Help with issues on mountain bike
 

Hello, I have been having issues shifting up/ down on the seven speed side, I will be in 1st gear but the chain will really be on the 3rd wheel, then when I hit 3rd gear on the shifter it will be at 4th wheel. Any suggestions?

OK, to be clear, do you mean that when the indicator on the lever is on "1" the chain isn't on the low gear (innermost) sprocket?

If so, this is a common cable adjustment. There's a threaded adjuster where the cable attaches to the derailleur. If you hold the rear wheel off the ground, pedal and turn the adjuster, the RD will shift. What you want to do is to keep adjusting this until the chain is on the sprocket that corresponds to the lever position.

Keep in mind that this is a very highly simplified answer, and there may be more issues, so after seeing if this helps, you need to find a turorial on derailleur adjustments and make sure ALL the adjustments are properly set.

If the two smallest cogs can't be used, you may have

Misadjusted H limit screw
Bent derailleur
Bent derailleur hanger
Rusted/kinked shifter cable or housing

Or a combination.

Of course if the shifter has a gear indicator then this feature needs to also be indexed with the shifter's actual gear position. Andy.

Thanks you so much for your help, I'm going to do this tomorrow when I have time so I'll let you know how that works out, much appreciated as I'm not to great with fixing things on a MTB, more just for riding trails lol

Keep in mind that this was a limited, single minded solution to a misadjusted cable. However, cable adjustment changes are often indicators of other problems, some of which can be more serious.

So, go ahead and give it a shot, but consider it only a start. Before riding the bike, you'll want to make sure that there are no other issues, most importantly incorrect adjustments that make it possible for the derailleur to overshoot and get snagged into the wheel.

That's not how I'd go about it.

More like

1. Shifter in the 7 position.

2. Loosen cable anchor.

3. Pedal. Observe if derailleur moves chain onto small cog.

4. If not, check for bent derailleur, hanger, bad canle, etc.

5. If so, pull slack out of cable and tighten anchor.

6. Adjust cable tension with barrel adjuster til shifting is good.

7. If largest cogs not useable, check for cable/housing corrosion or damage, derailleur or shifter damage or cable routing problem