By Will Soffe

Published: Tuesday, 07 June 2022 at 12:00 am


Mountain bike tyres face a tough life and, considering the plethora of technological developments in the sport, it’s perplexing that something as trivial as a flat tyre is still an issue.

Riders rightfully demand relatively lightweight, fast-rolling and supple mountain bike tyres, but they also want to ride over rocks without flatting. These desires are not easily compatible. Even when using downhill-casing tyres weighing well over a kilo, punctures are still a fact of life for many.

Tubeless tyre inserts have increased in popularity and, depending on your style of riding, could be a worthwhile proposition if you’re regularly flatting and are worried about damaging your rim or tyre.

Let’s take a look at the advantages and disadvantages of running a tubeless tyre insert.

Why should you consider running a tyre insert?

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There’s no sugar coating it – punctures suck.
Russell Burton / Immediate Media

Tyre inserts act as a barrier between the tyre and rim, and offer some distinct advantages. Firstly, you can afford to run your tyres at a slightly lower pressure on your mountain bike without having to worry about about pinch punctures, given there is no inner tube to pinch and the insert provides further stability against the tyre.

On the subject of the sidewall, tyre inserts increase their stability because they provide further support and reduce deflection. Tyre sidewalls can move or even fold when put under too much lateral force.

Tyre inserts also prevent rim damage, given they are the main contact point with the tyre should it be compressed. If a tubeless tyre is stressed beyond its capacity to create an airtight seal with the rim, air can escape out of the tyre, which is also known as ‘burping’. Inserts create a cushion between the tyre and the rim.

What are the downsides of running an insert?

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Tyre inserts aren’t for everyone and you need to weigh up whether the pros outweigh the cons for your riding.
Ian Linton / Immediate Media

Tyre inserts increase rotating and unsprung weight. The responsiveness of the bike is toned down due to the additional weight, which can be experienced when accelerating, braking, turning or jumping. They can also make suspension work less effectively, placing extra stress on the bike’s components and the rider’s body.

Installing a tyre insert can be quite a laborious process. They’re an extra item to cram into your tyre (which can also be difficult to fit on certain rim combinations) and that can be a real challenge.

Then, there is the additional cost. Ultimately, you need to consider whether the type of riding you participate in warrants the advantages a tyre insert can deliver.

How can I reduce punctures and protect my rim from damage without a tyre insert?

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Correct suspension setup is a must for mountain biking.
Immediate Media

It’s first important to keep a careful eye on your tyre pressures – buy yourself a proper tyre pressure gauge, and use it. That’s not to say crank your tyre pressures too high – lower pressures will give you more grip and better comfort; and in rough terrain, less rolling resistance. The key is to find the pressures that work for your tyre setup and riding style, then stick to them.

The next thing to look at is your suspension setup. Suspension that’s too firm, or bottoms out too easily, or rebound damping set too slow or too fast, will increase the chances of puncturing. Check out this guide to setting your suspension up properly.

Finally, if you’re experiencing tubeless tyre punctures or rim damage, you could opt to fit heavier tyres. Yes, that will increase wheel weight; but to some extent, so will any of the above systems. Tougher tyres have other drawbacks, though. Thicker casings are less supple, so you’ll get more feedback through the bars and rolling speed will suffer too.

So a lighter tyre with an in-tyre system is probably a better, if more expensive, solution, especially for racing.

Also, if you’re the type of rider who already runs full DH tyres and still suffers flats, these could be your best chance of eliminating those pesky punctures.

Seven mountain bike tyre inserts rated and reviewed

We tested six of the latest tubeless tyre inserts to determine the best option for protection, while balancing being lightweight and offering good value for money.

Rimpact Pro

4.5 out of 5 star rating
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The dual-compound closed-cell foam offers great rim protection.
Andy Lloyd / Our Media
  • Weight: 169g (29in)
  • Price: £44.99 (each, with valve) / £71.99 (pair, with valves)

We were impressed by the Rimpact Pro’s low-profile, continuous full-circle design, which resulted in excellent tyre deformation (and therefore more grip) because the insert doesn’t encroach far into the tyre. The dual-compound closed-cell foam offers great rim protection, but is relatively lightweight.

Its slow rebound characteristics mean an increase in grip because the wheel feels less prone to bounce back after impacts. Sidewall support is best on test thanks to the large, flat side-profile and tight-fitting nature of the insert.

Due to its large volume and tight fit, the Rimpact Pro is a chore to install and the insert benefits from being pre-stretched (fitted to a rim for a while) before fitting.