Author Topic: chain help  (Read 2000 times)

dyson

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chain help
« on: April 19, 2006, 09:28:42 pm »
my Raven has done nearly 1800 miles since I started riding it in January.

The chain keeps slipping off. Need some guidance on tightening the chain. I thought the manual would have step by step guide for newbies doing the basics, but no, unless Im missing something because it is so easy!

Is there a step by step guide on print on the website? Or could someone give a clueless newbie a lesson in sucking eggs. You just turn the shiny nut thing on the rear wheel right?
 

stutho

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Re: chain help
« Reply #1 on: April 19, 2006, 10:17:16 pm »
see Thorn Cycle User Guide pages 9 and 11

stutho

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Re: chain help
« Reply #2 on: April 19, 2006, 10:51:08 pm »
It isn't very difficult to adjust the chain tension.  

  1. Slacken off the two large screws under the bottom bracket (underside of the bike) this allow the eccentric bottom bracket (EBB) to rotate.

  2. Tighten up the chain by rotating the EBB away from the back wheel best done with a special spanner but can still be done easily without it. See page 11 of the Thorn Cycle User Guide make sure the "thin" part of the EBB is NOT towards the bottom of the bike.

  3. If you cannot get enough tension on the chain by rotating the EBB then you need to remove a link in your chain or possibly replace you chain.

  4. A slack chain is better than a chain that is too tight you should have 2 to 4 cm of vertical movement in the chain.

  5. Tighten the two screws under the bottom bracket - it is easy to over tighten these they only need 10 to 17 NM of Torque  (you can produce a lot more torque than this with a spanner a large screwdriver is better)

 

« Last Edit: April 19, 2006, 10:52:45 pm by stutho »

dyson

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Re: chain help
« Reply #3 on: April 20, 2006, 12:44:45 pm »
Thanks everyone for the advice I will give it a go. Final point though. Not many local bike repair shops \in London seem to know too much about Thorn Raven rohloffs. I enquired to a couple and they did not know how to adjust the chain! In future are there any specialist repair shops in London that I can take my bike to who would know what they are doing? Would the Evans chain store or the Condor Bikes in chancery Lane be recommended?
 

PH

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Re: chain help
« Reply #4 on: April 20, 2006, 05:55:40 pm »
The only difference between your Raven and most other bikes is the gearing system.  There are a few routine jobs, I’m sure you could find a bike shop to do them, but really they’re so simple it's worth learning to do yourself.  None of them are as complex as changing a tyre.
Chain tensioning - It doesn't sound complicated, it’s even easier than it sounds.
Oil change - if you can turn an allen key you can do it, just follow the instructions
Changing chainring and sprocket - both very simple, though the sprocket needs a special tool
Changing gear cable - this is the most fiddly, though it's not hard, I dreaded doing it, the instructions look complicated, once you've opened it up it's pretty logical.  Best done at home at the recommended 10,000 mile mark, rather than at the roadside.

I don’t think I’ve forgotten anything.  Hopefully it’ll never need more than that, if it does it’ll be a specialist job, involving a return to SJS or Rohloff.


dyson

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Re: chain help
« Reply #5 on: April 20, 2006, 08:56:32 pm »
Cheers for help

I did the chain this afternoon which was not as difficult as it seems.

Just one thing though. The manual mentioned when pushing the bike the pedals turn, to prevent it add more oil??? Strange that. Is it a bad thing if the pedals keep turning when pushing the bike? They were turning when I first got the bike in January, so could not be a lack of oil.
 

stutho

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Re: chain help
« Reply #6 on: April 20, 2006, 09:26:26 pm »
>Is it a bad thing if the pedals keep turning when pushing the bike?

It is perfectly normal (for a Rohloff) just ignore it!  Allegedly it stops after the first 20,000 miles!
« Last Edit: April 20, 2006, 09:26:50 pm by stutho »