Puncture Resistance- What can I do to Protect against Glass & Thorns?


Broken glass is a common cause of flat tires
Broken glass is a common cause of flat tires | Image credit Pexels.com

I’ve been riding a commuter e-bike for several years on a cycle path in a city. Unfortunately, the path has a lot of broken glass on it for much of the year from broken beer bottles, so flat tires were becoming a big problem and expense. I did research into the options, which I explore below.

Good ways to reduce flat tires include inflating to the correct pressure, regularly checking for items stuck in the tire, buying puncture resistance tires or rim liner, and going tubeless. My recommendation is to use puncture-resistant tires.

Summary of the options to increase your puncture resistance to glass and sharp objects:

  1. Inflating to the correct tire pressure
  2. Regularly checking the tube and tire for foreign objects
  3. Using puncture resistant tire liner
  4. Using puncture resistant tires
  5. Using puncture protection liquid
  6. Using tubeless tires

Read on to explore all these options, see product recommendations and more. First we explore how exactly your bike gets a flat, and the different types of flat tires that can happen.

How does my e-bike get tire punctures?

There are three main ways that bike tires get punctures.

Sharp objects, such as glass or thorns, that pierce through to the tube. Prevention – regularly scan the outside of your tires to see if any glass or other sharp objects are slowly making their way inside the tire. Remove them by hand or with tweezers if you spot any sticking into the tire.

Rim imperfections, which squeeze the tube and pierce it from the inside. Prevention – you should carefully check that the rim tape covers the holes with the spokes come up, to ensure that the inside is as smooth as possible, to reduce the chance of punctures caused by the rim. Don’t use electrical tape, as it will deform under pressure.

Hard impacts, which pinch the tube between the rim and the tire.

Methods to Protect Against Tire Punctures

These methods for reducing tire punctures are suitable for all types of bikes and e-bikes – whether it’s a road, mountain, hybrid, gravel, fat, touring or trail bike! There will be some slight difference depending on the type of bike, but the basic measures apply to all.

Correct Tire Pressure

Having a correctly inflated tire increases the pressure between the tire and the inner tube thereby reducing the chances of getting a flat. The correct pressure depends on your weight and the width of your tire. A person weighing 60-70kg should aim for about 90-100psi. Someone weighing 80kg+ should aim for 110+ PSI. You should regularly check your tire pressure at least once per month, I find that the increased weight of an e-bike tends to deflate my tires more quickly than on a normal bike.

Rider WeightPSIBar
132lbs – 154lbs / 60-70kg90 – 1106.2 – 6.89
176lbs+ / 80kg+110+ 6.89+

Make sure that there is no foreign objects when fitting a new tire, or a new tube

Run your fingers along the inside of a new tire before fitting it on the wheel. If there are sharp objects after working their way into the tire, remove them. Run your fingers along the metal wheel rim and try to detect sharp edges. File them down if needed, and fit bike wheel tape to reduce the friction between the wheel and the inner tube.

Puncture-resistant Rim Liner

It’s possible to fit puncture-resistant rim tape to the inside surface of the bike tire that you already have on your e-bike. I personally don’t recommend this method, as it’s easy to get it fitted wrongly, which increases the chance of it slipping and getting a pinch flat. Another possibility is that the join – where the two ends of the tape meet – crimp up together when under pressure and cause a flat. A much better option is to purchase puncture-resistant tires, which come from the factory already fitted with the layer of puncture-resistant material already fitted.

Buy Puncture-resistant Tires

Puncture-resistant tires are my recommended method of reducing the amount of punctures you need to deal with.

There is a slight trade-off, in that the weight of the tire is increased somewhat, but this is not really an issue for me. The tire also costs more than a non-puncture resistant version but this trade-off is easily worth it to me. I save time and headaches the very first time I drive through glass on the cycle path, which happens semi-regularly. If I must send my bike to a bike shop for a tire replacement, it will cost quite a lot, and I must take public transport for a few days, so in the end, I pay much more money overall by having non-puncture resistant tires.

