[ZiM]

hey peeps, i posted this in the main wheels and tires section but the boys in the US have a few differences i think which will affect my decision so i though i'd ask the home croud

pretty much immediately after getting the e92, i plan to get rid of the rft and stick on some nice non-rft eagle f1s or summat like that...

• is it possible to even put non-rtf shoes on the oem 230 style rim? nothing inbuilt etc?

• will it affect the sensors etc if i use a can of that quick repair stuff from halfords? (obviously this would be the backup plan since i dont want a spare tire)

i have a funny feeling i'm gonna get bad answers to these questions cuz if the answers were both fine i reckon everone would be stepping back to non-rft tires wouldn't they? seems a no-brainer in terms of comfort & performance :

no?

[- Paul -]

From what I've worked out so far - you should be fine. The flat detection is done by monitoring the wheel rotation.

[ZiM]

in that case... i genuinely dont see why everyone doesnt do this? we like bmws because they are drivers cars and its all about the excellent driving experience and performance - but the majority of people keep the run-flats so they can get to a garage and not have to get their hands dirty?

i've been driving a fair few years and i've never had a flat tire (touch wood) i sure as hell aren't willing to sacrifice a signifcant amound of ride quality etc on a rarity like that? why are all you?

the fact that the m-division, alpina boys and schnitzer people aren't going with RFTs says it all i reckon :

its obvious why bmw have used them tho, less weight, the fact that "professional" people like such conveniences, and they are using an emerging technology and trying to stay on top of the game... sod that!

[- Paul -]

Tough call. I ONLY have a 320D and it's mainly used for getting to work and back so the backup of being able to limp to the tyre place is reason enough to stay with them for me. If I had a 335 and was using it for pleasure /track days etc - the choice would be different.

[- Paul -]

Also just figured you have the coupe. Not sure if they have the same system as E90's for flat detection.

[vivekk]

Originally Posted by ZiM

in that case... i genuinely dont see why everyone doesnt do this? we like bmws because they are drivers cars and its all about the excellent driving experience and performance - but the majority of people keep the run-flats so they can get to a garage and not have to get their hands dirty?

i've been driving a fair few years and i've never had a flat tire (touch wood) i sure as hell aren't willing to sacrifice a signifcant amound of ride quality etc on a rarity like that? why are all you?

the fact that the m-division, alpina boys and schnitzer people aren't going with RFTs says it all i reckon :

its obvious why bmw have used them tho, less weight, the fact that "professional" people like such conveniences, and they are using an emerging technology and trying to stay on top of the game... sod that!

You need to be careful.

If you swap to non-runflats, there is the possibility BMW will claim you have not adhered to their guidance of sticking with run-flats, because 'that's what the car has been designed to work with'.

That leads to the possibility of them not giving a toss, if you have any damage (eg high speed blow out leading to 'non-standard' DSC/DTC functioning & resultant impact), which may or may not be attributed to not having run-flats. They will tell you that RFTs are there for safety & convenience (& that is probably true) and if you choose to ignore that & use non-RFTs, then the potential hazards of doing that is YOUR responsibility.

Unfortunately, I think they are likely to blame you for not adhering to their guidance & will treat you accordingly!

It is far easier for them to pass negligence over to you, than for you to claim negligence on their part- our American friends will be able to give you their experience of that!

Viv

[RockIt]

Originally Posted by ZiM

in that case... i genuinely dont see why everyone doesnt do this? we like bmws because they are drivers cars and its all about the excellent driving experience and performance - but the majority of people keep the run-flats so they can get to a garage and not have to get their hands dirty?

There's also the small matter of how much it actually costs to purchase 4 new tyres immediately after buying a brand new car... perhaps not all private owners can justify this cost.

I would prefer them for preference, but on our congested roads and with few opportunities to really push the car, the runflats will have to do for me.

[ZiM]

yeah, i understand what you're saying and i appreciate the advice... i'll think about it but i still think i'd go with non-runflats cuz the pros in my opinion vastly outweigh the cons, that is of course assuming that it doesnt mess with sensors etc... i'll have to try and find a definitive answer on this.

is there anyone on this forum running non-rfts on an e92?

RockIt: i intend to sell the rfts straight away so that'll take the brunt off it, in theory that is... if the sale won't recoup the majority of the costs i wouldn't do it anyway cuz a 7-800 quid bill is a big hit by anyones standards...

[RockIt]

I can see the logic of selling them when they are new. Now why didn't I think of that?!

[ZiM]

how much do you reckon you'd get for a set of four? and where do you think the best place to sell them would be?

[Raggie]

zim.. I'd say they only place to sel them would be e-bay..

but that said bying a new set should only be £500 ish. if you buy from somewhere like mytyres.

sell them for £250 ish.. so cost to change is not that bad imho..

Rags

[ZiM]

Originally Posted by Raggie

zim.. I'd say they only place to sel them would be e-bay..

but that said bying a new set should only be £500 ish. if you buy from somewhere like mytyres.

sell them for £250 ish.. so cost to change is not that bad imho..

Rags

do your reckon thats all they'd go for? they will be near to brand new and theres 700 quid worth of rubber there, at least, isnt there?

for the rubber i wanna get (either eagle f1s or ps2s, undecided) i'm looking at at least 650-700 quid so was gonna try and sell the rfts for about 500, do you think its not doable?

in fact there was another question, i cant even find any decent tires in 255/30/R19 - the selection is fine for the front tires but the back i dunno where you'd go... i have always used mytires but there selection for the rear size consists of about 5 tires, none all that appealing (i think the toyo proxies t1-r are the only ones i'd even consider but they aint in the same league as ps2s or the like...

