I first heard about the corrosive effects of magnesium chloride road de-icing spray on motorcycles last winter when John Parker, head motorcycle technician at Budds' BMW Oakville, Ontario, who works on my BMW F800GS, advised against post-November highway riding in Ontario.

According to Parker, this supposedly enviro-friendly road-salt-replacement has a sticky aspect to it, and 'when it gets up into a bike's intake and onto shocks and brake systems, especially those made of aluminum alloy, it corrodes everything rapidly.'

Evidently, the chemical has the effect of absorbing ambient moisture and holding it onto metallic surfaces, thereby accelerating oxidation, aka rust and corrosion.

Parker got more and more animated as he described the insidious effects he's seen on the Bavarian bikes he services. And the really bad news: Magnesium chloride doesn't wash off readily. You really have to scrub it with soap and water or use this stuff, http://esr.cc/z82Rld.

A search of several motorcycle forums yielded a number of comments and suspicions, with one thread at ADVRider -- http://esr.cc/yuUTGX -- delving into it substantially.

Digging further, this info piece http://esr.cc/xsjaZusurfaced from the US Dept of Agriculture, which summed up the situation rather grimly:

Two main issues have been raised regarding the anti-icer magnesium chloride as it relates to electric utilities: contamination of insulators causing tracking and arcing across them, and corrosion of steel and aluminum poles and pole hardware.

So it's not just alloy parts on bikes. It's also public infrastructure that's under threat -- the metals in bridges, the rebar in concrete and so forth, according to many reports found online.

And what of the other, heavier vehicles on the roads?

Apparently, truckers are well aware of the charms of magnesium chloride. From a truckers' website http://esr.cc/zVqfcg in Montana, where it's in heavy use, comes this news (edited for brevity):

(Owners of) fleets that have been exposed to mag chloride report that wiring systems are deteriorating at an alarming rate. Maintenance people believe that the chemicals wick into connection points and eat away at copper wiring, and truckers... are seeing damage that scares them. Corrosion in structural equipment could lead to catastrophic failure at highway speed. One maintenance vice president of a national LTL Fleet describes pushing his pen clean through a structural element on a trailer suspension that he believes had been rotted by mag chloride.

The Ontario Government is spraying this stuff on a great many of our highways. I've also seen Toronto city trucks applying it right in front of my house. The reasons are many. It's apparently less toxic to wildlife, flora and waterways, and because it can be used well in advance of snow or freezing rain, it saves on snow-clearing staff overtime pay during nighttime storms.

Contacting both city and provincial transport departments to see what they had to say about the de-icer, no one I spoke to knew what I was talking about.

Finally, here's a none-too-appetizing video of a truck spray-applying the stuff:

The last word on magnesium chloride for you riders keen to ride in winter goes to Parker, the BMW technician: 'Trust me, this stuff will totally destroy your motorcycle.'

http://EatSleepRIDE.com/rider/champers

1 Comment
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  • alex
  • 2012-02-14T05:23:59-05:00

What an uck-fup. I've not seen anyone spraying this yet, but it sounds like an unmitigated disaster. It's lovely it doesn't harm wildlife (as much) but the roads here are bad enough already.