Three Generations of Garmin HRM Soft Straps

This afternoon I received my third heart rate monitor Soft Strap from Garmin, seen at top. I hope this lasts for longer than the previous two. The one on the bottom is the first generation, and I’ve now gone through two of these. The first one worked pretty well, up until the day it started to read weird false-high values which — if real — would indicate that I was about to die. This happened about a year after purchasing it… I bought another, and it too failed in the same way in less than a year.

A phone call to Garmin last June resulted in my receiving the middle strap, a nicely redesigned model that has a conductive fabric layered over the sensors, connected to the side of one’s torso. This worked well up until a month or so ago when I began getting falsely low results. I could be pushing fairly hard, somewhere around 150-160 BPM, when I’d suddenly get a 70-90 BPM reading. Since this threw off my data I stopped wearing it when riding and called Garmin asking for help.

Today I received the one on the top, an evolution of the shielded second generation. It has a conductive vinyl patch — similar to the center electrodes — for the shield. It also has some silk screening over the front. I hope that this one lasts longer than the other two, although I can’t complain terribly as I’ve received a few years worth of straps gratis just by calling and asking for help. The replacement straps were provided at no charge, shipped to me within a few days of calling. With this, and previous support for my broken Garmin eTrex, I’ve been quite happy with Garmin’s support.

If all goes as hoped I’ll be able to give the HR strap a fair test tomorrow, as I’m aiming for a 5:30 moving time ride. Hopefully that happens…

(To note, I’ve taken particular care to follow Garmin’s washing instructions for the straps. For the newer models one is to rinse it after each use, and launder it every seven uses. Batteries were also replaced, just in case, before calling for support.)

Salsa Mukluk 2 as 1×10

I’ve been interested in moving the Mukluk to a 1×10 setup for a while now, and the culmination of a few things made me finally do it. Specifically, moving to 1×10 on this bike allows…

…more chain/tire clearance as I want to use 45NRTH Vanhelga this winter, and they need another 3mm on each side versus the Hüsker Dü.
…no more needing to keep 9-speed parts around.
…lighter weight / simplicity.
…less chain slap with a clutch derailleur.
…the 9-speed parts from the Mukluk to make the Salsa El Mariachi that I’m trying to sell into a geared bike.

This evening, after replacing the cracked Hope freehub I installed the parts and thus far everything seems to be working fine. I also removed the old cable-tied tube and wrapped the chainstay with Scotch 2228 to further cut down on noise, should any slap persist. Shifting to the upper part of the cassette is a bit stiff, this appears to be from the very stiff clutch derailleur. I suspect that in actual use it’ll be smoother to shift.

The biggest downside to a 1x setup is reduced range, which could be a problem in winter when I want to spin slowly on snowy climbs. It turns out that going to a 30t chainring and 11-36t cassette provides a very similar range to the 32-22t chainrings and 11-34t cassette that I previously had. Specifically, the original 2×9 setup ranged from 65% to 291%, while 1×10 is 83% to 273%. This means that I lose the two lowest gears (65% and 75%) along with the one top end gear (291%), but I think this’ll be a fine trade-off for the benefits. If this isn’t sufficient I can add a 40t or 42t add-on cog (such as those from OneUp Components or Wolf Tooth Components) and bring the lowest gearing to 75% or 71%, respectively.

The parts used for this were as follows:

Big thanks to Rochester Bike Shop for setting me up with these parts on short notice.

Weight was brought down another 0.9 pounds to 28.86 pounds (photo) beyond what the On-One Carbon Fatty Fork accomplished. If all goes as hoped I’ll get to try this out on some northern Michigan single track this upcoming weekend.

Cracked Hope Pro 2 Evo Fatsno Freehub Body

This evening when stripping down the Mukluk to make it a 1×10 I found that the freehub body on the Hope Pro 2 Evo Fatsno rear hub is cracked. I’ve emailed Hope asking if their warranty department will take care of it, as I’ve only been riding these since late August, putting 907 miles and just under 100 hours on them in that time.

I guess the 1×10 conversion is on hold for now… And I’m glad I didn’t find this in winter.

UPDATE: Hope sent out a replacement and it’s now installed and everything is set. This only took a couple of days to get things back up and running, which was great service on their part.

Road Tubeless Sealing Issue: Narrow Tape

I had to throw out six ounces of fresh Stan’s, but at least I identified the most-likely cause of my road tubeless issues: the rim tape. For some new wheels that I’m building for the Vaya, 1/2″ tensilized polypropylene strapping tape (McMaster-Carr part number 7637a31), which seems to be the same as Stan’s NoTubes 12mm tape, was chosen for sealing the rim. This width covers the spoke holes, but after being pumped up to 70 PSI it seems to have leaked as the tape stretched.

