Single Speed chain skipping on cog, is 18/12 just too small?

[gtluke]

Going out of my mind. I can't get my street bike to work properly.
18t on the front, 12t in the rear. If the bike is in motion and a decent amount of torque is applied the chain skips.
I put a new 1/8" chain on and it got WAY worse. Like you can watch the chain ride up on the rear cog just in the stand. With the 9 speed chain on it'll only happen while riding it. I can't take any more links out of the chain.
The front freewheel has a little bit of play in it, but not bad. I tried to swap it out but I think it's a permanent part of the bike now. Maybe heat will work, but if it doesn't I probably would cook the grease or the bearings so I don't want to try.
Chainline is dead nuts on.
I THINK the problem is using the chain tensioner which keeps the chain too far off the back. It won't work putting pressure upwards, not enough room.

Halp, it works with the old 18t cog in the rear but I wanted to try some higher speed fun times.
switching to regular MTB parts would require a new hub and new cranks. I have cranks, but I would rather not have to buy a hub and lace it up. A MTB rear wheel won't work because of the magura brakes needing a rim that's so wide.

Maybe I need a 3/32 chain with a half link and get push up mode to work? or maybe 12 teeth just isn't enough?

Chainline

Tensioner

I gave up, even the impact gun didn't move it.

 

[Magic]

Have the tensioner push up instead of down for more chain wrap. Got any pictures from the side?

Just read you can’t have it push up. Shit out of luck then unless you get a derailleur style tensioner like problem solvers or find magic gear.

 

[gtluke]

yeah the 12t in the rear makes the push up pretty impossible

 

[Sven Migot]

I had a similar setup with the same problem. Switched to DMR tensioner and works perfect. Even with some slack in the chain it never skips. Have it pushing up.

 

[Sven Migot]

 

[Steve Vai]

It's the tensioner, that's not enough wrap on the rear cog.

 

[GSTim]

That DMR tensioner is really nice looking too. Much nicer than the other ones I've seen.

Just looked it up <$20, awesome.

 

[jdog]

It's the tensioner, that's not enough wrap on the rear cog.

This and with 12t it makes it worse.

 

[KenS]

You know the freewheel is reverse threaded I assume? That c-clamp and breaker bar setup should easily remove the lockring.

 

[Sven Migot]

View attachment 62982

The downside is this tensioner will make your quick-release a slow-release. You'll need to carry a 5mm to get the wheel off.

 

[gtluke]

You know the freewheel is reverse threaded I assume? That c-clamp and breaker bar setup should easily remove the lockring.

eh, that would make it unthread while pedaling.

 

[gtluke]

The downside is this tensioner will make your quick-release a slow-release. You'll need to carry a 5mm to get the wheel off.

I have bolt on axles anyway. Not sure I can even fit that one, when down to a 12t cog getting room between the chainstay and chain gets to be a problem unless I can get the chain very tight before even adding a tensioner. I'm wondering if I might be better off with one of those Z type tensioners. Guess I could try an old derailleur first.

 

[Patrick]

tension up near the chainring instead?????

hey, is that freewheel and crank all steel? if the crank is al, put it in the freezer -
(i think al shrinks faster than steel w/temp change - it also expands faster)

is that a 3/8" breaker bar?

 

[Sven Migot]

I have bolt on axles anyway. Not sure I can even fit that one, when down to a 12t cog getting room between the chainstay and chain gets to be a problem unless I can get the chain very tight before even adding a tensioner. I'm wondering if I might be better off with one of those Z type tensioners. Guess I could try an old derailleur first.

You're right. I used it with an 18t and it was very close to the chainstay. Dual pulley is the way to go...

 

[Magic]

Solver of Problems.

 

[gtluke]

tension up near the chainring instead?????

hey, is that freewheel and crank all steel? if the crank is al, put it in the freezer -
(i think al shrinks faster than steel w/temp change - it also expands faster)

is that a 3/8" breaker bar?

that's a 3ft long snap on 1/2" breaker bar.
never mind the 1/2" impact gun I just had on it. I'm afraid to wreck the notches or break the tool though.
I think I'll just leave it on there. If I really need to get it off I have an oxy acetylene torch.

 

[gtluke]

Solver of Problems.

two 1 star reviews claiming it only works on tiny cogs. this is good.

 

[JimN]

I have a Yess tensioner that you could try if you think it will help.

 

[Magic]

two 1 star reviews claiming it only works on tiny cogs. this is good.

The maximum is 18T. I found that out the hard way when the chain started slipping under power. It does state this on the Problem Solvers site. You can use mine if you want, since SSaP is dead.

 

[soundz]