Geometry - Specs - Ride Report
Alright, this wouldn't be a Riddle Of Steel post without my own dorktastic additions. Firstly, Trek gave us all only the 22.5" (56cm) frameset geometry for all 1982 models (and 1983 and 1984...). Since I've been known to (still!) cruise the catalogs, I figured certain numbers would match from prior years and angles be retained from smaller models. So here we are, for posterity:
Seat Tube: 63.7cm CTC, 65.0cm CTT
Top Tube: 59.0cm
Chain Stays: 47.0cm to the center, 48.0+ to the backs of the dropouts
Head Tube Angle: 72.0°
Seat Tube Angle: 73.0°
The factory rake puts the trail in the 56-58mm range, which is very nice. I am so incredibly happy to have a 72° head tube angle bike again. Give me that smooth, stable, comfortable front end geometry again, please!
Serial Number: 033632
Out of 2,460 Trek 720/728s produced for the 1982 model year, only 300 were in the 25.5" size. My 1985 620 is technically rarer with only 250 25.5" examples produced, but still, that is not a lot to have a chance at surviving nearly 40 years after they hit the showroom. Trek would progressively produce fewer 720s as the years went on, finishing with about 75 (in the 25.5" size) for 1985.
Weight as bought: 13.13 kg / 28.9 lb -- Very heavy, especially with respect to the bikes I buy and build
Weight w/o accessories: 11.85 kg / 26.1 lbs -- No fenders, lights, rack, pump, mirror, etc--still kept the pedals and bottle cage on. Still a heavy build to me, and my guess of eventual frameset weight (along with ctak's) was looking to be too optimistic (3300g)
Frameset with Phil BB: 3.43 kg / 7.5 lbs -- This was an incredible turn of events: huge touring frame, lighter than all previous big touring frames, and with a bottom bracket still to remove!
Frameset (frame, fork, headset): 3.155 kg / 6.94 lbs -- !!!
Ok, so why the big deal with a touring bike's frame weight? Well, it tells of construction quality and intent I suppose. My guess of 3,300g was considerably over the mark. With all my touring bike frameset weighing experience, plus a 26.1 lb "starting weight" for a complete, running bike, having a frameset that clocked in at 3,500g would not have phased me. I would have considered it par for the course, especially before (it seems to me) production bikes really started to focus on frame weight for their top bikes, which seemed to be more of a mid to late '80s thing. Anyway, the only light 25.5" "long Trek," my former 1979 510 (44cm chain stays) weighed in at 3,180g, which I thought was very light. For reference, race bikes in the 63.5 to 64.0cm range weigh, at best ~3,000g. You can see why this is a feat to me.
******
Hooray, numbers, figures, theories. How does it ride? Well, before all this disassembly and weighing, I centered the brake calipers, pumped up the tires, and took off the five or so miles to Mr. 66's house to show him the score and to bring a tool or two for work on his Jack Taylor. Nearly 29 lbs of Fully Vintage going down, and up, several of Seattle's innumerable 15% grades, full of crummy pavement, cars, lights at the bottom of hills, no shoulders, construction, etc. I later found out the anchor bolt securing the Duopar rear derailleur was not fully seated, causing the whole derailleur to, in its under-tension state (aka while in use), be misaligned relative to the chain. Shifting performance was compromised and operational noise was up, and constant.
I didn't adjust the saddle angle (no tools for it mid-ride over), but set the saddle height up about an inch to help thanks to the 5mm allen wrench I packed. I changed pedals to my SPD-SLs and that did it for both trips.
The bike is smooth. The 40-spoke wheels are not harsh, but nicely firm in their handling of road irregularities. Even the dried-out Specialized tires did well. Brakes were acceptable at best, but I expected that. Shifting was an exercise in patience and trying to get a worn out chain and a too-narrow front derailleur cage (with a wide 6-speed chain) to contribute as little noise as possible to the 'orchestra' being conducted by the Duopar. Tracking was stable and steering was just so sweet. The Trek geometry just caresses the rider here, and its 531 construction makes for a beautiful-feeling out-of-saddle climber and accelerator!
I had to really crank on it, in low gear, going up a nearly 20% grade on the way home. The 720 did not lay over and die! My 510 would have been laboring and letting me know it was unhappy, but the magic that is 531 and however Trek brazed it up meant that my even-lighter-than-the-510 frameset worked with me, perfectly aiding my efforts.
This is gonna be good.
******
At the moment, the frameset is awaiting new decals and I do have a lead on a head badge (it's a bit tired, but year/period correct--so if anyone has a nicer one they'd like to sell me, let me know!!). It is also awaiting cleaning and waxing as I have been doing so to all the components that came with it, that I will be selling to offset the cost. I am excited to get this winter/rain/epic bike back on the road and gliding along over the fall and winter!