MY hand moved automatically to the neck on the handlebar. I quickly found the balance of my friend's machine as I wheeled it into the Bicycle Exchange in Harvard Square for repairs. This was near where my old Rudge had disappeared from the basement of Leverett House many years ago. It reappeared a few years later, a derelict by then, cabled to a galvanized iron bike rack in the Lowell House yard.Now, I have always had trouble with linear history. History appears less a sequence than a constant present. I occasionally startle young colleagues when I say they are not really younger than I am. They cannot be, because we both inhabit the same moment. And since there was never a newer moment than now, never a younger moment, we must be the same age. They can't gain on me until I check out. Bike stores, I noted at the Harvard Square shop, still smell the same - rubber, oil, metal, leather. The bikes hang down from racks. Little had changed in 40 years, I noted ... until I saw the price tag on a new Raleigh, $1,050. That's one-thousand fifty bucks! That's one thousand dollars more than I spent on my old Rudge. The Raleigh was the upscale model of a British line. The Rudge was under $60, the Raleigh over $60. This was price differentiation. Manufacturers had product pecking orders. The General Motors "Raleigh" was the Olds, GM's "Rudge" a Chevy: Detroit made sure then everyone knew a father's Oldsmobile was not his son's Chevrolet. It had been a reach to get the Rudge. Mother helped me with the last $15, saved from the grocery money no doubt. And Mike Walden, the gruff and burly owner of the bike store at Livernois and Six Mile Road in Detroit, came down from the list price to help the skinny 13-year-old who had not yet started his growth spurt - my frame would stretch out like so much bicycle tubing in another year. I had been saving for the bike from my paper route. It was the neighborhood Detroit News route that had been handed down among the half dozen Heims sons, to Wally Lambert, then to me, and from me to the Schwartz boys ... a sequence readily recalled. Earning $5 a week, I was already paying my expenses, for clothes, bus fare, music lessons. It had to be the Rudge and not the Raleigh - the gold metallic machine and not the lighter weight, more luxurious Raleigh red. But it was the first drop-handled bike on the block, and upscale from the $5 bike I had bought from Al Williams, a tenant in Mr. Freiwald's house next door. Every Wednesday evening, an Olympic training group called the Wolverine Wheelmen would meet at 6:00 and dash to Pontiac, or to River Rouge, 40 miles or so in two hours. I would be home by nine. My own tubing stayed skinny. I never put on the fabulous Popeye-sized thighs of the Olympic riders, whose musculature accumulated in their legs. Inflation in Harvard Square tuitions has been as great as in its bicycles. A year at a good private university used to cost a family about as much as a standard Chevrolet. My first Chevy cost $2,000; today they cost $15,000. A daughter is enrolled in the same graduate program I undertook three decades ago. What then cost $2,000 is now $30,000. Nothing in the program's rudiments - books, paper, classrooms - explains a doubling in the education inflation rate over that of manufacture. Today's $1,050 Raleigh has Reynolds 531 tubing, the bike dealer says. The Raleigh is not really the best bike. Here is another model for $1,375. And then the Greg LeMond bikes - a $2,500 model, and another "virtually the same as LeMond uses" for $4,000. LeMond returned to the Tour de France this past week. The cyclists started in Lyon, heading northward to Reims, thence across Normandy, out Brittany to Quimper, before plunging to the Pyrenees and over to the Italian border before returning to Lyon - and, after portage by train to Paris, a final dash to the Champs Elysee on July 28. In the bicycle shop, time seems as motionless as a spinning wheel.