Ultimately, by having puncture resistant tires, I have saved their cost several times over by not having to replace regular tires multiple times.

Puncture protection liquid

Normally puncture protection liquid is inserted into a tubeless tire, which I explore below. The idea is that the liquid will circulate inside the tubeless tire and quickly seal off any holes that form when riding over sharp objects. You will lose some air pressure as it takes a little time for the seal to form, but you should normally have plenty of time and air pressure left, enough to get you home. It’s a great way to avoid annoying tire and tube changes at the roadside.

In this video, a test was done to see what exactly would happen if puncture protection liquid was inserted into a normal inner tube, instead of a tubeless tire. Surprisingly, it seems to work well! This should be enough to get you home and dry.

Tubeless tires

Your bike tire actually just one of two components that sit between your metal wheel rims and spokes and the road surface. Inside the outer tire, there is an inner tube, which is actually the part that gets inflated with air. When you get a puncture it’s the inner tube that gets a hole in it and must be patched up or replaced. Therefore, eliminating the inner tube with a tubeless tire virtually eliminates the chance of getting a flat.

So what exactly is a tubeless tire? A tubeless tire is a special tire that comes from the factory designed to be installed and sealed directly to the metal rim of the wheel, and is normally filled with a latex sealant which quickly fills in any holes that appear.

It’s a great way to massively increase puncture resistance, since there is no inner tube to get punctured. Pinch flats which are punctures that happen as a result of the side of the inner tube getting pinched against the metal rim are eliminated.

Some claim that it improves rolling resistance and reduces weight.

The biggest disadvantage is that getting the tire on and off the metal wheel rim is significantly more difficult than a regular inner tube. This means that if you get a flat at the side of the road it can be very difficult to change the tire.

[YT install tubeless tire]

So how do they feel on the road? At higher PSIs, they generally transform more shocks and bumps from the road since the only structure between the stiff metal parts of your bike and the road is a single stiffer tire. In other words, the ride quality is more uncomfortable. The handling feel is also quite different, especially notable in bends. If you’re a hard-core cyclist this may not be to your taste.

[insert video of it in action]

What are are the best, high-quality puncture resistant tires?

Schwalbe Marathon E-Plus

Schwalbe puncture resistant tires | Image credit Schwalbe

Schwalbe (which translates as “swallow” – the bird, not the act of drinking) are a long established German bike tire company, known for their quality bike tire products.

They are especially relevant for e-bike users as they have a product line designed especially for e-bikes.

These tires boast “outstanding performance with regard to riding experience, all-round puncture resistance, rider safety and durability.”

Schwalbe Smart DualGuard

Image credit Schwalbe

Schwalble tires offer 4 mm thick SmartGuard special rubber (1), combined with 2 RaceGuard fabric layers (2).

I personally use them on my e-bike, and since then I have ridden over multiple areas with broken glass, without getting a flat tire. This shows to me their worth, since my bike is not out of action for several days, which costs me money.



Continental Continental Contact Plus Road Bike Tire

Image credit Continental

Continental are another well-established German tire company, known for producing high quality tires for bikes, automotive, moped and motorcycle industries.

They offer a range of puncture-resistant road tires developed for e-bikes, but also for urban bikes, trekking bikes, gravel bikes, mountain bikes and racing bikes. They additionally offer tires developed for different speeds of e-bikes, such as the 25km/h (15.5mph) limit for pedelecs and 50km/h (31mph) for higher speed S-Pedelecs.

All Continental city or trekking tires are rated to a standard speed of at least 25 km/h, and those marked e50 are also certified for S-Pedelecs. They offer high levels of puncture protection and low levels of rolling resistance, while providing protection from premature wear exerted by the extra weight and speed of higher speed e-bikes.

The combination of speed with puncture protection make this a good choice for those who don’t want to be slowed by having to repair a flat or by the tires themselves. It’s ECE-R75-certified, designated for usage on e-bikes up to 50km/h.