[Raggie]

only an opinion on the price. but they will go for whatever they do..

only the tyres sizes.. .not sure if bmw can or will reprograme the ecu.. or if they will fit under the arches.. but there is a much better selection of tyres if you look at 35's rather than 30's. (I know mazda have adjusted the ecu's in the past for the same reasons) and Mytyres have some nice RE 05A's @ only £183

Even if BMW will not do it you will need to do the maths but undereading on the speedo should only be 3% ish.. speado by design are set to overead.. so may.. balance out..

you wil lneed to do some more checks before taking that route..

rags

[ZiM]

i was thinking about tire sizes actually... do bmw set the suspension to be 5mm lower at the back (i figure they (front and back) are both 19" and the width shouldn't figure into the equation so the car would actually be higher at the back... is this the case?

[the_oracle1980]

BMW stopped using tyre pressure sensors circa 2003. They use the wheel speed sensors to detect a flat or loss of pressure in a wheel, as a lower inflated tyre/flat tyre turns slower in relation to the other wheels. Oh and that stuff about BMW saying that the car was designed to work with runflats. As long as you dont do silly tyres sizes away from the original tyre sizes possible, as written on the door pillar you will be fine. A BMW dealer will be quick to sell you a set of Alpina or AC Schnitzer rims which come with normal tyres. So they contradict themselves a little.

[ksfrogman]

Originally Posted by ZiM

in that case... i genuinely dont see why everyone doesnt do this? we like bmws because they are drivers cars and its all about the excellent driving experience and performance - but the majority of people keep the run-flats so they can get to a garage and not have to get their hands dirty?

i've been driving a fair few years and i've never had a flat tire (touch wood) i sure as hell aren't willing to sacrifice a signifcant amound of ride quality etc on a rarity like that? why are all you?

the fact that the m-division, alpina boys and schnitzer people aren't going with RFTs says it all i reckon :

its obvious why bmw have used them tho, less weight, the fact that "professional" people like such conveniences, and they are using an emerging technology and trying to stay on top of the game... sod that!

RFTs are not just a convenience, but touted as a safety feature. It's much easier to control a car with tires that do not blow out at 100 mph when going over a road hazard. Such was the case with that guy with an E90 330i as he evaded cops after being spiked.

[booforty]

Why do you want to change? The RFT's on the E90 are superb and the ride is surprisingly smooth and comfortable AND I'm on firmer sports suspension. The safety aspect is also a massive plus point

[NFS]

Originally Posted by ZiM

i was thinking about tire sizes actually... do bmw set the suspension to be 5mm lower at the back (i figure they (front and back) are both 19" and the width shouldn't figure into the equation so the car would actually be higher at the back... is this the case?

The second digit in the tyre size is the 'aspect ratio'.

Aspect ratio = height/width * 100

With 18 inch wheels you get:

225/40/18 front and 255/35/18 rear

The height of the sidewall would be 90mm front and 89.25 rear. So near as damn it the wheels are the same size.

I had 19 inch rims on my 530d which were:

245/35/19 front and 275/30/19 rear.

Front sidewall was 85.75 and rear was 82.50

These are slight differences which and this ignores the curvature of the tyres.

I dont think anything would be visible and the car would not be set up any differently just because of the mixed tyres.

The BMW oem wheels are perfectly capable of using non-runflat tyres. I'm not sure about the tyre sensor though.

I though the old system measured rotational speed, but that the new one did include sensors. I have seen posts on this forum where people have had problems with this one aftermarket wheels.

In theory though, I can't see how changing from runflat to non runflat with the same size tyres could cause a problem.

My 530d tyres were not runflats as they were not available in 19 inch format then. They worked perfectly well with my tyre monitor.

The downside is that 275/30/19's are not easy to get hold of (but then that is also the case for runflats).

[NFS]

Originally Posted by beauforty

Why do you want to change? The RFT's on the E90 are superb and the ride is surprisingly smooth and comfortable AND I'm on firmer sports suspension. The safety aspect is also a massive plus point

I agree on this. Loads of people on e60.net were very stressed about changing tyres. Since I didn't have runflats on my e60 I was a bit worried about them on the e90.

I have to say - I've had no problem at all. Handling is superb.

[the_oracle1980]

LOL this topic will be discussed for years and years on every BMW forum. I use to have a Z4. On the Z4 forum, every two weeks it was bought up. Each to their own. I am for runflats, rft and normal tyres both have pro's and cons.
More and more tyre makers are starting to make them and their ride is improving all the time. I had a 330 with Bridgestone rft's and now my current one has Michelin runflats which are not as hard.

[gjdavies]

What would an insurance company say in the event of a major accident where the cause of the accident or the results were attributed to having the incorrect tyre on the vehicle? Is BMW's recommendation somehting that an insurance company would look at? I think it might be.

For example, several acccident investigations have come to the conclusion that having Non Extra Load tyres caused a blowout. My fleet company made Kwik Fit swap 4 newish tyres for extra loads when they found out for this very reason.

Could the same scenario occur with non run-flats?

[Raggie]

Originally Posted by gjdavies

What would an insurance company say in the event of a major accident where the cause of the accident or the results were attributed to having the incorrect tyre on the vehicle?

or maybe... the cause of the accident was becuase the run flats BMW specifed had a fault.. say a batch problem.. does that make the fault of the accident BMW.. the tyre companys.. or the driver... .???

Surpose the tyres were over inflated.. this could have caused the runflats to fail.. ???

I think this is getting a bit extreme.. IMHO..

As long as you fit a tyre the correct size for the rim, with the correct speed rating.... and you ensure as a driver that the tyres are in good servicable condition inflated correctly and within the leagal wear limtis for the road..

I do not think for one second an Insurance company would give two hoots if the tyres were run flats or not.

And for the record.. when the first set of tyres need changing I will fit the best set I can lay my hands on regarding if they are run flats or not..