Bicycle Mechanics - Cracked Raleigh technium aluminum lug
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10-22-06, 12:13 PM
I have a 1990 Raleigh USA technium competition. It has aluminum lugs bonded to reynolds 531 steel tubing. The seat post lug is cracked at the binder bolt. It still tightens snug but my father in law tightened it too snug when it was his. I was told it was not repairable.
My question is if the lug can be removed with heat and be replaced with a conventional braze-on steel lug? My aim is to transfer all of the components to another frame and convert this one to a fixed or singlespeed bike. Or should I keep the fork and toss this frame in the trash?
10-22-06, 04:22 PM
ask in framebuilders. bonded aluminum is considered a bad idea by most.
10-22-06, 06:47 PM
I suppose for enough money it could be repaired but it wasn't that good a frame to begin with and I expect the repair will be very expensive. You will have to have the Al lug removed, a new steel lug brazed in (assuming your builder can even find a lug to match the seat tube and top tube diameters and accept the seat stays) and a repaint.
If it were mine it would be a dumpster decorator.
Sounds like a fun project.
I don't know about you, but for my bikes my labor is free...
10-22-06, 08:37 PM
I'm not so sure that bonded aluminum was a bad idea, and Trek at least did a very good job of it. But welded aluminum became very cheap to produce in mass quantities.
That said, while bonded aluminum is theoretically framebuilder-repairable to a greater degree than welded aluminum, I agree with HillRider that it's a dodgy operation and definitely ain't worth it in your case. The Reynolds 531 tubing is probably standard size, though, so a lug in the proper diameters and angle should be available if you really want to go for it. Also would be possible to do a local repaint if you want to do this on the cheap(er).
10-23-06, 09:30 AM
See previous recent thread. Someplace in that link I attached a link to the Technium Brochure located on the framebuilders
I like the Technium Frame and for it's day was not bad. There were other poorly bonded frames at that time and they seemed to get thrown into the same catagory. I saw one that fell off a car and run over and the Bonds and lugs were noy damaged.
These Frames did in the late 80-e 90's what many are doing now. Bonding different materials of construction for optimum performance. In this case it was Aluminum and Steel.
10-23-06, 09:32 AM
Heres the brochure thread.
keep in mind the scan is out of order
10-23-06, 10:42 AM
My frame is a bit opposite of the brochures. Steel tubes and AL lugs. As far as the ride, I really like it and have been riding it off and on this way for a number of years, but never feel fully at ease. I would do all the labor myself. Even if I fail I will have learned something. The picture tells more.
10-26-06, 07:38 AM
Update... The more I look at this problem the more difficult (impossible?) it looks. Like the brochures, the lug goes down about 3 inches into the seat tube (kind of a reverse lug) therefore I cannot heat it and take it off. The Aluminum will expand faster and split the tube. Cooling is impractical and likely won't work. Then I would have the lug problem. Oh well. Thanks for the help and opinions.
10-26-06, 09:29 AM
I would ride it and watch it. Plenty of insertion there and I doubt that it were to fail it would fail catastrophically. Now if it were a headtube joint crack I would scrap it.
Maybe you could have a small Bridge Brazed on a bit lower to isolate some of the stress to the portion of the tubing below the bridgeand equalize it between the stays.
Looking at your picture, is the crack the white streak coming from between the angled vertical tubes on the rear tube? If so, a standard crack stopper method is to use a very fine center punch and perhaps 1/16th inch drill and punch at the end of the crack and drill there. Converting the end of the crack into a round hole generally keeps the crack from propagating. Small hole won't damage the frame and could be sealed with a dab of grease or wax.
10-27-06, 05:33 AM
Both good ideas, Thanks!
10-27-06, 07:25 AM
OK who told you it wasn't repairable???
I have delt with this prob several times. All you need to do is find the right welder. Do you know where a small plane airport around you might be? Look for the guys who repair the engines. They will know who welds there!!!!
I find these guys to be very good in welding alloy parts and they charge a ok rate!!! They can put your pc back on or. another solid block you can drill thru and make your own nut and bolt. and not use the binder threads at all.
10-27-06, 08:14 AM
I think the issue was that the heat from welding the Al would compromise the bond between the Al and steel
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