How to Stop Treadmill Belt from Slipping and Changing Speeds

Fix treadmill belt from changing speeds and slipping on a Proform 995 SEL treadmill.
by Updated June 11, 2021

So recently I started experiencing the belt on my (out of warranty 5 year +) Proform 995 SEL treadmill start to slip constantly.  At slow speeds of around 3 or 4 miles per hour it was really bad, but at around 6 mph it was managable to run on, while still having a noticable slip to it.

To remedy the situation, I had tried tightening the walking belt using an allen wrench provided with the treadmill, but that didn't seem to make much of a difference. After reading that my treadmills walking belt should be able to lift up 3 or 4 inches in the middle, I decided to loosen the belt back to where it had been.

I was back to the drawing board, so I tried using some treadmill lubricant to coat underneath the walking belt, thinking that the belt might be sticking to the surface of the treadmill.  While this did seem to make a tiny bit of a difference, it didn't fix the problem. So again I was stuck with a treadmill that continued to slip and was unsafe to run on.  (I read later, that for my treadmill, you don't actually need to use a lubricant underneath the walking belt.)

Finally, I decided I would take the treadmill motor cover off and tighten the motor drive belt.  After opening the cover up I noticed little black shards of plastic near the motor belt.  While the motor belt didn't seem to be that loose, I decided to retighten the motor drive belt as best as I could. 

After loosening the two bolts holding the motor in place and then pushing down and back on the motor itself, and retightening the motor down, the drive belt did seem to be a little bit tighter.  Well to make a long story short, after plugging in the treadmill and turning it on, and then eventually walking on it, the treadmill was back to working like new!  I've since been running and walking on the treadmill many times and I must say I'm pretty psyched that I didn't have to scrap the treadmill.  This simple fix saved me from having to buy a brand new treadmill, or some expensive parts to fix it.

Here are the steps to tighten up a treadmill motor drive belt in order to fix a treadmill that is constantly slipping when walking or running on it.

  1. Turn off and unplug your treadmill from the wall.
  2. Take the motor cover off by unscrewing any screws hold ing down (or unlashing).  In my case, I had to flip the treadmill on its side to be able to unscrew the cover.
  3. Once the cover is off, look for any shards of black rubber plastic which will indicate that the motor drive belt is slipping or worn down.  If the motor drive belt is completely worn out you may need to get a new belt. (Note: a good place to find replacement parts and belts for your treadmill is at the Treadmill Doctor.)
  4. Unloosen the bolts holding down the motor itself.  Either by your self or with the help of someone else, push the loosened motor down and back to tighten the motor drive belt.
  5. Now tighten the motor down, making sure that the motor drive belt is tight.
  6. Test out the newly tightened motor drive belt.  Plug in the treadmill and start the treadmill up slowly (without anyone on the treadmill itself) at 1 MPH, or 2 MPH and slowly increase the speed until about 6 MPH.  If everything appears to be working correctly, stop the treadmill and start it up again at around 3 MPH, this time you can begin walking on it. Continue testing at higher speeds to make sure the treadmill is working correctly.
  7. That's it, hopefully after tightening the motor drive belt your treadmill will no longer be slipping!





anonymous by Tommy on 12/4/2010
Thank You! It worked!!!
Doug by Doug on 12/4/2010
Tommy, glad this fix worked for you...

My treadmill is still going strong and working fine (about 9 months later) since I fixed it by tightening the motor belt.
anonymous by Steve on 12/8/2010
Thanks for the procedure. My 995 SEL is back in action. My wife is happy, which means that I am happy:)
Happy Holidays!!
Doug by Doug on 12/8/2010
Awesome Steve, that's great to hear... Happy Holidays to you as well!
anonymous by Jerry on 12/26/2010
My treadmill slips, I can walk, but once I get it to about 5 mph and do a running motion the motor shuts off.

Is this the same or different from what you were experiencing?

Hey Jerry,

That kinda sounds more like an actual motor problem, than a loose "motor" belt problem. But I'm sure it wouldn't hurt to try and tighten up the motor belt just in case it's loose, and hopefully that might help fix the problem. Good luck!
anonymous by sofia on 1/11/2011
thank you thank you thank you!!!! been searching for the solution for what seems like ages! I'll try it as soon as I can and let you know how i did! :)
anonymous by Travis on 3/12/2011
I just did this on my Proform 995 SEL and it worked great! Mine was slipping even worse, it was unusable at almost any speed.

