Space saver in the frunk - safety?
01-19-2019, 05:25 PM
#1
Racer
Thread Starter
Space saver in the frunk - safety?
I’ve likely missed a discussion on this somewhere, but here goes.
- space saver tyre, does it have an expiration date? I looked at it and couldn’t find any date stamps. 28 year old tyre, or more, would it even hold air?
- is there a good reason to keep it in the car for a road car? I’ve bought goo, tyre plug and a small compressor - would rely on those first anyway. So thought about taking it out, along with the jack, BUT... is it better to keep it in case of front end collision? Wonder if it serves as a bit of a crumple zone...
- space saver tyre, does it have an expiration date? I looked at it and couldn’t find any date stamps. 28 year old tyre, or more, would it even hold air?
- is there a good reason to keep it in the car for a road car? I’ve bought goo, tyre plug and a small compressor - would rely on those first anyway. So thought about taking it out, along with the jack, BUT... is it better to keep it in case of front end collision? Wonder if it serves as a bit of a crumple zone...
01-19-2019, 05:34 PM
#2
Burning Brakes
I've read that it does absorb energy in case of an accident.
I have not heard from any credible source that it was designed to serve as a safety feature.
That said, I have tried to use the spare once... and I mean exactly that: tried and failed.
I leave mine in the frunk... it doesn't hurt in my case.
I have not heard from any credible source that it was designed to serve as a safety feature.
That said, I have tried to use the spare once... and I mean exactly that: tried and failed.
I leave mine in the frunk... it doesn't hurt in my case.
01-20-2019, 02:18 AM
#3
Rennlist Member
Per Adrian Streather and other 964 books I have read, the spare in the frunk is designed to be an integral part of the front crash safety system. It apparently absorbs energy. If you think about it, the tub is the only other sheet metal there if you really hit a pole or something, I would think twice before removing.
01-20-2019, 07:30 AM
#4
Burning Brakes
Per Adrian Streather and other 964 books I have read, the spare in the frunk is designed to be an integral part of the front crash safety system. It apparently absorbs energy. If you think about it, the tub is the only other sheet metal there if you really hit a pole or something, I would think twice before removing.
01-20-2019, 08:50 PM
#5
Racer
I was wondering the same about it being old and potentially not being able to inflate. Curiousity got the best of me. I took it out and it held air fine for over a week. I did not drive on it just used it to roll the car in/out of the garage. It still freaks me out that the tire folds on itslef and being this old. I deflated it and put it back in the frunk. In a pinch it would probably work. It would be nice to find a reasonably priced new tire for it to make me feel bwtter for longer trips.
01-21-2019, 10:04 AM
#6
I was wondering the same about it being old and potentially not being able to inflate. Curiousity got the best of me. I took it out and it held air fine for over a week. I did not drive on it just used it to roll the car in/out of the garage. It still freaks me out that the tire folds on itslef and being this old. I deflated it and put it back in the frunk. In a pinch it would probably work. It would be nice to find a reasonably priced new tire for it to make me feel bwtter for longer trips.
My front tires are 11 years old and look good so I don't care to change them before they are worn out!
01-21-2019, 10:17 AM
#7
Rennlist Member
I can understand that the spare tire/wheel being in place could only help with absorbing an impact, solely based on its location and structure. Yet considering it's something that's removable whether while being used or to save weight, I find it strange that Porsche engineers would have made the spare tire part of their impact safety design; something you could easily remove without breaking any laws that could in turn increase the chances of putting yourself in harms way. A life safety issue.
Does the owners manual mention any of this?
Does the owners manual mention any of this?
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01-21-2019, 01:10 PM
#8
Rennlist Member
I can understand that the spare tire/wheel being in place could only help with absorbing an impact, solely based on its location and structure. Yet considering it's something that's removable whether while being used or to save weight, I find it strange that Porsche engineers would have made the spare tire part of their impact safety design; something you could easily remove without breaking any laws that could in turn increase the chances of putting yourself in harms way. A life safety issue.
Does the owners manual mention any of this?
Does the owners manual mention any of this?
TUV (German official highway authority) requires certain equipment in the car to be always present by law and their safety / technical annual inspections are no joke (example is the safety triangle etc.)
