Sahmurai SWORD Tubeless Repair Kit
These days most people run latex based sealant inside their tyres. It helps to make ‘tubeless ready’ tyres air tight and also repairs many smaller punctures on the go. In some cases you won’t even know that you’ve punctured as the sealant will plug the hole before there’s any noticeable air loss.
Unfortunately tubeless systems aren’t totally impervious to flats. Some holes are simply too big for the sealant to repair. Sidewall cuts also cause issues as the liquid sealant always gravitates up to the crown of the tyre. The sealant can also dry out, so when you do eventually puncture, the self-healing properties are long gone.
All of this means that you still need to carry a spare inner tube for those worst case scenario trailside fixes. You’ll need to drain out the remaining sealant, remove the valve (hopefully it’s not too tight to undo), fit the inner tube and re-inflate. It’ll get you back on the trail but it’s a messy and time consuming job.
The Sahmurai SWORD offers an alternative. It’s a tyre plug kit that’s designed specifically for mountain bikes. Similar items have been around for years in automotive circles but the components are bigger and hard to carry safely (they’re pointy metal things that you wouldn’t want to land on in a crash).
With the SWORD, the reamer and fork are attached to a couple bar end plugs—once fitted the sharp bits are hidden safely away. They’re also smaller than the commonly available automotive kits, making them a better match for MTB tyres. The kit sells for $42 and comes with two nylon bar end fittings and five gummy tyre repair plugs. Spare plugs are available in a kit of 10 for $12. The whole kit including plugs weighs 30g.
To accommodate the plugs, you’ll need open-ended grips and handlebars with an internal diameter between 17 and 21mm. Additionally, they need to retain this diameter for almost 40mm inside of the bar. Once installed, you probably won’t notice the Sahmurai SWORD—although if you use slim grips, you may feel the knurled outer surface of the end plug when resting your hands at the outer edge of the bars. The plastic ends appear to be sufficiently robust; I clipped a few trees and drove my bars into the ground once and the plugs are still holding up okay.
Puncture Plugging
When it comes to fixing a puncture, you first need to grab the reamer; the aggressively knurled spike that’s mounted to one of the plugs. This spike was handy for holding the tyre plugs; you just slip the point between two of the sticky strands and they won’t disappear deep inside your handlebar. Use the rasp to clean out the puncture; it also opens the hole up to the right size for the plug insertion fork.
Thread one of the tyre plugs through the eye of the insertion tool—it’s a bit like threading a needle with a sticky thread (squashing the end flat will make the job easier). Both the rasp and the plug tool should be inserted at an angle so you don’t accidentally drive them into the rim strip.
Insert the plug around half way in and then pull it back out. You’ll be left with the remnants of the plug sticking out but the tyre should be airtight once more. The ends can be trimmed back or just left in place (don’t cut them too close to the casing or the plug may fail). All of my punctures were sealed by a single plug but you can use more than one if required.
Get to the puncture fast enough and you may still have a decent amount of air still inside the tyre—it’s substantially faster than fitting an inner tube. Carrying the Sahmurai SWORD in lieu of a tube will also save you 100-200g. Both the speed and weight factors will appeal to the racers out there.
While I was able to repair a multitude of punctures, I’d still feel more comfortable carrying a spare tube for general trail riding adventures. Combine a tube with some extra reinforcement (business card or a $5 note) and you’ll be able to repair the largest of tyre cuts. In fact I’d probably take both; the Sahmurai SWORD for quick and mess-free plugging of mid-to-large holes and a spare tube to get you home after a total tyre apocalypse.
