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Day: December 3, 2014

Garmin Hub-based Speed Sensor for Fatbiking

Published December 3, 2014

For years I’ve advocated for the use of a wheel speed sensor to augment the data of GPS-based bike computers in order to alleviate distance issues caused by aliasing. Up until recently the only good options for this were traditional magnet-and-reed-switch units like the Garmin GSC-10 Speed/Cadence Bike Sensor and the Wahoo Cycling ANT+ Speeed/Cadence Sensor. These sensors work well in general, but I’ve had issues with them on my fatbike.

Because of  snow buildup on the rim (photo) the sensor is positioned closer to the hub (photo) to keep it from scraping in the snow. Withof the further-back position near my heel and the frequency of falling over when when riding in snow, it’s not uncommon for the sensor to get knocked around and tilted slightly inward. This causes the reed switch arm of the sensor to knock against spokes: the usual tick-tick-tick sound. It seems that these repeated, gentle physical impacts break the switch, as I’ve now had two which stop picking up wheel speed after a year or so on my fatbike. The rearward positioning also makes it impossible to use the cadence side, which feels a bit wasteful.

Garmin recently released a new series of speed/cadence sensors which use internal motion sensors instead of magnets (sensor bundle page on Garmin’s site). These were reviewed in great detail over here by DC Rainmaker, and the hub-based speed sensor seemed a perfect fit for my fatbike. This design will stay away from both the snow and my heels, and lacking a reed switch there isn’t that part to fail. The lack of cadence sensing on a fatbike is fine with me, as it is used in such mixed conditions such data isn’t very useful. When cleaning up my fatbike earlier this week I ordered the standalone speed sensor ($39.99 from Amazon) and fitted it last night before heading out for a ride.

My first impressions are very positive. It connected to my Garmin Edge 510 just as I’d expect, and a ride through River Bends parking lot automatically calibrated it to a sane number. A 1.5 hour trail ride near dark went fine with it, and it just seemed to work, similar in function to the GSC-10, but with a technical implementation that is more suited to fatbiking. I’ll stick with the traditional reed switch sensors for my other bikes, as I haven’t had the same kind of difficulty there and I don’t strap-to-crank-arm sensors, but for here on the Mukluk, it seems a good fit.

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Bike Stuff for Sale

Published December 3, 2014

Shuffling around bike parts and upgrading things have left me with some spare parts that I’d like to sell. Prices and photos are listed below, and I’ll consider reasonable offers. I live in Shelby Township, MI and work in Warren, MI and will be glad to meet anywhere in this general area to handle a sale. Contact me at c0nsumer@nuxx.net if you are interested.

Stan’s NoTubes Arch EX / Shimano XT Wheelset – $350: These are the stock wheels from my Salsa El Mariachi Ti, replaced only when I built up some carbon fiber wheels. Front is a 15mm TA and rear is QR, centerlock rotors. Very solid  build and the freehub was recently replaced. Comes set up tubeless with Racing Ralph (2.25″) and Small Block Eight (2.1″) tires. The tires are well used, but still have some life in them, so I figured I’d include them.

SRAM Rival 2×10 Gravel Road / CX / Touring Drivetrain Kit – $600: All new parts purchased for a gravel road bike build that fell through. This would also be a great touring setup, CX setup, etc. All that’s missing is brakes and a frame to put it on. This is an outstanding value build kit, all-Rival solid stuff that works well. Items included are all SRAM Rival level: 31.8mm front derailleur, short cage rear derailleur, front derailleur shim (1-1/4″ seat tube to 1-1/8″ clamp), DoubleTap shifters (retail box, with full cables and housing), crankset (172.5mm arms, 50-34 chainrings), bottom bracket, PG-1050 cassette (12-28), PC-1051 chain.

SRAM Apex 170mm Crank Arms – $20: Very mildly used set of solid cranks. I removed these from my Salsa Vaya to go to 172.5mm cranks and have no need for them. I’ve got a set of new 50-34 rings, new chainring bolts, and new bottom bracket for it that I’ll throw in for another $45 ($65 total) if you want to make this a complete crankset. Want to try out different length cranks? Need a cheap but solid set of cranks? This is a good way to go.

Serfas Seca FPS Road Tires – $Free / Beer: 28c Serfas Seca FPS wire bead road tires. Cheaper tires that came on a used bike I bought, but plenty of life left in them. I prefer wider tires and have plenty already, so I don’t want these… Got a use for them? They are yours… I’ll trade for beer, a good story, etc.

 

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