Connex Single Speed Chain and KMC Half Link
November 19, 2004
One of the annoying things about converting your geared bike to a single speed is the need to run a chain tensioner. Not only do chain tensioners make noise, but they also add friction and complexity to the drivetrain. Some chain tensioners are as simple as an old rear derailleur. Others have the look of a derailleur, but are lighter and designed specifically for being a chain tensioner. Yet more can be as simple as a springloaded metal bar with a tensioning wheel on the end that takes up a little chain slack. They are available from people like Soulcraft, Surly and Paul's Components to name a few.
But this little tidbit isn't about a chain tensioner. In fact, it is about getting rid of a chain tensioner. When I was working on my bike last, I noticed that my chain was almost exactly 1/2 a link too short (or long). I had read on MTBR.com how some people had used half links to make their chains the right length to eliminate the chain tensioner. I got on the web and did a little research and decided to give it a try.
I dropped an e-mail to my friends at Speedgoat.com and asked if they carried half links for BMX chains. They had some laying around and so I purchased one and a new Connex single speed chain. The half link was $3 and the chain cost $16. As is always true with Speedgoat, the shipping is free and the customer service is amazing.
I attached the outside half of the half link to the end of the Connex Chain and then measured out the correct length of chain by wrapping the chain around the cog and chainring as though I were installing it. It came out perfect. I used a regular chain link tool to remove the extra links and attach the outside link of the chain to the inside half of the half link. The chain tension is almost perfect. Had it been a little too tight, I could file off a milimeter or so of the dropouts in order to get the tension right. As it is, it feels perfect. I may end up shimming the axle a tiny bit to take .5mm or less of the chain slack out. That is easy to do since there is that much blay in the dropouts.
As always, this post would be useless without photos. Here you go...
My SS with a Paul's Melvyn Chain Tensioner on the back. This is the "Before" photo
This is the chain I used.
Wide angle shot of the bike with the Connex BMX Chain and half link.
Half Link from above
Half link from the side
BMX Chain on the rear freewheel
BMX Chain on the front chainring
The Whole Drivetrain