Last Updated on November 4, 2021 by Jeff
Whether you have a Weslo treadmill, Hiit sprints treadmill, Weslo crosswalk 5.2t treadmill, or something else, you may have felt the treadmill belt sliding to the side while you were running. This issue can be hazardous, as you might fall on that moving surface, rubbing salt into the wound. This article will go over the potential reasons and fixes for slipping belts.
6 Reasons Treadmill Belt Slip
1. Lack of Maintenance 
Friction between the belt, rollers, and deck will have the belt wearing out fast if you don’t maintain it. In other words, the belt could’ve done with some lubrication to lessen the friction. Your user manual tells you how often to lubricate your treadmill belt and which type of lubricant to use.
Pro Tip: Silicon-based lubricants are commonly used because they don’t evaporate. However, oil-based ones aren’t a good idea because they make rubber components degrade.
The Fix
Lubrication may help you avoid the treadmill slipping in the future. To reverse the damage that’s been already done, follow these steps:
- Put a hex wrench on the tension bolt to the left and turn it quarter a turn in a clockwise direction, thus drawing the rear roller and tightening the belt.
- Do the same for the tension bolt to the right. Be careful to turn the two bolts an equal number of turns to keep the rear roller square relative to the frame.
- Try walking on the treadmill to determine if slipping is no longer an issue. If it still slips, repeat the process until you get there.
Tip: Don’t over-tighten your treadmill belt because that’ll put too much pressure on the front and rear roller bearings as well as the running belt seam, damaging the treadmill belt and roller bearings.
2. Loose Treadmill Belt 
Slipping is bound to happen if the treadmill belt is too loose, as it’ll slide to the side. There’s a simple way of evaluating your treadmill belt’s tightness. Turn off the treadmill, place your hand beneath the belt, and lift it. If there’s a gap of more than 2-3 inches, the belt is too loose.
The FIx
You may refer back to the instructions we’ve detailed previously on tightening your treadmill belt. Follow them until it only lifts around 2 inches.
Tip: Don’t forget to align the belt to the center before adjusting its tightness.
3. Worn Out Treadmill Belt 
A potential cause for the treadmill to slip is that it’s wearing out. This is pretty common, especially with excessive use of the machine or using second-hand ones. For that reason, high-quality treadmills are a smart investment, such as the ones in these treadmill reviews.
The Fix
You can try lubricating the slipping belt. But, if that doesn’t help, you’ll need to replace the belt, as tightening will be ineffective and even damaging in this case, as we’ve illustrated.
4. Loose Drive Belt 
Not to be confused with the treadmill belt, the drive belt lies between the first roller under the deck and the motor, channeling the motor’s power to the deck. A loose drive belt can result in slipping.
Scenario 1
If the drive belt slips and stops turning even though the motor is still running, it’d be wise to take a look at the front roller.
The Fix
In this scenario, you can fix your slipping problem by either lubricating the front roller or realigning it.
Scenario 2
The roller and the pulley driving the drive belt might stop working too, which signals a problem with the drive belt.
The Fix
You may use a belt dressing (a similar solution to lubricants) on the drive belt. But it’s better to replace it altogether.
5. Loose Pulley 
Your treadmill could be slipping because the pulley gave away from the press-fit on the roller’s metal tube. Accordingly, the front or driving roller can cause the belt not to run if it’s unaligned.
On stepping on the walking belt, if the pulley is still turning but the roller has stopped, that means that the pulley is loose.
To test the pulley, stick a colored paper strip between the roller and the pulley during your HIIT treadmill workout, ensuring that it’s straight. After you turn on the treadmill and it slips, turn it off. Note whether the tape has been separated, for that means the pulley and the roller aren’t aligned.
The Fix
You should either secure the pulley by drilling a pilot hole and using a sheet metal screw to fasten it or buy a new roller. It could be difficult for you to figure out the right solution for your circumstances, so you may want to hire a professional.
6. The Tension Bolt Pulling Through a Plastic End Cap
This tends to happen in cheap treadmills. If the belt is tensioned using plastic parts, the bolt responsible for adjusting the tension might pull through the plastic if the latter is worn out. Thus, you become unable to tighten the belt sufficiently.
The Fix
You can merely replace the end caps. A more permanent solution would be to use a fixing kit to cover the original plastic with a metal kit.
Final Thoughts
With treadmills, slipping is quite common and can happen due to various problems. Check to see if the motor, pulley, front roller, and other parts are working, and use our hints to help you identify the problem. Then, you’ll find that the issue has a quick fix or, otherwise, requires replacement parts, and you’ll get your treadmill working in no time!