.
All of course IMHO
Various people opinion various views..some people say when not if and cite multiple failures ,,others claim it’s not an issue, especially if you avoid runflats.
Obviously it’s your call..often the first clue is a gradual loss of tyre pressure.
In that context I’d go for 235/35 19 and 265/30 19 to give a little extra rubber n air..
Tyre wise I’d suggest GY Assy 5 as a good trade off cost vs performance
Others would cite Vredstein as very cost effect but I have no knowledge.
Dunlop Sportmax work well as a premium tyre but not quite in the top 3 which are usually Conti, GY and Michelin.
Bridgestone have come out with some competitive tyres but few reports on Z4.
Michelin PS4 may have an edge , I’m not so sure unless you go for PS4S..I would forget PS4SS for UK.
All of course IMHO
