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Road Racing

Bontrager TLR Flash Charger floor pump review: Tubeless without a compressor

As far as tubeless technology has progressed, it’s still more often than not that you’ll need more than a standard floor pump to get tires seated. If you’re not interested in adding a good air compressor to your home workshop, something like Bontrager’s TLR Flash Charger floor pump might be…

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As far as tubeless technology has progressed, it’s still more often than not that you’ll need more than a standard floor pump to get tires seated. If you’re not interested in adding a good air compressor to your home workshop, something like Bontrager’s TLR Flash Charger floor pump might be up your alley, and the latest redesign is a big improvement over the original version.

Getting some big air

Seating tubeless tires is all about one thing: injecting a large volume of air into the tire very rapidly so that the beads can be forced on to the outer shoulders of the rim bed before air is allowed to seep out through the various interstices. It’s that volume of air, and the speed of the delivery, that makes compressors so well-suited for the job, and why so many conventional floor pumps aren’t up to the task.

Bontrager’s original Flash Charger — first introduced almost six years ago — basically took a conventional floor pump and added a supplemental high-volume air chamber. The floor pump portion was used to pressurize the second chamber, and with a flick of a switch, all of that air was instantly released into the tire, making easy work of most stubborn-to-seat tubeless tires. It was also far more portable than a conventional air compressor, and took up a lot less space.

This second-generation version expands on that highly successful concept, retaining the basic layout, but adding several welcome changes and features.

The TLR Flash Charger features a two-chamber design. The larger-diameter chamber is used to quickly inject a large volume of air to help seat tubeless tires. The smaller-diameter chamber is used to pressurize the bigger one, and for general pumping duties.

With this second-generation pump, there’s now a second valve that allows you to bypass the high-volume chamber altogether when it isn’t needed, and Bontrager has switched from an analog to a backlit digital gauge (with 0.1-psi resolution!) for better accuracy and legibility. Bontrager even beefed up the handle, and also added built-in storage inside for tidbits like valve adapters and ball needles.

Retail price is US$130 / AU$260 / £TBC / €TBC.

So how well does it work?

When it comes to seating tubeless tires, the Flash Charger’s dual-chamber design was already very well proven, and it’s no different here. I tried this latest version on tubeless road tires, mountain bike tires, gravel tires, and even fat bike tires with very few of them presenting even the least amount of difficulty when it came to getting them seated.

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The updated TLR Flash Charger now has an additional switchable valve that bypasses the larger chamber completely for easier inflation when you’re not trying to seat tires. There’s also a convenient bleed valve if you need to bring the pressure down a bit.

Both valves are operated by sturdy-feeling levers, and are clearly marked.


The additional cut-off valve is perhaps the biggest improvement here, as it makes this updated Flash Charger a much better standard pump than its predecessor. With the original Flash Charger, the two chambers were forever attached in series, so that when you just wanted to use the old Flash Charger as a regular pump, you had no option but to pressurize everything all at once. Moreover, when you attached the old Flash Charger to your tire, the high-volume chamber bled off so much pressure (in order to equalize the entire system) that it made for a lot of extra work when all you wanted to do was top things off.

Think of it this way: If you want to boil some water for tea very quickly, does it make more sense to start with a single glass of cold water or a giant pot of it?

With this latest version, the pump just works as you’d expect when you’re just trying to top things off.

The digital gauge is backlit for easier viewing in dim light.

The new electronic gauge agreed very well with other digital pumps and gauges I had on hand, too. I only noted occasional variations of a single psi or so at typical road pressures, and the 0.1-psi resolution is a boon for lower-pressure setups like MTB and cyclocross, where small changes can yield big differences in performance. Once winter arrives again here in Colorado, I’ve no doubt I’ll be reaching for this thing when getting my fat bike ready for a ride.

