Maintaining Tension in a Single Speed Chain

[BannanaMan]

Recently I took the bike into the workshop because the Shimano Nexus hub was playing up. Whilst they had it in the mechanic put a new chain on. Unfortunately the chain includes all the links that I paid for consequently the new chain is worse than the old one was.
If I had done it myself I would have bought a single half-link and used that to substitute for one of the links.
The mechanic seemed to suggest that I should consider a device which looks like a derailleur arm or to use a complete half-link chain.
Another option is to change the ratio of Chainring to Sprocket to negate the problem.

Is there anything wrong with using a single half-link in the chain?

 

[FrankCrank]

Your description is not exactly clear, but to answer the last question, half-links are fine for this application.

 

[lenfield]

Why not try taking links out of the existing chain? If you can't get the tension exactly right you can buy a single half link for it. It would be cheaper than buying a whole new chain.

 

[FrankCrank]

....the other thing is Nexus, as with all internally geared hubs, are fitted to horizontal dropouts, to allow correct chain adjustment.
The Nexus could of course have been retro fitted to a bike that had vertical dropouts, in which case it gets more difficult.
The 'magic' gear can usually be found with a combination of swapping out rear sprocket, a half-link, filing flats on the axle, filing the dropout to elongate the hole.
An element of luck is needed, but can be done

 

[EckyH]

The mechanic seemed to suggest that I should consider a device which looks like a derailleur arm

There is nothing wrong with a chain tensioner.

From my own experience: If weight isn't important, then any old rear derailleur which can take the width of the chain will be the most flexible solution.

E.

 

[mickle]

You're running a single sprocket set-up with vertical dropouts presumably. The only acceptable solution is a chain tensioner.

 

[Ming the Merciless]

Slide wheel back in the horizontal dropouts. Make sure nuts done up tight to keep it there.

 

[ColinJ]

From my own experience: If weight isn't important, then any old rear derailleur which can take the width of the chain will be the most flexible solution.

That is what I did for the singlespeed bike that I put together for my smart turbo trainer. I use a Zwift Cog and virtual gearing, but I obviously needed the chain tension to be right. I adjusted the Zwift cog to give me a perfect chainline then moved the derailleur by hand to the optimum position and held it there by screwing in the appropriate endstop. No cable or shifter required!

 

[FrankCrank]

There is nothing wrong with a chain tensioner.

From my own experience: If weight isn't important, then any old rear derailleur which can take the width of the chain will be the most flexible solution.

E.

Certainly, there is nothing wrong with adding a chain tensioner, but for me I'd try to exhaust the other options first.
I did fashion a tensioner for one project out of an old v-brake arm with a jockey wheel bolted on.

 

[BannanaMan]

Thanks for the advice. When I bought the bike nearly new I thought it was as it shipped from the factory. A couple of years back I put a new chainring on which altered the ratios.
The bike had to go into the workshop because I did not have the confidence to repair it. When I went to collect it the mechanic tried to imply that it was a Frankenstein. It is an Orbea and does have a derailleur lug, presumably they designed the frame for use with dérailleur and then made a hub gear variant. I have never questioned this in close to two decades of commuting on it.
I do have to do something about the chain and wondered if there was a reason the mechanic did not do what I thought was obvious.

 

[scotsbikester]

Thanks for the advice. When I bought the bike nearly new I thought it was as it shipped from the factory. A couple of years back I put a new chainring on which altered the ratios.
The bike had to go into the workshop because I did not have the confidence to repair it. When I went to collect it the mechanic tried to imply that it was a Frankenstein. It is an Orbea and does have a derailleur lug, presumably they designed the frame for use with dérailleur and then made a hub gear variant. I have never questioned this in close to two decades of commuting on it.
I do have to do something about the chain and wondered if there was a reason the mechanic did not do what I thought was obvious.

What sort of dropouts does it have?