Protecting Your E-Bike From Puncture Vines & Other Thorns (Part 1)

If you’re a regular reader, you’ve probably noticed that we do a lot of e-bike reviews, and that I’ve done a number of them. Not only are they a lot of fun to ride, but e-bikes are also one of the most environmentally friendly forms of electric transport. They’re light, they have small batteries, their tires don’t shed a bunch of nasty particles, and they don’t contribute much to urban congestion. They’re also a great way to save money if you only own gas-powered cars and can’t afford an electric motorcycle. In other words, there’s a LOT to like. But, there’s one problem: “Puncture Vines.”

Puncture Vines: A Nasty Invasive Species

In many places, you can just ride around with a regular tube and tire. Yes, there are thorns almost everywhere in the world, but they tend to be on branches that you can easily spot should they fall into a bike’s path. Carrying around a spare tube or two and a compact air pump works because flats are pretty rare. Many e-bikes don’t have a quick-change stem on the rear wheel (the little lever you can use to quickly remove it for a tube change) because it’s not that common to need to do that away from home.

Like normal bikes, e-bikes suffer from an invasive species problem in warmer climates. Its scientific name, Tribulus Terrestris, is fitting. Instead of having short, easily broken thorns like most plants bearing stickers, the “Puncture Vine” has relatively long and hard spines on it, making them like little caltrops (multi-way spikes designed to hurt feet, hooves, and now tires). In fact, caltrops were called “tribulus” by the Romans, who lived in the same area of the world that the cursed plant comes from. The idea may have been inspired by nature, as it’s known that Japanese warriors once used the larger seeds of another plant as caltrops.

The species has spread globally, inhabiting warmer areas from 35 degrees south to 47 degrees north in latitude. So if you live in one of the areas where the species thrives, you’re going to have problems with bike tires. Even on paved trails and roads, it’s common for the stickers to get left behind after they’ve stuck to people’s shoes and other riders’ tires. Unlike the branches of thorned plants like Mesquite and Holly that sometimes break off, Puncture Vine seeds are just too small to see until you’re already in the middle of a big patch of them and you hear them grinding and crunching on pavement.

I live in an area with lots of different thorned plants, some even worse than the common Puncture Vine, so I’ve done a lot of trial and error over the years. I’ve had to do it again with fat tires, as they’re a little more susceptible to getting deflated by thorns. For the rest of this article, I’m going to share what I’ve learned actually works at keeping a tire inflated for months.

Slime vs The Puncture Vine

One of the common solutions to this is the use of Slime, a thick fluid you can put into your bike’s tubes. If you’ve got a bike with Schrader valves, you can use the cap of the Slime bottle to remove the valve stem core, and then you can pour the slime into the tube. As the wheel turns, the slime distributes around inside the tube and gets pushed against the sides by centrifugal force. If something small pushes and pokes its way through the tube, the sticky slime goes into the hole and seals it up, keeping the air inside.

I’d personally recommend using 2-3 times what slime recommends on the bottle, and for fat tire e-bikes, that means 2-3 times the recommended amount for a motorcycle tire. That sounds like a lot of slime, but it takes a lot to cover multiple punctures at a time. If you’re riding a bike with Presta valves, you can’t put slime in, but you can buy tubes for most bikes that come with Slime pre-inserted into the tube from the factory.

The problem with Slime is that it’s only a good way to extend tube life, and not prevent punctures. As you rack up more and more holes, you’ll get to the point where the tire doesn’t hold air between rides because the slime drips away to the bottom of the tube and lets the air go out. This is easily fixed, as you can just turn the wheel a few times, add air, and then ride off. But, as you get more and more holes, you’ll eventually get to the point where you actually see Slime leaking and the tube can’t hold air long enough to go for a whole ride.

So, I’d definitely recommend Slime, but I wouldn’t rely on Slime alone.

Thick, Self-Sealing Tubes

While you’re not going to be able to trade self-sealing bike tubes for Cardassian Yamok Sauce, you can save on Slime if you use them. Basically, you’re looking at getting thick, thick rubber tubes. Self-sealing tubes are made with special compounds that can mostly close back up if a hole gets punctured in them. They can’t handle all punctures, and they often don’t close up perfectly. So, you’ll want to put slime in these tubes or order tubes that come with slime already inserted. What the self-sealing tube can’t seal, the slime almost always will.

This still doesn’t completely solve the problem, but it puts off the inevitable for longer than Slime alone would. It takes longer to get to the point where your bike is flat between rides and puts off the time you can’t finish a ride even longer. In other words, it’s still not a complete solution, but it’s one that you can live with for a lot longer.

I can’t recommend any specific brands of tube, because e-bikes come in all shapes and sizes, but it really comes down to just getting the thickest self-sealing heavy-duty bike tube you can get in a size that fits your bike.

In Part 2, I’m going to cover a couple more things you can do to put off tube replacements almost indefinitely, and then discuss some things you shouldn’t do.

Featured image: My 2020 Radrover ST, part way through the thornproofing process.