How to Measure a Bike Chain for "Stretch"

I always go over my son's bike after a long offroad rides, cleaning, looking for anything broken, etc. This time I realized I had never checked his chain for wear. So, out came my trusty ruler. I know the bike was not well taken care of before we purchased it so I was not too surprised with what we found: it was clearly "stretched." It is time for a new chain and more than likely a freewheel.

How did I know it was no longer good? Let's measure the "stretch." Using an inch ruler, put the "0" in the center of one of the chain pins and go down to the 12" mark. When the chain was new, the 12" would be exactly in the center of a chain pin.

In our case the chain pin center was more than 1/16" past the 12" line.

Stretched chain? Well, not really. What is happening is the tolerances between the parts are getting looser. More space, the longer or "stretched" the chain becomes.  With any wear item determining how much wear is too much is the difficult part. According to every biker's favorite info website (Sheldon Brown's Bicycle Tech Information Site):

• Less than 1/16" past the mark, all is well.
• If the rivet is 1/16" past the mark, replace the chain, but the freewheel/cassette sprockets are probably undamaged.
• If the rivet is 1/8" past the mark, you have left it too long, and the sprockets (at least the favorite ones) will be too badly worn. If you replace a chain at the 1/8" point, without replacing the sprockets, it may run OK and not skip, but the worn sprockets will cause the new chain to wear much faster than it should, until it catches up with the wear state of the sprockets.

Clearly we have waited too long. We plan to get a new chain. And though we might get away without changing anything else, we plan to use a "parts bin" freewheel I have.

Watch for an update soon, after I gather parts and tools, showing how to change the chain and freewheel.

Warm Winter Weekend Ride

This winter has had its share of temperature extremes. The typical winter weather for here in East Tennessee is either bitter cold or rainy. But this weekend we had record high temps with breaks between the rain clouds... on a Saturday! Of course, we were not going to waste it on the couch!

Again, we boys headed out on another Greenway that we had not tried. This time we chose the Third Creek Greenway. The thought was to start in Bearden and go until the young ones started looking tired. The hope was to at least make it to Knoxville Skateboard Park before heading back.

The "trailhead" started in the parking lot of Earth Fare in Bearden. Technically, the trail runs beside the parking lot so there is no real entrance, but we figured it out. We headed out with the many runners, walkers, and bikers taking advantage of the awesome weather.

Eventually we arrived at our target goal: the skatepark. Most people are surprised that such a nice facility is tucked under the interstate. Surprisingly, the kids were up for more riding. The goal changed to simply getting to the river. Still, they wanted more. The carp under Calhoun's was our next landmark. Yes, we made it but the kids were starting to grumble a little. They had just done 7.1 miles one way!

Nearing the basketball stadium at UT

One of the many tunnels along the way

Gay Street bridge being repaired

The great thing about this Greenway is that the scenery is so varied that one never knows how far one has ridden, especially for a first-timer. And if you stop often for short rests, the kids will get a second (and third and fourth) wind. Bridges criss-cross many creeks, there is a playground at Safety City, another playground at Tyson Park, a couple tunnels, the gardens at UT's Ag Campus, the mighty Tennessee river, going by both stadiums at UT, and of course the fish under the Calhoun's restaurant. There were hills but they did a good job of designing them to be bike-friendly.

This a great trip for kids. We did the 14.2 miles in 2.5 hours and that includes the many stops along the way. This have become a new family favorite!