Eccentric BB chain tensioning

[middleagecyclist]

I've got a Rohloff geared bike with chain tensioning done via an Eccentric Bottom Bracket (EBB). It's 2.5 yrs old, still has the original chain and I normally retension it every 3-4months/1000 miles. I noticed the chain was sagging a bit recently and tried to adjust as per normal but could not achieve adequate tension with the EBB as its furthest rotated position from the rear wheel. The wheel is in vertical drop outs and not horizontal ones so no issue there. I can only think the chain links have 'stretched' but find it difficult to believe this would account for this much chain sag. I may give in and take it the LBS but would like to do it myself with some CC advice if possible. Cheers for any help.

 

[SatNavSaysStraightOn]

normal - this happened to both of our bikes - but you only need to worry about chain tension with a rohloff hub if the chain is physically coming off the bike (one test is to simply lie the bike down and pick it up, if the chain is off - you need to tighten it), as I am sure you know.
I simply removed 2 links from my chain and carried on - it is nowhere near as critical as it is with deraileur bikes. I got 14,500km from my chain and around the same from the cogs/sprocket. My OH only got around 9,000km but had an oil leak that added the wrong type of oil onto the chain that attracted dirt and formed a fine sandpaper tyre substance which mostly likely accounted for the difference.

We ran the bikes on £5 chains, so I would not worry about changing to a new chain.

I can't find the link I was after on the Thorn site but this one will do http://spoke2spoke.com/2011/07/31/m...the-chain-tension-on-a-thorn-rohloff-bicycle/. It does eventually make sense, but takes a couple or reads on a a Friday afternoon!

 

[srw]

Thorn specifically recommend taking out a couple of links once the EBB has go to its limit. Something we need to do sometime this winter on the timing chain.

 

[middleagecyclist]

Thanks both.

I'll try removing a couple of links and then readjusting. I suppose I have done near 9-10,000 miles on it though so maybe will need a new chain...

 

[SatNavSaysStraightOn]

Thanks both.

I'll try removing a couple of links and then readjusting. I suppose I have done near 9-10,000 miles on it though so maybe will need a new chain...

this is the chain we use. http://www.sjscycles.co.uk/kmc-z51-chain-116-links-7-8-speed-prod14135/ £4.49, so don't worry too much about it - not worth loosing sleep over for nearly 10,000 miles!

 

[shouldbeinbed]

agree, I'm on an alfine hub with an EBB. I've had a link out without problem to manage tension.

Aslo on my hack bike I used an Asda chain £5 and cables £3. Coudn't spot a difference in going forwards and then stopping from more costly ones over the 6 months before the bike went walkies from my son.

 

[P.H]

What Sartnav says. I also find my Rohloff runs better on a not very tight chain.

 

[SatNavSaysStraightOn]

What Satnav says. I also find my Rohloff runs better on a not very tight chain.

agreed, but fixed the typo!

 

[middleagecyclist]

agreed, but fixed the typo!

Come on Fartnav. It's only a typo'. Don't make a big thing about it!