Back when I was in high school I had my first bicycle stolen from me. A Motive mountain bike. Feeling my loose, my buddy from the Polo team gave me an old bike. A Trek road bike. That Trek, which I never knew the make (since it had already had a custom paint job), has been with me since that day. It was last configured as a flat bar road bike.
When I was employed as a bike mechanic, a customer brought in a Centurion bike as a parts donor. The bike was blue with chrome lugs. After I created a monstrosity of a bike for this customer, he gave the frame to me. A friend of mine had always liked those bikes. After a year went by and the bike never saw a complete build up, he propositioned me for a trade. The beautiful Centurion for a Yellow Trek 360. I accepted.
The 360 was almost identical to the Trek I was given in high school. Same size, and basic build, lugged steel. However there where three features that made this bike more appealing. 700c wheels, recessed brake bolts, and better frame material. My old bike had 27" wheels. This was the popular American "10 speed" size. Modern road bike typically run 700, millimeter diameter, "C" lincher wheel/tires. All modern road bike caliper brakes use a nut that fits into a frame recess. Modern dual pivot brakes are the equivalent to disk brakes vs drum brakes, when compared to old single pivot side pulls. Though I never knew exactly the frame material of my first Trek, due to the weight, I did not think that the steel was of the highest quality. Though the 360 is their lower line bike, the frame build up is still high quality. Often times the lower line is simply the same frame as the high end bike, with cheaper components.
So what makes a high quality steel frame? Cromoly Steel, double butted tubes, with investment cast lugs. Steel alloyed with Chromium, and Molybdenum, is often referred to as Cromoly, Cromo, aircraft tubing or aircraft grade steel. Any of the various Cromoly steels will have a numerical designation which starts with 41xx. 4130 is the most popular for bikes. Cromoly steel has great strength to weight ratio, stronger and harder than the average steel, and easy to weld. Used in bike frames to AK-47 receivers. Stronger also means lighter since less steel is required to make the frame. I once read that a lightweight steel frame, if melted down, would result in a brick the approximate size of a deck of cards.
Straight gauge, single butted, and double butted are the various forms a bikes frame tube comes in. The primary difference being the thickness of the tubes. The primary stresses of a section of tubing exist at the ends where it is connected to another piece of tubing, either by welds or by lugged fittings. The center portion sees less stresses and thus does not require the same thickness of tubing as the ends. Double butted tubes are the lightest and most refined of the three configurations.
The preferred method for joining steel tubes of a bike frame is with lugs , or specially designed fittings which the tubes slip into. The tubes are then brazed to the lugs. Lugs are made in two ways: cast and stamped. Due to the complex geometry of lugs, stamped lugs are made in halves then welded together. The rough stamped lugs are then filled down. This filing make for poor fitting tubes and slope in the design angles. Investment casting is just a fancy way of saying lost wax casting. A wax part is created. A clay mold is made of the wax. The wax is melted out and replaced with steel. I am sure there is a more efficient mass production method of this form of casting which is used. I was very impressed with the lugs on this bike. The top tube/ seat tub lug, as a built in seat post binder, and strengthening nubs on the seat stay attachment. The rear dropouts which technically is not considered a lug shows it attention to detail. The chain hook, and the "69" which I am sure is not a serial number.
The thing that throws most people off is that I use a flat bar instead of the standard road styled drop bars. I am foremost a mountain biker. When on a road bike I never use the drops, and am not completely comfortable in that position. Thus I use a mountain bike type flat bar. I fitted the bike with primarily Shimano Ultegra parts with a few Dura Ace goodies thrown in the mix. I used a XT long cage derailleur mated to an 12-34, 9 speed XT cassette. Rear shifting is achieved by a Shimano Rapid fire shifters. However the front shifting is accomplished by a grip shifter. Rapid fire front shifters only allows a single fix position for each chain ring. However the grip shift have several clicks per ring to allow for fine trimming. I used non "V" brake style brake levers, which pull the correct amount of cable to match my dual pivot brake calipers. Rear wheel is a beat to hell ex San Fransisco messenger wheel, Shimano Ulterga hub and Mavic Open Pro rims. Front wheel is some dumpster radial laced jobbie.
Overall this is a very fast old steel bike. The frame has considerably more pop to it then the old Trek. I still need to dial in some cable routing and finding a properly size stem. But I have been riding it. Next time you see me rolling through your neighborhood on my Trek 360, you'll know: I am keeping it REAL!