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Old 11-03-09, 02:10 PM   #1
fatsoforgotso
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Using an Italian cup and cone BB with two adjustable cups?

I'm gonna build a single speeder around a steel frame with a 70mm Italian BB shell.
I was thinking of using an old 115mm 600EX or 105SC Italian BB, instead of going the sealed cartridge UN54/UN72-3 route.

I'm taking a guess that the rear hub (Miche Primato) and crank (Sugino XD2) call for a chainline that dictates the use of a BB in the 107-110mm range, so using a 115mm spindle the chainline would be at least 2.5mm off to the right side on the chainwheel (maybe as much as 4mm if my 107mm guess is correct).

I was thinking of doing the following, is it worth a try?
a) Using 2 adjustable cups instead of just 1 on the left side as usual.
b) Adjusting both cups to the left side 2.5mm from where they would normaly seat to correct the chainline inwards. The spindle, crankarms and pedals would obviously be moved 2.5mm to the left also, but I can live with this and I actually see some benefit as I usually sit a little on my right buttcheek and not directly over the midline of the saddle.
c) Using loctite on the right side cup to keep it from unthreading (a lockring on the right side will be useless).

Should I try it? Will I be dismounting every 5 miles to adjust the cups? Am I crazy?
I know there's some Miche Italian BBs where both cups are adjustable. Does the right side use glue on the threads to keep it still?
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Old 11-05-09, 01:47 PM   #2
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Bump!
Can any of the "usual suspects" offer any help?

RetroGrouch?

DannoXYZ?

JohnDThompson?

o...o-operator?


I invoke thee!
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Old 11-05-09, 02:50 PM   #3
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There's no technical reason that you couldn't use two Left Italian cups with lockrings. It would give you a degree of freedom to adjust chain line, but don't get too carried away because you still want max thread engagement. Also don't forget that unless you have a spindle intended for a wider shell than yours, as one side comes out the other will recess and not leave room for the lockring.

This might work out if you have a 68mm BSC shell that was tapped out to Italian, or used a 73mm spindle in a 70mm frame, but otherwise there's very little benefit to be had.
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Old 11-05-09, 03:07 PM   #4
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(...) Also don't forget that unless you have a spindle intended for a wider shell than yours, as one side comes out the other will recess and not leave room for the lockring.(...)
True true, but a lockring on the right side is useless, because the unthreading effect that comes upon the pedalling action unthreads the right cup counter-clockwise (the right cup would spin left-handed).

In this instance -it's an Italian BB after all-, putting a lockring on the right/drive cup -besides the problem of there being any sufficient threads left on the cup- is useless because the lockring would not press against the BB shell, because as the right cup unthreads the lockring will just move away from the BB shell. I make a reference to this point in my original post.

The critical question of my original post is this: can I put some glue on the threads of the right/drive side cup, instead of a lockring -again, it's useless putting a lockring on the drive side cup- to keep it from unthreading? (which would occur counter-clockwise, thus rendering the use of a lockring useless) ?

I'm thinking of using red loctite, but tell me if there's any better compound to put on the threads of the right side cup...
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Old 11-05-09, 03:24 PM   #5
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Park talks about using Loctite as standard BB installation technique.
It would seem strange to me to not be able to cinch the thing against the frame, and rely totally on a chemical bond.
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Old 11-05-09, 03:55 PM   #6
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Well, it seems strange to me too, on the grounds that I've never done it before.

Thanks for the link. Loctite #242 is their suggestion.

"It is especially recommended for bikes with a right-hand thread for the drive side to use a thread locker in addition to full torque."
In the case of a right adjustable cup, I wouldn't have the option of "full torque" as it would just keep threading into the shell unimpeded. Would the thread locking compound be enough? That seems to be the million dollar question.
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Old 11-05-09, 04:04 PM   #7
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Quote:
Originally Posted by fatsoforgotso View Post
I'm gonna build a single speeder around a steel frame with a 70mm Italian BB shell.
I was thinking of using an old 115mm 600EX or 105SC Italian BB, instead of going the sealed cartridge UN54/UN72-3 route.

I'm taking a guess that the rear hub (Miche Primato) and crank (Sugino XD2) call for a chainline that dictates the use of a BB in the 107-110mm range, so using a 115mm spindle the chainline would be at least 2.5mm off to the right side on the chainwheel (maybe as much as 4mm if my 107mm guess is correct).

I was thinking of doing the following, is it worth a try?
a) Using 2 adjustable cups instead of just 1 on the left side as usual.
b) Adjusting both cups to the left side 2.5mm from where they would normaly seat to correct the chainline inwards. The spindle, crankarms and pedals would obviously be moved 2.5mm to the left also, but I can live with this and I actually see some benefit as I usually sit a little on my right buttcheek and not directly over the midline of the saddle.
c) Using loctite on the right side cup to keep it from unthreading (a lockring on the right side will be useless).

Should I try it? Will I be dismounting every 5 miles to adjust the cups? Am I crazy?
I know there's some Miche Italian BBs where both cups are adjustable. Does the right side use glue on the threads to keep it still?
Have you considered using a fixed cup but turning the spindle around? It should give you the proper chainline for a single. If the chainline is too close to the frame, you can always insert a spacer.
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Old 11-05-09, 04:07 PM   #8
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Originally Posted by fatsoforgotso View Post
Would the thread locking compound be enough? That seems to be the million dollar question.
More like the twenty-five dollar question. I mean, this is all so you can use some old salvaged part, right?
Why not try it out?
And whatever Loctite 242 is, you might want something a little stiffer for a non-cinched application.
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Old 11-05-09, 04:21 PM   #9
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Actually, I don't have the cup and cone BBs. I would have to buy two of them, to get hold of 2 adjustable cups. But they're fairly inexpensive. I've taken a certain fondness to old cup and cone BBs from using them on one of my bikes. I've got a 105SC BB running smooth as butter, compared to the UN54 I'm running on another bike.

I think #241 is a more locking compound than #242, from the literature. Maybe it's better for this purpose.

I'll do it for the sake of bicycle science, if nothing else.
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Old 11-05-09, 04:26 PM   #10
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Godspeed to you, Luddite scientist.
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Old 11-05-09, 04:29 PM   #11
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The second lockring is not useless since it's main purpose is to pull the threads of the cup tight against the frame. The friction of the lockring against the BB shell also adds to the locking force. If it were me, I'd use 2 lockrings and blue locktite. Red locktite is stronger and requires heat to remove the part.
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Old 11-05-09, 04:45 PM   #12
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I 2nd Iowegian, the 2nd lockring is not at all useless. In fact, I suspect it would be enough to hold it on its own, but I'd locktight as well. I've never tried it, but I suspect JUST using locktight won't cut it. There's too much stress in this area unless for it to hold for long unless you use something so strong that won't ever come out.

BTW, cartridge BBs always feel stiffer when you turn them with your fingers. However, the resistance "under load" is as good as a cup and cone BB, at least ones of comparable quality. That said, I like cup and cone too. Just cooler.
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