Hey, I just picked up this bike yesterday for $30.

However, it's missing the downtube bosses. I'm not exactly sure where to start in order to fix this. I wanted to put some downtube shifters on the bike. I know there are some that clamp around the downtube and some that screw into the downtube boss/frame.







Also, the frame is slightly damage. Do you think this makes riding the bike dangerous?

what is that in the 3rd picture , looks like solder was dripped on it..

theres housing stops that clamp on for bar end shifters, the clamp on band shifters were more for 9/8 steel downtubes
than oversize aluminum ones

Maybe the missing pieces are available thru a Trek dealer..

you may be able to have a Riv nut set in the place where the down tube shifters used to be

then a long bolt would both hold on the boss and the shifters, kind of a kludge, but mechanically do able..

safety inspection remotely is difficult..

looks like someone botched removing the bosses.
that K sticker is melted from the heat.
I'd be a bit worried about heat damage to the aluminum too.

The last picture? Those are actually small dents in the frame.

Hi Ptle I just saw this on the other forum. I don't know if you know this but those bosses bolt on. a screw passes through one then through the DT and screws into the other.

it looks to me like someone may have tried to soldier the bosses back on after they broke off.

I would check with your local Trek dealer and see if he can get you a new pair of bosses.

Thanks for the suggestion... I wasn't sure how they worked exactly. The hole in the frame is very small, probably 3mm in diameter? I'll check and see what they say.

I appears the idiot that tried to remove the bosses (probably for a fixie conversion), tried to pry them off with screwdrivers. That's what caused the dents on one side. Then they tried to burn them off. They may have finally looked inside the left-side boss and realized there was a screwdriver slot in there.

Anyway, here's how the bosses attach:




It appears they are off-the-shelf braze-on bosses welded to curved washers. The washers adapt the boss's 1-1/8" curvature to the larger diameter of the Trek aluminium tubing. The washers are then epoxied to the tubing. The screw is very small and only serve to hold the bosses in place as the epoxy cures. It's the epoxy that takes the majority of the load.

Best bet is to try a Trek dealer to see if replacement bosses are available. Then use a strong 2-part epoxy to glue them back on. If you can't get replacement parts, there's an easy way to adapt standard braze-on shifter-bosses to fit. We can look at that option if you can't get the Trek parts.

Thanks for the picture, it clears things up a bit.

I may call the local Trek dealer in town later today and see what they have to say. I plan on taking it n to work on the campus bike shop to see if I can find some pedals and brakes for the bike.

As fietsbob noted, clamp-on dt shifters are limited to "standard" 1-1/8" diameter downtubes and won't fit oversized tubes. If you are willing to use barend shifters or brifters, you can bolt a set of Shimano downtube cable stops over the existing holes in the down tube using a long 8-32 or 10-32 bolt and nut through both stops and trim off the excess. You may have to drill the downtube holes slightly larger as a 10-32 requires a 3/16" clearance hole.

I once repaired a late '90's Klein frame with the same type of glued/bolted shifter bosses that way and it's held up for over 13 years so far

Let me check my spare parts collection to see if I still have a pair of shifter bosses laying around that I can give you for free. New replacement parts probably will cost you more than what you paid for your bike.

Thanks! I wouldn't mind paying some for them... you don't have to send them to me for free.

Vitus makes bosses for their 80's carbon and aluminum frames that attach the same way.
Mike Fraysse was selling them on his eBay auctions earlier this year. Although you might have to modify them a bit because the tube diameter on that Trek looks to be bigger than the ones on Vitus bikes, it might still be a viable option if you cannot find the Trek made replacements.

Chombi

OP, I found one of the bosses so far (the female side). I checked with my Trek 2000 (same vintage as yours) and it fits perfectly. The part is yours as far as I am concerned. I'll see if I can find the other half. Give me a few days.

Type in "shifter boss" in Ebay. For $9.95 you can get a brand new clamp-on style shifter boss shipped.

I figured even if I can find the other half of the boss and send you the pair for free, you still need to get a special long screw and epoxy. You end up spending pretty much the same amount of money.

I recall seeing bosses with a thru-screw attachment for this application on some frame parts website - I'll look around to see if I can find it.....

The OP needs an oversize clamp. I expect your reference is the old standard 1-1/8"

I forgot to ask the important question. What do you want to do with the bike in that area? Attach downtube shifters? Or just cable-stops?

How about these:

https://www.cycle-frames.com/bicycle-...-AL-FRAME.html

Those probably won't fit the oversized downtube. Thanks to Dr. Cannondale I ordered some for my old C-dale from a place. They might be able to special order for your trek... It took about 3 weeks to get them in though. Call Mikes Bikes and see if they can order the parts if your LBS/Trek dealer can't. Don't clamp anything on the tube, it will probably just crush it.

The diameter of the tube is 35.2mm

I'm still undecided about whether I want bar ends or DT shifters. If I decide to keep the bike, I think I would use bar end shifters, however, if I decide to sell it, I'd probably go with DT shifters to save some money.

Do they make any clamp on cable guides/stops for a tube of that diameter?

Also, how necessary is the small, long screw that connects to the bosses? Could I not just epoxy them in place, and hold it while it drys?

I'm still meaning to take it to the local Trek dealer and see if they can order the piece. I just haven't gotten the chance since it's on the other side of town.

The Nova parts WILL work, although, it may take a bit of fiddling. For starters, the threaded through stud on the Nova bosses look to be a little larger diameter than the through hole on the Trek downtube. Would have very carefully step drill the downtube to match. If the contoured base is made to fit a smaller diameter tube, you simply take a half round file, and adjust the contour a bit. It really isn't structural, so no issue.

I may have an unused set of these in a drawer somewhere. Will look tomorrow.

Wow, the cheapest shipping for the product from Nova Cycle is over three times the cost of the product... $13.31 (total = $17.97)

I'm gonna go out on a limb and say epoxy probably won't hold in the long run. And again, clamping anything on these aluminum tubes isn't a smart thing to do. I know waiting for the correct parts is a pain and that the cost to fix it correctly really sucks compared to what you gave for it but once its done you only spent 50 on the bike which is still one heck of a deal.

If you can't find the Trek ones, the Cannondale ones from Mike's should fit. Downtube size is pretty close, although I agree you'd have to slightly enlarge the hole for the throughbolt.

Ptle how is this coming? I think I stumbled across a pair today. it doesn't matter if you use DT or barcons you still really need these. a clamp on housing stop may slide and cause problems