Archive for March 2018

A Surprising Little Pump

Wanting to reduce the size of the tools carried on the Vaya I went looking for a new pump, and what I found surprised me: the diminutive Mobo Pocket Air Pump (4″). Despite being marketed by a company that seems otherwise known for low-cost and kid-branded recumbents, this seems to be a quality pump for MTB and gravel road emergency use.

Looking for a small emergency pump my primary requirements were functionality and size, followed by the amount of time it’d take to inflate a tire. I have tubeless setups on all my bikes, which tends to be pretty reliable. Flats are pretty rare, so when they do happen I’m okay with taking my time installing and inflating a tube. Being something that’ll be packed away for non-routine use I’d prefer the emergency gear to be small and reasonably light. The Mobo pump seemed like it might be too cheap to work well, but just about $20 (via Amazon) I figured I’d give it a go.

Ideally I’d like to be able to fit a tube, multi-tool (including chain tool), pump, and a car key inside of a small seat bag. With this pump I think I’m on the way, as it had no problems fitting into a slightly-older, small-sized Timbuk2 saddle bag along side a Crankbrothers M17 multi-tool, with plenty of room to spare. Along with a bottle cage mount it ships with a nice brass Presta to Schrader adapter and sports ball inflation needle. The inclusion of an adapter is good, because the pump itself is Schrader-only. Thankfully packing either the stock adapter or an aluminum one into the bag isn’t a big deal.

Inside the expectedly cheesy (but well packed) box is a solid-feeling pump that measures in at 3-7/8″ long, 7/8″ diameter at the body, and 1-1/2″ across the pump head. At 56g it’s lighter than a 16g CO2 cartridge, and right about the same size as a cartridge + valve head. Somewhat to my surprise it has a very nice, light, smooth pumping action and check valve sound. Basic tests in my basement showed to work reasonably well.

My first test was inflating a 700 x 35-43c Kenda tube from flat to shape, as one would do before fitting it into a tire. This took 42 pumps — none of which required any notable effort — and took well under a minute. The second test was inflating the front wheel from my Specialized Camber, a 30mm internal width rim fitted with a 29 x 2.3 Specialized Purgatory tire, from atmospheric pressure. After pumping for four minutes the tire had 22 PSI, which is my normal front tire pressure for rocky trails. Finally, the third test was re-inflating the Vaya’s front wheel — a WTB KOM i23 rim and 700 x 38c Specialized Trigger tire set up tubeless — from atmospheric pressure to 43 PSI. This took a total of around six minutes, with some pauses sprinkled in as my arm got tired. Nearing the final pressure the pump got fairly hard to press, leading me to believe that the claimed 100 PSI maximum is probably more a technical than functional limit. Getting a wheel to 100 PSI with this pump would be… a challenge.

Sure, four minutes for an MTB wheel and six minutes for my road bike is a while, and the low volume won’t be re-seating any tubeless tires, but as an emergency pump this should be fine to get one rolling again. While some folks prefer CO2, as a one-shot item I’d want to carry a pump as a backup… Being small enough to tuck in a saddle bag with other parts, and right about the same size and weight as a CO2 cartridge, but multi-use. It’s what I plan to pack into a seat bag on future rides. While I hope it works when I need it — and seems like it will — needing to use a pump in the middle of a ride is something no one wants.