X5 E70 - M Sport - changing to non run flat tyres ?

[xkrsupercharged]

My 40D M Sport needs new shoes and I am thinking of ditching the run flats and going for regular tyres - has anyone done this and is the difference noticeable?

[gizlaroc]

Depends on the tires, I have been impressed with the Michelin Lattitude Tour HP tyres on everything that is shod with them, seriously comfy and ridiculously quiet.

They do a Lattitude Sport as well, but I think the Tour is better suited, same tread as a pilot sport 2 but has snipes as well so pretty good in the winter too.

I hate run flats, well on the E90, E60, X5 etc. The new generation of cars seem much better, but still prefer proper tyres.

[xkrsupercharged]

Thanks - will look in to them.

My 20" Bridgestone Run flats are mounted to the new 333M Style Alloys (the ones notorious for corroding issues around centre cap!)...and the sizes are:

Front - 275/40/20
Rear: 315/35/20


If I moved to non run flats would it be a like for like swap in terms of tyre sizes or would I need to change the tyre size to compensate for the run flats stiffer side walls?

[LeoSayer]

Don't change the tyre size, speed rating or load rating from standard, run flat or not.

I found a big improvement in ride on my E70 with 18" wheels, but some have commented that the improvements are not as marked on larger wheel sizes.

[xkrsupercharged]

Thanks both

[Cheib]

xkrsupercharged said:

Thanks - will look in to them.

My 20" Bridgestone Run flats are mounted to the new 333M Style Alloys (the ones notorious for corroding issues around centre cap!)...and the sizes are:

Front - 275/40/20
Rear: 315/35/20


If I moved to non run flats would it be a like for like swap in terms of tyre sizes or would I need to change the tyre size to compensate for the run flats stiffer side walls?

Basically your only choice are the Vredstein Sessanta in that size....I am on my second set. There are some other makes available like Michelin but they aren't made to the correct load factor. The Vredstein are about £900 for a set.

The ride will be better than RFT's but not night and day. The 20" wheels are very low profile for such a big car....the profile is 911 esque.

I also have a set of 18" winter wheels which have RFT's, they ride better than the 20's with normal tyres.

[gizlaroc]

Cheib said:

Basically your only choice are the Vredstein Sessanta in that size.

There are two versions of that tyre, looking at specs I can't see what is different, but one is 72db and one is 69db, so I am guessing the compound is slightly softer on the quieter one.

I would go for that, loosing a bit of firmness is going to matter on a 20" 315/35 profile tyre.

http://www.camskill.co.uk/m77b0s265p111513/Vredest...

http://www.camskill.co.uk/m77b0s265p111513/Vredest...

[Cheib]

gizlaroc said:

Cheib said:

Basically your only choice are the Vredstein Sessanta in that size.

There are two versions of that tyre, looking at specs I can't see what is different, but one is 72db and one is 69db, so I am guessing the compound is slightly softer on the quieter one.

I would go for that, loosing a bit of firmness is going to matter on a 20" 315/35 profile tyre.

http://www.camskill.co.uk/m77b0s265p111513/Vredest...

http://www.camskill.co.uk/m77b0s265p111513/Vredest...

I didn't get that option! Vredstein UK didn't have a full set in when I bought mine, had to bring them in from Holland.

[gizlaroc]

I have noticed it alot recently, looking for tyres for my ML, there seem to be lots of variations of the 'same' tyre available, some up to 6db quieter than the next.
6db is a massive gain in noise, 10db is double the volume to the human ear as a rough rule of thumb.

[xkrsupercharged]

Thanks Giz - you have always been the Tyre Guru on all the BMW forums I have been on

Top man

[gizlaroc]

xkrsupercharged said:

Thanks Giz - you have always been the Tyre Guru on all the BMW forums I have been on

Top man

Haha, because when I was doing 40k miles a year and some cars were eating them every 10-12k miles on the rear you start to look into them in a big way!!

Replacing rears every 3-4 months was getting expensive!

[rj1986]

Thread revival time.
Stupid question- Can you run 275/40/20 all round, rather than manufacturer's recommended staggered 315/35/20's on the rear?
IS the bolt size difference on the fronts or rears?

Edited by rj1986 on Tuesday 19th November 14:25

[E30M3SE]

You can, will probably look a little stretched on the rim, but do you really want to? Bolt size is same front and rear.

[rj1986]

E30M3SE said:

You can, will probably look a little stretched on the rim, but do you really want to? Bolt size is same front and rear.

I should say theres a set of winters on ebay with 4x 275/40/20. Which would mean all 4 corners are the same rather than the wider rears.

Is there any reason mechanically BMW have a staggered set up? I know the wider tyres make a lot of difference on a 458, but on my soccer-mom mobile?
Is the lower profile on the rears just due to the percentage difference of the rears being wider?

[Cheib]

rj1986 said:

Is there any reason mechanically BMW have a staggered set up? I know the wider tyres make a lot of difference on a 458, but on my soccer-mom mobile?
Is the lower profile on the rears just due to the percentage difference of the rears being wider?

It's all about looks. My BMW supplied/specced 18" winter wheels and tyres are identical on all four corners.

[E30M3SE]

BMW offer a staggered winter wheel/tyre package running the summer tyre sizes, but does it really need a staggered set up in the first place, probably not, more style over substance. If you chose to run a square set up don't forget to tell you insurers you've 'modified' the car.

Yes, the lower profile on the rear is to compensate for the width, the overall diameter of 275/40 front and 315/35 rears has only a 1mm difference.

[rj1986]

Cheers guys- to ebay!!

I assume the load index can be the same all round as well? (275/40's 106 XL, and 315/15's 109XL)

Edited by rj1986 on Wednesday 20th November 08:47

[gizlaroc]

Most modern BMWs feel much nicer on a square set up anyway, gets rid of that bit of understeer they tend to build in.

[gizlaroc]

Just thought, maybe someone should let Audis owners know that running wider fronts may help their cars feel like they have some soul?

[Technomad]

gizlaroc said:

Most modern BMWs feel much nicer on a square set up anyway, gets rid of that bit of understeer they tend to build in.

That's funny - when I put my winter setup on my X5 (symmetrical) I get more pronounced understeer than I do on the assymmetric summers. Go figure…