Help...F11...weird handling after new rear tyres
Discussion
Help!
I took my F11 520d (RWD) touring into my local tyre place the other week to get a rear puncture fixed. It's a good independent tyre place, the boss is hands on, a car enthusiast and I've used them for years. He said although the puncture was repairable, I really needed new rear tyres as the inside shoulders were starting to collapse, a known problem on those particular Goodyears. Up until then, the car had always felt fine, but I went for the new tyres on his recommendation as clearly there was something wrong.
So the car now has the existing Goodyear Excellence 245/40/R19 98Y RFT on the front, and Goodyear Eagle F1 RFTs on the back, the same size (unusual for BMW). However, the car just does not feel planted on the road. Initially it felt like it needed a lot more small steering inputs at higher speeds to keep it on the straight and narrow, but also as if the handling was just a bit wayward.
Let me explain, it's a fast A road and I'm coming up to a bend that I'll take at the same speed, no braking, no change on throttle. I turn in, just a tiny amount, and immediately it feels as if I am straightaway having to back off on the steering input, no matter how small that initial input is. Almost as if the turn-in has been sharpened up to waaaay over the top levels.
Last week it got really weird. I was going from the southbound M5 onto the westbound M4 at the RAC control tower near Bristol. Totally dry road, oodles of grip. Speed, probably somewhere around a genuine 70mph, (indicated slightly more). I turned in very gently, immediately had to back off the steering input (and I'm talking teeny, tiny amounts here) and as I felt the outside side of the car load up and unload with these tiny inputs, I seemed to get into an increasing cycle and after about two cycles the traction control light actually started coming on...although clearly I was absolutley categorically nowhere near the limits of grip. It then did exactly the same thing on the return journey and the corresponding slip road. I can understand TC coming in when driving like an utter tool in the wet on a tight bend, but cruising at 2000rpm on trailing throttle on a motorway slip road that has huge grip due to the conditions just does not seem right at all. I consider myself to be a pretty adaptable driver...my other cars are a Defender and a Porsche, both devoid of any driver aids, and I keep them on the straight and narrow just fine...in fact I think the Defender would have made it round the bend with less drama! The BMW at normal speeds almost feels like the Porsche on the absolute limit, as if the Porsche is warning me it's about to break into oversteer because I'm pushing too hard on the track or something...however the BMW feels like that when I'm just trying to get around a gentle bend at totally normal/sensible road speeds!
The tyre place has said bring it back in...start with the obvious and check the tracking, pressures on the computer against a known accurate gauge, and also see if there is a difference in rolling diameter which is somehow confusing the driver aids and they are kicking in when not needed. However I am just wondering if anyone else has had a similar issue?
Thanks in advance!
I took my F11 520d (RWD) touring into my local tyre place the other week to get a rear puncture fixed. It's a good independent tyre place, the boss is hands on, a car enthusiast and I've used them for years. He said although the puncture was repairable, I really needed new rear tyres as the inside shoulders were starting to collapse, a known problem on those particular Goodyears. Up until then, the car had always felt fine, but I went for the new tyres on his recommendation as clearly there was something wrong.
So the car now has the existing Goodyear Excellence 245/40/R19 98Y RFT on the front, and Goodyear Eagle F1 RFTs on the back, the same size (unusual for BMW). However, the car just does not feel planted on the road. Initially it felt like it needed a lot more small steering inputs at higher speeds to keep it on the straight and narrow, but also as if the handling was just a bit wayward.
Let me explain, it's a fast A road and I'm coming up to a bend that I'll take at the same speed, no braking, no change on throttle. I turn in, just a tiny amount, and immediately it feels as if I am straightaway having to back off on the steering input, no matter how small that initial input is. Almost as if the turn-in has been sharpened up to waaaay over the top levels.
Last week it got really weird. I was going from the southbound M5 onto the westbound M4 at the RAC control tower near Bristol. Totally dry road, oodles of grip. Speed, probably somewhere around a genuine 70mph, (indicated slightly more). I turned in very gently, immediately had to back off the steering input (and I'm talking teeny, tiny amounts here) and as I felt the outside side of the car load up and unload with these tiny inputs, I seemed to get into an increasing cycle and after about two cycles the traction control light actually started coming on...although clearly I was absolutley categorically nowhere near the limits of grip. It then did exactly the same thing on the return journey and the corresponding slip road. I can understand TC coming in when driving like an utter tool in the wet on a tight bend, but cruising at 2000rpm on trailing throttle on a motorway slip road that has huge grip due to the conditions just does not seem right at all. I consider myself to be a pretty adaptable driver...my other cars are a Defender and a Porsche, both devoid of any driver aids, and I keep them on the straight and narrow just fine...in fact I think the Defender would have made it round the bend with less drama! The BMW at normal speeds almost feels like the Porsche on the absolute limit, as if the Porsche is warning me it's about to break into oversteer because I'm pushing too hard on the track or something...however the BMW feels like that when I'm just trying to get around a gentle bend at totally normal/sensible road speeds!
