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Hands-on Gear Review
Bontrager TLR Flash Charger Review
Cons: Robs air from tire, plastic head with thin lever, poor gauge
Bottom line: A solid option for tubeless tires without shelling out too much cash.
Weight: 6.2 lbs
Hose Length: 42 in
Manufacturer: Trek Bikes
When this pump came on the scene, it was a game-changer. With tubeless tires quickly becoming the norm, the ability to seat a tubeless tire bead onto a rim without the need for a powered air compressor is a function that a growing number of cyclists have come to desire. The high-pressure auxillary air chamber was successful at seating all but one tire/rim combination we threw at it. To be fair, this pump's main competitor in our test, the Topeak Booster was denied as well.
When used as a portable compressor, we have few gripes. It takes an average of 53 pumps to charge the high-pressure chamber, only slightly more than what the Booster required. The Flash uses a bit more plastic than we'd like to see, especially given the high use we anticipate from loaning this pump out to friends. Our main gripe comes when this pump is used as a traditional floor pump. When the hose is attached to a valve, air flows out of the tire and fills the pump. The tire is robbed of a huge amount of air which translates into more pumping. It's annoying.
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Our Analysis and Hands-on Test Results
Everyday, another mountain biker discovers the relative flat-proof joy of riding tubeless tires. A couple month later, they discover how much of a pain in the rear tubeless tires are to install onto a rim without the proper equipment. For those without an air-compressor and the patience of a monk, what was once a 10-minute job now results in going down some YouTube wormhole on how to McGyver some useless contraption using baking soda, a floor pump, duct tape, and a soda bottle to seat a tire bead. Luckily, the Bontrager Flash Charger came to the rescue. It has its quirks; mainly the way it steals air from tires before asking your triceps to put it back where it belongs. We don't really like the gauge with it's broad pressure measurements and small font. The head has a delicate feel to it but it seals tight and fits any valve without moving around parts. It'll set you back a Benjamin, but it might be the most practical hundo you ever spend.
Comparatively, this is a big pump. Luckily, it features a metal, 3-legged base wide enough to prevent it from falling over and breaking toes; there is no rubber or plastic on the base where it contacts the ground. Scratching of delicate surfaces is especially likely with this pump because of its significant weight. The polished alloy cylinder and meaty compressor cylinder rest in a plastic cradle atop the base, which is secured by a plastic mounting plate on the underside of the base. Given the significant amount of force it takes to fill the secondary chamber to 160 psi, metal would have been a more welcome choice for this part. However, the cradle is significantly recessed, allowing the barrels to fit securely and deeply enough to prevent unwanted movement.
Ease of Attachment/Detachment
The "auto-select" head fits both Schrader and Presta valves without unthreading or flip-flopping internal pieces around. The head is entirely plastic; although the long lever made it easier to secure the head to the valve, it felt a bit delicate and thin for our liking.
Although we can appreciate the user-friendliness of a single auto-select head, this design may wear out a bit faster than those heads with separate ports for each type of valve. Ours still sealed tight onto valves by the end of our testing period, but it was bit chewed up. Pumps of this sort are still relatively new and we found ourselves lending it out quite often to friends replacing tires that didn't have access to an air compressor.
Despite the gauge being mounted towards the top of the pump, the miniscule type and brushed metallic background proved difficult to read for many testers. There is no chronograph dial that could be set beforehand if reading the dial is difficult. The diameter of the gauge inside the housing is less than two inches and our biggest gripe was with the spacing. Displayed in increments of 20 psi, this was far too generous to obtain a reading with much accuracy. The red lever that is contoured to the shape of the gauge (and flips up and down to activate the pressurized chamber) is made of plastic and often the first thing to hit the ground when the unit is pushed over.
The hose on this contender is 42 inches long. It attaches towards the top of the pump, which makes filling both tires possible without moving the pump around. For such a large pump, we expected this to be one of the fastest pumps in the test and we were surprised when it placed towards the bottom of the barrel in our tests. When connecting the auto-select head to the tire valve, the pump fills with air from inside the tire. The long hose and large barrel suck out a ridiculous amount of air, leaving the tire at a much lower starting pressure. As a result, simply topping off a tire turns into a full-fledged pumpfest. Think we're kidding? A road tire starting 100 psi dropped all the way to 40 psi when we hooked up the Flash Charger. It required 35 pumps to get the pressure back to 100 psi where we started! When you disconnect the hose from the tire, all the air escapes from the pump and the hose hisses at you for 10 seconds like a Cobra poised to strike.
In everyday use, accuracy is difficult to determine with this pump. Due to the spacing of pressure values on the gauge, readings are often a best guess, especially on road tires. The lower values between 10 and 40 psi typically encountered with mountain bike tires are spaced 10 psi apart (i.e. 10,20,30,40) and can be read with better accuracy. Past 40 psi, pressure values are given in increments of 20 with no intermediate markings. Thankfully, we chose even pressure values for our testing, which were marked on the gauge. This pump was consistently accurate to within a couple psi; however, in the real world, we feel accurate pressure readings will pose a much greater challenge.
This pump's strength definitely lies in the application of seating tubeless tires. We successfully seated numerous tubeless tire combinations including 27.5 inch, 29 inch, fat bike, plus, and cyclocross tires. If you don't have access to or don't wish to purchase an air compressor, these pumps are the next best choice. On a past mountain biking trip to Gooseberry Mesa, where a buddy blew out the sidewall on his rear tire, having the Flash Charger at camp would have saved him a long drive into town.
At around 120 dollars and recently on sale for 99 dollars on Trek's website, this tubeless ready pump is significantly cheaper than the other compressor-type pump we tested, the Topeak Joe Blow Booster. The Flash Charger was just as successful at seating the bead on tubeless tires; innovation costs money and Bontrager effectively keeps the cost of this pump down by using plastic parts on the head, handle and compressor chamber lever. Those in the market for a pump that costs 100 plus dollars might be willing to spend a few extra bucks to get more metal on such high-use pieces of the pump.
Our arms were ready to fall off from all the pumping required to test bike pumps. Having already recouped the money on having bike shops install our tubeless tires, we're definitely digging on these style pumps that act as air compressors. With this pump, we really couldn't get over the amount of air drawn out of the tire when attaching the hose. To make matters worse, the extra effort required to regain our starting pressure and fill the tire further was blown in our face when we detached the hose.
— Sean Cronin
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