Space saver wheel

UK forum for general and technical discussion about the Z3 roadster
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bowei001
Joined: Mon 13 Apr, 2009 16:38
Posts: 212

  Z3 roadster 2.0
Location: Sudbury

Space saver wheel

Post by bowei001 »

For those who have checked their space saver and found that it has fallen apart or that the tyre is so old that it is a liability, I tried to sort out possible combinations of wheels and available tyres as replacements. BMW didn't make it easy with the plastic carrier and limited space but there are solutions. I've made an Excel spreadsheet of what I think are all the options and hope it may be of use to someone. My apologies if it has been done before.
Space saver options.jpg
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Robert T
Site Admin
Joined: Mon 12 Jun, 2006 10:35
Posts: 10172

  Z3 roadster 1.9
Location: Cheshire

Re: Space saver wheel

Post by Robert T »

Good info. Thank you for posting.

If memory serves, the original 15" wheel rim is NLA, so if you are replacing, you'll need to go to 16" anyway. This is what I did a few years ago, as my rim was badly corroded. I'd also recommend coating the rim (not the tyre!) with something like waxoyl.

Cheers R.

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Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
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tiggercoco
Joined: Tue 25 Oct, 2016 20:41
Posts: 20

  Z3 roadster 2.8

Re: Space saver wheel

Post by tiggercoco »

Despite owning three Z's only now on my most recent acquisition have I sussed how to get the spare wheel out!...god what a hassle!...who designed that?...imagine if you had a puncture in the rain and had to go through all that rigmarole.

I only use the Z for local country lane pub jaunts...I think I will take my spare out to save weight then put it in the boot for any longer journeys.
EarlLeeBird
Joined: Fri 24 Jun, 2016 18:39
Posts: 9

  Z3 roadster 1.9i

Re: Space saver wheel

Post by EarlLeeBird »

Im pretty sure E36 and E46 models 316-325 use exact same 15" and E46 316-328 models exact same 16" space saver wheel. Im saying pretty sure, since RealOEM only shows part number for steel rim and not for the tire. Cross checking the part numbers for steel rim, they are same (36111095069 for 15" and 36116750006 for 16").
Not really sure what decides the 15" or 16" choice on smaller engines, maybe the market derived weight limitation or the alloy wheel option when the car was spec-d, so you have to check with the dismantler, what size it is (it could also be a full size alloy).

The good thing with E36 and E46 is that all models, except compact (TI), have the spare wheel mounted inside the boot, this means that it is not open to environment hazards and they are usually like new and usually also really cheap. So if you want a cheap rust free replacement, keep an eye out for selling for parts ads and verify the wheel size and tire specs with the seller 8-)

I got my 15" replacement from an 1999 E46 320 sedan, looks brand new, has all the same specs on wheel and tire and cost me only 15 EUR.
The only thing that I had to transfer over was the valve extension hose, which had some rust on the metal but the rubber was OK and if it is needed, it is still available as new since the same part (31106783425) was used on various Mini models until 2015.

From practicality and weight saving point of view, I'm most likely tossing the space saver and everything related off the car for the next season. It has no use when you have upgraded front brakes from E46 330i (17" wheel is required and Z3 carrier cannot fit a 17" space saver from E46 330i) and it is not good to use at the back either due to smaller diameter compared regular wheels and tires - it will put extra load on the rear diff since the wheels are constantly spinning at different speed.
Practice shows that instead of the space saver it is OK to have a battery or 12v (cigarette lighter socket) powered small tire inflator and instead of the repair foam that BMW provides (part of M roadster tire mobility set), a cheap tire repair string with the installation tool - it is easy to use and works well, just get the tool that is all metal and not with plastic handle. Don't even need to jack up the car as long as the puncture hole is accessible.
And to be completely honest, I'm pretty sure the 17" rear wheel with 240/40 tire will not fit in the boot of a Z3 roadster, maybe even the 225/45 front one wont fit :lol:
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Robert T
Site Admin
Joined: Mon 12 Jun, 2006 10:35
Posts: 10172

  Z3 roadster 1.9
Location: Cheshire

Re: Space saver wheel

Post by Robert T »

None of the normal road wheels will fit in the boot. BMW supplied a plastic bag to put the flat in to keep your seats clean. Do not be tempted to put the wheel on your passengers lap. A girl was killed when a damaged tyre exploded.

R.

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Arctic Silver '99 Z3 1.9 & Black '59 Frogeye 1275cc
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