The other night after the kids were asleep, I was chatting with my spouse.

“Sharrow,” I said, considerately massaging her feet. “I think what we really need in this family is for me to have a new Trek Madone.”

Sharrow — which is short for “She wHo Adores Really Rickety Old Wheels” — didn’t bother looking up from her magazine and said, “Maybe after we buy the kids some new shoes, and replace the old computer … and get the Xtracycle.”

“But,” I protested, “the computer is four years old. Do you realize that my bike, were it a human being, could legally buy cigarettes?”

“Your bike’s hard drive isn’t about to explode,” Sharrow countered. “Besides, old enough to buy cigarettes is not really that old.”

By Sharrow’s standards, this is true. This is the bike Sharrow loves best:

It’s a Columbia from, oh, I’m guessing the 1960s. Riding it feels a like being in a canoe. But Sharrow adores stuff like this. The older, the ricketier, the more worn-out the better. Just like she likes her husbands.

Anyway, Sharrow’s birthday is coming up, and this year Eugene Bicyclist has been on the ball. And during the above conversation — or something like it — I could barely contain myself. You see, the Xtracycle longtail conversion kit — unbeknownst to Sharrow — had already been purchased and was sitting not 15 feet from her, hiding quietly in the attic.

A couple of days later, the much desired Xtracycle happened to come up again, in passing, during conversation at breakfast. It was at this point that my 4-year-old stopped eating her yogurt and said to her mother: “Mama, we got you the Xtracycle.” I tried to act like this was a wild piece of misinformation akin to this preschooler telling us she had once seen “a poop-poop cross the road.” And as I tried to shrug it off, the girl leaned toward her mother and whispered, “Yes.”

This was about six weeks before Sharrow’s actual birthday. I had coached this child about not revealing the surprise, but — oh well, why let an Xtracycle languish in the attic? Early present this year.

So, off we went in search of a bike to attach the so-called “longtail kit” to. I had planned to do this myself before Sharrow’s birthday, but now Sharrow had the chance to participate. So after an unfruitful detour during which we tried to see if we could use a 35-year-old Peugeot mixte frame (known in real estate lingo as a “fabulous vintage charmer”) …

… we ended up at that recurring used-bike yard sale at 13th and Charnelton, looking at a promising candidate that at least Sharrow did not find repulsive: a Trek 820 mountain bike, late 1980s vintage, the frame of which is built like a battle ship.

Ah, this was the Golden era of mountain bike simplicity — before Gary Fisher sold out to Trek (in 1993), before shocks and suspension, before oversized tubing, before Biopace chainrings flopped. (Yes, this bike has Biopace chainrings!). Before the superfluous rear wheel was added.

And well before the garish billboard-style graphics we are accustomed to today. The Trek 820 is still being manufactured and sold. Here is the graphic design monstrosity that is the current incarnation of the Trek 820:

Sharrow would not be caught dead on this.

Our Trek was marked at $119 and they came down to $110 since it had a flat tire. (I notice that a brand new Trek 820 is about 350 bucks, but to tell you the truth, I think I’d rather have the vintage model.)

By the way, I often find the bikes at that 13th and Charnelton yard sale rather overpriced. But $110 seemed like a decent price, especially given that we were in a hurry.

Rickety vintage Schwinn 10-speeds are actually priced much higher, which I guess says something about what’s cool at the moment. Old mountain bikes, not. Retro road bikes, yes, especially if there might be a fixie inside screaming to get out.

At home we went to work on the installation. Right off, the Xtracycle instructions will admonish you thusly:

FAILURE TO FOLLOW THESE INSTRUCTIONS PRECISELY MAY RESULT IN INJURY OR DEATH! … This installation should only be undertaken by a professional bicycle mechanic.

Not one to disregard warnings of death, I began work under the counsel of a seasoned pro:

First, check that no Cheerios have fallen down inside the tubing:

This mechanic also delivered an eloquent explanation of the proper routing of the chain and rear derailleur cable through the maze of stays and braces that make up the Xtracycle longtail. Do not get the brake and derailleur cables mixed up, she counseled.

All in all, the Trek served admirably during the conversion, the lone problem being that the rear brake was not compatible with the Xtracycle. So for the moment we are operating with a front brake only. But rear brakes would seem to be overrated, judging by all the single speed coasties I see around town these days pretending to be fixies and sporting only a front brake.

Given the physics of the longtail, I think there is little chance of flipping the bike and going over the handlebars. Needless to say, the Xtracycle instructions warn never to ride with only a front brake. So, yes, the V-brake is on order and should be here shortly.

The instructions said nothing about beer, but if I could make a humble suggestion to the Xtracycle folks, I think they really ought to point out that the installation is a two-beer project. At least.

Meanwhile, the other child — the one who spoiled the surprise, remember her? — she was recounting the events of her most recent street fight.

In the end, the whole thing is just Xtra-awesome. Here’s Sharrow, taking the maiden voyage on her new wheels …

… skirt, Dansko sandals and everything.

Perhaps I now have scored a few points with Sharrow for a new bike for myself. Of course, having dug that deep into my pocket for the Xtracycle, I am left destitute and penniless. Do you know that if you dig far enough into your pocket you come out in China? And did you know that in China there is a man standing there, next to a big pile of money? He has you sign a piece of paper and then he gives you some of the money! Fantastic.

Actually, no. I did pony up with cold, hard cash. Borrowing money sucks almost as much as buying gasoline.