The tyre place has said bring it back in...start with the obvious and check the tracking, pressures on the computer against a known accurate gauge, and also see if there is a difference in rolling diameter which is somehow confusing the driver aids and they are kicking in when not needed. However I am just wondering if anyone else has had a similar issue?
Thanks in advance!
superlightr said:
I Had an e39 M5 a long time ago and had a similar thing - not with tyre wear but how you describe the handling/feel. In my case it was a rear anti roll bar had snapped/failed. So like you on a mway normal safe speeds, gentle bend it felt like the car was about to slide away and I had to back off - this despite bone dry and other cars going around fine. I know when it broke as it was on over taking - pulled out fine with the same amount of steering input when went to go back in with similar input it didn't want to/wasn't consistent input to get the car back. It feelt dangerous and out of control.
Had lots of other faults with that M5 that BMW bought it back and paid compensation. So perhaps the anti roll bar is broken?
Thanks but I don't think so. The handling changed immediately when the tyres were changed, so I'm convinced it's tyre related.Had lots of other faults with that M5 that BMW bought it back and paid compensation. So perhaps the anti roll bar is broken?
Guys
Thanks for the help, there's some really interesting stuff here. If the problem is that it's the difference between the tyres front and rear that's disappointing...you'd have thought that the same size RFT tyre from the same manufacturer would not be trying to throw me off a dry motorway slip road with zero provocation!
TBH I think I might just get the fronts changed for a matching pair. My tyre man showed me that the inside shoulders were starting to wear on the front too and would need changing in the not too distant future, so perhaps now is the time. Quite frankly the car is currently ruined...it's supposed to be my waft along luxury family/work meeting barge yet somehow it needs more input than the 32 year old Defender with it's multitude of steering joints and rods to keep on the straight and narrow, more skittish than the Porsche in snow and is just not relaxing to drive at all.
Kawasicki, thanks for the technical advice, I did think "who is this person" but a quick look at your profile shows you know your stuff! Thanks for the compliment on my description
, if you have any chief test drive jobs going in the future I'm sure we can work well together, for example I could describe "it swapped ends five times and ended up in the armco at 80mph, there's definitely something not quite right!"
Will report back on how things end up...thanks again people!
Thanks for the help, there's some really interesting stuff here. If the problem is that it's the difference between the tyres front and rear that's disappointing...you'd have thought that the same size RFT tyre from the same manufacturer would not be trying to throw me off a dry motorway slip road with zero provocation!
TBH I think I might just get the fronts changed for a matching pair. My tyre man showed me that the inside shoulders were starting to wear on the front too and would need changing in the not too distant future, so perhaps now is the time. Quite frankly the car is currently ruined...it's supposed to be my waft along luxury family/work meeting barge yet somehow it needs more input than the 32 year old Defender with it's multitude of steering joints and rods to keep on the straight and narrow, more skittish than the Porsche in snow and is just not relaxing to drive at all.
Kawasicki, thanks for the technical advice, I did think "who is this person" but a quick look at your profile shows you know your stuff! Thanks for the compliment on my description
, if you have any chief test drive jobs going in the future I'm sure we can work well together, for example I could describe "it swapped ends five times and ended up in the armco at 80mph, there's definitely something not quite right!"Will report back on how things end up...thanks again people!
Thanks guys...it was indeed the tyres.
I went back to my tyre place...he'd ordered a pair of F1s in for me, but insisted on swapping them round first before fitting them. The handling was totally different. I can best describe it now as if the car has had a slightly slower rack fitted. The twitchiness on the straights and constant on-off-on-off steering input on sweeping bends has now gone. But there's no hint of understeer, and fortunately it's not quite the lumbering tanker that Kawasicki has suggested it might be, however it's perhaps not quite as sharp as it was on the original tyres. it just feels like it needs perhaps a little more steering angle input than originally, but actually still feels perfectly safe and planted. I had a "play" on some bends that were scary as hell before, and the car feels fine, even at significantly higher corner speeds.
