July ’13 Update:
The tubeless conversion has held out great. Lots of miles ridden, both with bikepacking gear and in my local, rocky trails. No issues at all. Since then, I’ve used the same method to run a Rabbit Hole with my Rohloff hub, and then swap out a set of Schwalbe Smart Sams (29×2.25) for the Knards and fit them to my Ogre frame – using the same 24″ inner tubes I’d already sliced. In hindsight, it’s probably best to leave a little more of a ‘skirt’, so it’s easier to reuse the inner tube again.
More semi-nerdish gear talk, I’m afraid. A persistent cold and rattly lungs have delayed my travels plans – I’ll be heading off for a few days of Arizonan bikepacking very soon though, hopefully returning with a story or two to tell.
In the meantime, I’ve been inspired by nearly-neighbour Gypsy by Trade, and his pursuit to fine-tune his tubeless fat tyre conversions. Nick and an ever growing legion of fat bike riders are doing goathead-battle along Albuquerque’s river trails. They seem to be winning.
When it comes to prickly things, Santa Fe isn’t so different – indeed, the same could be said for the whole of the South West. Devil’s eyelashes, as goatheads are more poetically called (not that there’s anything romantic about them) mine the bike paths around town. It’s not uncommon to discover a dozen of these vengeful thumb tacks clinging tenaciously to your tyres, should you inadvertently stray off trail. To avoid a lifetime of patching inner tubes peppered with puncture wounds, you can inject in a few globs of sealant. If a goathead or thorn worm its way through your tyre, this sealant reacts with the air, plugging the hole. A few strokes of bike pump and you’ll be ready to roll again.
Better than this though, for various reasons, is moving over to a tubeless tyre system. To anyone unfamiliar with the concept, it’s basically a tyre that doesn’t require a separate inner tube to hold its pressure. Instead, the bead of the tyre presses against the lip of the rim to create a seal, secured in place with the addition of some sealant. Again, puncture = air, and air = seal. Clever stuff. There’s several brands around to choose from, the most popular being Stan’s Notubes. You can even make your own with stuff like liquid latex, water and glitter. Whichever brand you use, you’ll need to top up your tyres occasionally, as the sealant dries out over time. A small price to pay for a puncture-free existence.
Most mountain bike tyres and rims nowadays are designed to be run tubeless. Even if they’re not, there are various official conversion kits to help you. None exist for wide rimmed fat bikes as yet – such as the Krampus I’m now riding. Thankfully, this homemade conversion is surprisingly straightforward, as the Knard bead and Rabbit Hole rim play particularly nicely together. In fact, although more fiddly than simply throwing in a new tube, I’d say it proved easier than my recent endeavours to convert the Ogre, using one of Stan’s expensive tubeless conversion kits.
Compared to running tubes with sealant, the perks of tubeless riding include a slight loss in rotational weight, which is always welcome. But it’s the puncture-proofing them aspect that interests me the most. Inner tubes filled with sealant works ok-ish, but they’re nothing like as effective as a proper tubeless setup. This is just as well, as heavyweight Knards (1200g or so) have a large, grippy tyre patch, and have a habit of hoovering up goatheads and other prickly flora.
Performance-wise, a tubeless setup promise lower tyres pressures without fear of pinch flatting, translating into better grip and a more comfortable ride. I’d even go as far as saying that tubeless tyres are such an improvement that it’s hard to go back to tubes once you’ve tried them – only the fact that they rule out changing or rotating tyres easily deters me from running them while long distance touring.
As I mentioned, the downside to tubeless is that it’s a fiddly process to swap tyres, or rotate them, as you might do on a long journey. For shorter tours though, they make a lot of sense.
Tubeless tyres are more prone to sidewall failures than regular ones, so it’s worth knowing what to do in an emergency situation if you’re going light and not carrying a spare. Here’s Minimal Master Gary’s advice:
‘I carry a heavy needle with some dental floss for thread and a couple of the Park TB2 glueless tyre boots for smaller cuts, which will cover most repairs. For longer, 2-3 ” long for gashes, I add I cut a section of sidewall cut out from an old tire, using Shoe Goo (you can get 1oz tubes) to glue the boot in after sewing the cut. Let the glue dry overnight with the tube in place; just a bit of air to hold pressure on it – I’ve not had a cut so bad that I couldn’t wait till night to do this. Usually you can just use a Park boot and maybe sew it up. I carry superglue to hold the cut together – this isn’t an issue with tubes as it’s easy to get inside and boot it. The Saguaro I was using on our trip had 2 spots with minor cuts. I just covered the cut area with Shoe Goo and let it sit on it’s side overnight.’
‘Shortly after I wrote the advice above I came across the tubeless plugs, or ropes. I highly recommend them. They work really well for punctures that are too big for the sealant but not so big you need a boot. I’ve used them twice, once on my tire and once on a friend’s and it worked great both times. It seems to be a permanent repair too. I also now carry a curved needle so I can sew the outside of a sidewall without removing the tire.’
Dave and Mark at Mellow Velo, Santa Fe’s sharpest bike shop, for use of tools and compressor. I was able to benefit greatly from Nick and Jeff’s R&D at 2WD in Albuquerque – which made this conversion far more straightforward than it might have been otherwise.
Any more tips? Please let me know.