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Discussion Starter #1
Hopefully some Alfine 8 gurus here who can help me. I'm not a complete novice but a few issues are bugging me. Running one of these on a Pinnacle Arkose with eccentric bottom bracket. I wore down the last sprocket and chain so decided to spring for new FSA 40T chainring, new alfine 19T sprocket and paired with a KMC Z1 Wide SS chain. My problems are two-fold:
  1. After a couple of rides the chain loses tension and starts to slacken a little...so much that it starts to rub against the top of the Alfine gear arm. The EBB bolts are fine but I think after some bumps the alfine gear arm shifts (or the wheel does in the dropouts) which then creates a bit of slack. I've bodged it with a zip-tie round the gear arm and rear dropouts but it's not ideal and affects shifting to 1st gear a little.
  2. There is only 700km on this chain yet I stuck a Park Tool chain checker on it and it's already past 0.75...WTF? I've looked after the drivetrain and wasn't expecting chain to be so worn unless I'm missing something and the chain checker doesn't work the same with a SS chain?
Thoughts or help anyone?
 

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All chains have a tight spot.....sounds like chain is too tight. Adjust tight spot with 10mm of free play.....
 

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Discussion Starter #4
thanks guys. Yeah so had a in-depth look. A couple of problems...i think there's a wave/bend in the chain over a number of links which may have contributed. Also, when the bike takes a bump or small drop the hub axle shifts out a notch so that the chain is rubbing the gear arm. I think one of the dropouts has been gouged out a little so what could be happening is the wheel is slightly out of alighment meaning excessive chain wear. I also found a few posts not recommending single-speed chains due to their thickness...that they can touch the gear arm assembly which is exactly my issue. Shimano recommend 9 speed chains for Alfine so I've ordered one and might have to try to find something to repair the drive side dropout.

Chain line is best as I can get it and I always make sure there's a little slack as per the excellent Park Tool video guide on setting up a single speed chain.
 

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First post some pictures, then it's so much more easy to be helpful.

Anyway, if the chain loses tension after a few short rides it HAS to be either the rear wheel not being secured, your eccentric bottom bracked not being secured or both not being secured.

Do not zip-tie the arm that extends from your alfine hub. It's not designed to keep the axle from rotating in the frame and it's not designed to withstand high torque powers.

On my bike I noticed I need to tighten the rear wheel axle nuts (that secure the non-rotating washes ) very, very tightly! And on top of that I had to use lock-tight fluid.

Otherwise the axle would rotate ever so slightly inside the frame dropouts while accelerating (standing on the pedals). This would cause the torque arm to rotate and the nuts to loosen over time.

The Alfine axle is made of a harder/stronger metal then the nuts, so don't worry about over tightening them. Just keep a spare set handy.
 

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Discussion Starter #6
First post some pictures, then it's so much more easy to be helpful.

Anyway, if the chain loses tension after a few short rides it HAS to be either the rear wheel not being secured, your eccentric bottom bracked not being secured or both not being secured.

Do not zip-tie the arm that extends from your alfine hub. It's not designed to keep the axle from rotating in the frame and it's not designed to withstand high torque powers.

On my bike I noticed I need to tighten the rear wheel axle nuts (that secure the non-rotating washes ) very, very tightly! And on top of that I had to use lock-tight fluid.

Otherwise the axle would rotate ever so slightly inside the frame dropouts while accelerating (standing on the pedals). This would cause the torque arm to rotate and the nuts to loosen over time.

The Alfine axle is made of a harder/stronger metal then the nuts, so don't worry about over tightening them. Just keep a spare set handy.
Thanks for your post. This is exactly what is happening...the axle is rotating inside the dropouts ever so slightly, causing the arm to rotate upwards resulting in chain rub/chain slackening. I stopped zip-tieing the cable as it does affect shifting performance. I ditched the standard Alfine axle nuts ages ago as they're made from chocolate and too easy to strip. I've replaced with BMX style axle nuts but based on what you say I'm probably not tightening enough as I was worried about stripping those too. I'll go tighter and use some loctite too. The EBB is solid and tight so no issue there. I've got a new 9 speed chain which isn't as thick as the single-speed and the sprocket and chainring still look fine so hopefully will get it sorted this week.

This particular bike (Arkose) has been as hassle since I bought it. After much back & forth with Evans Cycles I eventually got them to warranty replace the Alfine 8 hub. The one on my bike packed in after 7 months and was corroded/rusted and not through my like of care. Also, the wheel was built terribly and I started losing spokes...I since got it rebuilt properly. I think Evans have now discontinued this model. It's a pity cos it is actually a great commuter and I even did the Dirty Reiver on it.
 
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