Hi Everyone,
I'm a maintenance guy at a large oceanfront condo on the ocean in Florida, my commute is 6 miles each way which have always enjoyed in my old topless Jeep. Eventually I realized I would probably enjoy the commute even more on a bike with the nice bike lanes we have here on the beach. I happened to be talking to elevator mechanic guy about this and he says I've got the bike for you. Turns out he was a bike mechanic for many years some time ago and now has over a 100 bikes. This belonged to a fellow bike guy that was about your size he says. (Please see picture) Anyway now I'm commuting and also riding on the weekends and loving it! Got my wife a used Trek 1000 and all is great. So, where is this going? Now I'm curious as to what model I have. There is no serial # anywhere. All I have is 58TSI on BB, whuch according to vintage Trek is Tim Issac and the angle between seat tube and downtube. Also the cables are routed below the BB first year but then were routed through right chainstay. I guess my question is there a way to determine model and maybe size without serial #? Thanks for any help, this is a great site. (Very addicting this biking thing).

My guess is a 720/728

Mutt

https://www.vintage-trek.com/TrekBrochures.htm
It'll be in there somewhere. I think all the 72* had cantilever brakes. I know the 'Trek' stamped bottom bracket is post 82, so that narrows it down somewhat. If i had to guess, either a 4** or a 6**

Over 100 bikes? This fellow is not in Miami, is he?

P.S.: It's a Trek 728/720. 720 if purchased originally as a frameset, 728 if bought built-up.

-Kurt

Kurt - the 72* would have cantilever brakes. This one doesn't look to have those.

The BB looks quite a bit like the investment cast one that is on top of the line models (at least in 1984) on the 760, 770 and 170. (My '84 has that). Of course if it's a different year, it could be a different model - but not a 72*.

OP - they really didn't make very many without serial numbers. Get it really clean and look hard in good light. It can be tricky to find.

Did a bit more poking around through the Trek brochures. The 520 was made with that same bottom bracket starting in 1986. If the cable routes through the chain stay, this - along with the somewhat more relaxed-looking geometry would seem more likely than it being one of the 1984-ish racing models.

If it is a 728 he could have put whatever brakes on it he wanted. Strange no serial number though.

Mutt

But where are the cantilever posts?

Your Phil Wood bottom bracket = good stuff!

Thanks everyone for taking the time to research this bike. I'm just having a good time riding and I was curious what I was on. Best $100. I've spent.

Gentlemen, as much as I hate to contradict the experts, I have a 720, which is a 1982 frame purchased new as a frame in 1983, that does not have cantilever studs (and never did, by the way. I always wanted them, but they were not available at the time!).

But I will go along with that. Mine has "Cinelli" cast into the bottom of the bottom bracket. Oh, and to thoroughly confound you, mine is Italian threaded!

Just in case you're wondering how I know mine is a 720... a few months ago I had the fork off so I could rattlecan the frame, and I found some markings on the steerer. Stamped into the steel were the letters "REYNOLDS 531 DB" and, very near there, the number "720" which looked like it was done with a dremel tool.

OP: it could be that if you take the headset apart and look at the steerer tube you will find the information you're looking for.

--Rudi

No worries there. Many things I "know" I learned from reading or using reference materials - which would make me "informed" rather than an "expert" . As one pokes through catalogs attempting to figure out just what that is, bear in mind that that is the "Trek investment cast bottom bracket with integrated cable routing". According to the catalogs, that wouldn't appear on a bike with this geometry until the 1986 model year. For whatever that's worth.

Rudi is correct - the 1982 models did not have the canti mounts. They were adapted in '83, and lasted until the model's demise in 1985.

-Kurt

Despite what the catalogs may say, my 1982 720 had the same BB and also did not have canti posts.

My '82 720/28 was the same as Digitalbike's and the OP's - cast with the TREK logo.

-Kurt

Who painted the frame/added the downtube decal?

That shade of blue and the lack of the typical vertical seat tube Trek decal make me think this was a custom build. There were a number of such custom frames built for friends of Trek framebuilders. Last may, I built up one of such anomalous frames (sport touring geometry, but with Columbus SL frame and fork and Campagnolo dropouts/fork tips) with Campagnolo 10 speed for my dad. The gentleman who sold me the frame (then built up with Suntour BL) had received the bike in 1982 as a gift from a friend who worked for Trek.

I have seen two other "blue mystery" Treks around Madison (WI). A Reynolds 531 touring bike (essentially a 720) on Craigslist and a Reynolds 531 sport-touring bike that is typically locked up outside of Ag. Hall (sigh).

I'll try to get pictures of the completed build the next time I head home. Here're some pre-build pictures of the "anomalous" frame (the pictures don't show the depth of the blue paint . . . it's really quite beautiful):

Here is a pic of my mystery blue Columbus Trek, I never really found out what model it was, notice the short chainstays, anyway I sold it.. I just found one like it, but in green. Will post pics of the green one later.

The third water bottle mounting below the downtube and those great long chainstays certainly say 720 on 'em. The paint on the OP's bike is not that deep metallic imron that is on dziehr's bike...matter of fact, it looks a lot like powder coat to me. That would explain the lack of a serial number.

At $100, this is probably one of the best deals that Old Surfer will ever make on a bike.

This one is a TX900 or thereabouts. They only built one model in Columbus tubing. I have a TX900 in green, a 1979, complete with the original sales slip.

I have a maroon 84 or 85 720 and it has that cast bottom bracket.

It's been a while since I dug up the information. I believe the SN puts it made in 84 but the head badge puts it as an 85 model. I could be way mistaken.

I think that's my bike, I think trek only had bikes without the color wrapped seat tube in 83 to 84. Looks like a 610/620/600, my bike, in my color, even my size. You were clever enough to switch out most of the components so I wouldn't notice.

Wait, I take that back, yours seems to have brazed on cable guides, mine are clamp on. Maybe not an 1984 600 series then.

Third water bottle mount? How on earth can you make something that small out from the picture?

Mystery solved, finally got a hold of elevator guy (lost his #) and the story was he bought the bike from a fellow mechanic who worked for Campy and was one of the mechanics for the Tour De France back in the day. Elevator Guy bought the bike from him, pulled all the Campy gear off it for a build he was doing. Installed all new Shimano (105) everything except wheels and cassette and sold it to me. I'm loving it and the Jeep hasn't moved in 5 days. And yes it is a 1982 720, and yes he did know someone at Trek. Thanks everyone for all your help.

thought for a moment that I was losing it. If you look at the third picture in the original post, they are there, and what looks like the original bolts in the holes.

back when I worked at trek in '77-'78, every bike was custom. And when I say that, I mean we built standard geometry frames, and then a couple guys did braze-ons to the customer's order.

I don't remember custom colors though, when I got my frames painted it was one of their standard colors because they had an incredible deal for us if we did that, I'm remembering $18. I don't remember what the deal was on bikes, they were quite generous. The one I remember building didn't have Trek decals or headbadge though.

The 900 above is a bit of an oddball since it doesn't have fastback stays. The vintage trek site says they had trouble with those, and although I don't remember any such problems, I observed some people having problems with them.