I hve a new 21 speed mtn bike. When I shift, when I let go of the lever it goes back to the original gear.?

Question

It basically stays in the smallest gear in front and smallest gear in back. BTW, does anyone know anything about the Upland Vengeance brand? I can't find a website for them or find out who the parent company is.

Answer 1

I'm thinking you have thumb shifters like mirage stated. They need tension on that s***w. Tighten until the shifts stay, don't over tighen.

Answer 2

Not sure what you are describing. Does it pop back several gears at a time to the smallest gear no matter how far up you shift or are you talking about mis-shifting one gear at a time?

If it dumps back several gears to the smallest, it sounds like either a bad/stripped indexing gear or, more likely, a shifter set to run in friction mode without enough tension to hold the derailleur.

If it slips back when you upshift, it is most likely the cables. Cables stretch when they are new. You need to compensate for this by tightening the cable a little. You probably have adjustment nobs (barrel adjusters) at the rear derailleur and/or probably somewhere near the shifters which pull the cable tighter. Lift the rear wheel, spin it and shift to the misbeaving gear. Turn one of the barrel adjusters a 1/4 turn at a time pulling the cable tighter (if you look closely you can see the derailleur move) until it shifts and stays in gear (the derailleur pulleys and the gears should line up perfectly.)

The first time you'll probably need to turn it a lot. If it's too stretched you need to loosen the clamp that holds the cable, pull the cable tighter with a pair of pliers and reclamp to get back the lost (stretched) cable. If you do, make sure to run the barrel adjusters in so you have more adjustment room in the future.

The good news is, once you have it adjusted after the initial stretch it pretty much stays put until it dies of old age.

Finally, if the chain is really bad, with dirty and tight links it might cause this too. But probably not.

BTW, the stop screws would only cause the problem you're seeing on the top and/or bottom gears:  they just limit how far the derailleurs swing. Use caution if you mess with them. Too much travel and you can send the chain/derailleur into the spokes.

Answer 3

I assume you have a thumb shifter. There is a s***w on top of the shifter- it might be covered with a sticker or plastic cover.

Tighten the s***w.

Answer 4

sounds like your derailleur stop screws need to be adjusted