The photo above shows where the tape slightly puckered and allowed air (and sealant) out when under high pressure.

The proposed solution for this issue is a double-layer of tape, partially off set side to side, to both make the area over the spoke holes thicker and have more tape stuck to the inner wall of the rim (photo). I would have used a wider tape, but the next size up is 21mm, and this doesn’t sit nicely in the U channel in the center of the rim (cross section).

Creating a Bridge with a Span Port on OpenBSD 5.6

Since OpenBSD moved the bridge commands into ifconfig(8) I hadn’t been able to find quick info on creating a bridge(4). Presuming you’ve got some em(4) interfaces (for naming purposes) here’s all you need to do:

ifconfig em0 up
ifconfig em1 up
ifconfig em2 up
ifconfig bridge0 create
ifconfig bridge0 add em0
ifconfig bridge0 add em1
ifconfig bridge0 addspan em2
ifconfig bridge0 up

This will result in em0 and em1 bridged together, and a copy of all frames that it sees going out to em2 for monitoring.

After this, if you want it to come up every time you boot the machine, do this:

Create three files, /etc/hostname.em0, /etc/hostname.em1, and /etc/hostname.em2 all containing the single line:


Create one file, /etc/hostname.bridge0, containing the following lines:

add em0
add em1
addspan em2

Reboot the computer and netstart(8) will use these files to create the bridge for you.

One very important point to note if using this to troubleshoot 802.1x: this sort of bridge cannot be used to troubleshoot 802.1x because it does not pass LLDP frames, nor does it drop/raise the link, which switches commonly use as a trigger for initiating client authentication. For situations like this a tap such as the NetOptics TP-CU3 is much more useful.

On-One Carbon Fatty Fork on 2012 Salsa Mukluk 2


Wanting to keep my fat bike around for a while longer I’ve been looking at cost effective ways to improve it. Last year this was new tubeless-ready wheels, and recently it’s been a great-value carbon fiber fork: the On-One Carbon Fatty Fork. At about US$250 shipped it’s considerably cheaper than many other options, and it’s geometry just happens to be close enough to that of the Mukluk’s original Enabler  fork. (468mm A-C and 45mm offset on the Enabler vs 470mm A-C and 55mm offset on the Fatty.) There is a 10mm difference in offset, which hopefully will not affect handling too much. Per various online bicycle geometry calculators there should be about 11mm less trail with the Fatty.

Trail calculations, for reference, per Bicycle Trail Calculator w/ 559mm BSD and 95mm tire width:

2012 Mukluk w/ Fatty: 79mm

2012 Mukluk w/ Enabler: 90mm

2015 Mukluk w/ Rigid Fork: 94mm

2015 Beargrease: 94mm

2015 Blackborow: 87mm

2015 Pugsley: 88mm

2015 Moonlander: 88mm

2015 Ice Cream Truck: 102mm

On-One Fatty w/ Carbon Fork: 94mm

2013 El Mariachi w/ Fox F29: 82mm

This ~11mm decrease in trail will likely make the front end feel much twitchier, bringing it just a smidge shortern than my favorite XC bike: the Salsa El Mariachi Ti which has 82mm of trail. If my understanding of trail is correct this’ll make the bike a bit twitchier and quicker to turn. Hopefully this won’t cause problems riding it at higher speeds, or keeping a line at slow speeds in the snow.

This fork is also set up with rear brake spacing — something that’s going away on newer fat bikes — which generally means that no special adapters are needed to get the brake caliper to align with the front hub. I did have to use two 1.5mm washers to space the caliper over for nice alignment with the rotor (photo), but this shouldn’t be a big deal. I’ll likely get some longer IS mounting bolts since the thread engagement isn’t quite enough to make me comfortable. Despite having a straight steerer the fork has a large crown intended to match the On-One Fatty frame. This results in a slightly awkward step below the headset (photo), but with the mostly-black bike I don’t think it looks too bad. I’m also not too keen on the orange logos, but in person I think it goes well enough with the sun-faded anodized red to not be a problem.

The originally intended purpose of this fork — front end weight reduction — seems to be successful. After replacement the weight has gone done 1.08 pounds, to 29.74 pounds (photo). The original steel Enabler fork, with crown race and star nut, was 1134g, while the On-One Carbon Fatty fork is 637g with crown race, compression plug / bung, and the steerer tube cut to length.

Now to wait for the trails to dry and see how it rides…

UPDATE: The decreased trail definitely makes the bike twitchier. It’s now a lot harder to ride no handed, but on single track it feels plenty lively and fun to ride. For now I think this is a good thing, although it’ll be curious to see how this pans out come winter.

