Ditching the spare

[cyberman]

The compact spare on my 96 Z3 Roadster is, probably, more than 10 years old. I'll check it next time I'm under the car. Based on old threads, that tire went out of production in 2010 and supply dried up completely a few years later.

I'm not keen on driving any distance on ancient rubber. It was at 10 PSI when I bought the car recently and it didn't explode when I put it up to 5 bar and then back down to 4 bar. But still.

My logic is to buy a can of flat repair and hope for the best to get me to a shop. I have towing service as a back-up and here's my reasoning:

1. If I'm close to home, the towing service gets me home assuming the fix flat stuff doesn't fix it.
2. If I'm on a trip, well the best the spare could do is get me to a shop (maybe) and it's not going to get me home anyway so if the flat fix stuff fails, I can get a tow to the nearest town with a motel and/or a shop.

So, ditching the spare, the jack and other cheap stuff under the carpet, as well as the tire mounting swing bar saves weight, frees up some space in the trunk and helps me avoid the temptation to actually drive on old rubber.

Again, I'll check the manufacturing date - if it's 1996, that thing has to go. But I expect it's at least 10 years old and thus time to go to wherever tires go when they die.

I'm interested in other opinions on this - so if you're inclined to chime in I'd like to hear what you have to say.

[zellamay]

My Z3M has no spare. In a previous sports car, I took out the spare to create some trunk space. Never had a problem. Flats are so rare with the tire technology today. I do keep flat-proof and tire repair kit, but never used them.
Should have said: "No Z3M has a spare"

[KBH22102]

I upgraded the brakes on my 97 2.8 such that the spare would no longer clear the rotors. I removed the spare and carried a patch kit, air pump, fix a flat, and of course, a cell phone.

[Vintage42]

My original Continental T125/90R15spare looked new, but in 20I3 I replaced it with one of the last available spares made in 2010. If I am in a place where I can change it, figure it will get me to where a flat tire can be repaired.
If on a roadside too dangerous to take the time to change a tire, I carry a Conti Comfort Kit (sealant and compressor).

[cyberman]

Thanks for your votes: The ayes have it, the spare shall go.

[Vintage42]

The compact spare on my 96 Z3 Roadster is, probably, more than 10 years old... I'm not keen on driving any distance on ancient rubber. It was at 10 PSI when I bought the car recently and it didn't explode when I put it up to 5 bar and then back down to 4 bar. But still... I'm interested in other opinions on this - so if you're inclined to chime in I'd like to hear what you have to say.

Thanks for your votes: The ayes have it, the spare shall go.

Outcome was predetermined, so why ask? My vote was to keep the spare. The inside and outside of my 1997 and 2010 spares looked the same, and I have seen a lot of old vs new tires in the course of restoring and riding a half dozen vintage BMW motorcycles since 1985. If the rubber looks and feels live, why not keep it for a spare to get you to safety?

[Tigershark48]

Cyberman,

Agree. Out of the tens of thousands of cars on the road, how many times have you seen anyone changing a tire? If your tires are in good shape, there’s little to worry about. A decent plug kit and mini-compressor beats a spare tire any day in our mini-cars. In 60 years of driving, I’ve repaired one tire and did it with a plug. The plug was still in that tire over 20k miles later when we traded the car in.

[wildspeed]

Unfortunately I'm one of those people who have to put a spare on a regular basis.... not the Z3 in particular.

I replaced the original 15' spare with a Kumho 121 T 125/80D16 and BMW 36-11-6-750-006 wheel

Won't fit in the tray fully inflated (60PSI), but fit at 30PSI so you still need to carry a compressor.
Actually fit at 60psi, you just can't pull it out of the tray.. .

[KeysCoupe]

I have an M Coupe and have been know to take it on long trips, so I carry a compact spare. It hasn't ever been needed, yet! It could keep me from being stuck on the side of the road, but there is still the issue of where to put the full-size (rear) flat tire to keep travelling; in the front passenger seat? My compact spare fors snugly in my rear hatch with plenty of room for luggage/tools.
You can usually find a replacement compact spare tire at U-pull yards where the donor car is less than 2-3 years old, at least keeping your spare "fresh". This is what I have done.
-Donny

[caglar]

I have been debating this as well but one piece I cannot solve is how to close the big hole that is left in trunk of the spare is not there. How would you seal off the part that attached the spare to the trunk?


