While running on the treadmill there is loud noise

To be honest with you, these could be symptoms of a few different problems. Here are the most common ones and what it possibly sounds like:
1) It could be that the front roller has dislodged itself from the roller pulley. In other words, the motor keeps turning, and when you step on the walk belt, the pulley (the one with the small rubber belt) keeps turning, but the roller stops. This can cause grinding noises, and the pulley to "skid" the black belt, which can account for the black dust. You can usually tell this is the problem when it runs fine with nobody on it, but when you step on it, it grinds
2) It could also be that the walk belt is rubbing on the sides of the deck and/or side rails. This happens when the belt shifts over from the center. It would definitely sound like a grinding noise, and the black dust could be from the walk belt particles wearing down due to the rubbing.
3) It could also be the drive motor brushes. Let me explain. The motor has two small blocks on either side of it (inside the metal casing). Those two blocks actually carry electricity into the spinning part of the motor (called an armature). They actually make contact with the armature at all times while it spins. Those "small blocks" are made of a graphite (what pencil lead is made of). Well, with so much spinning, and so much contact from the armature, those things grind down with time. They sometimes grind down until they are stubs only. Then they start grinding. The powder in this case would be the brush graphite piling up (this would often be shiny dust, and is a dark grayish).
4) The grinding could also be roller bearings going bad.
**For #3, and 4 above, you have but to remove the small belt that attaches to the motor (rubber, black, and small attached to pulleys), and let the treadmill run for a few seconds by itself. You may get a "speed error code' after the treadmill does not detect speed, but at least you'll know if the grinding is coming from the motor. If it runs super quiet, even for a few seconds, then you know it may be #1, 2, or 4 above.
These are the most common issues based on your symptoms.

The grinding noise could be asking for lube. If that is possible, do it.

1)you must LUBE the DECK BELT, inmediately, for to avoid the friction
2)LUBE the rollers bearing.too
3) See the main motor for bearing and repair the motor for bearint too.
4) If the problem persist you have worn deck belt, and replace.
God bless you

Dear Sir:

I will help you inmediately.

The troubleshooting is Mechanical here is the details:

Treadmill Noise:

1)Front or rear Roller(PULLEY) ASSEMBLY BEARING: Solution: Isolate and replace roller assenbly

2)Drive Belt loosing ......................................................Solution: Adjust tension belt

3)Idler PULLEY.........................................................Solution: Replace Idler Pulley

4)Belt Seam Need breaking in...................................Solution:New Belt Replace

Thank you in advance,If you need some extra help reach me, sincerely. blessing.

E.CUADRA
Managua, Nicaragua. C.A.

hi,
Try to lubricate the running belt. If the lubrication is not proper then the belt will make noise. You have to use silicon lubrican for the same . Watch the following video to know how to lubricat the treadmill.
OK

no motor should be loud. no grinding noise at all. you my Friend ,have a defected motor

ALWAYS UNPLUG & Remove the hood or motor cover. There's probably anywhere from 2 to 8 screws. *Now vacuum the dust from around the motor and drive mechanisms. What you can't get to with the vacumn, use a small cloth or brush. A clean motor doesn't become clogged and overheat. *After you have cleaned around the motor, look for any grease fittings, these are usually found on commercial grade units, but your's might have some also. For those of you who have never seen one, they are about the size of a pencil eraser and have a hole in the end. they are usually found on bearings. If you don't have a grease gun you can buy a small gun and grease at your local auto parts store for less than $10.00.If your unit is chain driven, clean the chain of excess dust, and apply a small amount of grease to the chain, also grease the drive chain and elevation chain as necessary. Use white lithium grease if available.Check all drive belts for wear, look for cuts and nicks, and replace as needed.

*Raise the belt and inspect the underside for wear. If it looks worn or burned you need to replace the belt.

*Wipe the deck and underside of the belt with a soft cloth, should lubricate the walking deck at least every 6 months with ilicone spray or gel or wax. Check your owners manual for what the manufacturer recommends.

Repair of Your Treadmill

Walking belt moves, but there is a loud grinding noise.

Loosen the belt and see if the noise goes away, if it does you may have a bad front roller. Sometimes you can spray the bearing in the roller with a lubricant like WD40 and this will solve the problem, but you may need to replace the roller.If the noise does not go away then the motor bearings are probably bad and you will have to replace the motor.

You can visit his treadmill website at:http://treadmills.cc/

Thanks for the rating

Good luck

Could be a number of reasons - where is the black dust coming from? remove the motor hood and check for misalignment of the drive belt from motor to the front roller.

Your belt is worn and stretched and so it is slipping on the motor drive shaft. That is why it is noisy and smells like burning rubber. You simply need to replace the belt. You can get replacement belts here:

Replacement Vacuum Belts

This definitely sounds like the drive motor. One way to check is to remove the drive belt and run the motor without the walk belt connected. Obviously if you still have the noise it will be a motor issue. If not then it will be one of the 2 rollers. Good Luck! Tim