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-   -   Curious about this frame (https://www.bikeforums.net/showthread.php?t=1170542)

Bonzo Banana 04-14-19 04:15 AM

Curious about this frame
 
On the image below where the downtube connects to the bottom bracket what is the connection there, is it some sort of simplistic lug and the downtube is brazed inside? Not seen a bike frame that looks quite like that before. It's an old Raleigh Gritstone from about 1994/5. Just curious about the braze/weld. It's a step up quality bike for Raleigh at the time utilising a Altus drivetrain with 7 speed freehub so neither bottom or top of the range of bikes. The frame is a basic high tensile steel frame with what they call 'energiser' stays presumably because they don't flex and quite thick or even solid. While the bike is definitely assembled in England I'm unsure if the frame was manufactured in the UK or imported.

https://cimg2.ibsrv.net/gimg/bikefor...aa96ec1e98.jpg

Andrew R Stewart 04-14-19 09:12 AM

This frame has the look of MiG welding, but I'm no welder so... can't be sure. MiG is not a common joining process for steel bike frames. This frame's shell doesn't seem to have any sockets/lugs but the tubes are directly contacting the shell and then "butt" welded to the shell. Not so well it seems:)

More views from different angles might confirm if the shell has cracked (looks like it IMO) and whether the weld bead got any penetration on/in the seat tube and shell.

This is not at all what most here would call "a step up quality bike" at all. Rather a very entry level low price focused bike. Andy

Bonzo Banana 04-14-19 01:10 PM

Another image from a different angle that also shows the thickness of the join of the chainstay.

https://cimg8.ibsrv.net/gimg/bikefor...cc7bbb7b91.jpg

CliffordK 04-14-19 02:03 PM


Originally Posted by Andrew R Stewart (Post 20884054)
More views from different angles might confirm if the shell has cracked (looks like it IMO) and whether the weld bead got any penetration on/in the seat tube and shell.

I don't think it is broken.

It looks like a very odd derailleur hanger sitting on top of the shell, also what looks like an integrated chain catcher.

It may be removable.

I see some writing on the top of bracket. Perhaps clean off the writing and give more info.

Andrew R Stewart 04-14-19 06:42 PM

On third viewing I think you are correct. The shadow in photo 1 looked like a real nasty crack. My comments about the joining method and bike grade stand. Andy

Bonzo Banana 04-15-19 02:13 AM


Originally Posted by Andrew R Stewart (Post 20884054)
This frame has the look of MiG welding, but I'm no welder so... can't be sure. MiG is not a common joining process for steel bike frames. This frame's shell doesn't seem to have any sockets/lugs but the tubes are directly contacting the shell and then "butt" welded to the shell. Not so well it seems:)

More views from different angles might confirm if the shell has cracked (looks like it IMO) and whether the weld bead got any penetration on/in the seat tube and shell.

This is not at all what most here would call "a step up quality bike" at all. Rather a very entry level low price focused bike. Andy

I wasn't stating the frame necessarily represented step up quality but the Altus components with a 7 speed freehub was well above bottom end pricing of the time when many of their models featured lower end components and freewheels. It is my intention to convert the bike into a drop bar touring bike with a 1x wide range 11-34t 7 cassette setup. The bike seems exceptionally strong and of course a bit heavy.

http://veterancycleclublibrary.org.u...20Library).pdf

unterhausen 04-15-19 07:09 PM

I am not fully up on all forms of welding in manufacturing, but I think the technique used on that frame involved just getting everything very hot and smashing the parts together. That's why the weld beads are so large, they are really part of the tube. I'm sure it's quite strong and that frame is probably very heavy.


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