993 Space Saver

[Ocho]

Hello all

Just a heads up message.

I had a flat on the M25 today and called my Roadside Recovery service to get home and to my surprise they decided that due to the high mileage on my car and because it was a weekend they were going to charge me £280 - unless I paid it the call couldn't be booked in, however much I argued. So I did.

Then I remembered about this 30 year old mini wheel and tyre under the bonnet and thought, "Hmm, I wonder if it all still works - if it does it'll save me £280 so surely it must be worth a try?" Before I did anything I plugged in the compressor just to check that was still doing something. It whizzed and whirred so in the hope that this wasn't all just hot air (excuse the pun), I cancelled the call-out (they tried to tell me there would be a £95 cancellation fee seeing as the service had already been booked - to which I told them in no uncertain terms that I did NOT authorise them to take any payment from my credit card!).

Anyway, back to the Space Saver.

Got it all out, jacked the car up, put this tiny thing on and wondered how it could possibly get big enough to fill the arch and match the rolling radius on the other side, but connected up the compressor and let it do it's thing and this 30 year old piece of rubber magically unfolded as it inflated and got bigger and bigger and after about 8-10 minutes it looked like something from the 90s (so quite appropriate, then) but big enough.

Drove gingerly off and set the sat nav up for the non-motorway route home. Stopped after about half a mile just to check it out and it all looked good. 23 miles later at no more than 40mph and I'm safe home. It says up to 50 but I decided that 30 years later 40 would be better...

So to sum up, 90s German engineering wins the day again and these things do actually work even after all this time. I suspect that was the first time either the wheel or compressor have ever been used before.

A few take-aways:
1. I wouldn't necessarily rely on one of these to get you home - I might well have just got lucky.
2. Buy a little tyre pressure gauge to keep with the toolkit - the compressor doesn't have one (and probably wouldn't be very accureate anyway) and given the unusual nature of this type of wheel and tyre combo you really won't be able to guess it.
3. Whilst putting your tyre gauge in there, put in a big bin bag with a tie so you can put your dirty tyre inside the car without getting everything filthy.
4. A pair of disposable gloves might be an idea too - it's dirty work.
5. Check the small print on your Recovery Service, especially if you've gone off AA / RAC (I was with RAC but they tried to more than double my premium at the last renewal which I didn't take kindly to!!!)

Hope that helps someone someday!

Edit: Max pressure on the Space Saver is 40PSI - I went with 37.

Edited by Ocho on Saturday 30th November 17:53

[Orangecurry]

Thanks very much for bothering to post all that - it's something you don't 'think' about with a car with differing front/rear sizes and a crazy spare.

My space-saver is in the loft!

[Ocho]

Orangecurry said:

Thanks very much for bothering to post all that - it's something you don't 'think' about with a car with differing front/rear sizes and a crazy spare.

My space-saver is in the loft!

With the state of our roads these days, sadly punctures or sidewall tears are more and more likely. This is my second in a year.

The space saver would work front or rear - rolling circumferences are close enough, if not the same.

And I also recall reading somewhere that the weight of the spacesaver was designed into the planned weight distribution of the 911 by Porsche. Might even improve the experience to put it back in...

[n12maser]

I also read somewhere that it contributes towards more front collision safety on a 993...no idea of true!

[C4ME]

Ocho said:

...
3. Whilst putting your tyre gauge in there, put in a big bin bag with a tie so you can put your dirty tyre inside the car without getting everything filthy.
4. A pair of disposable gloves might be an idea too - it's dirty work.
...

Pretty sure the car came with a version of these when new. Also from memory the rear will only fit on the passenger seat and nowhere else. Maybe the fronts too.

[harrykul]

Yep, the full size wheels don't fit in the boot, which is handy...

[Orangecurry]

Ocho said:

And I also recall reading somewhere that the weight of the spacesaver was designed into the planned weight distribution of the 911 by Porsche. Might even improve the experience to put it back in...

...from another thread, I tried a weight saving exercise, so my car is already way off....

Front total weight reduction = 24.5kgs

spare wheel = 12900
6 CD changer + base that sits in spare-wheel = 5212
boot carpet = 2300
tool roll without towing eye = 1684
compressor = 1196
aluminium jack = 1030
towing eye = 380
number-plate - changed to sticker = 197
spare wheel clamp and bolt = 121
number-plate plinth = 112
change front PU corners to Aero = -612

n12maser said:

I also read somewhere that it contributes towards more front collision safety on a 993...no idea of true!

I think that is not true for a 993, but I can't remember where I read that either

[Pickled Piper]

n12maser said:

I also read somewhere that it contributes towards more front collision safety on a 993...no idea of true!

It's an integral part of the crash structure (just look where it is positioned. Between the front chassis rails) at the front of the car. So it plays a part in how the car deforms in a frontal crash and how effectively the airbag is triggered.

[Orangecurry]

Pickled Piper said:

n12maser said:

I also read somewhere that it contributes towards more front collision safety on a 993...no idea of true!

It's an integral part of the crash structure (just look where it is positioned. Between the front chassis rails) at the front of the car. So it plays a part in how the car deforms in a frontal crash and how effectively the airbag is triggered.

I've seen that repeated many times, but never found any facts or Porsche documents to support it.

Genuinely interested - do you have any facts?

