Run flats front, standard's rear?
Discussion
Hello there,
I'm thoroughly enjoying my new "sensible" E90 touring BMW a little too much and it's making me think about tyres (as I'm assuming the rears will wear out first
).
It's my third beemer, the first (E39) had normal tyres, the 2nd (645 'Vert) had run flats but didn't really encourage any 'spirited' driving, so never replaced them (apart from punctures grrr).
I've always intended on swapping the run flats for standard tyres, but is it stupid to keep run flats on teh front whilst replacing teh rears only? Or is it just like running different tyres front to back?
I'm thoroughly enjoying my new "sensible" E90 touring BMW a little too much and it's making me think about tyres (as I'm assuming the rears will wear out first
).It's my third beemer, the first (E39) had normal tyres, the 2nd (645 'Vert) had run flats but didn't really encourage any 'spirited' driving, so never replaced them (apart from punctures grrr).
I've always intended on swapping the run flats for standard tyres, but is it stupid to keep run flats on teh front whilst replacing teh rears only? Or is it just like running different tyres front to back?
Thanks for the info, looks like it shouldn't be much of an issue.
5678 said:
How would it be any different to running different non-rfts/rfts front to rear?
I assumed, because the run flats have much stiffer sidewalls (hence the reduced ride quality) that they'd have very different characteristics. More so than two different tradtional tyres. bobalog said:
I assumed, because the run flats have much stiffer sidewalls (hence the reduced ride quality) that they'd have very different characteristics. More so than two different tradtional tyres.
I've recently switched to non-rfts and the sidewall difference is noticeable (for the better.) V8mate said:
I can confirm that no deaths ensued.
- Likes this*
I did precisely this with my 335D Sport. I ran NRF Michelin PS2s on the rear and RF Michelins on the front for at least six months and 5K miles. It felt strange to start with, purely as a result of the increased compliance in the NRF sidewalls (the DSC light seemed to light up more frequently, but I suspect the system may be addaptive and it subsequently settled down to the point whereby it came on as infrequently as when the car had the RF tyres all round)
The guys in the tyre fitting bay thought I was crazy when I told them I was just having the rear tyres replaced, much shaking of heads, sucking through teeth and "you'll have a massive accident blah blah blah" type comments. I told them as I saw it. The only thing fitting NRF tyres does to a modern BMW, is improve it.
The guys in the tyre fitting bay thought I was crazy when I told them I was just having the rear tyres replaced, much shaking of heads, sucking through teeth and "you'll have a massive accident blah blah blah" type comments. I told them as I saw it. The only thing fitting NRF tyres does to a modern BMW, is improve it.
Don't do it!
It's silly to mix tread patterns let alone RFTs with standards. The tyres are the only part of you car in contact with the road (well unless you runn really rubbish tyres and drive at pace in which case probably the sides and roof will also be in contact with the road/pavement/lampost etc). It's not a cheap rubbish car so why be foolish and do silly things with the tyres???
It may not result in an accident but if you are involved in an accident and someone is hurt then the police and insurance company will find this on your car and you will get done for it (possibly even prison if really bad and it is decided by specialist investigators that the car has effectively been modified and this interference has responsibility for the incident). Don't forget the insurance company will probably also get out of paying.
Just get decent treads all round so you can enjoy the car as it has been designed!
It's silly to mix tread patterns let alone RFTs with standards. The tyres are the only part of you car in contact with the road (well unless you runn really rubbish tyres and drive at pace in which case probably the sides and roof will also be in contact with the road/pavement/lampost etc). It's not a cheap rubbish car so why be foolish and do silly things with the tyres???
It may not result in an accident but if you are involved in an accident and someone is hurt then the police and insurance company will find this on your car and you will get done for it (possibly even prison if really bad and it is decided by specialist investigators that the car has effectively been modified and this interference has responsibility for the incident). Don't forget the insurance company will probably also get out of paying.
Just get decent treads all round so you can enjoy the car as it has been designed!
dasherdiablo1 said:
Don't do it!
It's silly to mix tread patterns let alone RFTs with standards. The tyres are the only part of you car in contact with the road (well unless you runn really rubbish tyres and drive at pace in which case probably the sides and roof will also be in contact with the road/pavement/lampost etc). It's not a cheap rubbish car so why be foolish and do silly things with the tyres???
It may not result in an accident but if you are involved in an accident and someone is hurt then the police and insurance company will find this on your car and you will get done for it (possibly even prison if really bad and it is decided by specialist investigators that the car has effectively been modified and this interference has responsibility for the incident). Don't forget the insurance company will probably also get out of paying.
Just get decent treads all round so you can enjoy the car as it has been designed!
What is the law that would have been broken?It's silly to mix tread patterns let alone RFTs with standards. The tyres are the only part of you car in contact with the road (well unless you runn really rubbish tyres and drive at pace in which case probably the sides and roof will also be in contact with the road/pavement/lampost etc). It's not a cheap rubbish car so why be foolish and do silly things with the tyres???
It may not result in an accident but if you are involved in an accident and someone is hurt then the police and insurance company will find this on your car and you will get done for it (possibly even prison if really bad and it is decided by specialist investigators that the car has effectively been modified and this interference has responsibility for the incident). Don't forget the insurance company will probably also get out of paying.
Just get decent treads all round so you can enjoy the car as it has been designed!
Roger645 said:
What is the law that would have been broken?
Indeed, as long as there is the required depth across the tread, its legal. The only law i know applying to tyres thats different is don't put crossplies and radials on the same axles. Have a suspicion that may be out of date now though...Roger645 said:
What is the law that would have been broken?
There isn't one. If the tyres fitted to the vehicle are of the correct speed rating, and have at least the minimum legal tread depth, there is not an issue.And let's not forget Alpina fit NRF tyres (albeit it in complete sets)
Just be aware that if you're unfortunate enough to be involved in an accident in which a lose of grip is cited as being a cause, your insurance company will have an instant "get out of paying" excuse.
The first thing they will do is quote BMW themselves who say not to mix runflats and standard tyres.
The first thing they will do is quote BMW themselves who say not to mix runflats and standard tyres.
4rephill said:
Just be aware that if you're unfortunate enough to be involved in an accident in which a lose of grip is cited as being a cause, your insurance company will have an instant "get out of paying" excuse.
The first thing they will do is quote BMW themselves who say not to mix runflats and standard tyres.
Have I missed the studies that show that run flat tyres give more grip, then?The first thing they will do is quote BMW themselves who say not to mix runflats and standard tyres.
Output Flange said:
Have I missed the studies that show that run flat tyres give more grip, then?
It doesn't matter to the insurance companies what any studies say. The tyre manufacturers and the car manufacturers all say do not mix runflats with standard tyres in any formation on the car.That's all the insurance companies need to be able to refuse to pay out in the event of an accident.
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