How much room IS in a roadster? This wheel is about 4" thick.
Tire is 125x90-16 on a 3.5"rim
Also, looks like the best price I can find bolts is Pep Boys for $3.50 each. Under $19 with tax pickup in store!
Dorman
Pik-A-Nut (Bagged) M12-1.5 Wheel Bolt - 17mm Hex, 19mm Thread Length
I used 1908 300D for the bolt search, FWIW.

 

I like real spare tires as well, but this is a huge improvement over nothing.
50mph limitation is NOT a limitation! I can't walk that fast, so it is all bonus.
I'll weigh it as well, and the air pump & goo canister, It can't be that much more than those 2.

 

Just a bit shy of enough room to cuss a cat.
Actually, the real limitation is the trunk depth, only 24" ( with the top up and the divider panel stored forward ).
The trunk opening is probably large enough.

 

Well according to calculations the mounted tire should be 24.9" tall. I'll let the air out and see how much it will squarsh down to. I assume the Roadster has the same compressor and stuff in the trunk, correct?
Anybody in the Pittsburgh area with a Roadster want to try it out?
Maybe once I am all done, a new thread can be made into a sticky in wheel/tire area.

 

Hope you never need to use it. If nothing else, you improved your front to rear weight ratio.

 

How much thread engagement is there in the hub with the 19 mm bolts?
Just for the record.

 

I'll check when I get them. My guess, 19mm - whatever they stick through the other side, the ball seat basically sits flush with the inside of the stamped steel rim.

 

I don't know if adding weight is an improvement. The best thing is for me to keep losing it, not the car!
I hope I never need it either, but I'm glad to have it. Plus I have a spare 19" tire off a rim now as well. Trunk is still very much usable, and I will probably keep it in there all the time once I get the mount setup.

 

Try it on the rear as that is where the bolts could possibly touch the e-brake springs.

 

FWIW, here is a picture of the bolts I got.




Dorman 98405.1

 

I came across this website that will cross reference bolt patterns. So if you find a spare Mercedes tire on Ebay, Craiglists etc. and know which car it came out of you can see if it will fit the Crossfire

Side-by-Side Comparison of Vehicle Rim Fitment - Discount Custom Rims | My Bolt Pattern

 

I found this Mercedes part number for a set of steel donut wheel lugs 2035800010

https://www.ecstuning.com/b-genuine-...et/2035800010/

 

Wow, nice price, $13 shipped! Mine were $18.
Now I need to peruse that site and see what other gems are there.


Also, FWIW, those are 21mm, and the ones I got state 19mm, I have not actually tested mine yet, but I don't expect any issues. They fit almost flush, so maybe 18mm of thread left, and 1½ of diameter is 18mm for fastener through standards, sounds about right. I was out of town since last Wednesday, but since it hit 9 degrees below F, I wouldn't have tested this weekend anyway.

 

Well, it's free shipping if you spend 200 bucks.

The MB part number 2035800010 is for a "Spare Part Box".

It's 9.99 here A2035800010 SPARE PART BOX with 5.00 dollar shipping

 

Nice, that is what I actually wanted, one of those bolt holders, but on eBay they go for $25 and up for that with used bolts, for basically a blister pack. I'll find one in a junk yard eventually for free someday. Or I will make a retainer of my own. I do need to fasten the wheel securely soon, I don't like the noise on a stiff bump I get now.

 

I understand you sold the x-fire. Did you ever get the spare mounted,an did you take pictures???

 

No, I just left it under the rear trunk floor. I tried to explain in some detail to the dealership I traded it at, but who knows. It is at an Acura dealership in Falls Church Virginia. I wasn't even going to leave it in the car, but since it was over a 2 hour drive to see the SLK350 I wanted to see, I didn't want to feel like a dolt if I got a flat on the road and left the spare at home.
One thing I can say for me is, the $50 I spent was a huge improvement in piece of mind, and the loss of space is minimal for day to day use.

 

I picked up a Mercedes 2094000302 spare wheel that fits CLK320 CLK350 CLK500 CLK550 W209 from a fellow Crossfire Forum member( thanks Johnny!) The tire size is 125/80-17 and the diameter is about 26".





I mounted it on the front and back of my SRT-6 and and clears the front larger calipers. Note the high performance red wheel lugs.



Put a tire cover on it and it fits nicely in the hatch.

 

I went to a Junk Yard and pick up a rear tire and rin for 150. But a dounut spare would be nice to fit in my Roadster. I am south of Pittsburgh a small town Waynesburg. Would like to try the dounut spare? I will be leaving Thursday for N.C. for the tour. If I call the Junk Yard what should I ask for If I ask for R171 SLK will that work?

 

My brother crashed his Volvo S60R and I will try out his donut spare on my SRT6 when I get the chance.

It is a 17 in rim to clear the factory big brakes and aluminum so it may not need shorter wheel studs like a steel rim.

The nice part about this donut is the the fact that the tire itself is collapsible when not inflated to save room. This is no big deal as anyone with a Crossfire should already have an air compressor from the factory kit.