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[solimans]

Took my spare out...but I only drive in the city. no long or interstate trips. I could see how it might be a good idea to hold on to it if you were making longer trips...

[bkirk]

I have been debating this as well but one piece I cannot solve is how to close the big hole that is left in trunk of the spare is not there. How would you seal off the part that attached the spare to the trunk?

Because I largely drive in the city, carry a spare fix a flat can, and have AAA on speed dial, I decided today to ditch my spare, which is always controversial, but to each his own. After dropping the spare and the carrier I was left with the two holes that the drop down handle and bracket formerly covered.

I found two bolts in my spares box that were long enough and several large washers. On the hole in the rear passenger side cubby, I fed a bolt with a large washer up from under the car and used the large round nut bracket that was originally used to cover the hole. From top side, its the same nut/bracket as was originally used, from underneath, its just the head of a stainless steel bolt on a two inch washer, it completely covered the hole.

On the hole where the handle and drop down cable were formerly mounted, I used another bolt that matched the thread of the 18 mm nut that was formerly used and the round bracket that had the pull up cable and handle pass through it. This time, the bolt head is in the trunk side and the nut and large washer were threaded on underneath the car. From the trunk side, everything looks normal and the entire project took 30 minutes. I haven't pulled the scissor jack yet, but might if I decide to purchase a portable compressor so that I'd have a place to store it.'

[caglar]

Thanks . My bad for not clarifying. In my case the spare is mounted to the bottom through a much larger piece as seen in the pictures. Basically the tire sits on top of the mount which the. Connect into the car with some sort of a quick release. This leaves a 3” diameter hole. Maybe time for me to 3D print some sort of a cap.


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[Randy Forbes]

Find these at Home Depot, Lowes, etc. Available in a wide range of sizes, conduit knock out seals, for 1/2" (7/8" hole) up through at least 4". All sizes available in either enameled or stainless steel.



I't's been a while, but I'm thinking it was either the plug for 1-1/4" or 1-1/2" conduit that fit (?)

There're lots of possibilities; I've cut the ends off the original basket and used them to plug the holes.



I've also used the washers that come with Ireland s/f bushes, the original rubber seals and a nut & bolt.

[caglar]

Thank you Randy. Great idea. Let me see if I can make that work as well.

[cyberman]

Nice solution Randy. In my 2/96 manufacturing date Z3, I removed the spare and found it was just about exactly 25 years old with an 10/95 (~week + year) production date. From videos I'd watched, I thought there was a hinged swing are under the car, but no and since the back end was on ramps when the carrier popped loose, it dropped a long way. I have a tool kit bag, so I removed the tool tray (took some bending of edges on one side) and freed up all kinds of space in the trunk (relatively speaking). Removing all the carpet, I found two nice pockets on either side of the car too. For the big hole revealed, as a temporary fix I put some form-a-gasket on a BMW emblem I had lying around and fastened it with the three existing posts and the plastic nuts with large "washer" protrusions. I'll find some rubber pop-in plugs for the two small holes adjacent (what were they for?).

Now, I've decided to go Berman engineering on the thing and not worry about sacred (to some) original appearance. So, I decided to leave all the trunk "carpet pieces out" and spray the entire trunk (boot to you Brits) with Dupli-color premium solvent based truck bed liner coating ($20/can on Amazon). I figure the grit in it will keep stuff from sliding around and I ruled out Plasti-dip due to durability concerns. As an engineer, I wondered about the lack of symmetry in the trunk with what appears to be an extra reinforcement on the right side - but since life is short, I didn't spend much time wondering about it. I'm sure there was a reason as engineers generally do everything for a reason.

Removing all the dingy and aged carpet exposed a perfectly rust free paint, albeit slightly greasy surface. It also exposed the neat little tray holding the god-awful factory no provision for rear speakers 10% total harmonic distortion amplifier that is soon to go along with the Alpine Business radio and 6-CD changer taking up a significant percentage of space in said trunk. But that's for another time and will take a bit of finagling to squirrel away the cash without the spouse noticing.

