My REAR WHEEL has a ludicrous wobble. I glance at it as I pick up speed down Capitol Hill, and there seems to be as much side-to-side movement as there is forward roll. The missing spokes have been replaced several times, but they keep popping away from the rim because of some insidious flaw in the wheel itself.

My consulting mechanic has predicted an incessant loss of spokes, an abnormal rate of blowouts and the dread fatigue de derailleur until the wheel is replaced. However, as my freewheel is fitted with "French threads," it would have to be replaced, too, and he would not be surprised to then find my old chain rejecting the new freewheel, as bodies sometimes do new kidneys. Who can say where this metastatic cancer of repairs might end? Certainly not my mechanic. Still, if we diagnose it early enough, if we have hope, if we spend money . . .

These larger problems are not on my mind now. Nor is the cold, though my pocket thermometer reads -4*c. What concerns me, enrages me, is the wind. Twenty-four mph. gusting to 32, the guard at Longworth told me. It is coming out of the north-west -- out of 1700 North Moore in Rosslyn, to be exact, the destination of this extremely important paper in my backpack.

On the relative flatness of Pennsylvania Avenue, where I can normally fly, I am forced to jump on the pedals to make headway. It is the last run of the day.

I have delivered letters, memos, books, films, soundtracks, chef's salads, press releases, court dockets, "a bill for the purpose of" anything conceivable (3 copies each); chocolates, freedom of information requests, party invitations, unnecessary regulations, postage stamps, the wrong thing, airline tickets, a swell fountain pen, these notes and other items too urgent for mere mailing. In many cases, I suspect, it is this aura of urgency, more than a message, that I am hired to convey.

I curl off Penn. at 12th, only to encounter a stronger wind. On H Street it blows me sideways, as it does through the impatient traffic of Georgetown and across Key Bridge (where by bike is canted at an alarming angle to comensate). My thighs are pretty well burned up when I reach North Moore just before 5. The dispatcher tells me there are no Rosslyn pickups; I might as well go home.

Home is Adams-Morgan, and the wind is no kinder to me on the way. Molly Peter walks in the door. I shower; we walk to beer and tacos. Saturday

Molly visits Baltimore. I write, clean a sink, write, buy groceries, write, rearrange a drawer. A day of gratifying discipline, I plan to write all day Sunday, too. Every minute. I mean it. Sunday

Molly and I rustle through The Post and The Times, munch fresh croissants from Avignone Freres, then head for a suburban mall. A good friend of ours, Mary Averett Seelye, is to perform one of her "kindesis" pieces -- a choreographed interpretation of a poem, this one Lebanese, set to music.

Mary Averett moves through the poem, reciting first in Lebanese, then in English. She is very slender and tall, strickingly angular when she chooses to be, or fluid and encircling great spaces. People cluster along the mezzanine railings above and on the carpeted steps in the amphitheater. Adolescent boys cease their cutting-up. Ignoring the shoplights, the intrusive din of Muzak and mall commerce, we all watch and listen to Mary Averett. Monday

When I go to work at noon the day is bright and clear, like so many we've had this winter. Perfect for Homo deliveries. The first run is from 1875 Eye to the Cannon Building. Normally I make my way down the Mall for a run to that side of the Hill, but for variety I take Eye to 11th, cheat down to H and follow that through the site of the new convention center, a ghost town now, cordoned off from traffic. I slant onto Mass. at 5th. Traffic always moves fast along there. Sprinting is a necessity. Up to the Capitol, across to Cannon for the drop. The bike always feels good on Monday.

A pickup at Longworth. Walking past rooms where I used to attend meetings in a coat and tie, I feel a pang of regret. I miss the socializing. I will not discuss writing except to say that the loneliness of it is accentuated by my messenger work. I once read a interview with a tool-booth operator who had held his job for several decades because he loved to meet people. Messengers meet them in much the same way.

Down to 12th and Constitution, up to 16th and K. From there to HEW, then to Dirksen, back to Farragut Squareh. At one point in the afternoon I'm killing time at Union Station when a young man in front of me has a seizure and falls to the ground. I have only a vague idea of what to do. A cop arrives after 30 panicked seconds. He puts the man on his back. Is that right? I don't know, but the man recovers. I'm furious with myself. How can I not know these things?

The day is ruined. I rush home -- Molly and I are to watch Tim and Wendy while their parents are gone overnight -- but stop off at the 18th Street Red Cross and sign up for courses. Tuesday

"Aren't you cold?" Having just ridden 5 miles at full speed, I am sweating profusely under by gray wool knickers, bright red knee socks, green wool shirt, white helmet and dayglo orange whistle. The temperature outside is in the low 30s; in this elevator it is twice that. The woman is looking at my outfit. I am looking at more rabbit pelts than I have ever seen in my life. "Yes ma'm. Very cold."

Downtown to the ITC, up to the Hill, to a subcommittee for defense appropriations. Neat-o model planes on the shelves. Down to 22nd and N, back to K Street, across the Mall to HUD. Up 15th to McPherson Square. My ticket book gets fat. At an office on L St. an older man asks me if I'm making any money today. I'm surprised, because that is what messengers usually ask one another at stoplights and elevators. It turns out he rode a bicycle for the old Dime Messenger Service in the Depression. "Lotta fellas scurrying' round here than." For a dime per trip. Wednesday

Snow. I have encountered it only once befre, a miserable Friday afternoon when my chain would freeze up every few blocks and the front sprocket in a stiff loop. Today the flurries don't stick but the streets get wet and icy. The office is crowded with messengers when I arrive. Eating, talking, reading. Helmets, parkas, tire pumps, burger wrappers, newspapers -- most of them wet. Miraculously, I receive four tickets right away, the promise of a lucrative day.

I slide down to Mass. and North Capitol. Wrong address. Redeliver to 12th and Penn. More money in my pocket. It also affords me a visit to a minor shrine to those of us in the envelope hauling biz: a bizarre diptych painted on the second floor of the "new" Post Office Building. Thursday

In early, to make up for yesterday' six-run fiasco. Dry streets, air crisp enough to create the illusion it is also clean. The first four deliveries are within walking distance.

Though both of my hands are free, I give the ritual by. An experienced bicycle messenger has a certain rhythmic, insouciant style of moving through traffic. At 17th and K I see the balance on his 10-speed at a stoplight as he talks into his radio. (I tried this once and landed in an embarrassing heap at 18th and Penn). Others wind through the cars and people, cut lights, roll onto sidewalks -- always moving, some carefully, others recklessly.

By contast, casual city cyclists make jerky starts and stops, weave as they glance over their shoulders and have this terrifying habit of swerving into traffice to avoid a little booboo in the pavement.

I believe it is possible to have fun and make money as a bicycle messenger without terrorizing pedestrians, without getting flattened by a bus, without flipping over a suddenly opened cab door. Many of my colleagues disagree. One of them rammed me recently to prove the point.

There are thrills aplenty out there as it is, but I hesitate to call bicycle messengers brave because I am never very comfortable with the thin distinction between the virtue and stupidity.

More downtown runs, then a sprint to the Hill for a poetry reading by freind David McAleavey at the Floger. To House Doc, to Senate Doc, for bills and resolutions. A TV newsman paces near the empty bike rack as he membles, memorizes his insights. Down the Hill toward the incredible talking elevators of Humphrey HEW.

The snow and marble on the Mall are dazzling bright. Noontime joggers steam by. One runs in place next to me at a stoplight (a nearby scootercop keeps us honest).

"Does the whistle help?" she asks. I take it from my mouth long enough to reply.