SUNringlé MüleFüt Leaky Valve Stem Fix

My 2012 Salsa Mukluk 2 has SUNringlé MüleFüt rims on it, but I’ve been having intermittent leaking around the valve stem since receiving them last summer. It turns out this is because the single rim wall keeps the the WTB TCS Valve stem from being tightened down far enough to make a good seal. By adding the white nylon washer seen above — spares from a Velocity Velotape set — I can tighten it down enough to make a great seal.

With some 45NRTH Hüsker Dü tires put back on the bike, set up tubeless, it’s now ready for spring time. If only the trails were as well…

A Time for Tubes

I’m very fond of tubeless fat bike wheels and moved to a set of SUNringlé Mulefüt rims (on Hope hubs) in mid-2014. These have worked great until the last two weeks when they went wrong with the On One Floater tires I’ve been using in snow. I was experiencing slow leaks on the rear that seemed to get more rapid as the day progressed, yet when aired up at home and in room they’d hold air reliably for days on end.

After a real rough time at the FunPromotions FatBike Series race yesterday at Addison Oaks (rear went flat slowly making for a hard ride / need to stop / etc) I gave a more serious look at the problem. Here’s what I found… The side knobs on one half of the rear tire (drive side) have become torn. I had noticed some slight tearing along the edge knobs before, but as the tire held air fine as tubeless for numerous rides before this, I didn’t think it was a problem. Apparently now it is. (This high res photo shows a bunch of the typical diagonal wrinkles, and the end of each one has a torn side knob.)

I suspect that a combination of new tears developing while riding and the freezing cold keeping the sealant from working normally resulted in the flats I was experiencing. I could dump more sealant in, get these holes to seal, and hope for the best, but I’m not sure that’s the best idea…  Instead of hoping for reliability out of something visibly failing I’ll switch to a tube on the rear.

The Surly Nate has seemed like a good winter tire and I could grab a pair of them to replace the Floaters, but I’m not too keen on rushing to buy new tires now just for the remainder of winter… Maybe I’ll just stick with a tube on the rear for the time being, and then decide what to do snow tire-wise some time before the next winter.

Kurt Kinetic Road Machine + Pro Flywheel

Earlier today I purchased a used (but nearly new) Kurt Kinetic Road Machine and Pro Flywheel from someone local for cash plus a set of nearly-new tires that I didn’t need. I’d been interested in trying out a trainer with a heavier flywheel than the Cycleops Fluid 2 that I’ve used for the last few years as I suspected it’d smooth out my pedal stroke and make for a more outdoors-y feel. I’ve had problems getting my heart rate to the same levels on the trainer as when riding outdoors, and I suspected it was from the higher drag, constant hill climbing feeling that I was getting with the Fluid 2.

For my first ride tonight I did TrainerRoad’s 8 Minute Test (without the Pro Flywheel) and thus far I’m very happy. There is a much longer coast/spin down time with this trainer vs. the Fluid 2 resulting in less of a climbing-stairs feeling and something more like riding into a strong headwind. This I’m fine with. The result of the power test put me at a 304W FTP, and during the test I was able to reliably get my HR to roughly my maximum, somewhere in the mid 170 BPM range. The last time I did a test (back in October) I was barely able to hit the 160s.

On my first try with the large flywheel — after removing it to wipe everything down — I noticed that there’s a bit of vibration when I’d get it to higher RPMs. I imagine it just needs a little aligning, but if I continue to have issues hopefully Kurt will help sort things out. The larger flywheel provided an even more intertia, and it almost felt like riding down a gentle grade with a steady headwind when using it. Serious effort was required to get it started, but once it was going it seemed to smooth things out even more.

I’ll try it out on some longer sustained-effort rides in the near future and perhaps even do another power test with it, just to see what happens. I really hate power tests, though…

† TrainerRoad claims that it’s Virtual Power is roughly 3% off from a power meter when used with a Kurt Kinetic Road Machine. It’d be nifty if this is the case, as I wouldn’t mind having a 300W FTP… That’d put me at roughly 3.79 watts per kilogram.

Low-Cost 29+ Stand

Building on the Low-Cost Fat Bike Stand idea and needing a way to support the forthcoming Jones Plus build I’ve built a 29+ bike stand from PVC pipe. By taking the previous plans, narrowing the main section, and adding length and height I got something which securely holds a 29+ (700c x 3.0″) wheel.

Modifications to the original plan involve narrowing the center pieces by 1″, adding 0.5″ to each support leg, adding 1″ to the pieces between the upright and the back side, lengthening the horizontal pieces for an 11.75″ opening, and increasing the height of the upright for a 25.5″ opening. This results in a stand which allows the wheel to set in, touch the ground, and slightly lean sideways against one of the uprights. The stand can also be placed directly against a wall and approximately 1″ will be left between the tire and the wall.