Compact spare wheel/tire solution

There was another thread running on this, but I thought I'd summarize here to make the info easy to find. Thanks to Tom Tarzian for a lot of the work on this. The goal was to come up with a compactg spare solution that would clear the stock brakes w/o a spacer and come as close as possible to the stock tire OD.

To clear the front brake requires an 18" wheel, or perhaps a heck of a spacer on a 17. The X6 has a 5" wide wheel that seemed to fit the bill. Only thing is its hub is slightly larger (74.1 vs. 72.6 mm), so a centering ring is the right way to go.

Finding a suitable tire was a challenge, because manufacturers don't seen to list info on compact spares, and most tire dealers are unclued. I eventually found a 135/70-18 as used on the Cadillac CTS, and was able to track down the manufacturer (Maxxis) and a local dealer (Les Schwab). It took about two weeks to order in.

I test fit the setup today, and it clears the front brake caliper by about 1/4", and seems just fine. The OD of the tire is just about 0.3" smaller than the stock fronts (a little more in the rear, of course), but seems well within tolerance, IMO. Tom had used a 125/70, but I thought that a little small.

Weight complete is 37 lbs. (47 bs. for OEM 19F). The stock lug bolts work fine.

So, here's what you need:

- BMW 36-11-6-768-861 black steel wheel; $155 list Edit 9/29/09: Kyoshi71 says this wheel is OEM, at about half the price: http://www.worldimpex.com/parts/bmw-black-steel-emergenc_1533872.html.
- BMW 36-12-1-116-326 rubber valve stem, $5.35 list
- Centering ring, 74.1-72.6 mm; 1010 tire (mis-labeled 74.1-72.56 http://www.1010tires.com/hubrings.asp?gclid=CPy2-rytg5kCFU0wpAodcQqcmw); $30 shipped for set of 4 (you can sell extras)
- Maxxis T135/70R18 104M M9500N (#TP10655100), $85 + $10 shipping + $12.50 mount & balance

All-in-all, not inexpensive, but a nice bit of security to have in the trunk for trips, and about half the size of a full-size spare.

wow thats some good info... great alternative to carrying a full size... i usually bring along one of my winter wheels when i do very long road trips ... thats what i use as a spare.

montreal red wrote

wow thats some good info... great alternative to carrying a full size... i usually bring along one of my winter wheels when i do very long road trips ... thats what i use as a spare.

also a very creative idea!!

good info Greg...thanks for sharing!

How much does it weigh?

Seriously, though, thanks for doing the legwork. I'm probably going to get this setup. I'm always a bit nervous driving on a dark highway late at night with only the M mobility system to rely on.

alpineweissM3 wrote

How much does it weigh?

I added the weight info to the OP.

FWIW, the wheel can be ordered online from Tischer BMW (in MD) here:

http://www.trademotion.com/partlocator/index.cfm?siteid=214672&catalogid=0

I used the 125/70 18 tire, as well--the Maaxis looks like a better solution, but if you have trouble tracking that down, Tire Rack sells the Continental 125/70 18 tire. It's hard to find online, but if you call them they have no trouble looking it up.

That's great for trips! I guess you also need to add to the kit means to lift the M3 enought in order to change the wheel.

Does anyone know where from I could get all this sent to Europe / Greece?

gr8000 wrote

That's great for trips! I guess you also need to add to the kit means to lift the M3 enought in order to change the wheel.

Does anyone know where from I could get all this sent to Europe / Greece?

Good point--I carry a 3-series jack and lug wrench.

You should be able to get the wheel through a dealer there, and Maxxis is distributed in Europe. You can contact Brad Barrett with Maxxis International USA (bbarrett@maxxis.com) for that info or who to contact.

GregW / Oregon wrote

Good point--I carry a 3-series jack and lug wrench.

I guess there is dedicated room for the 3 series jack to be kept rigidly fixed in the trunk? DO you have the part number of that handy?

As an alternative means to lift the M3, I remember seing in an old commercial (10 years ago or so!) a special "balloon" in the shape of a pillow, which gets inflated from the exhaust gasses. I know it sounds funny but I remember seeing it! If this works, then it saves a lot of space & weight!

GregW / Oregon wrote

You should be able to get the wheel through a dealer there, and Maxxis is distributed in Europe. You can contact Brad Barrett with Maxxis International USA (bbarrett@maxxis.com) for that info or who to contact.

Very helpful, many thanks

A couple of follow on questions (sorry that all this comes in bits & pieces):

1. Can the wheel & tyre fit securely in the trunk (eg by taking out the BMW OEM mobility kit and the soft material that keeps it in place)?

