New & Improved Emergency Tire Inflation Kit

by Deryle Mehrten ††††

Recently Wanda and I had a front tire weird out on us.† It didnít go flat, but did strand us.† Iíve carried an emergency tire repair kit consisting of CO2 cartridges and an inflator device for a bunch of years that I have never used.† After this experience I decided to see just what I could do with all those CO2 cartridges and inflator.

†††† I found five sizes of cartridges available at† The smaller, 12 gram, un-threaded type were the cheapest so I used them to see how much air I could get into our K1200RSís rear tire.† One cartridge, on a fully deflated tire, put 4 pounds of pressure in.† I used a second one and the pressure went up 4 pounds to 8 psi.† I inflated the tire to 38 psi with my air compressor and used another cartridge.† Darned if the pressure didnít go up 4 pounds.

†††† So, using 4 pounds per 12 grams as the basis, it would take 11 of the 12 gram size cartridges, 8 of the 16 gram size, 6 of the 25 gram size, 3 of the 45 gram size, and 4 of the 40 gram size to inflate the rear tire on our K1200RS.† This assumes the inflator device works and I donít loose any of the stored air.† After using ten of the small size cartridges, I got pretty good at it.† Still it wasnít hard to loose some of that precocious stored air. †Wouldnít it be nice to have unlimited air.

†††† Recently there have been advertisements in the BMW MOA Owners News for a very small 12 volt inflator.† A really neat but very expensive item at close to $80.00.† On the other hand, per recent discussions on several internet motorcycle lists, you can buy a cheap portable inflator at WalMart for $10.00, strip off all the ďbody workĒ and end up with a reasonably sized portable inflator.† I decided to buy one of these emergency inflators and see if I could modify it to fit under the seat of our K1200RS.

†††† From the pictures you can see that size wise the cartridges and their corresponding inflator are pretty small.† Even after adding enough cartridges to insure sufficient inflation the kit would still fit under the seat.† The WalMart pump would have to be reduced quite a bit in size in order for it to fit under the seat.

†††† I removed the five Phillips screws on the back of the case and the whole unit came apart.† I unsoldered the wires from the motor and shortened the wire by about half making sure the wire would allow the pump to reach both the front and rear tire.† Two small blade connectors were used on the end of the wire so that I could unplug the power cord from the motor for better storage.† I also removed the cooling fan from the end of the shaft to prevent interference with the wires.† A small inline on/off switch finished off the power wire.†

†††† The inflation hose was also much longer than needed, so I pulled the tire inflation clamp off the end of the hose by cutting off the small crush clamp.† I shortened the tube by half and using a small fuel injection hose clamp re-attached the tire inflation clamp.† Now the unit was not much larger than my CO2 with inflator kit and it fit under the seat of our K1200RS in the same bag.

†††† From zero psi it took about four minutes to inflate the rear tire of our K1200RS to 40 pounds with the stripped down pump.† And yes, I still lost a bunch of air getting the hang of putting the tire connector clamp on the stem of the tire.† But no problem, I had as much air as I wanted.

†††† A couple of cautions.† First, the pump and the hose get hot after a minute or two.† Be careful where you hold it.† Second, the little motor pulls more current as the pressure builds up.† I suggest you have your bike running at a fast idle or more to insure you do not strand yourself due to an exhausted battery.

†††† Now I have an emergency repair kit with an unlimited supply of air.† Sure hope I never have to use it!


Home Page