So...I can live with the current set up for now (but definitely not the previous), and as my tyre guy reckons there's still 4000 miles left on the current tyres, the new ones can sit on his shelf until they are needed...perhaps I'll get them on regardless when we start getting proper damp roads and ice (remember that?) but I may as well get what I can out of the current ones.
Thanks again for everyone's input...and I'm genuinely gobsmacked about how identically sized RFT tyres from the same manufacturer could have a car like that snaking and hobby horsing around a motorway slip road at perfectly sane and legal speeds with the traction control light flashing...just unbelievable.
I went back to my tyre place...he'd ordered a pair of F1s in for me, but insisted on swapping them round first before fitting them. The handling was totally different. I can best describe it now as if the car has had a slightly slower rack fitted. The twitchiness on the straights and constant on-off-on-off steering input on sweeping bends has now gone. But there's no hint of understeer, and fortunately it's not quite the lumbering tanker that Kawasicki has suggested it might be, however it's perhaps not quite as sharp as it was on the original tyres. it just feels like it needs perhaps a little more steering angle input than originally, but actually still feels perfectly safe and planted. I had a "play" on some bends that were scary as hell before, and the car feels fine, even at significantly higher corner speeds.
So...I can live with the current set up for now (but definitely not the previous), and as my tyre guy reckons there's still 4000 miles left on the current tyres, the new ones can sit on his shelf until they are needed...perhaps I'll get them on regardless when we start getting proper damp roads and ice (remember that?) but I may as well get what I can out of the current ones.
Thanks again for everyone's input...and I'm genuinely gobsmacked about how identically sized RFT tyres from the same manufacturer could have a car like that snaking and hobby horsing around a motorway slip road at perfectly sane and legal speeds with the traction control light flashing...just unbelievable.
gizlaroc said:
I have been laughed at and ridiculed over the years on the BMW forums for shouting this fact out.
Even when people are swapping control arms, dampers, springs, bushes etc. they still won't listen to me when I say "You have different tyres on the front to the rear."
They keep throwing money at it and simply won't accept how much different it makes.
People surely buy a BMW because of the way it drives? So why then go and try and save £150-200 buying mismatched tyres, at best it will not be as good on the limit......you know? When you really need them to be. But more often than not it feels like you have blow dampers or like you are driving on a damp road all the time.
The Traction Control Light should never really come on on a BMW, with decent tyres all round you have to really provoke the car to get it to flash, taking burying the throttle pulling out of a wet junction. If you traction comes on easier than that then you need to take a seriously look at your tyres.
Well you need to keep shouting this out and point people at this thread if needed. I could not believe how totally awful and borderline dangerous it was with 4 legal tyres from the same manufacturer fitted. Even the worn tyres are still perfectly good with plenty tread left. And just to highlight, yes I am a PHer and an enthusiast driver, but I'm not some obsessive expert or Hammond-esque "driving god". I've done a couple of beginner track days in my life, but I'm not going to pretend to know the issue was camber-this or toe-in-that. But I could not believe how unstable the car felt, and for the TC light to be flashing on a motorway slip road bend in the dry at a steady 2000rpm is not good at all. I do suspect that if I'd been towing something it could have gone horribly wrong quite quickly.Even when people are swapping control arms, dampers, springs, bushes etc. they still won't listen to me when I say "You have different tyres on the front to the rear."
They keep throwing money at it and simply won't accept how much different it makes.
People surely buy a BMW because of the way it drives? So why then go and try and save £150-200 buying mismatched tyres, at best it will not be as good on the limit......you know? When you really need them to be. But more often than not it feels like you have blow dampers or like you are driving on a damp road all the time.
The Traction Control Light should never really come on on a BMW, with decent tyres all round you have to really provoke the car to get it to flash, taking burying the throttle pulling out of a wet junction. If you traction comes on easier than that then you need to take a seriously look at your tyres.
Now that I have got used to the car in it's current config I am going to say that yes, it does feel nowhere near as sharp as it did originally. The F11 is a big, long heavy beast, but always amazed me with it's handling...now it just feels a bit dull so I will get the rear tyres swapped for F1s too.
I agree with the point made above...if the new grippy tyres were on the back, I'd have expected a feeling a feeling of mild understeer, and when the new ones went on the front I would have expected mild oversteer...not the opposite. And again, when I say "mild", please bear in mind that I am going nowhere near the limits...so I'm expecting more of a feeling/loading...not actually losing grip.
Anyway...lesson learned...still utterly amazed just how bad it was and thanks again to the experts here!!
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