In most cases Germans can't even imagine removing a part of the safety equipment from their cars for a weight saving reason / law braking…
Imagine that in order to obtain a driver's license you need to go for a 6 month long course that includes mandatory driving of a company owned stick shift in City / Suburb traffic at different times of the day / night weather conditions, cost equal to 3-4 months of average pay and final examination with two instructors present in the car with you...
All that after a 3-5% max wrong answer rules of the road test (if you fail you pay the whole thing all over again).
Driving there is a privilege and you earn it while learning a lot more signs, rules and responsibilities.
Drivers in EU in general take things very seriously and have a very hard time trying to imagine how easy it is to obtain DL and drive in USA.
I got my DL in Europe 33 years ago and I'm pretty sure my knowledge of all the signs / rules is probably under par by now...
Very different mentality for sure.
Last edited by velocitylover; 01-21-2019 at 01:31 PM.
01-21-2019, 01:41 PM
#9
Rennlist Member
This discussion comes up occasionally but no one has ever shown any actual evidence that the spare makes any difference.
Porsche may well have crash tested the car with the spare in place but we don't know if or how it would have performed differently without the spare, and any comments on that are purely speculative.
Frankly, a much bigger problem is the height of the crash bars behind the bumpers of our cars compared to the height of the average car (SUV) on the road today. Especially on a lowered car, both the crash bar and the spare wheel would pass completely under the bumper of an average SUV, rendering any effect of the spare (good or bad) irrelevant. That said, I've never seen anyone posting that we should raise our ride heights for safety - I wonder why.
Porsche may well have crash tested the car with the spare in place but we don't know if or how it would have performed differently without the spare, and any comments on that are purely speculative.
Frankly, a much bigger problem is the height of the crash bars behind the bumpers of our cars compared to the height of the average car (SUV) on the road today. Especially on a lowered car, both the crash bar and the spare wheel would pass completely under the bumper of an average SUV, rendering any effect of the spare (good or bad) irrelevant. That said, I've never seen anyone posting that we should raise our ride heights for safety - I wonder why.
01-21-2019, 01:49 PM
#10
Rennlist Member
This discussion comes up occasionally but no one has ever shown any actual evidence that the spare makes any difference.
Porsche may well have crash tested the car with the spare in place but we don't know if or how it would have performed differently without the spare, and any comments on that are purely speculative.
Frankly, a much bigger problem is the height of the crash bars behind the bumpers of our cars compared to the height of the average car (SUV) on the road today. Especially on a lowered car, both the crash bar and the spare wheel would pass completely under the bumper of an average SUV, rendering any effect of the spare (good or bad) irrelevant. That said, I've never seen anyone posting that we should raise our ride heights for safety - I wonder why.
Porsche may well have crash tested the car with the spare in place but we don't know if or how it would have performed differently without the spare, and any comments on that are purely speculative.
Frankly, a much bigger problem is the height of the crash bars behind the bumpers of our cars compared to the height of the average car (SUV) on the road today. Especially on a lowered car, both the crash bar and the spare wheel would pass completely under the bumper of an average SUV, rendering any effect of the spare (good or bad) irrelevant. That said, I've never seen anyone posting that we should raise our ride heights for safety - I wonder why.
That is precisely why early 964's had that 4x4 tractor high suspension setup... I believe it was to keep the bumpers level with most cars on the road in late 80"s and early 90"s
01-21-2019, 01:58 PM
#11
Rennlist Member
Remember that Germans in general are very disciplined and they rules of the road are vey strict (even if they allow for unlimited autobahn speeds in some areas)
TUV (German official highway authority) requires certain equipment in the car to be always present by law and their safety / technical annual inspections are no joke (example is the safety triangle etc.)
In most cases Germans can't even imagine removing a part of the safety equipment from their cars for a weight saving reason / law braking…
Imagine that in order to obtain a driver's license you need to go for a 6 month long course that includes mandatory driving of a company owned stick shift in City / Suburb traffic at different times of the day / night weather conditions, cost equal to 3-4 months of average pay and final examination with two instructors present in the car with you...
