In Part 1, I covered the problem of Puncture Vines, and two things you can do that work well together to combat them. But, as I pointed out, they’re not a complete solution as much as just something you can do to delay the inevitable. So, we’re going to need another layer or two of defense to get the chance of a thorn flat down to almost zero. We’re going to switch from tube defense to thornproofing outside the tube.
My Solution: Add Thornproofing Outside The Tube
While there are fancier solutions that probably work better, I’ve found that tube liners work pretty well for me. I have almost completely eliminated my flat tires this way for both e-bikes and normal bikes with normal or fat tires.
Basically, you’re just adding a bit of tough plastic between your tubes and your tires. They’re a little harder to find for fat tire bikes, but they’re still readily available online. When a thorn gets into the tire, the thick, relatively hard plastic blunts the end of the thorn and keeps it from popping your tube. This isn’t perfect, as the thorns still sometimes get through, but that’s why you have Slime and self-sealing tubes, right?
These come in a wide variety of brands, including Mr Tuffy and Slime. Make sure you get one that’s wide enough for your bike to add adequate thornproofing outside the tube.
Installing them can be a bit of a pain, so here’s a few tips! It’s best to partially inflate your tube before installing it inside the tire. Then, slip the tire onto the wheel, but leave one side out and not on the rim. Unroll the tire liner first, and then start stuffing it into the space between the tube and the tire. Once you have the whole thing slipped in, check around and make sure to fix any misalignments. Then, pop the second side’s bead into the rim and finish inflating the tube.
There are even beefier solutions if this doesn’t solve your thorn problems. On top of all this (Slime, self-sealing tube, liner), you can buy a thorn-resistant tire for yet another layer of protection. Some fat tire bikes come with them. There are also super thick liners, like Tannus Armor. I haven’t tried that, but it seems like a sensible next step in thornproofing if what I’m doing wasn’t working.
Another Solution: Eliminate The Tubes
There’s another option that takes the Slime approach to the extreme: eliminate the tubes completely instead of adding thornproofing outside the tubes. Most car and truck tires haven’t had tubes for decades, so it’s not a completely insane idea, but without buying a new wheel that’s more like a car’s wheel, you can’t just throw your tubes away. For bikes, tubeless tires require extremely good sealant and a kit to convert your valve stem to not use a tube.
This isn’t something I’ve personally ever messed with, but I’ve got friends and family who swear by it and the guys at the local bike shop recommend it. It allows you to run really low pressures (which is great for mountain biking), and is generally very good at preventing thorn flats. At first glance, it seems like you’d be less safe from flats, but with the sealants tubeless setups use, they are quite good at sealing up even nail holes, as you can see in the following video:
The only problem is that sometimes punctures are too much for these setups to successfully seal up. When that happens, you’ll need to have a tire repair kit (usually plugs) and know how to use it, or you’ll need to have a backup tube with your bike tools to go back to running an inner tube for the remainder of that ride.
In some ways, this is like the Slime solution, but on steroids. It will work until the tire itself accumulates too much damage to hold pressure, and then you’ll have to do a repair or replace it just like a car’s tubeless tire.
Things To NOT Do To Thornproof An E-Bike
After experiencing flats and fighting with them, it might start to feel like dealing with air in your tires just isn’t worth all of the hassles. So, it’s tempting to look for airless or solid solutions to replace tubes and even tires entirely instead of adding thornproofing outside the tube. But, like with automobile tires, the technology for that is still in development.
Airless tubes, which are basically foam-filled tube-shaped-and-sized replacements for normal air tubes have been around for a long time. Many parents who don’t want to be working on several kids’ bikes all the time put them on their kids’ bikes, but there are reasons we don’t see them much for more serious use. Airless tubes weigh a lot more, and that reduces bike performance. They’re also less able to give and absorb shock when hitting bumps or going off curbs, so they’ll pass that energy into the rims, which can then get bent up. There’s also no way to air them up or down for different situations.
Airless tube replacement and tire systems have improved quite a bit in recent years, but there’s still plenty of debate about whether they’re ready for prime-time. For some commuters who don’t mind reduced comfort and performance, they’re becoming a viable alternative, but most cyclists are staying away from them for now. Future developments, which look similar to a Michelin Tweel, promise to do better and very well might. For now, though, it’s probably better to go with a tubeless setup or armor things up the way I do.
E-Bike Manufacturers Should Be Pushing This More
The most important thing is that you don’t give up on cycling because you get a few flats. Sadly, many e-bike manufacturers are setting new riders up for disappointment by not offering better tire protection from the factory and heavily promoting that in the options drop-down list. To be fair, Rad Power Bikes does offer custom-fitted Tannus Armor for its bikes, but I had to look for that instead of knowing about it when I purchased two bikes from them. Knowing that there are options to add some thornproofing outside the tube would be nice.
Putting up with flats every few miles isn’t something that we should just assume is a normal part of riding bikes, or only the most committed will get into that in places where there are abundant thorns. That wouldn’t be very good for the future.
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