Hey guys I have found a trek 720 1984 bike. I'm looking to get a commuter and touring bike. I have a question about the bike though. The seller claims that it has been modified to fit 700c wheels.
-This is what the seller said about the modification "My friend is actually a local framebuilder and all he did was lower the cantilever posts because they were positioned for the 27"x1 1/4" wheels the bike was spec'd for. The posts were fillet-brazed rather than welded so as to keep the chainstays from going through another extreme heat cycle. The work was professionally done with a cantilever jig and it came out really well.
-The components are a mix of late '90s Shimano mountain bike parts (LX and XT) with a modern Sugino Touring Crank. The bike is mechanic owned and has been recently tuned. I replaced the drive train and cables. It comes with a Blackburn Rear Rack and Blumel Fenders. The front wheel is also equipped with a Shimano hub dynamo
The seller is asking about $450. Is the modification going to effect the strength of the frame? Thanks!
I'd be somewhat suspicious. It's a lugged frame- it never went through the extreme heat cycle of welding since it was brazed in the first place. Canti-posts don't need to be fillet-brazed, just brazed. I dunno about the posts needing to be moved- often canti posts are located so that the 4mm difference can be taken up with pad adjustment. Maybe the frame never had canti's in the first place?
That being said, it's a lot of bike for $450 if everything is in good shape. Hub dyno, Sugino crank, bar-end shifters, fenders, rack. If the wheels are quality (XT hubs and 36-spoke double-walled eyeletted rims), then you won't need anything else. No worries about the strength of the seatstays- they never break in the middle- but if the fork were altered, I'd be concerned enough to contact the framebuilder myself.
Sounds like a nice upgrade (one of many!) to me. I've heard that the Trek 720/620 cantilever studs were positioned a bit differently from modern standards and only worked with a small list of cantilever brakes. If the studs have been repositioned to the modern 700c standard I'd call that an improvement. I can't say whether the fork or frame has been compromised by the re-brazing but it's not a hard job and any semi-competent welder could do it without trouble. I wouldn't be overly concerned unless the seller seems like a total crook and based on the bike, I'd trust him. Finally, for $450 you best decide quickly, that's a good deal for that bike.