I'm trying to ss a 16" Kona mtb frame. I now own 2 Singleators, one about a year old, the other brand new and I can't get either of them to hold tension in push down mode (I've read the instructions and followed them carefully). I've tried swapping the spring to run it in push up mode but I don't seem to be able to shorten the chain enough - it just sags. Has anyone else found that the spring in the Singleator just gives up after a while? On this performance an old rear mech would be better, for all its imperfections.

my bet is that you're still doing something wrong, but i can't imagine what.
pics? or take it to a shop

A pic probably wouldn't help right now, altough I could upload one of me holding a singleator and cursing. I can't see that I've done something wrong, I really have followed the instructions, several times. So it's back to the lbs where I bought it for their advice (not that they use them).

shorten your chain?

I was under the impression that the chain should be as tight as you can get it first, and the singleator takes up 1/2" or so of slack.

likw so:
https://picasaweb.google.com/adamogan...81815667198754

I like those pics. I took my bike back to the lbs - the shop manager said that he also once had a Singleator which gave way and started to flex. We tried the new one that I'd bought and using both the flat wrench (for the spring) and the hex wrench (for the pivot bolt) together we got it to tension up. The shop manager then said that there was still a possibility of flexing if I took the bike off-road and he would let me change the Singleator for a rear mech which is what he would recommend. So my new chain tensioner is a Deore rear mech, lots of chain wrap and no flexing at all. More wrap means more resistance, so it doesn't feel quite as nice as the old Singleator did, but at least I know I won't have to walk every hill to get home.

If you want something that holds solid without the resistance of a derailleur, look at the Rennen Rollenlager. It's a rigid tensioner with a urethane roller for the chain. I had one on my older SS MTB and it worked like a champ. I'm not sure if your LBS can order it or not, but it's something to think about if you've got an extra 50 bucks or so sitting around.

Ditch the singleator and get an ENO eccentric rear hub
https://www.sheldonbrown.com/harris/white-hubs.html or an eccentric bottom bracket. That way you can adjust chain tension with vertical dropouts.

Getting a wheel built around an eno hub = expensive.

Getting one of those new EBB's that fits in a normal bottom bracket = even more expensive. Not to mention the fact that it hasn't really been around long enough to decide if it'll stand up to real life experiences.

Did you think if trying push-UP mode it has be there for reason?

I ran a road bike SS in push-up mode for more chain wrap but I wouldn't do it for off-road. It will bounce down when you are jumping about and your chain could fall off.

Not if you run a solid tensioner. No bouncey bounce there.

You're right, I was talking about the singulator. I never have tried the rigid ones.

This bike is for winter commuting in England and the occasional off-road jaunt so expensive solutions like the ENO hub wouldn't be right for this one. The rear mech as tensioner has been the best solution for me and I like the confidence of knowing it can't flex (the guy in the shop even zip-tied the mech body to the chain stay for extra anti-flexiness).

Come on over American friends and sample the off-road riding in the UK. More mud than you've ever seen but we're still smiling and the 'cross races are packed.

Sorry I didn't mention this before but you can find an old chain ring and wedge it in the chain between the chainring and cog. As long as you get it in tight and you have a decent chainline it will stay in place. This only really works for single speed applications not fixed gear.