[TinySteel]

Hello,

I’ve a question regarding the boot space on my 325i (Auto) coupe and was hoping the experts on the forum could give me some advice?

The car currently has 19” run flats, which I was wanting to swap out for regular 19” tyres and get a space saver spare wheel.
– But there is no spare wheel well in the boot of the car. Instead, there’s a plastic insert component, which I understand from the realoem website to be called a “Multifunctional Tank – Rear: Part 41147120020”.

So, I was wondering the following:

Is there anything under this “multifunctional tank” or is it just a space filler? Should I not even consider removing it, or is it just a plastic part that BMW puts on its models that come with run flats to sound proof/fill in the spare where a spare wheel would normally go?

If, it is safe to remove it and it’s not protecting some vital organ of the car, would I be able to fit a space saver spare wheel in there?

Has anyone else done this? I’ve read in one thread, (which I can’t find now) that another owner had swapped out his run flats as part of his own larger modification program – so I'm assuming that he’d also got some kind of spare wheel in the boot?

Any advice on this would be appreciated, Thanks.

[sal_park]

I might be wrong, but I don't think a space saver will fit because the exhaust is in the way. I've ditched the run flats and have a can of spray foam to inflate the tyre.

[TinySteel]

Have you ever had to use the spray foam?
I'd considered it until one of my colleagues used it at work on his brand new Mercedes A-Class and it didn't work. In the end the dealer had it recovered and whilst the recovery driver was winching onto the flat-back, he said the foam spray is Si#t and never works.

[AWSAWS]

I also have regular tyres and tyre weld.

Worst case, call out recovery. I'm usually within 10 miles of home.

[Dace64]

I've read good reports about this...
http://www.tyre-sealant.com/car-tyre-sealant/

[Aragorn30d]

The plastic tank IS the boot floor.

If you take it out, you'll be staring at the road!

The E9x doesnt have a spare wheel well. You can buy a space saver "kit" but it just sits inside the boot:

http://farm3.static.flickr.com/2657/...e8230691a9.jpg

[TinySteel]

Thanks for your insights.
I didn't really want have a spare taking up room in the boot, as I have a young family and the boot gets used quite a lot.
I'll have another look at the tyre sealant options, I'll just have to live with the run flats for now.

Thanks for your advice.

[Jeff123]

Originally Posted by Dace64

I've read good reports about this...
http://www.tyre-sealant.com/car-tyre-sealant/

I have used it; don't bother. Wheel wobble, expense (£40+ for 4 wheels), doesnt always work, etc..

[Raju88]

Originally Posted by TinySteel

Thanks for your insights.
I didn't really want have a spare taking up room in the boot, as I have a young family and the boot gets used quite a lot.
I'll have another look at the tyre sealant options, I'll just have to live with the run flats for now.

Thanks for your advice.

You could do something like in the link and then buy the BMW boot netting to keep it in place

https://www.bmwland.co.uk/forums/vie...9&f=4&t=137989

[HighlandPete]

Originally Posted by TinySteel

Thanks for your insights.
I didn't really want have a spare taking up room in the boot, as I have a young family and the boot gets used quite a lot.
I'll have another look at the tyre sealant options, I'll just have to live with the run flats for now.

Thanks for your advice.

Remember if you do go for a space saver spare wheel option and are short of space in the boot, if you ever have to use it, you need to have room to put a full size spare in the boot space. Not an easy solution, been there with spare wheel in the boot space.

As we know, it will most likely happen when we have a loaded car and full boot.

Best solution may be to ensure you get the best riding RFTs available, next time you need new tyres.

HighlandPete

[TinySteel]

Hi Pete,
Can you recommend any run flats?
The cars currently running on Bridgestones. The ride is really hard, I'm not sure if it's the run flats, or the fact that their 19" rims - which can't really help, especially with the state of the roads around here (well anywhere in the UK really).

[John320d]

My last run-flats were on my 58 reg bmw. Has there been any improvement in ride or sound quality since then?

[TinySteel]

Originally Posted by John320d

My last run-flats were on my 58 reg bmw. Has there been any improvement in ride or sound quality since then?

This is my first BMW with run flats, previous car was an E46 convertible that had regular tyres fitted and from memory they were on 18" rims.

In comparison, I've found the ride very, very firm.

As for noise level - they are a little more audible that is was on the E46 - but I've got kids, so I do tend to turn up the radio just to drown them out!

[John320d]

I am thinking of any differences between 2008 runflats and 2015 runflats?

[djgandy]

They are still crap!

[Digitalize]

They're slowly getting better but it will never come close to a regular tyre.

[djgandy]

In fairness, if you are running a thicker profile they aren't awful. So 16/17's with a 45/50 profile are not too bad.

Runflats on 18's and 19's however are just pointless if you value ride quality at all.