How to true a bike wheel - GMC Denali 700C Road Bike

First thing to do is check your oil levels. I'm not sure if that bike uses a separate transmission oil. Low oil can cause strange noises when in gear.
Can you be more specific about the noise? Is it a metal against metal sound? Is it a rattle or a smooth noise? Does it disappear between gear changes, when you pull in the clutch?
Check the easy stuff first. You don't need tools fo these checks. If it has a centre stand raise it onto that. Get a helper to gently put some weight on the back of the bike to raise the front wheel off the ground. Spin the front wheel by hand and listen. You should only be able to hear a very quiet gritty noise from the front brake. Spin the front wheel a bit faster and check it's spinning straight and true.
Get your helper to move to the front of the bike to raise the rear wheel off the ground. Put the bike in neutral, spin the rear wheel and listen. There should be two different, quiet noises. A gritty one like the front wheel and a quiet rattle as the chain moves through the rear wheel sprocket and transmission sprocket. Put the bike in gear and pull in the clutch so the wheel will turn. Spin the wheel again and listen to see if the noises change. Lastly spin the wheel faster and check it's lined up and spinning straight and true.
Use the comment button below and i'll see if I can help you more.

not a job for an amateur as it has to be spot on or control will be lost at speed
find a bike repair shop with facilities to straighten wheels or buy a new wheel

Not enough info here. Is it the rim or the hub that is wobbly? If the rim is out of true (and not actually bent) the spokes can be tightened to bring it back into true. If the hub is loose then the bearings need to be adjusted. Either adjustment can be done by your local bike shop for $10-20. A broken spoke can also make the wheel go out of true, this will cost a little more to fix.

There are a number things that could cause your problem.

First place start is with the rim. Is the rim (wheel) true (straight), if it is bent it could have the tire or brake rubbing. If that is the problem you need to true or straighten or have the rim straightened.

2nd place to go is are the brakes too tight? If so adjust brakes.

3rd place to go could be a seriouse problem. Is the axle frozen. To test you will have to take the wheel off the bike. With the wheel loose from the bike see if the axle will turn if not try to loosen the bearing lock nut just a very little (like 1/8 of a turn) did it free up the axle or does the axle bind a little but still turn smoothly? If so Loosen the lock nut a little more. Just enough that the wheel will allow the axle to spin freely but not so loose as to allow the wheel to wobble sideways at all. If the axle turns and grinds and clunks your bearings likely need to be replaced and or greased. Do not just squirt oil into the bearings it is too light and will not last.

I hope this helped, good luck!

there should be an allen key screw at the top of your stem. sometimes there is a plastic cap on top of the screw head, if so you should be able to pry it off to get to the screw. get the right sized allen key, loosen it, true the stem to your wheel and tighten it back up

To change just the rim is a pretty big job, since you would have to remove every spoke and assemble a new wheel. But maybe you are asking how to straighten the wheel? If the bend is a bit of a wobble, and not a sharp kink, then you can usually true-up the wheel by adjusting the spokes. If this happened kind of suddenly, then you probably have a broken spoke. Pull on every spoke one at a time to see if that is the case. If none are broken, then you only need a spoke key. There are several styles, all pretty cheap, but they aren't all the same size. Look on YouTube for a how video on trueing bike wheels.
If you do have a broken spoke, and it is on the left side, then it's not too hard to replace. Just get the right size spoke and spoke key and you can do it without even removing the wheel. If you have a broken spoke on the right side you will almost certainly have to remove the wheel from the bike. There are several types with corresponding different tools and can be a bit tricky. Look for info on Parktool.com

I ride a Trek 6.9 and have had spokes break for no apparent reason. Most of the time the spoke will break from over tightening on initial installation or just plain fatigue. Replacing the spoke is fairly straight forward. Remove the wheel from the bike and remove the tire. Remove the protective tape on the inside of the wheel to gain access to the spoke nut. After replacing the spoke you must make sure the wheel is true. If you do not have a set up for this, reassemble the wheel with the new spoke and take the assembly to your nearest bike store. They should have the equipment to true up your wheel assembly

The set screws in the center of the axle are there to keep the axle centered in the frame. Only the right wheel is powered which also means only the right wheel brakes when operating the rear brake. This is because the rear wheels must be able to spin independently when turning because the outside wheel will move faster. Unfortunately no one builds differentials at this price.

If you have wheel wobble you need to determine if the axle is bent or the wheel is not true. Prop up the rear of the bike on a stand and remove the problematic wheel. Manually pedal the bike and check the axle as it spins. If the axle is wobbling then it is bent and will need to be replaced. If it spins true then the wheel is the culprit.

The axle is relatively inexpensive and can be ordered through a Schwinn dealer. Any bike shop should be able to true a wheel for around $15-$20.

More than likely the wheel is out of true. There are 2 choices,

1 Buy a spoke wrench and attemp to true the wheel. You can do this by spinning the wheel to locate the spot where the wheel goes furthest to one side then tighten the spoke coming from the opposite side. Do this slowly 1/2 turn at a time. Do not over tighten the spoke. It may be necessary to loosen the other side slightly.

Alternate spokes between both sides of wobble.

2 Take bike to a good local bike shop to be tuned and have the wheels trued. Most shops offer a tune up at low cost. A well tuned bike will last a long time.

http://www.sansaworld.com/
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did they not have spacers when you took them offf the bike?