Problem tensioning chain with EBB
11-10-11, 01:24 AM
#1
Tawp Dawg
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Problem tensioning chain with EBB
**Cross posting from Mechanics forum**
Since y'all in SS/FG are chain tension experts, I figured that I'd ask here as well. If that isn't kosher, then feel free to close the thread, mod(s).
I'm having trouble getting proper tension on a BB30 eccentric bottom bracket with a 1/8 x 1/2 inch chain running to an Alfine IGH. First I left enough slack to rotate the BB shell as far forward as possible (if the shell were a clock, this would be 3:00).
A little slack, but that was fine until winter hit; now I'm riding over some pretty rough terrain at times, and twice today I bounced the chain off the ring while riding over really bumpy ice.
So I try to remove a link and tighten up. But when I remove a link, the chain tightens so far so as to create an unrideable amount of tension/friction, even when the BB shell is rotated as far back as it will go (9:00).
This seems like some BS (why would someone design a tensioning system that won't accommodate a 1/2 inch chain?), but I think that maybe I can fix it by changing the chainring/cog combo. So I switch out the chainring from 40t to 38t (cog is 19t).
No change. I mean, now the chain has gone super slack with the BB in the 9:00 position. So I rotate to 3:00, and I've got the same amount of slack as when I first started. Remove a link, and again it's too tight to run even with the BB at 9:00.
*sigh* I miss my sliding dropouts. But I want the frame with the EBB to work with the IGH. Am I missing something? Any ideas?
Since y'all in SS/FG are chain tension experts, I figured that I'd ask here as well. If that isn't kosher, then feel free to close the thread, mod(s).
I'm having trouble getting proper tension on a BB30 eccentric bottom bracket with a 1/8 x 1/2 inch chain running to an Alfine IGH. First I left enough slack to rotate the BB shell as far forward as possible (if the shell were a clock, this would be 3:00).
A little slack, but that was fine until winter hit; now I'm riding over some pretty rough terrain at times, and twice today I bounced the chain off the ring while riding over really bumpy ice.
So I try to remove a link and tighten up. But when I remove a link, the chain tightens so far so as to create an unrideable amount of tension/friction, even when the BB shell is rotated as far back as it will go (9:00).
This seems like some BS (why would someone design a tensioning system that won't accommodate a 1/2 inch chain?), but I think that maybe I can fix it by changing the chainring/cog combo. So I switch out the chainring from 40t to 38t (cog is 19t).
No change. I mean, now the chain has gone super slack with the BB in the 9:00 position. So I rotate to 3:00, and I've got the same amount of slack as when I first started. Remove a link, and again it's too tight to run even with the BB at 9:00.
*sigh* I miss my sliding dropouts. But I want the frame with the EBB to work with the IGH. Am I missing something? Any ideas?
11-10-11, 04:22 AM
#3
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Cheapest and best avenue, half-link like above.
Don't let the mechanics overthink the situation.
You could swap cogs. Or drop the chainring by a tooth. But money.
Half-link is a couple dollars.
Don't let the mechanics overthink the situation.
You could swap cogs. Or drop the chainring by a tooth. But money.
Half-link is a couple dollars.
11-11-11, 01:31 AM
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still surprised that the bb30 can't rectify this situation. There should be enough movement to tune it right.
This slack, is too much...? Half an inch in the chain is acceptable, actually preferred.
This slack, is too much...? Half an inch in the chain is acceptable, actually preferred.
