When I first ran into Lezyne’s mountain-specific Dirt Floor Drive line of pumps at Interbike last fall, I admittedly didn’t get it. With an oversized barrel (30% larger than the standard Floor Drive) and a gauge topping out at 70psi, the Dirt Floor Drive seemed oddly limited- especially in a road/mountain household. It was only after repeatedly hearing a local shop owner rave about the durability of their shop’s Floor Drive and getting the rest of the story about the Dirt Floor Drive from Lezyne that it started to make sense. Read on to find out why, after two months’ use, I’ve made the mental U-turn to embrace the Dirt Floor Drive- and why my air compressor has largely been sitting silent.
It turns out that Lezyne have increased not only the Dirt Floor Drive’s barrel volume, but also reworked the rest of the pump’s internals to allow for substantially increased air flow. 
It’s that combination of increased stroke volume and decreased flow restrictions that allows the three pump Dirt Floor Drive line to effectively seat about 3/4 of the tubeless tires I’ve tried it on. It’s not quite as effective as a small workshop air compressor- but with a bit of effort it sure comes close. And it’s against that of an air compressor that the purchase of a Dirt Floor Drive should be considered.
The Dirt Floor Drive range starts with a $75 steel-barreled version, proceeds to the tested $85 Alloy Dirt Floor Drive, with its wood handle and aluminum barrel, and then on to the blingtastic $110 CNC Dirt Floor Drive with still more machined aluminum hardware and an aluminum handle. All three use Lezyne’s presta/Schraeder reversible thread-on chuck and the hose is long enough to comfortably reach the wheels of bicycles mounted in workstands. The large gauge is located at the substantial cast base- not great for legibility, but probably the best location given its size and heft.
It didn’t take long for me to get in the habit of using the big Lezyne over my air compressor to mount tubeless tires. First, it’s considerably quieter. Second, when time waiting for the compressor to reach pressure is taken into account, it’s almost always faster. Finally, it has a gauge (reducing the need for a second operation).
The thread-on chuck is a double-edge sword. Its simplicity is wonderful and leaves far less to go wrong or to be fouled by sealant than do more ‘modern’ designs. Its downside is the possibility of threading tubeless valves into the tire (through their lock rings) when installing the chuck, and the inevitability of removing the occasional valve core (along with all of the tire’s air) when removing the chuck. In order to facilitate trailside valve stem removal and sealant injections, I’d been in the habit leaving both fairly loose but have had to snug things up in order to use the Dirt Floor Drive. Lezyne’s $10 aftermarket push-on Slip Chuck head should address these complaints, though, and is high on my shopping list.
Another reason that the Lezyne has been so eagerly adopted as part of my workshop is that it’s just satisfying to use. The polished aluminum makes it look like a serious piece of equipment and the stained wood handle is not only pretty but a pleasure to hold. The height of the pump is just right, allowing average-height adults to manage full strokes without uncomfortable bending. The overall impression the Dirt Floor Drive gives is one of solidity and durability.
Along with a push-on head, I would love to see Lezyne equip the Alloy Dirt Floor Drive with a bleed valve of some sort. This would allow tires to be seated at 50 or 60psi, then bled down to the riding pressure. 
But this is a minor request- none of the pumps I own have one- it’s just that much more noticeable because the thread-on chuck can make the letting small bits of air out a bit fiddly. The $85 price is high, but as it could largely take the place of an air compressor (and is considerably more portable), the Alloy Dirt Floor Drive could be justified on those grounds- anyone changing tubeless tires at a race will love you for bringing one. I’ll be changing and inflating loads more tires as the year goes on and report back if anything interesting happens…
marc
