Reinforcement ring under DT-HT lug?

[suhacycles]

Hey guys,

I want to increase the HT length below the DT on a 31.8 HT (Deda cromo) and have about 4-5 mm left under the lug. Looks like a perfect fit to braze on another reinforcement ring and it'll sit right up against the lug. From the POV of heating up the area twice (using silver of course) I take it this is ok?

Thanks,
Hansen

[e-RICHIE]

Hey guys,

I want to increase the HT length below the DT on a 31.8 HT (Deda cromo) and have about 4-5 mm left under the lug.

why do you want to do this ^ ^ atmo?

[suhacycles]

why do you want to do this ^ ^ atmo?

Hey, it's the holidays, why not?! =)

OK, seriously, I've got a main triangle for this road frame done so now it's ready for the chainstays. Problem is it looks like the CS-ST socket angle for this BB shell is closer to 64 deg when it would be 'ideal' to have it around 62 deg. With these being round sockets I can't seem to do much bending and grinding without ending up with a sloppy fit. With the CS's in the most acute angle I can get and the BB in it's original spot, the main triangle would be rotated forward slightly and the bottom of the head tube would end up at the fork crown, leaving no space for the bottom headset cup. Plus now the head and seat angles are steepened and the level top tube would slope slightly downwards. Anyway, if you're still with me, it's looking like the 'easy' solution is to just use that extra 4-5mm of HT below the bottom HT lug and braze a reinforcement ring which would bring the angles back to how they are on the drawing. The only 'loss' is that my BB drop would be more like 60mm rather than the planned 70mm which I'm not worried about. So, I guess I'm wondering if heating things up again to braze a ring at the bottom will affect the strength of things down there. My guess would be no but I'd rather ask first...

[e-RICHIE]

i can't in good conscience recommend a path that takes a design and makes it fit the available materials such as you describe here atmo but i would question any inability to rearrange 22.2mm chainstay pockets in a shell. that's got to be the easiest area on a frame to show it who's boss. once the main triangle is assembled, simply insert a two foot long 7/8" steel rod in it and yank. the chainstay fit won't be that bad that you couldn't get a bond that works. that part is up to you. lastly, if all is effed as you describe, maybe change the length of the fork blades a bit to compensate for the head tube length that you are considering adding to. better yet, don't care so much that the frame slants up (or down). you're on the left side of the evolutionary time-line; finish what you have with the skills you do have rather than borrow trouble.

Hey, it's the holidays, why not?! =)

OK, seriously, I've got a main triangle for this road frame done so now it's ready for the chainstays. Problem is it looks like the CS-ST socket angle for this BB shell is closer to 64 deg when it would be 'ideal' to have it around 62 deg. With these being round sockets I can't seem to do much bending and grinding without ending up with a sloppy fit. With the CS's in the most acute angle I can get and the BB in it's original spot, the main triangle would be rotated forward slightly and the bottom of the head tube would end up at the fork crown, leaving no space for the bottom headset cup. Plus now the head and seat angles are steepened and the level top tube would slope slightly downwards. Anyway, if you're still with me, it's looking like the 'easy' solution is to just use that extra 4-5mm of HT below the bottom HT lug and braze a reinforcement ring which would bring the angles back to how they are on the drawing. The only 'loss' is that my BB drop would be more like 60mm rather than the planned 70mm which I'm not worried about. So, I guess I'm wondering if heating things up again to braze a ring at the bottom will affect the strength of things down there. My guess would be no but I'd rather ask first...

[EricKeller]

I had an answer that was probably more unkind than I want to be. You can beat the sockets closed on the bottom once you bend the tops a little.


To answer your original question directly, re-heating it isn't going to cause you problems if you haven't totally screwed up the joint. Don't use that solution though, it's horrible.

[suhacycles]

e-Richie: Gotcha... thanks for the tips and ATMO.

EricKeller: Unkind? Hey, lay it on me... it's the season of giving. BTW, when you say that the reinforcement ring idea is "horrible" do you mean from an aesthetic or structural POV? Again, were talking the ring positioned right up against the bottom HT lug, not an upside down Pegoretti head tube extension...