mrmb

So I installed a half link yesterday. When I installed it it was very stiff on the pivot joint, so I bent it from side to side to free it up, now it is just as smooth as the other links in the chain.

HOWEVER, with the wheels off the ground, spinning the crankarms by hand and watching the half link as it goes around, it does not engage as well as the other links. There is a slight bump each time it goes around the cog (single speed bike). Its fine on the chainring though. It does not engage and disengage with the teeth of the cog as nicely as the other links.

It is a KMC 3/32 chain and a KMC 3/32 half link.

Any thoughts?

ramzilla

Take it out on a test ride. Maybe it will break -in and be OK. If not, just get a new chain.

Andrew R Stewart 

Likely the OP will still need the half link with a new chain though. I would carefully look at the half link's meshing with the rear cog. Tyr to figure out if the link is still a bit stiff in motion or is catching on the teeth somehow. Either the link is too narrow and catches on the teeth's side edges or the top of the teeth is somehow the half link's pitch is different from the cog's. The first way this might be the case is if the cog is well worn. This might also suggest why a half link was thought to be needed too. Since no mention as to the reasons of the half link need or otherwise condition of the chain/cog who can say what's really going on? Andy

mrmb

Cog has very little wear on it.

Half link was used because this is a vertical dropout equiped frame set up as a single speed and I wanted chain length to be as close as possible to ideal. I dont want to have to bottom out the tensioner (rennen rollenlager) to get tension just right and better yet I don't want to have to use a tensioner a at all, and if I have to use one I want to have as much room for future adjustment as possible.

Half link is definitely not stiff...at all. Chain and cog have maybe 500 miles on them, tops. I replaced the chainring to get a different ratio, used a new chain and opted for a half link to optimize chain length.

mrmb

Havent test ridden it yet, but I do notice that the more I run it by hand on the stand, the less it "bumps" when the half link goes over the cog. Good sign I guess!

Andrew R Stewart 

No chain adjustment ability (vertical drops, no axial/hub adjustment, no BB eccentric) makes for a poor choice. But it's what you have. good luck as things wear. BTW you do know that the proper chain tension for a single speed (fixed or FW) is NO chain tension? Andy.

mrmb

At the tightest spot, there is 1/2in slack as I press/pull on the chain with my fingers....thats 1/2in down from the relaxed position and 1/2in up from relaxed position. I would have liked a magic gear and I thought that maybe the 1/2 link would have given good chain length. The rollenlager works well.

mrmb

After 40 miles of riding, it still does it. Let me be clear that while riding everything feels fine. On the stand while watching closely and spinning the cranks by hand the half link does not engage/disengage the cog smoothly.

If I use a new chain without a half link I will have to push in on the chain a decent amount with the tensioner (rennen rollenlager). I am thinking about doing this.

Thoughts?

FBinNY 

It could be chainline related. If the chain line is a bit off so links rub the sides of the teeth, the part where the plate narrows may bump the side of the tooth as it engages. Offhand, I don't know if makers specify an orientation but I suspect that having the narrow end first might be marginally better. (note I said marginally).

Otherwise there might be residual stiffness, or a minor pitch error due to variation in tolerance. These will break in pretty quickly, so just ride the bike.

fietsbob

Chain tools offer the potential to spread out the side plates when they are binding, after pressing the pin in .

but this is just an old style chain feature, the pins have to be wider than the rest of the chain ..

the OldGuy at your local bike shop can demonstrate this. Perhaps ?