Chain loosing grip with the chainrings

[Guest]

When I ride in a gear past 4 my chain starts to make a popping noise. It does it more and more the faster I go. It's like when you shift to 1st gear then stop on a hill then try to go again in first gear it loose grips with the chainrings. It looses grip with the rear chain rings for about a second then regains grip. This only happens when I go to any gear past 4. Also when I stand up to pedal faster the chain just makes this weird pop sound and I loose all my speed because it looses grip with the rear chain rings. So do you know what is wrong?
David

[Alex Ramon]

Hi David,
It sounds like your chain and sprocket are worn. The chain and rear sprocket cluster wear out together, so you can try replacing just the chain, but you'll likely have to replace the rear sprocket cluster as well.

[Guest]

It can't be because this bike is no more then 3 weeks old and the chain shouldn't be worn. Like I said the chain literally makes a snapping popping noise while I pedal.

[Alex Ramon]

Yeah, it takes a few years to wear out a drivetrain. Maybe it's a stiff link? Check this video and inspect the chain: http://bicycletutor.com/stiff-chain-link/

[Guest]

Yeah I think it might be the chain but it only makes this sound when I'm riding, not putting it up in the stand like you had it in. Also my chain won't stay in its gear, if I go in to 1 I have to hold the shifter while I bike, or if I let go the chain will go into second by itself.

[Alex Ramon]

It sounds like your shifter may be broken or have sticky pawls. Try squirting some light oil into the shifter and then working through the gears. If that doesn't work you may need to replace the shifter. I'd take it into your local bike shop for a quick assessment.