2. I am not sure I understand what the centering rings are for and where are they placed. A hint will be much appreciated!

gr8000 wrote

A couple of follow on questions (sorry that all this comes in bits & pieces):

1. Can the wheel & tyre fit securely in the trunk (eg by taking out the BMW OEM mobility kit and the soft material that keeps it in place)?

2. I am not sure I understand what the centering rings are for and where are they placed. A hint will be much appreciated!

The spare tire won't fit under the trunk carpet; the space under there is far too small. None of the E9Xs have a spare tire well under the carpet, but the M and dual exhaust 335s are particularly bad in this regard (since the floorpan has been reshaped to make room for the giant mufflers on these cars).

Carrying the spare thus means you lose some trunk space. It's not too bad; I can still get all of my normal luggage in the trunk (on top of the spare).

I use bungee cords from to the tie-downs in the trunk to hold the spare in place. It's kind of cheesy looking, but it gets the job done. The jack and a lug wrench fit underneath the spare wheel; I've wrapped them in packing foam, which keeps them secure and prevents them from rattling around.

Horrible pics taken in the dark with my iPhone are attached.

EDIT: The centering rings go in the center of the wheel, in the large hole at the center of the lug nuts (the hub bore?). This hole is designed to mate with the hub on the wheel, in order to center the wheel properly, but since the X5's hub diameter is slightly larger than the E90's, the wheel doesn't quite center itself when you put it on the hub. The centering rings are literally just plastic rings that fill the (very narrow) gap between the spare wheel's hub bore and the hub of the car.

A far better choice of tyre is a 145/70R18 as fitted to Mitsubishi, its a slightly wider tyre which makes for a better fit to the rim.

std wheel front 18" has a diameter of 653mm
145/70r18 >>>>>>>>>>>>>>>> 660mm = +7mm
135/70r18>>>>>>>>>>>>>>>> 646mm = -7mm

std wheel rear 18" >>>>>>>>>>> 669mm
145/70r18 >>>>>>>>>>>>>>>> 660mm = -9mm
135/70r18>>>>>>>>>>>>>>>> 646mm = -23mm

gr8000 wrote

A couple of follow on questions (sorry that all this comes in bits & pieces):

1. Can the wheel & tyre fit securely in the trunk (eg by taking out the BMW OEM mobility kit and the soft material that keeps it in place)?

2. I am not sure I understand what the centering rings are for and where are they placed. A hint will be much appreciated!

1. No, the area is too small. Best bet is to put it on the forward area of the trunk floor with a bungie cord over. The jack will fit under the floor panel.
2. The centering ring reduces the ID of the hub hole in the non-stock wheel to make sure the wheel is more accurately centered on the hub than with the bolts alone.

SenorFunkyPants wrote

A slightly better choice of tyre is a 145/70R18 as fitted to Mitsubishi, its a slightly wider tyre which makes for a better fit to the rim. It has a 7mm larger diameter than the std wheel rather than the 135/70R18 wheel which is 7mm smaller (assuming my calcs are correct).

That would be a good size -- Any info on the tire make or where to obtain it?

In the USA the Lancer Evolution has them.
Google with "T145/70r18" gives some good results.
Struggling to find the size in the UK though! grrrr.

SenorFunkyPants wrote

In the USA the Lancer Evolution has them and also Lexus.
Google with "T145/70r18" gives some good results.
Struggling to find the size in the UK though! grrrr.

Thanks. 2009 Evo shows same size. This calcs out to almost exactly 26" OD, which would be right between stock 25.8" F & 26.3" R sizes. I will contact a Mitsu dealer and inquire.

The G37 also uses the 145/70 18 size, apparently.

http://myg37.com/forums/brakes-suspension-wheels-and-tires/186639-quick-spare-tire-question.html

If anyone finds out the tyre manufacturers name could they post it up as I'm struggling to find the 145/70r18 tyre in the UK so I might have to call the manufacturer directly.
Thanks.

True Faith wrote

The G37 also uses the 145/70 18 size, apparently.

http://myg37.com/forums/brakes-suspension-wheels-and-tires/186639-quick-spare-tire-question.html

Good find--confirmed this on the Infiniti website. It's standard in the G37 Coupe "Journey" model.

gGreat information. Question - If you have 19 inch wheels at all 4 corners, can you still use this Maxxi spare solution? Or do the wheels have to be usin 18 inch wheels?
Thanks
cpd

This should be a sticky in the DIY section, or in a DIY Master Thread.

cpd wrote

gGreat information. Question - If you have 19 inch wheels at all 4 corners, can you still use this Maxxi spare solution? Or do the wheels have to be usin 18 inch wheels?
Thanks
cpd

For this purpose, the main thing that's important is the outside diameter. Both the OEM 18s & 19s have about the same OD. These tire are close to the same, so will work regardless of whether you're running 18s or 19s.