This Space for Rent

Don’t underinflate the beams

I don’t know if it was an artifact of forcing the tires onto the rims, or if it’s an artifact of slightly underinflating them, but I managed to get pinch-flats on both of the mlcm’s wheels when I was trying to ride down to the post office to mail a couple of packages.

Annoying, particularly when the sequence was that the rear tire went flat, so I stopped to change it, and after I changed it I realized that the front tire was going flat, so I had to actually patch it (since the new tube went on the back tire), and then by the time I’d wedged the front wheel back together and (slooooowly, thanks to using a minipump) inflated it I discovered that the rear wheel had gone flat, due to an imperfect patch on the new tube, so I had to pull the rear wheel off and apply more patches.

20 minutes per tirechange. × 3. sigh. I need to (a) inflate the tires a lot closer to 120psi, (b) be even more paranoid about checking that the tube isn’t pinched under the tire, and (c) get a better pump to carry on the mlcm (a large amount of the 20 minutes per tirechange is pumping air into the tires, and even then I couldn’t get more than about 40psi (measured at home after I limped home at 15mph)) pushed into the tubes.

On the bright side, the tires remain unpunctured. Just like my surly disposition.

Comments


Have you considered carrying an inflator and some CO2 cartridges instead?

Planet Bike Red Zepplin CO2 Inflator” gets excellent reviews at MEC.

The basic device is cheap (10 CAD) and compact (device + 3 cartridges reported to fit in an inner tube box) so it might make a good choice for the mlcm flat kit. (At the rate you seem to get flats it might be a significant expense in CO2 cartridges, but at (roughly) a cartridge per 700C tire to ~100psi, you’d get home a lot quicker.)

I have a compact pump I like, but it’s the rack-pack size, not the seat-back or front-bag size(Filzer Mini-Me Pump) so probably not suitable for the mlcm. Kevlar tires, bless them, have left me mostly using the floor pump the last couple years, for which I am devoutly grateful.

Graydon Sun Jan 3 09:53:05 2010

CO2 inflators have the decided disadvantage of using CO2 cartridges, which need to be thrown out. The Zefal pump I’ve got on my Trek has some disadvantages (it’s old enough to be quite finicky about how it latches onto a valve stem) but all it needs is muscle energy to fill a tire. (The Crank Brothers mini-pump is, theoretically, also capable of pumping up a tire, but it’s got this teeny little barrel that’s only slightly more efficient than lungpower.) If I get a long-barrel frame pump, I can fasten it to the bike either along the toptube or the non-drive seatstay, and then it will be less in the way than the little minipump which I have to wedge into my toolbag.

David Parsons Tue Jan 5 22:01:07 2010

Certainly having to be thrown out is a major strike against CO2 cartridges.

Though there’s the stuff the paintball guys use, which is small, light, and refillable; there’s also http://www.turanairsystems.com/home.html whose smallest air bottle is four pounds full and a foot long but which would do a very great many tires.

Graydon Wed Jan 6 15:46:35 2010

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