Coming in a huge variety of different sizes, with 700c, 650b and 26-inch options, these present a versatile offering.



Michelin ProTek Max City puncture-resistant tire

Image credit Michelin

Michelin is an internationally renowned French tire manufacturer, one of the largest in the world. They produce a range of bike tires for all types of uses, including for e-bikes.

The Michelin ProTek Max City certainly isn’t light, but it is a tough product that is also rated as e-bike ready and is most certainly durable. Standard 700c is available, 26-inch options, 24 and 20-inch versions are available as well.

It has reflective sidewall stripes for increased night time visibility and a 5mm thick strip running under the thread for resistance against sharp objects poking through.

Features to look for when buying a puncture resistant tire

Tire Width

Simply put, wider tires can be used at lower pressures than narrower tires – without increasing the risk of punctures. This can make them more comfortable and provide more grip, which is important if you commute to work in all weather.

However, its possible to set your tire pressure too low on the front tire, increasing the stress on the tire wall and potentially risking damage to the frame. It also reduces your speed and needs more energy to pedal.

Understanding the Trade Offs with Puncture Resistant Tires

There are trade offs to be made when selecting a puncture resistant tire, in particular between speed, comfort and grip. If you are a casual cyclist or commuter, speed is likely to be less of a concern compared to comfort.

It is possible to buy solid rubber tires which are virtually impervious to punctures, but at the cost of sacrificing comfort. For most riders, it’s too great of a compromise. This is why I recommend the puncture resistant tires above as a good middle ground– there is an increased cost, but at the greatly reduced risk of flat tires, without compromising comfort. I don’t notice any difference in comfort between regular tires and puncture resistant Schwalbe tires on my e-bike.

If you are a casual cyclist, having a lot of discomfort is likely to mean not using your e-bike at all, and missing out on the benefits that e-bikes offer.

Wire Density

Rubber coats the visible outer surface of the tires, but inside the structure are wires that give the tire rigidity. Different tire makers have different approaches in how they make tires, some have a smaller amount of large wires, and some have a large amount of thinner wires.

More wires per inch (TPI) means the tire is more flexible. The downside of thinner wires is that they are more susceptible to breaking under stress. A middle TPI is a good compromise. Bear in mind that this is not too important for those cycling on flat roads, but more for those on off road situations.

Rubber Composition

Tires will generally use a variety of ribber compounds for various performance improvements. Harder compound is normally used in the center of the tire, to make the tire more durable and more resistant to punctures.

The sidewall compounds are usually softer and provide more grip in the corners. This part of the tire has less contact with the ground, so wear is less of a problem.

Generally, this is more of a consideration for more serious cyclists, such as those taking part in races.

Conclusion

I hope that you enjoyed this article, which covers almost every aspect of reducing the chances of you getting a flat tire.

We have looked at the main ways that punctures actually happens, we’ve looked at some methods to reduce the chances of that happening the First place. These include methods like increasing tire pressure could correct amount, regularly checking sharp objects that have become embedded into the tires, and purchasing rim liners (not recommended), puncture resistant tyres and puncture protection liquid sealants.

We then looked at some specific brands of tires from quality manufacturers and the models of tires that they offer. You are sure to find the exact tire that suits your exact needs, regardless of the road conditions (or a lack of road!), the type of cycling you do, the width of your wheel, the size of your wheel, the maximum speed of your e-bike and so on. There are such a massive array of tire products on the market, every single scenario has been covered, including tires designed specifically for e-bikes.

Lastly, we’ve looked at some of the features of tires that you may wish to consider when making a purchase, including the tire width, the tradeoffs involved, the wire density and the rubber composition.

With all this information, I hope you can make an informed decision on how you can avoid those dreaded flat tires.

Happy Cycling!

Nikolaj Carlsen

Nikolaj loves cycling! He currently owns two bikes. He used to commute to work with a car but switched to an e-bike in 2017. He loves e-bikes and sharing his knowledge on everything cycling related. He has been part of the Amped Cycling Team since early 2020.

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