When to change a chain ?

[flw]

When should a chain (chain drive) be changed before it becomes a problem when your on the road with no tools?

Tensioner position?

[Kal]

In my opinion the best times to change it are;

if it has lots of tight spots, rust damage, the sprockets are being changed, the wheel adjustment is all the way to the back or your intuition is just telling you to.

Maybe not the most technical list but should avoid any unpleasantness and promote confidence in your ride leading to loony riding.

[Scott58]

I usually get about 25,000 miles out of a chain. for the most part alot of them were probably still usable, but i'm just more comfortable at that interval. I usually get alot longer out of sprockets, but it would depend on how many miles I had on my chain before i decided to change it out when sprockets need replacement (haven't yet). it will also depend on how hard you ride. Like Kal said if you start getting tight spots you know it's time. Or if it's stretched past its point of adjustment.

[hot_shoe_cv]

Aside from obvious damage such as kinks, rust, or frozen links, the chain should be replaced when it is stretched beyond safe limits. To determine that, adjust the chain to factory specs. Then, grasping one link at the 3 o'clock position on the rear sprocket, attempt to pull the chain away from the sprocket. If you can see more than,1/2 a link the chain should be replaced and probabably the c/s sprocket also. A stretched chain can cause the c/s sprocket to become hooked and will quickly ruin the new chain.