OK, I didn't want to keep hijacking Jerseygirl's thread about the spare tire bag, but I did want to respond to the comments about my questioning the safety of carrying a donut spare in the boot secured only by a bungee cord.

First, let me say that I'm not a vehicle crash safety expert. I wish I were, and had some fancy computer modeling software (and about a million bucks to run the thing But the point is, we don't drive (or shouldn't drive) with these things in our cars all of the time (that's what I tell my wife at least when I go to clean out her car once a season). Doing something infrequently reduces the already low risk to a very tolerable level. But, carrying a loose (or effectively loose) spare in the boot all of the time (which is sort of the whole point of a spare) increases this risk to what I at least feel is an INtolerable level.

So, there you have it...sorry for the long post. I just didn't want to leave this unexplained. And of course I want for us all to be as safe as possible as often as possible.

 

F=m*a (Force = Mass * Acc)

lets see...

20lb = 9071g (aprox)
70mph = 31m/s (aprox)

if you figure that it would take 1/2 seconds to come to a stop in a crash that would be...

9071g * (31m/s / .5s) = 562402N

562402N = 126432lbf (aprox)

or it would be like someing 126432lb siting on you head.

 

I really like Jerseygirl's idea and hope that she can build up a home business selling these tire bags.

The only reason I would not get one is that I need all the space in the boot I can get and carrying a spare tire in my MCS is out of the question.

Heavy cargo is always an issue in a hatchback type of vehicle just because the seat backs in the rear seats are acting as a "barrier" to prevent such cargo from being ejected into the passenger cabin in the even of sudden braking, etc.

 

Hmmm...I owned a 1998 Olds Intrigue and although not a hatchback, both rear seats folded forward if need be, secured only by a latch similar to that in the MINI. The rear seats in this car acted as the barrier to prevent cargo in the trunk from being ejected into the passenger cabin in the event of an accident.

So, I don't think it matters whether you own a hatchback or a regular sedan: if you have 50/50 folding rear-seats that act as a pass-through to your trunk...it's just like the MINI. And I'd think that the majority of cars on the road today have this feature.

Moral of story is...to each his own. If you don't feel safe with a spare in your boot, don't drive with one in there. I'm no physics expert, but I did stay at a Holiday Inn Express last night, and I'd say the chances of the spare becoming a missile in an accident are about the same as dying from cancer...about 1 in 509, which is higher than the chances of dying from heart disease: 1 in 301.

Gotta run, the Mega Millions lottery is up to $102 Million! Chances are 1 in 80 million that I'll win, but hey...you never know.

Rock On,

-MB

 

Is there a danger, probably, how much of a danger...slight I would think. This is a cargo area and people will put items in it (filled suitcase, cleaning supplies, small child, etc..) The seats should take the impact and having any item secured to the tie-downs in the back make it that safer.

On the side note, I'm getting a spare because I'm placing normal tires (not run-flats) on my S. For daily driving I have a can of fix-a-flat and a battery operated air pump but for those longer trips (The Dragon, The Keys, etc) I would like the option of a spare. Last year someone had a run-flat go out on them on the Dragon and was lucky enough to go to a dealer that had one I repeat one available. I don't want to deal with this so I'm going to have a spare and I don't feel the safety issue is significant.

 

wouldn't it e easy to attach the handles of the bag to one or two of the tie down points in the trunk? A climbers caribiner would probably work great. As long as the handles held and the bag didn't rip open, you'd be set.

 

You have a unit conversion issue problem:

A Newton (N) is a Kilogram Meter / Sec ^ 2, not a gram Meter per second Squared.

You need to divide by 1000, to get grams converted into kilograms.

Therefore your answer actually computes to 126 lbs not 126,000 lbs.


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Does Jerseygirl have anything to worry about regarding lawsuits then if a freak accident does arise? Any lawyers or people with legal backgrounds out there that might know?

 

It's a bag. It's not the tire. The owner of the vehicle still has free will to decide whether or not to add the spare tire in the first place. I don't see how anyone who makes a nice storage bag is really facing liability here.

 

MINI sells custom luggage to fit in the boot. I bet lots of people can stuff more weight in one of those than a spare tire weighs. I know my wife and daughter do it with ease

I would not be concerned at all with a spare in a bag that was attached to a tie-down point with a snap clip like early apex suggests.

I have tried using some of my carabiners to do this, but they are a bit big.

 

Anything is possible in today's overly litigious society, but that seems rather far-fetched.

And if that were the case, then one could sue, for instance, Campbells, if, in an accident after a trip to the grocery store, a can of Chicken Noodle went flying into the driver's (or passengers) head. Or what if one happens to have a bunch of quarters in their cupholder, and one comes flying out during an accident and pokes an eye out? Can they sue the U.S. Mint? Or, what if they've got a Taco Bell beef and bean burrito on the passenger seat, and in an accident, it becomes airborn and smacks them in the face? Can they sue TriCon Global Foods (owner of Taco Bell) for their errant burrito?

This thread is getting out of hand... :smile:

-MB

 

I'll use the same answer here that I put on a previous thread. I carry a spare whenever I go out of town. It's lying flat on the folded rear seats, secured by 2 very heavy duty rubber (not elastic) straps. Having worked with these straps a lot in the past. I'm confident that by the time they get to the breaking point in an accident, I'll have much bigger worries to deal with, such as the motor and tranny trying to do a lap dance with me.

 

For those carrying a spare (or any other large item regularly) in their boot, use nylon lashing straps instead of rubber bungee cords. These straps can be fed through the tie points on the trunk floor and crisscrossed over and/or through the tire or other item. These straps when tightened wont allow cargo to shift as it would with elastic straps, plus they are far more able to restrain cargo from moving during spirited driving or even in some accidents. An added safety bonus is removing the likelyhood of a bungee cord hook flying around in those cases where you lose grip of it when attaching or removing it under tension.

Keeper Corporation as well as many other make lots of different straps that would work in this application. I use lots of different sizes and types when carrying items in my trucks. These straps are the type useful for tying up items in the trunk.

 

It has been 5 years since my last Physics class. I'm suprised I remebered most of it, just forgot about the kg part

 

I work for a hospital system as a corporate & medical photographer - with all the crazy HIPAA regulations we face and the lawsuits that fly around, there's always something in the back of my mind like that. I didn't intend to throw the thread out of hand - but if you pose the question of associated dangers with a product, then one could go the next step. I know it's far fetched, and it's a tire holder...