Mixing runflat tyres with normal tyres

Scuzi

Scuzi

Scuzi

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As the clock has just rolled onto 15k on the Z4, the rear tyres are becoming quite close to the markers and this recent spell of greasy roads has given me more than my fair share of brown trouser moments. It's time to change the tyres and I have decided to ditch the runflats for three reasons.

1 - They're bloody expensive.
2 - There are only two different tyres available in my size. Bridgestone Potenza RE050 and Michelin PS2.
3 - The Bridgestones are absolutely rubbish in the wet and the ride quality suffers badly due to their stiff sidewalls. I don't know how the PS2s perform since I can't find a reliable review on their runflats.

The front tyres have at least 3mm left on them so I'd prefer to keep them but this poses a problem since I want to stick normal tyres on the back, probably Vredstein Ultrac Sessanta or Goodyear Eagle F1 Assymetric. Am I right in thinking that having normal tyres on the back and runflats on the front isn't a good idea?

The other option is to change all the tyres and sell the current front tyres as part worn but I don't know if they'd be worth anything.

There's also another option. I could put on the PS2 runflats in the hope that they're up to the job but at about £700 for all four as opposed to £420 for Vredsteins, it could be an expensive mistake should they turn out to be crap.

What do you reckon?
 
Vredstein came second in the evo test and F1's coming first, so I think you've answered our own question - why not just pay for all round?
 
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i don't think it would be a problem, as far as the car's concerned it's just a harder front tyre and people mix front and back all the time. As long as it's not a mix of left to right i wouldn't have thought it'd make a great deal of difference, it would just slighter alter the handling characteristics, and probably for the better

B@
 
The recommendation is to change low profile tyres at 3mm anyway, so I doubt you'll get any takers for those. I would suggest just getting four new boots.
 
I asked this on here a few weeks ago as the front tyres on my gf's z4 are pretty low but the backs are almost new. A lot of people said that you can't mix them, but fox said that his mum's had them mixed and her's was from an official dealer.
 
I'd change them all (infact I did a few months ago)
There will be quite a big difference between the stiffness front to rear.

The Michelin runflats are even more expensive than the bridgestone, something like £850 for a set.

Falken 452's are very popular on the z4-forum too and can be had for £320 delivered (fitting seperate) for a whole set. I went for Eagle F1's for £560 fitted but for a £200 saving and glowing reports, I'll probably try the Falkens next time.

As for dealers mixing tyres, I'd never go by what they do, I looked at a 3 series at a BMW dealership with one new tyre that was a completely different brand and quality to the other part worn tyres, so they hadn't even kept them the same on each axle. They just did whats cheapest and hoped it wouldn't be noticed.
 
Looks like I'd be better off swapping the lot then.

I've narrowed it down to two tyres, the Vredstein Ultrac Sessanta and the Goodyear Eagle F1 Assymetric. From camskill.co.uk, a set of Vredsteins comes to about £420 whereas a set of Eagle F1s comes to about £500. Having looked at the evo tyre test and a few others online, the Eagles perform the best when it comes to hard figures but the Vredsteins seem to be the favourite when it comes to personal opinion. I'm leaning toward the Vredsteins as they're cheaper for pretty much the same performance and a lot of petrolheads seem to rate them highly for feel, ride and their breakaway characteristics.

Falken FK452s won't be considered because I'm convinced that the only reason they're rated highly is because they're a reasonably good performer and are significantly cheaper than "proper" performance tyres. I very much doubt they're in the same league as the more expensive tyres.

The car is due it's first oil service fairly soon and I'll be leaving it into BMW to get this done. If I give them a set of tyres will they fit them for me or do they take the stance of refusing to fit non RFTs? Has anyone any experience with this?
 
Ive read about one owner who had his local BMW dealer refuse to fit non-runflats.

Also a few owners inform their insurance that they no longer use the run-flats, although Im not sure this is necessary.
 
I can get PS2s for 159 inc vat, each, around here, where did 800~ come from?
I don't think mine are run flat, though.
 
SaBBz said:
A lot of people said that you can't mix them, but fox said that his mum's had them mixed and her's was from an official dealer.
Click to expand...

This is correct but all that really proves is that:

a) I didnt check them before I bought the car
b) The dealer is inept
 
I've got on fine with different tyres on front and back.

Sure it changes the characteristics but you soon get used to it and it becomes normal.
 
I'd inform your insurance company, some can be fussy but it usualy makes no difference to your insurance costs. Mine said it's fine since it's not a performance mod, better to check with a 5 minute phone call than give them a chance to kick up a fuss later.
 
[TW]Fox;13229261 said:
Not different tyres but completely different types of tyres.
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If you are taking it to the track I can understand it, but for normal every day driving, I very much doubt you would notice any difference with 2 run flats on the front / others on the back.

If you spank it round corners / break on the limits then yeah, but most drivers wont.
 
s0ck said:
I can get PS2s for 159 inc vat, each, around here, where did 800~ come from?
I don't think mine are run flat, though.
Click to expand...

They're Runflat tyres which bumps the price up considerably. The size probably plays a big part too, 255/35/18 on the rear and 225/40/18 on the front.

I'll definitely be telling the insurance company for peace of mind more than anything. I'm giving them no excuses :p
 
[TW]Fox;13229261 said:
Not different tyres but completely different types of tyres.
Click to expand...

Why, cause they have stiffer sidewalls? Tyres vary in many ways, one of which is sidewall stiffness.

The front end of a Z4 has a very different role to play to the back end anyway.
 
Scuzi said:
Falken FK452s won't be considered because I'm convinced that the only reason they're rated highly is because they're a reasonably good performer and are significantly cheaper than "proper" performance tyres. I very much doubt they're in the same league as the more expensive tyres.
Click to expand...

I think your right there, they (the 452's) are good, but, Comparing my old 18in Bridgestone Potenzas to FK 452's when I had my e38, they wore a lot quicker - 8k for the 452's compared to around 13k for the Potenzas. :)

Run flats are awful until you get a puncture & its peeing down. ;)
 
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