Iron Horse Quantum Mountain Bike

My bike is new, he told me in February, but it took today for the third round probably his. I do not know much about bikes, but it has three forward gears, 8 reverse speeds. When I'm pedaling, the bike sometimes drag the string to jump like a link or something. This occurs regardless of which of three forward gears, I'm in. Sometimes bad climbing the hills, but I thought it was probably because the train was not low enough. (?)

If it helps, it is an Iron Horse Quantum II ... I looked online, but I suppose it is sold exclusively in Sports Authority stores. It has Shimano Acera travel, I have heard is decent.

Nevertheless, if you know the problem, please help me. Moreover, if this is something I did or am doing wrong when passing (I'm still kind of learning the whole trip, too) please tell me. Thank you!

http://sheldonbrown.com/gearing/index.ht ...

learn something about bicycle wheels, or is it for pros LBS. This could be a bad freehub body, stretch the string, ill-fitting rear derailleur limit screws, bent derailleur hanger, over strain the derailleur cable.

Acera is correct for recreational use, but in the family of Shimano products, it is the second from the bottom of the barrel. They are seen as willing and wear out more quickly at this price.

Try entering a gear jumps, he throws it upside down and look where he leaps.

I had a problem with some gear on my old freewheel and I diaginosed some teeth bent outwards and I really do not know how they got like that, but they climbed onto the teeth.

I replaced the clutch and they work sweet and I listen to my derailleur limit screw / and even on a bike cheap enough I'm moving well.

Mine does the same thing, a friend told me to adjust the derailleur ER, I do not know much either, but it would probably cost $ 8 to 10 have a professional solution properly.

Sounds like a tricky question - if an LBS near you, ask them ....( Do not tell em where you got it.)
I assume a close link in your chain. Sit there with gloves, plastic bag and Flex all the links in your chain 1X1

Firstly if your bike is new, then the store must solve if you talk to them. Anyway crafts must not slip even if you jump up and down on the pedals. Im not sure if the front or rear gear you mention, but this applies to both.
1. Look at the bolt that holds the cable to the derraileur, check that the cable does not seem to have slipped. If yes go up a gear and change down (but the pedal speed). This should create a bit of slack rope. Unscrew the bolts and remove the cable from 2 mm to 1 o and tighten the bolts securely. (Not stupid or hard it snap). You can repeat this several times if it is unsuccessful.
2. It's more complicated if the site consolt Shimano. Basically there are two screws one which when released allows derraileur to go above and one below. You can play with these for the right place but I do not recommend it unless you know what you do

If any of these checks help,
bent wheels
bent links
If the chain is oiled
abnormalities in the cable
Cable split

hope this will help!