Adjusting tension with a half-link chain

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I have a 2005 cannondale chase size small frame that i have converted to a single speed but it has vertical dropouts. I have tried tensioners and have not had any luck with them so I decided to try a half link chain since it looks cleaner.

I took the bike to a local bike shop and they tried swapping the rear cog to different sizes and now have a 36t front and a 17t rear. They tried a 18 rear but it was so tight the cranks would hardly turn. The 17t works but has alot of play until you put pedal pressure on it, but has never fallen off.

Can you help before I start buying hundreds of dollars of chainrings and rear cogs trying to find a good combo.

thanks, Kevin

Hey Kevin,

Nice little question.



Hmmm. I learn something every day.

First, what is a half-link chain?

As most of us know, a standard chain alternates narrow and wide links. Each link is a half-inch long. When you adjust chain length, you must add or remove two links at a time (one narrow and one wide). That changes your chain length in one-inch increments.

A half-link (pintle) chain uses the same link throughout. You can add or remove one link at a time. This lets you adjust length in one-half-inch increments.

Pintle chains let BMXers and singlespeeders get more precise adjustments without relying on chain tensioners.

As for your bike …
From what you’re saying, your ideal rear cog would have 17 1/2 teeth. That would give you ideal chain tension, but you might experience a slight skipping problem.

But seriously. No matter where you add a tooth — chainring or cog — you’re going to make the chain too tight. So you have two choices:

1. Ride it as is. The international standard chain tension is one-half inch of vertical play halfway between the cog and ring. As long as you’re close to that, you should be OK.

2. Tighten that chain. Have you tried a Surly Singlelator? I’ve heard only good things about that item. If tensioners don’t work, there’s always …



Pro.

The ghost ring

This was recently featured in Bike Mag, and I use one on my tandem’s idler chain. Sweet little trick.

Basically, get an old chain ring and cram it between the top and bottom of your chain. If you pick the right size ring (usually 30-34t), it’ll create the perfect amount of tension.

Bonus: It will turn backward. Cool!

Good luck!

— Lee

Know more. Have more fun!

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