What is wrong with my bicycle? My chain keeps coming off the front crank!?

I have a brand new single crank on the front
a brand new 7 speed on the rear
a brand new chain
the chain seems to be at the correct tension
the back shimano derailleur seems to be the correct tension
the back wheel is on straight
Suggestions please
 
Either the chainwheel/crank are a bit soft and when you put on the power they flex enough to de rail the chain, or the alignment between the freewheel and chainring is way off in certain gears, if it always comes off in 1st or 7th this is more likely the case.
Either issue can be cured with more upgrades, or simply bolt on a front shifter and trim it to act as a chain guide.
 
In the lowest/highest gear, your chain is at such an awkward angle that it forces itself off the teeth. It is also possible that your front chainring is bent, which would make it easier for the chain to pop off.
 
Back
Top