Welcome to Tech Talk, where our resident BMW tech Nick Owen answers all your pressing BMW technical questions, frustrations, and issues. Have a question for Nick? Email him at techtalk@roundel.org. Let’s get into it.
Not the tasty kind of donut!
The car in question is my 2004 330i Performance Package, sedan, MT, about 123,000 miles, no run-flats/TPMS.
I believe the stock 330 alloy wheel was a 17×7, with a 205/50-R17 tire. I believe they came with a full-size alloy spare, at least in the non-TPMS versions. God knows there’s a spare tire well about that size.
ZHPs, though, came with 18-inch Style 135 staggered wheels, which won’t fit in the spare well, so, be joyful, ZHPs come with a 17-inch toy donut spare. Hooray!
My original toy donut spare has developed a leaking stem. Local vendors won’t repair the stem due to the age of the tire itself, regardless of its looking brand-damn-new, and the problem being the stem, not the tire.
Cheapest solution is to simply replace the toy tire and get a new stem (all in, maybe $150-200), but I’m noodling over a more full-size/useful spare.
The car routinely wears 17×8 Apex Arc-8 wheels, with 235/45 tires. The ZHP 135s are sexy as ever can be, but heavy and terrible to clean; the Arc-8s are lighter, easier to clean, give me a square setup, and are identical to my track wheels. They look good on an E46, too.
A 17×8 Style 44 wheel, with a 225/35 tire (that I have lying around) will fit into the well, but is too wide/deep for the well, so the trunk floor panel won’t lie flat with that wheel/tire in the well. Very not ideal.
The spendier solution: I’m betting that a 17×7 wheel, with a 205/50 tire, would fit correctly in the well, and be a much more serviceable spare, being much closer in size to what I use on the car than the bicycle-tire donut. As well as perhaps having greater range than the toy donut spare. Far as I’m concerned, a steelie would be fine for that, though Real OEM claims that the original NLA Steelie is not suitable for ventilated rotors, AND is for winter tires only. These two things don’t quite follow, for me.
My questions:
- Is my idea of subbing in an original-size 17×7 wheel with 205/50-17 tire vs. a new toy donut tire a solution that gives enough bang-for-the-buck to warrant the cost difference? I especially like the idea of a spare that doesn’t have the speed/range limits that the toy donut has.
- Do you believe that the 17×7, 205/50 combo will cleanly fit into the spare well?
- Is there a reason to not use a simple steel wheel for this job, and just get a correct 17×7 alloy, new or used, instead?
Andrew Saboe
Northstar Chapter
The only way you can try and figure out if a full-size wheel/tire will fit is to use a tape measurer and measure the width and depth of the spare tire well. A 205/50R17 wheel/tire is about 8 inches wide, maybe a little more once inflated. It’s your prerogative to use a full-size spare vs a donut. I suppose if even the choice, I would go full size since a full-size spare is more than likely going to drive better than a donut in a flat tire scenario.
1982 BMW (E21) 320i Brake Booster Remedy (P/N)
The brake booster (P/N 343311175490) in my 1982 (E21) 320iS is leaking and needs a remedy! The part is NLA, as I have not been able to locate one in almost a year. Also, I have not been able to find a shop that is willing to rebuild it, including those that rebuild muscle car boosters. This is a pristine example of the rare S Pack from the 80s and I’d love to drive it more regularly and longer distances this summer, going to car shows and BMW events. Any words of wisdom on options out there is truly appreciated.
Reza N. Tavakoli
Try this place: Bush Power Brake Services