All that after a 3-5% max wrong answer rules of the road test (if you fail you pay the whole thing all over again).
Driving there is a privilege and you earn it while learning a lot more signs, rules and responsibilities.
Drivers in EU in general take things very seriously and have a very hard time trying to imagine how easy it is to obtain DL and drive in USA.
I got my DL in Europe 33 years ago and I'm pretty sure my knowledge of all the signs / rules is probably under par by now...
Very different mentality for sure.
TUV (German official highway authority) requires certain equipment in the car to be always present by law and their safety / technical annual inspections are no joke (example is the safety triangle etc.)
In most cases Germans can't even imagine removing a part of the safety equipment from their cars for a weight saving reason / law braking…
Imagine that in order to obtain a driver's license you need to go for a 6 month long course that includes mandatory driving of a company owned stick shift in City / Suburb traffic at different times of the day / night weather conditions, cost equal to 3-4 months of average pay and final examination with two instructors present in the car with you...
All that after a 3-5% max wrong answer rules of the road test (if you fail you pay the whole thing all over again).
Driving there is a privilege and you earn it while learning a lot more signs, rules and responsibilities.
Drivers in EU in general take things very seriously and have a very hard time trying to imagine how easy it is to obtain DL and drive in USA.
I got my DL in Europe 33 years ago and I'm pretty sure my knowledge of all the signs / rules is probably under par by now...
Very different mentality for sure.
Honestly, what you've said coupled with what the USA would have Porsche do for imported cars further cements to me that the spare tire is not designed as part of impact protecting, since it can be removed for the reasons stated above (for use or to save weight) and Porsche doesn't have written instructions not to remove. It would create liability.
Last edited by dukmon; 01-21-2019 at 06:20 PM.
01-21-2019, 02:47 PM
#12
Rennlist Member
Honestly, what you've said coupled with what the USA would have Porsche do for imported cars further cements to me that the spare tire is not designed at part of impact protecting, since it can be removed for the reasons stated above (for use or to save weight) and Porsche doesn't have written instructions not to remove. It would create liability.
01-22-2019, 09:13 AM
#15
Rennlist Member
The rules have changed considerably since the 90's. SUV's were just becoming a thing and most were the small AMC Jeep Cherokee or Ford explorers which were far smaller than todays SUV.
The ride height was two fold, one part was for compliance with the 5 MPH impact bumper laws of the time which were mandatory in the US but not ROW the other for the headlights. The spare tire is part of the crash worthiness of the cars. It is bolted down to the tub and fits under a lip which keeps it in place in the case of an accident. The heavy aluminum wheel is used for crash protection and the manual is very specific that the spare should be returned to its storage place as soon as possible if used. Also the spare should always be fitted to the front. So if a rear tires goes flat a front tire should be moved to the rear and the spare fitted to the front. This is especially important for cars with LSD. Drive on the spare as little as possible. They also claim it impacts the handling of the car when removed. This is all spelled out in the manual and they even included a supplement reiterating what the manual says regarding reinstalling the spare after use.
I have seen these cars in accidents with and without the spare. It becomes quite apparent that it is an integral part of the crashworthiness of these cars when comparing the aftermath. For street driving I would not remove it, on track with a full welded in cage I remove it.
The ride height was two fold, one part was for compliance with the 5 MPH impact bumper laws of the time which were mandatory in the US but not ROW the other for the headlights. The spare tire is part of the crash worthiness of the cars. It is bolted down to the tub and fits under a lip which keeps it in place in the case of an accident. The heavy aluminum wheel is used for crash protection and the manual is very specific that the spare should be returned to its storage place as soon as possible if used. Also the spare should always be fitted to the front. So if a rear tires goes flat a front tire should be moved to the rear and the spare fitted to the front. This is especially important for cars with LSD. Drive on the spare as little as possible. They also claim it impacts the handling of the car when removed. This is all spelled out in the manual and they even included a supplement reiterating what the manual says regarding reinstalling the spare after use.
I have seen these cars in accidents with and without the spare. It becomes quite apparent that it is an integral part of the crashworthiness of these cars when comparing the aftermath. For street driving I would not remove it, on track with a full welded in cage I remove it.