Quick, if you were to just glance at the photo below, what year would you think it was from?
1986?
1988?
No sir, as you can see by the Primo logo, this is a stack of brand-new Primo Balance rims. From this year. The goofy colors don't appear to be in stock anywhere yet, but I'm sure it's just a matter of time.
But I had no intention of getting into colors. If shops want to start stocking products in a dozen different colors again, so be it. Not my problem. What I wanted to touch on today was the upcoming magnesium Balance rim.
Magnesium wheels are nothing new—it's where the term "mag wheel" originally came from. A company called Halibrand started making magnesium wheels for race cars all the way back in the '40s. They're not even new to BMX—Mongoose founder Skip Hess turned out some one-off magnesium Motomags in the '70s. But while magnesium is indeed lighter than aluminum, true mag wheels never became the standard for either industry.
Why?
Well, there's the little matter of magnesium being highly flammable. Obviously it's not a matter of spontaneous combustion, or even friction causing it—people do pedal grinds on magnesium pedals and they still have feet. Magnesium needs to be heated to over 800 degrees before it ignites, so leaving your bike in the sun should be fine. (If it does catch for some reason, though, forget it—magnesium burns at 4,000 degrees.) But it does make welding it a bit of a challenge.
Also, magnesium oxidizes like crazy. The atmosphere likes magnesium, and it wants it back. And it has a tendency to weaken over time in certain load-bearing applications. Um, like wheels. And apparently they go out of true faster than aluminum—you might want to read this thread on magnesium road bike wheels. Obviously the magnesium Balance rims will be coated, but how long does it take to put the first couple of scratches and scrapes in a rim? (Or wear the stuff off if you use brakes.) You gonna want to touch them up every day? Mongoose figured out 30 years ago that a magnesium production wheel didn't make sense. Halibrand moved on to aluminum as well—you'll only find true "mag" wheels on vintage race cars. Is it lighter? Yes. Is it worth the trouble? Doesn't seem like it.
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