bmw 2008 320d funflat problem. can you help??

[hprice1099]

Hi guys, need some of your expert help as i'm banging my head against the with this one.
My current car bmw 320d se saloon has 16" alloys with runflat tyres, i've bought 18" alloys and normal tyres for the rims, i did this after speaking to the tyre man at bmw and reading lots of reviews about runflats giving a poor ride so i got the impression from both parties that this is fine and would cause no problems.
I spoke to bme yesterday (a differant bloke) about something else and we got on to what i was doing, he told me that you should keep runflats on as the suspention will be damaged if you dont!!!!! does anyone know if this is true??? he wouldn't say if i could use normal tyres as he just went done the line of bmw will always recommend using the spec parts, blar blar blar. I'm thinking i may need to adjust the suspention but i'm not sure, or am i just over thinking it and swap them over???? help would be very gratful.
cheers guys

[DSM2]

Thousands of owners have replaced the RFTs with normal tyres, with no adverse effects - assuming they don't get a puncture, of course!

Just pack a 12V compressor, aerosol goo and /or temporary repair kit.

[gizlaroc]

hprice1099 said:

......... he told me that you should keep runflats on as the suspention will be damaged if you dont!!!!!

People like this really shouldn't be working for BMW!!


You'll be fine, just get a compressor and gunk for a spare.

There have been loads of cases now of shot to bits suspension, well bushes actually, and these are all cars with runflats on them, your suspension will think you for not having concrete tyres killing it.

[hprice1099]

Thanks guys, very useful info. cheers

[hprice1099]

Quick question guys about using that sfuff to fill your tyre with, if this is used it it possible to have the tyre reparied after use or will i have to throgh it away? cheers

[DSM2]

hprice1099 said:

Quick question guys about using that sfuff to fill your tyre with, if this is used it it possible to have the tyre reparied after use or will i have to throgh it away? cheers

The odds are it won't be repairable. Theoretically it can be but, once you have been charged for cleaning it out it's probably not viable. In any case, when it has been washed out the tyre needs a thorough drying. Can you have the car OTR for that long?

[hprice1099]

Thanks for the advice guys

[christer]

hprice1099 said:

Thanks guys, very useful info. cheers

Please also get a full alignment done so that you don't get any weird tyrewear on new tyres

[reeventu]

DSM2 said:

hprice1099 said:

Quick question guys about using that sfuff to fill your tyre with, if this is used it it possible to have the tyre reparied after use or will i have to throgh it away? cheers

The odds are it won't be repairable. Theoretically it can be but, once you have been charged for cleaning it out it's probably not viable. In any case, when it has been washed out the tyre needs a thorough drying. Can you have the car OTR for that long?

They are repairable just go to a local garage rather than the Kwik fit type places.

They have been repairing them for years , the 'goo' has been around for at least 10 years to my knowledge.

Some ' majors' just do not want the hassle and would rather sell you a new tyre.

[hprice1099]

cool thanks, it would be alot better just getting it repaired than buying a new tyre, any chance you know how much it would to have the goo removed and tyre fixed?
cheers

[vimulator]

If anything RFTs are wear out suspension components faster. They need to support the car with no air pressure, which usually means they are firmer, which means they absorb less shock, resulting in more shock to the suspension. Sidewall height matters too though, usually going from a 16 to an 18 wheel means less sidewall, less shock absorption.

[DSM2]

reeventu said:

DSM2 said:

hprice1099 said:

Quick question guys about using that sfuff to fill your tyre with, if this is used it it possible to have the tyre reparied after use or will i have to throgh it away? cheers

The odds are it won't be repairable. Theoretically it can be but, once you have been charged for cleaning it out it's probably not viable. In any case, when it has been washed out the tyre needs a thorough drying. Can you have the car OTR for that long?

They are repairable just go to a local garage rather than the Kwik fit type places.

They have been repairing them for years , the 'goo' has been around for at least 10 years to my knowledge.

Some ' majors' just do not want the hassle and would rather sell you a new tyre.

It's been around since the '70s and its no better now than it was then. There is a good chance that it won't seal an injury, especially if whatever caused the puncture has fallen out. If you're lucky it will get you home.

And, even if you can find someone who will clean the tyre out at a sensible cost don't let them repair it until it has been thoroughly dried or you risk a repair failure.

[DSM2]

vimulator said:

If anything RFTs are wear out suspension components faster. They need to support the car with no air pressure, which usually means they are firmer, which means they absorb less shock, resulting in more shock to the suspension. Sidewall height matters too though, usually going from a 16 to an 18 wheel means less sidewall, less shock absorption.

Of course the sidewalls are firmer. All of the runflats that BMW fit are SSTs (Self Supporting Tyres) and the stiff sidewalls are the basis of the design.

However, the suspension and spring rates are designed with them in mind and I have seen no evidence of premature suspension wear becasue of the SSTs. In fact it is difficult to see how they could do that, to be honest.

[vimulator]

DSM2 said:

vimulator said:

If anything RFTs are wear out suspension components faster. They need to support the car with no air pressure, which usually means they are firmer, which means they absorb less shock, resulting in more shock to the suspension. Sidewall height matters too though, usually going from a 16 to an 18 wheel means less sidewall, less shock absorption.

Of course the sidewalls are firmer. All of the runflats that BMW fit are SSTs (Self Supporting Tyres) and the stiff sidewalls are the basis of the design.

However, the suspension and spring rates are designed with them in mind and I have seen no evidence of premature suspension wear becasue of the SSTs. In fact it is difficult to see how they could do that, to be honest.

Well of course they have it in mind.... just saying if it does make a difference, the RFT will transmit more shock to the suspesnion, not necessarily premature, but they might last longer with regular tires of the same size.