4. How to Calculate Chain Length
Measure the correct length of a new bike chain.
When you purchase a new chain, it usually comes with extra length so that it is compatible with most drivetrains. How do you know how much length your bike will need? Well, it's really quite simple...
The first step is to wrap the chain around the largest sprockets on the front and rear, so that the ends meet on the largest front chainring. For this step, it really important to not run the chain through the rear derailleur.
Next, position the chain on the chainring's teeth at the tightest spot you could connect the chain. Now add one whole inner and outer link, so that you have approximately one extra inch of slack in the chain. That will be the optimal length for most systems.
i've recently started riding my bike for exercise. was going well for a couple weeks, but a few days ago the chain on my bike has been slipping off of what i think is the gear shifter. it is very annoying and i haven't been able to ride my bike because of it.
Edit More info: i have a Schwinn Ranger 10 speed. the gear only slips like that in high gear. it does not slip while in low gear.
i have a video of basically what happens. can't get a video of it while riding. it is a video of it slipping off stationary.