rs10

I was all set to leave it home when I came upon this old thread:

https://rennlist.com/forums/996-foru...tire-bolt.html

Where it quotes a Porsche service bulletin, as follows:

TSB 1/98 4427 Spare Wheel Removal (dated 9-11-98)
Vehicle Type: Boxster ...
"In addition to its intended purpose, the spare wheel fitted in the luggage compartment also serves to absorb some of the impact energy introduced into the front of the vehicle in serious frontal collisions. Please take this into consideration and drive with the appropriate care when, in exceptional cases, the spare wheel is not carried in the luggage compartment."

Anyone know if this still applies to the 996.2 (and facelifted boxer)? I suppose yes, but all that extra weight in the facelifted cars must be somewhere, and I seem to recall reading that Porsche stiffened up the dash/front end in order to add the glove box ...

Also, suppose the frunk is instead full of luggage? Same safety benefit? Probably some benefit if the luggage is neither too crushable, nor solid like a rock. Particularly if the safety benefit from the spare is in case of impact at the bottom of the trunk, but I can easily imagine it is for impact at the top. I can also immagine that in case of impact at the top, the spare transfers force to something solid near the screw holding the spare, whereas with luggage the force would stay at the same level ...

(But please someone tell me that either Porsche solved this, or luggage is good enough - I'd love to get rid of this thing, even if only when I have a lot of luggage!)

sfv_rider

If you have an impact great enough that the rigidity of the spare is your salvation, then you've had one hell of an impact.

My non-engineer impression? That's one of PCNA's attorneys talking. IIRC, later models do without the spare in the frunk, and rely on Fix-a-Flat and possibly a portable compressor.

If you don't want the spare, have a charged cell phone and drive in an area with good cell coverage, and have good roadside service insurance, feel free to roll the dice. But if (or when) lightning strikes, that spare would look like a valuable bit of kit.

But I've run tens of thousands of miles on a motorcycle, with nary a spare, and few problems. A few punctures with slow leaks, but no explosive pressure losses.

Seeeu911

Perhaps the Porsche engineers know something about the crash structure they designed ?
I leave mine in.

rs10

You could be right about the attorneys, but they would have zero incentive to repond in this way if there were zero safety benefit.

So the 997 has no spare? Perhaps not, but it might also have a lot more crash protection built in - it does weigh a lot more.

DBJoe996

Really? Really?? You are really going to think about this and actually do something?? If you are considering a frontal impact with enough force to crush the front of the car all the way to the spare tire to where it MIGHT become a factor....you're last consideration will be gosh..whether the spare tire is in there or not. Hitting a bridge abutment at highway speed...hmmm...should I have left the spare tire in there or not? C'mon.....

onewhippedpuppy

In my daily driver 996, I left mine at home. I suspect it has a negligible impact on your front crush zones. Most likely that's how they tested the car (spare in place), and therefore cannot say with certainty that the car will provide the same level of protection with it removed.

Dennis C

My 996 C4S had a collapsible spare tire underneath the floor of the front luggage compartment. I can't imagine that added much safety in a major front end collision. As mentioned above, the 997 doesn't have a spare tire.

fpb111

I can certainly see it helping with the early cars. Later ones not so much. Maybe it would help spread the load if the bumper gets pushed back to the fuel tank?

Hurdigurdiman

I should imagine that the spare in the frunk would come in very handy when a deer comes crashing through the front windscreen into your face lol.

Cuda911

Interesting timing with this thread. Today I was on a drive with about 10 or 15 other Porsche owners. One of the guys had a serious head-on collision that ruptured his fuel tank. It was a very serious fire hazard.

Several people were commenting that if he had left the spare in, it may have prevented this. It was an '84 993.

onewhippedpuppy

If it was an '84 it was a Carrera. 993 didn't start until 1995.

I can see where a full sized spare tire, turned sideways, could help with frontal impacts on the off chance that the impact was down low. But let's face facts, compared to a modern car you're really not that safe in a 30 year old 911 without ABS, airbags, or modern crumple zones.

rs10

Maybe it's helpful to clarify a bit. The Porsche service bulletin is about a 986.1 Boxster, which has the same front end frame and body parts as the 996.1 C2. So what the bulletin says about the Boxster is 99.9% sure to apply to the 996.1 C2. Not to the C4 (nor the GT3 which I think uses the C4 chassis?). The C4 has a horizontal (space) saver spare, but it also has a lot of metal where the C2 and Boxster have the vertical spare. So the fact that the C4 does not need the spare to protect against impacts above the bumber doesn't mean that the C2 and Boxster don't. (And is the C4's spare involved in protection from a lower impact? Who knows? Someone at Porsche, probably ... .)

The 997 may again be different. Did none of the 2wd, non GT3 models have spares? Not sure. But they are also heavier, and some of that weight is crash protection. So if some 2wd models did not have spares, that would not automatically mean it is safe to take the vertical spare out of a 996. Probably not unless someone can tell us that the front of a 997 is structuraly identical to that of a 996 (presumably a 996.2).

Which leaves what is for me the key question: What about the 2wd, non GT2/3 996.2?

DBJoe996

Got to love Google images.
A study of front end crumple zones



Our cars are really pretty solid



Thought this one was cool