Look, I love most of my Garmin gear – I love the heart rate monitor, I love my little foot pod (for running) and I love the little contraption near my bike’s rear wheel that logs distance and cadence. When working properly. You see, the way that it logs cadence and distance are my two little magnets that are fixed to the pedal crank and to the spokes of the rear wheel. So you need the magnet. The rear wheel magnet is fine – it’s tightened onto the spoke with a nut-and-screw-style setup – the magnet is the “screw” and a little piece of plastic is the “nut”.
It’s the crank magnet I’ve had problems with. All you are provided with are stickers and cable ties. You stick the magnet onto the inside of the crank and then tighten it with the cable tie on the outside of the magnet. It’s a shit system. The cable tie easily slips off, and the sticker doesn’t hold. I ordered a replacement crank magnet online (which comes with the spoke magnet), and after thoroughly cleaning the crank, tried again. A few weeks later I lost the magnet again. Bah! I don’t really want to build a stock-pile of spoke magnets… so I just gave up.
Now that my bike’s rideable again, I started looking into the matter again. Garmin themselves weren’t helpful, just telling me to keep purchasing the replacement set. Then I found a random review on Wiggle about how I wasn’t the only one with crank magnet problems and that they solved theirs with the help of a Cateye magnet.
Well guess who turned up in the post a few days later?!?!
And yes, he works perfectly well with the Garmin. If you’re making other purchases, then go for Wiggle or ProBikeKit (both have free postage if you spend over 80 pounds, and the magnet is about 3 pounds). If you just need the magnet, I used a seller on Ebay located in Australia. At about $10 (incl. postage), it cost less than the Garmin pair of replacement magnets, and thus was still a bargain in my opinion. Particularly as I don’t expect to have to purchase it again. (Of course, if you’re purchasing other stuff on PBK or Wiggle and meet free shipping, spend the $3-$4 there).