Single speed conversion - which chain?

[Percy]

My old MTB was converted to a single speed by a shop a couple of years ago, using a chain tensioner. I've renovated it myself recently - new crank, chainring etc. - including a new chain - a 'single speed chain'.

I'm just putting the whole ting back together again and am having problems with the drivechain as a whole - getting chain tension is one issue (but possibly with the set up of the tensioner and something I'm going to look into - any tips?) but the main problem seems to be with the chain catching on the tensioner's 'guide' - the little bracket that hangs over the wheel. Tensioner I'm using is very similar to this one:

http://www.stevecramerproducts.com....tion=display_product&product_id=431&B=32&BT=2

Have I made a mistake in buying a dedicated single speed chain? If so, what chain should I look at getting? A normal, nine speed chain, designed to run through a derailleur and, presumably therefore, better suited to running through a tensioner?

 

[RedBike]

Whats is a single speed chain?

Do you mean a half link chain or a bmx chain?

Different chains are different widths. Perhaps that tensioners not designed to accept anything wider than an 8speed chain?

 

[buddha]

Also, are your chainring, rear spocket and tensioner in-line?

 

[MartinC]

The tensioner cage may not be wide enough for a single speed (1/8") chain and may need you to run a 3/32" chain. The external width of a nominal 3/32" chain will vary depending on make and whether it's 7/8, 9, 10 or 11 speed.

 

[pedallingpasty]

Looking at the tensioners spec for 8/9 speed conversion, i suspect it is designed for 3/32 chain. I have done the same on my mtb with a similar tensioner and fitted a good 3/32 7/8 speed chain and it all worked ok.
Most important thing as already mentioned is to everything in alignment including the tensioner jockey wheel. Also run the chain with minimum length, they are not really designed to have too much slack.
If your jockey wheel isn't aligned correctly, there will be an irratating clicking all the time.
Hope this helps.

 

[Percy]

Thanks all.

This is the chain I have:

http://www.chainreactioncycles.com/Models.aspx?ModelID=11282

Further messing around seems to suggest the chain does fit through the tensioner OK, although I am still struggling to get decent tension on the chain. At best, it's pretty floppy.

I am running it on a Shimano triple chainset with the smallest two cogs taken off and a single speed conversion kit on the cassette hub. In its current state, with the chain slightly floppy, there is a lot of 'chain noise' that I can't identify - I'm hoping decent tension, when (if?!) I manage to get it, will sort that out, but perhaps this is an issue with the chain not suiting the crank/cog? Or, as suggested, with all cogs being in line - they look pretty good by eye but is there a more definitive way of getting them 'perfect'? (maybe they don't have to be absolutely perfect?)

To complicate matters, the spring in my chain tensioner broke and I've replaced it with an old derallieur one (rather than replace the tensioner for £20) and I think that might be contributing to the lack of tension. I dunno - this started a month ago as 'I think I'll spruce up my work bike' and has turned into an epic mission!

 

[battered]

This is the chain I have:

http://www.chainreac...x?ModelID=11282

looks ok. Chains designed for 6 speed etc are good in SS applications as being thicker they stretch less under load and feel nice and solid. All other things being equal of course.

Further messing around seems to suggest the chain does fit through the tensioner OK, although I am still struggling to get decent tension on the chain. At best, it's pretty floppy.

I had this, fixed it by putting a twist on the tnsioner spring BEFORE I loaded up the chain, if you see what I mean. This ensures a nice tight tensioner.

is there a more definitive way of getting them 'perfect'? (maybe they don't have to be absolutely perfect?)

There isn't, and you don't need to. If it's out of line it will dump the chain, that's all.

To complicate matters, the spring in my chain tensioner broke and I've replaced it with an old derallieur one (rather than replace the tensioner for £20) and I think that might be contributing to the lack of tension.

Doesn't sound good. I might be trying a new tensioner or at least a new spring from the LBS.

I dunno - this started a month ago as 'I think I'll spruce up my work bike' and has turned into an epic mission!

Often the way. Anyone who tells you SS bikes are maintenance free doesn't really use one very often.

 

[Percy]

looks ok. Chains designed for 6 speed etc are good in SS applications as being thicker they stretch less under load and feel nice and solid. All other things being equal of course.

I had this, fixed it by putting a twist on the tnsioner spring BEFORE I loaded up the chain, if you see what I mean. This ensures a nice tight tensioner.
There isn't, and you don't need to. If it's out of line it will dump the chain, that's all.

