Hey ive just built up my first singlespeed. Got a problem when i put pressure on the cranks. It pedals fine but when i need to put a good bit of weight on the pedals it jumps! It feels its missing a gear that it doesnt have. Chain stays in place and is tight (using a superstar tensioner) Its not the freehub as ive swapped my wheels with my other bike, have tried to adjust the rear gear spacers but doesn’t make any difference.
Any ideas?

It feels its missing a gear

That’s your problem, x9.

Is it a push down or uP tensioner? If its down could be lack of chain wrap.

What does that mean? It feels like its jumping up and down a gear.

Its a push down tensioner. Does that mean i need to take more links out?

Possibly. You need to make sure that as many teeth on the rear sprocket are “wrapped” or engaged as possible, otherwise it may well slip.

Alternatively, have you checked the chain for stiff links?

Perhaps post a pic of the tensioner if you’re still having problems.

Thanks ill get another look at it tomorrow night.

I had the same and as suggested it was lack of wrap around the sprocket – worked on 18t, but slipped on 16t.
Adapted tensioner to push up and now fine.

same thing, I took another link out, problem solved….

Are you using non ramped ss specific chainring and cog? If not that could be the cause of your problem, in addition to the chain wrap thing as above.

ditto sam. ‘Normal’ chains are designed to ‘de-rail’ and SS ones aren’t.

Just as an aside, I found that those push up/down chain tensioners were a bit rubbish. Couldn’t get them to work very well, they took the chain away from the rear cog, plus they look ugly.

I found the neatest solution was instead to use an ISCG-mounted bottom roller guide for the front ring. You don’t have any of those problems and your chain is wrapped tight to both rings. It also looks a lot better imho. Only thing is you have to do it up through the gaps in your chainring in tension. Simple and rad.

could also be a chainline issue which kicks in when the frame flexes under power

so I would try checking the line and sorting the chain wrap

To the OP, are you mixing new and old chains and cogs? That could cause the problem.

To kayak23, I ran my first singlespeed with that system and got ‘tip of the month’ in MBUK for it. Only problem is that it doesn’t give a full links worth of adjustment so you have to be lucky with your combination of cog sizes and maybe change the chain earlier than you might otherwise.

Thanks for all the responces.
Ive had a look at it and im putting it down to the tensioner (superstar one that pushes the chain up) causing a lack of chain wrap. Does anyone know if the so called heavy duty tensioners on superstar will work?
http://superstar.tibolts.co.uk/images/heavyduty.jpg

I had the same trouble with the standard superstar tensioner.

I took off the stop pin to allow me to increase the spring tension (use a cone spanner to hold the spring in tension as you tighten with an allen key).

After this it worked fine in the push-down position.

I’ve tried to get it to work with the tensioner I’ve got but can’t get it to do what I need. Do u think the zinger tensioner would work?

I’m currently using a Gusset jobbie in push down configuration on a 32/16 drivetrain, there’s certainly a problem with chain wrap causing a bit of skip when you really torque it on a climb.

I think I might have to find a pull up tensioner or a BB mount one like kayak above, no ISCG tabs so BB mounter (probably a Blackspire stinger I expect) any thoughts Yall?

I was really hoping not to have to use a front tensioner as I prefer the look. Bit sad I know.

Had a similar issue when I built my first singlespeed. It jumped when i put the power down.

I used a ‘push down’ tensioner. I just couldn’t get the chain tension right. It was either too loose and skipping. Or if I lost one more whole link it was WAY too tight.

In the end I bought and replaced a whole link with a half link from Charlie the Bikemonger. It solved all my problems.

I had the same problems using an On-One doofer in pull down config. Changed to a Surly Singulator in Push up and all is fine. They come with 2 springs so can be push up or pull down. Hoghly recommended.

Watch the bit where I set the chain tension. Nalso get your chain as short as possible. And go 36:18 rather than 32:16 as more teeth means less slip.

Superstar tensioners are easily modded to push up – problem solved here (so far….)

How do u mod it to push up? I’ve had a good look at it but can’t see how to change what way it pushes.

Take the spring out and then space the bolt out to take up the ‘slack’. It’s left unsprung, but locks in the position you need. I’ll take some pics if you can’t work it out.

Ah get it now. I was trying to keep the spring in place. I’ll have a go tonight. Thanks