Kudos to Bontrager for the newly reinforced handle as well, and the built-in storage has proved more convenient than I anticipated. I haven’t had much use for the included sports ball adapters, but the otherwise empty compartment on the other side is now the permanent home of a Presta valve core tool (which, oddly enough, is not included).

As before, the cast metal base is admirably stable, and at 3 kg (6.6 lb), the whole thing feels pretty substantial. Bontrager even makes several key parts available aftermarket, which bodes well for long-term viability.

Slow leaks

That’s not to say the TLR Flash Charger is perfect, however.

The biggest issue I noticed is that the main pump barrel size is a bit of a frustrating compromise: it’s too big to easily charge the secondary chamber to its recommended 160-psi operating pressure, and yet also too small to inflate that chamber quickly. I counted 61 strokes to get the tubeless chamber fully charged, and it gets very hard to pump toward the end. At one point, I had a 53 kg (117 lb) friend try her hand at fully inflating the Flash Charger, and she literally had to forcefully bounce all of her weight on to the handle for the last dozen strokes.

The handle is noticeably sturdier than before, but still a bit flimsier than I’d prefer.

Otherwise, the barrel diameter and stroke seems like a decent compromise for all-purpose use, especially given how road tire pressures have been trending downward, anyway. Nevertheless, for tubeless applications, smaller and/or lighter riders should beware.

That was the case with the original Flash Charger, too, and the beefed-up handle helps some in that regard. However, it’s still plastic, and still doesn’t feel anywhere near as sturdy as wooden handles from companies like Silca and Lezyne. But at least it no longer feels like it’s going to snap off in your hands at higher inflation pressures.

The cast metal base is heavy and stable.

Unfortunately, the dual Presta/Schrader head still feels super chintzy with full plastic construction (albeit fiber reinforced) that doesn’t lend a lot of confidence. It does work just fine, though.

The battery-operated pressure gauge is a bit quirky in terms of its auto-off feature, in that it sometimes shuts itself off, but not always.

“There are a couple of ways to put the pump to sleep,” explained Bontrager marketing manager Nick Anger. “You can either let all of the air out of the chamber by flipping the ‘release pressure’ lever to let all of the air out, [or] you can set the opposing lever to ‘inflate’ if you don’t want to let all of the air out. After doing one of the above, it takes about 40 seconds for the pump to fall asleep.”

Call me crazy, but I’d rather that auto-off feature work regardless of how the pump is configured. In one instance, I set up a tire and then walked away for a while, coming back after about half an hour only to find the gauge was still on. Nevertheless, Anger says that most users should expect to get a full season of use from the TLR Flash Charger before the CR2032 battery needs to be replaced.

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Both ends of the handle have integrated storage.

This end is left empty, but it’s the perfect place to stash a valve core tool.


Riders living in particularly humid environments might be wary of the tubeless chamber’s steel construction. When air is compressed, any water vapor it contains tends to condense, which can then pool at the bottom of the chamber. Anger says that’s something Bontrager engineers already thought about, but it still seems like it could be a problem over the very long haul.

“Corrosion is something our engineers took into consideration on both old and new pumps during development/testing to ensure that corrosion wasn’t causing any structural damage or issues with the pumps performance/longevity.”


As good as the TLR Flash Charger is, the market for tubeless air inflation devices has gotten more crowded since Bontrager first bust on to that scene. Standalone tubeless inflation canisters (such as from MilKit, Schwalbe, Airshot, and others) are slightly less convenient, but work just as well. They also cost roughly half as much, assuming your current floor pump can handle the required pressure and you’re generally happy with it.

Even cheaper are DIY hacks using generic pressurized sprayers from various home improvement and hardware stores. Those are decidedly clumsier to use, but also work decently well, and are far cheaper still.

Convenience at a price

I was a big fan of the original Flash Charger — quirks and all — and despite this second-generation version still not quite being everything I’d like it to be, it’s still a meaningful improvement and a super convenient tool for the job.

Is it perfect? Nope. But then again, few things are, and this thing will be close enough for most.

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