Doesn't sound good. I might be trying a new tensioner or at least a new spring from the LBS.
Often the way. Anyone who tells you SS bikes are maintenance free doesn't really use one very often.

Thanks for that battered. I've got it to almost OK. Might just pop into an lbs tomorrow and get an opinion then probably replace the tensioner.

When you say you twisted the tensioner, do you mean you assembled and fitted it entirely then gave it a full spin before fitting the chain? Under tension? That sort of pressure is what broke my other spring I think! Although, the new derallieur spring doesn't quite fit I don't think - it's larger than the tensioner spring so I don't think it has the right tesnios behind it.

I'll give it a trial tomorrow - took the step of fitting the pedals tonight so it is (finally) 'complete'. Hopefully, one day soon, I'll be able to ride the bloody thing!

 

[battered]

Thanks for that battered.
When you say you twisted the tensioner, do you mean you assembled and fitted it entirely then gave it a full spin before fitting the chain? Under tension?

Yes, that's what I did. Maybe not a full turn, I can't remember exactly, but basically I fitted it and just hooked it over the chain, then went for a ride. It was skipping and dropping the chain every 2 minutes. I had a look and established how to increase the tension before doing it up. No bother since, apart from when I used it on Sunday and failed to get the wheel fully square in the dropouts before doing up the QR so the brake rubbed and the chain fell off. Oops. Of course not all tensioners are the same, but mine certainly needed a fair bit of tension on it to take up the slack.

If yours has a non standard spring I'd start by looking at that.

 

[Percy]

Approaching baffled now. The line of the chain seems OK, tension is adequate and I don't have any stuck links...but I can't ride two metres without it skipping. What am I missing?!

 

[pedallingpasty]

Percy, what size cog and chainring are you running?
I am assuming you have refiited what the lbs fitted.
I ask because it sounds like it may be a chainwrap problem. My own bike has 36 chainring and 18 cog, both from surly so no ramps. This is the max size chainring i could get to achieve the 2 to 1 ratio i needed, it does go offroad now and again. This ensures max chain wrap as recomended. It may be that the rear cog is quite small, so giving only a few teeth engaged with the chain.
Also how long is your chain and what angle has your tensioner enede up at?
So say that the tension is pk, but you may quite a long chain. I measured my chain as if i wasn't fitting a tensioner so that i could join it, then added 2 links to be able to join using the tensioner. Think this makes sense . This ensures there is minimum chain length for using the tensioner.
Click on attached photo of how the tensioner ended up. Love the simplicity and quietness.
Also did you replced the rear cog?
Apologies if i am telling you how to suck eggs, just my own experience.
Cheers.




PS, I have managed to fit a 1/8 chain with no tensioner, so far it hasn't jumped and there is no binding.
.

 

[battered]

If you're stuck and near Leeds, drop me a line and bring it round. Other trhan that PPs advice seems good.

 

[Percy]

Thanks both. I think I've sorted it now - does seem to have been a tension problem. Taking another two links out and adjusting the tensioner a little makes it ridable. It is a little clunky though - I think a new tensioner is in order - it's a bit old this one.

I did pretty much fit what was originally done on it, pedallingpasty. Was 46/16, now 48/16 (it's a commuter, not off roader!)

Might as well stick a photo here now it's (finally) sort of finished! Thanks for all the help/advice.

 

[pedallingpasty]

Yes, your ratios make mine look a bit tame . As you say, different uses.
I think a tensioner that pushes the chain up with that kind of gearing, rather than the one we have fitted that pulls the chain down would be better. This will give greater chain wrap. These have no spring fitted, just locked in place with a bolt. Also they dont use a jockey wheel, just a roller. Recomended to fit an old inner tube over the roller to quieten it down a bit.
I have used Charliethebikemonger up to now for ss spares, and so far have recieved great service from them. They have also got some good info on the site.

Cheers.

 

[Percy]

Yes, your ratios make mine look a bit tame . As you say, different uses.
I think a tensioner that pushes the chain up with that kind of gearing, rather than the one we have fitted that pulls the chain down would be better. This will give greater chain wrap. These have no spring fitted, just locked in place with a bolt. Also they dont use a jockey wheel, just a roller. Recomended to fit an old inner tube over the roller to quieten it down a bit.
I have used Charliethebikemonger up to now for ss spares, and so far have recieved great service from them. They have also got some good info on the site.

Cheers.

Just had a look at them PP - they look good. Might give it a go. Cheaper than a sprung one too, which is a bonus!