Moving on to something totally unrelated: I got a cheap nylon wind deflector from Jason on Etsy that fits perfectly on my non-functional decorative roll (eh, style) bars. It works very well except for a small amount of buffeting at the top of my bald head. So, I could not resist this idea: I will put a small deflector at the top of the roll, er style bars. Since I have no crafts ability, I had to come up with something so simple even I could manufacture it. It has three components:
1. I ordered a pre-cut 5" X 36" piece of clear plexi-glass (1/4" think) online. The website (which I'm too noobie to post a link to, but sounds like professionalplastics. you can guess). The per-piece price was $20 but they tacked on $10 since their minimum order is $30. They also tacked on shipping so the it came to ~$50 and in retrospect I should have order two or three pieces of different sizes as this is a prototype. They offer black (which wasn't clear if they meant tinted black or really black) and one just inputs the required dimensions and spits out a price. They probably don't polish the edges but even a clumsy monkey like me can probably do that and, if I muck it up, there are black trim edge moldings to cover it up.
2. Two each 2-1/2" ID U-Clamps off Amazon. I couldn't find it in stainless so I order a 10-pack of zinc-plated and will spray them black with plasti-dip. The diameter is specific to my bars.

Manufacturing: I will drill two sets of holes for the u-clamps spaced as close to the mid-point of the apexices (apexes?) and oversize the holes to allow for some error in my measurements. The plastic will sit on the flat steel pieces of the u-clamps, facing forward. If I hit the measurements well, I'll be able to rotate the deflector from about flat to the wind to the opposite extreme and determine the best angle to minimize buffeting on my bald head which doesn't like feeling the wind much and fears further brain freeze in addition to my age-related freeze. I'd didn't measure or check, but if I'm lucky they'll clear the top which is usually down. It's experimental.

Talking to Jason from Etsy, he experimented with modeling clay and mounted a deflector to the top edge of the windshield. He tested it a lot at 60 MPH in various wind conditions and he said it worked very well. That got me thinking: if I could scavenge a used convertible top frame and remove that front piece, well that would clamp to the windshield and perhaps suffice to block the wind sufficiently. And, if not, at least it would a handy mounting point for a deflector of some sort. But frames are dear as far as I could find and I can't justify the expense now: the audio, coolant system, injectors, O2 sensors, coils, spark plugs and wire all scream they are much more important and I can't help but agree.

If anyone is interested, let me know and I'll post picks and results for my deflector experiment. I don't expect the parts for another week or two and hopefully, it shall be such a booming success that I'll be motivated to show it off. PM me if I fail to post.

[cyberman]

Almost pre-determined. But when I checked the date on the spare, it turned out it was OEM to the car and manufactured in late 1995. It looked surprisingly good, but I decided to ditch it rather than be tempted to drive on it. Tire manufacturers recommend 6 years max and BRMA and JATMA say to replace at 10 years. Yes, maybe the tire could get me home, but if it blows, it could cost me more than just being nerve-wracked driving on it. It would look rather ridiculous too, not to mention the blown tire riding in the passenger seat

[LannVouivre]

If the rubber looks and feels live, why not keep it for a spare to get you to safety?

Even if an old tire looks and feels good, if it is much older than 4 years old, it has deteriorated significantly. My fiance's grandfather insisted that the 15-year-old tires on his truck were fine because they didn't look dry-rotted and he didn't go over 35 mph. A few months later, the tread on one detached and hit the fender so hard that it left a dent. I guess the aging process is more of a chemical stability issue that doesn't always manifest as obviously as dry rot.

A half-size spare is already pretty poor, and if you've got a need to use it, what kind of mood do you think you'll be in if the spare tire unexpectedly shreds itself? That's all I have to offer as my input.

[cyberman]

My early production car has the battery up in the front. Later they moved it to the trunk for weight distribution, I'd guess. So, a few pounds off the rear helps with balance although I doubt I'll ever notice it.

[ThatZ3Guy]

I have the spare tire still...That's not something I think about and I wouldn't gain much from getting rid of it. I have free tow service with my insurance also.