But as Rennlisters point out, if it WAS integral in any way to safety, the inside of the 'frunk' would be covered in safety warnings about how it must be in place, to prevent potential litigation.... especially in America; and there is none.

[Armitage.Shanks]

The space saver is marvelled by many 993 owners. Some will even fill those dark winter nights by going into the garage, looking at the 993 in the carcoon (SORN since September until March) taking out the spare wheel and marvelling how it swells when inflated and then shrinks back when you let the air out. Afterwards relaxing with a nice cigar from Hamlet.

[Pickled Piper]

Orangecurry said:

Pickled Piper said:

n12maser said:

I also read somewhere that it contributes towards more front collision safety on a 993...no idea of true!

It's an integral part of the crash structure (just look where it is positioned. Between the front chassis rails) at the front of the car. So it plays a part in how the car deforms in a frontal crash and how effectively the airbag is triggered.

I've seen that repeated many times, but never found any facts or Porsche documents to support it.

Genuinely interested - do you have any facts?

But as Rennlisters point out, if it WAS integral in any way to safety, the inside of the 'frunk' would be covered in safety warnings about how it must be in place, to prevent potential litigation.... especially in America; and there is none.

It's glaringly obvious to a crash safety Engineer.

[C4ME]

Whilst I am one who feels the way the front chassis is laid out means having a spacesaver in place helps in a crash, there is the paradox that it cannot be essential otherwise the car would be unsafe if you were in an accident whilst driving with the spacesaver fitted to one of the wheels after a puncture.

Mind you that would be minor compared to having a full size wheel flying around inside the cabin during a crash!

Edited by C4ME on Sunday 1st December 21:03

[Super Sonic]

C4ME said:

Whilst I am one who feels the way the front chassis is laid out means having a spacesaver in place helps in a crash, there is the paradox that it cannot be essential otherwise the car would be unsafe if you were in an accident whilst driving with the spacesaver fitted to one of the wheels after a puncture.

Mind you that would be minor compared to having a full size wheel flying around inside the cabin in a crash!

I guess with the space saver fitted you're only doing 40 rather than 90+ so any frontal impacts will be much less severe.

[C4ME]

Super Sonic said:

C4ME said:

Whilst I am one who feels the way the front chassis is laid out means having a spacesaver in place helps in a crash, there is the paradox that it cannot be essential otherwise the car would be unsafe if you were in an accident whilst driving with the spacesaver fitted to one of the wheels after a puncture.

Mind you that would be minor compared to having a full size wheel flying around inside the cabin in a crash!

I guess with the space saver fitted you're only doing 40 rather than 90+ so any frontal impacts will be much less severe.

Perhaps although you have no mitigation on how fast the oncoming vehicle is travelling. In a decent impact the full size wheel on the passenger seat will likely kill you first.

[Orangecurry]

Armitage.Shanks said:

The space saver is marvelled by many 993 owners. Some will even fill those dark winter nights by going into the garage, looking at the 993 in the carcoon (SORN since September until March) taking out the spare wheel and marvelling how it swells when inflated and then shrinks back when you let the air out. Afterwards relaxing with a nice cigar from Hamlet.

Well that's my Christmas sorted.

[Wozy68]

C4ME said:

Ocho said:

...
3. Whilst putting your tyre gauge in there, put in a big bin bag with a tie so you can put your dirty tyre inside the car without getting everything filthy.
4. A pair of disposable gloves might be an idea too - it's dirty work.
...

Pretty sure the car came with a version of these when new. Also from memory the rear will only fit on the passenger seat and nowhere else. Maybe the fronts too.

The 993 indeed did.

The tyre gauge (with Porsche stamped on it), clear plastic bag and disposable pair of gloves are still stashed within the 31 year old (on the 7th of this month) never used spare tyre in mine still.

[Pickled Piper]

C4ME said:

Whilst I am one who feels the way the front chassis is laid out means having a spacesaver in place helps in a crash, there is the paradox that it cannot be essential otherwise the car would be unsafe if you were in an accident whilst driving with the spacesaver fitted to one of the wheels after a puncture.

Mind you that would be minor compared to having a full size wheel flying around inside the cabin during a crash!

Edited by C4ME on Sunday 1st December 21:03

It's safer with the spare wheel in place. It's not unsafe without it. Just less safe, because the wheel is a significant part of the frontal crash structure. Also, the airbag will trigger earlier with the spare wheel in place. This is always desirable.

This applies to all vehicles where the crash safety Engineering was carried out with the assumption that the spare wheel is in place. Usually applies to rear impact in conventional vehicles.

[mlsporsche]

Space saver should only be used on the front wheels

[Orangecurry]

I love all these 'factual' statements.

The people who built and supplied the car don't say there is any restriction on where the collapsible wheel goes.


Can't be bothered to type it all out. As hardly anyone seems to have (or bothers to read) the Driver's Manual, here's a photograph or three.

Note on p2 it shows both front and rear jacking points. It doesn't say you have to move a front to a rear or anything else. It was written for people in the 1990s, who had common sense.

[mlsporsche]

OK, Space saver should really only be used on the front wheels but thats pretty obvious for most as the drive wheels are on the rear on most 911's, 4WD cars still have most drive to the rear

Edited by mlsporsche on Wednesday 4th December 08:17