Measuring your new chain

If you buy a new chain, you’ll find that it’s probably much too long for your bike — manufacturers sell chains longer than necessary so that they can fit a variety of different types of bikes. You need to make sure you’re using the proper length chain for your particular bike. If you use a chain that’s too short, you won’t be able to shift it into some gears. If you use a chain that’s too long, shifting will become sluggish or the chain will start to fall off.

To measure a chain, follow these steps:

Wind one end of the chain around the smallest cog and through the rear derailleur.

Make sure the derailleur is shifted to the smallest cog or the position far­thest to the outside.

2.

Wind the other part of the chain through the front derailleur and around the largest chainring.

Make sure the front derailleur is shifted to the smallest chainring or the farthest gear away from the bike.

3.

Using a little bit of force, bring both ends of the chain together (as shown in Figure 10-12).

This will pull the pulleys of the rear derailleur forward.

Shorten the chain by hand, one link at a time, until you get the correct length.

You know you’re at the right length when there’s approximately ‘/2 inch to 1 inch of space between the top pulley and the chain.

On the end of the chain with extra links, pinch the link with your thumb and forefinger where you need to cut the chain.

This will help you remember where to break it.

Figure 10-12: Measuring the chain

Reassembling your chain

After you’ve repaired and measured your chain, it’s time to reattach it to your bike. If you have an SRAM PowerLink-type chain, here’s how:

1. After having measured the chain (see the preceding section), remove any extra links using the chain tool.

2. Grab both connecting pieces that make up the master link.

3. Making sure to use inner links only, connect one piece from the inside of the chain and another piece from the outside of the chain.

4. Press the pins on both pieces through the rollers in the links, and snap the master link together (as shown in Figure 10-13).

5. Pull the chain to lock the pieces in place.

6. Visually examine the master link to make sure it’s securely in place.

If you have a Shimano — or Campagnolo-type chain or a chain with reusable rivets, follow these steps:

1. After having measured the chain (see the preceding section), remove any extra links using the chain tool.

2. Making sure to use inner links only, connect one piece from the inside of the chain and another piece from the outside of the chain.

Figure 10-13: Connecting an SRAM PowerLink — type chain.

3. Where the two ends of the chain come together, insert the replace­ment pin into the links just far enough to hold the chain together while you place it into the chain tool (as shown in Figure 10-14).

If you have a chain with a reusable rivet, the rivet will already be in place.

The pin has a tapered head that looks like a rocket ship. Make sure you insert the pin with the tapered head first. The head of the pin is designed to guide the pin into the chain and not to hold the chain together.

4. Rotate the handle of the chain tool to press the rivet into the chain.

Be careful not to push the rivet too far into the chain. You want to push the tapered head of the rivet all the way through and out the other side to have the non-tapered head protruding only as far as the neighboring rivets protrude.

5. Using pliers, snap the tapered head off the pin (as shown in Figure 10-15).

If you have a chain that uses reusable rivets, here’s how to reinstall it:

1. Grab both connecting pieces where the chain was broken.

2. Join the links together and place into the chain tool.

3. Turn the handle of the chain tool until the rivet is pressed into the chain.

An equal amount of rivet should be showing on each side of the chain

4. Remove the chain tool from the chain.

Figure 10-15:

Snapping off the replacement pin’s head.