You don't actually have to tip the treadmill on its side, which could be quite a pain if you have it in a small room like I do. You can remove the screws by rotating the walking surface to the storage position and using a small screwdriver or a ratchet with a Phillips head. The screws are accessible, you just need something short enough that it doesn't hit the floor.
anonymous by BK on 5/30/2011
Thanks! We actually had to raise up the treadmill and stand down on the motor to get it tight enough, but after that, it worked great.
Doug by Doug on 5/30/2011
Hey BK, that's an interesting way to do it... I can see how you might need to stand on it, just to get enough force for it to move it a little bit and stay there while you tighten it. When I tightened the motor belt on my Proform treadmill, it seemed like I barely moved the motor back at all, but sure enough it ended up being tighter.

Just an update... on the article above, it's been over a year since I tightened the motor belt on my Proform 995 SEL treadmill and it's still working great. I haven't yet had to go in and retighten the belt, so I've been pretty happy with result of not having to spend money on repairs or a new treadmill.
Doug by Doug on 5/30/2011
@Travis thanks for the tip on removing the screws by just rotating the walking surface. I didn't think of doing that at the time.... It was definitely a bit of a pain tipping the treadmill over on it's side.
anonymous by GLEN on 7/1/2011
anonymous by Jeff on 7/12/2011
You are my hero! By tightening the end roller, as the manual suggested, I did not get rid of the herky-jerky motion that could have killed me. Your tip, however, makes the treadmill run like new. I am now wondering if the setbacks I have had were due to the deterioration of the treadmill and me not realizing how bad it was.
Thank you!

And, to travis - you not only need a screwdriver/ratchet that is short enough, but for the screws closest to the tread, the tool has to be long enough to even *reach* the screws!
anonymous by Gina on 12/15/2011
Oh man, I wish I saw this article before yesterday and before I had a repairman come to the house. He didn't realize he was getting a flat rate, so he milked the repair time by taking out the computer board and unscrewing every single screw in there. He replaced the belt, but I bet he just needed to tighten it like you did. He came back with a $230+ bill, and he was a little distressed to learn his company was subcontracted out for a flat rate of $109--He could have done it in 1/2 hour, rather than 2 1/2! Thanks for sharing!
So sorry to hear that Gina... I'm sure you're not the only one who's paid a lot of money to have their treadmill fixed (or just ended up buying a new one), when it really only needed to have the motor belt tightened. I have a feeling this happens quite a bit, because I know I was thinking the same thing when I started having the slippage problem on mine. At any rate, hopefully your treadmill is working much better, now that its been fixed.
anonymous by Brendan on 1/2/2012
Yep, it worked. I was no longer able to run on mine at all and now works fine without slipping. However, It does seem like it is running slower than the projected speed. Did anyone else have this problem?
anonymous by Jose on 1/14/2012
i have the same brand, model 665, and your advice sure as heck worked.. thanks for taking the time and posting your findings..
Doug by Doug on 1/14/2012
@Brendan It's possible that you may have tightened the motor belt a little too tight, which is causing for the slower treadmill speed (just a thought).

@Jose Great to hear that it worked for you!
anonymous by lukuanv on 2/20/2012
This is great! I had a similar problem. I used this opportunity to show my son how he can fix equipment in the house. After we open up the cover, we had a few problems:

1) One of the two screws holding the motor to the frame broke. The remaining thread section stayed in the screw hole. It is probably not a surprise since the low quality screw is not really capable of taking the cyclic loads. We decided to buy three hose clamps to hold the motor to the frame (replacing the broken screw).
2) That solves the problem However, we got another problem of belt shifting to the right side. I will have to do some more search to see how to fix that.

Thanks for sharing the experience.
anonymous by jdh on 4/15/2012
Thank you! I just followed your suggestion and it worked perfectly. I was racking my brain to come up with a solution as every day I was experiencing more and more slippage. My wife found your post and the rest is history. Thanks again. Joel
anonymous by Steph on 7/7/2012
Thanx Doug!!
I used your solution on a different proform model and it worked perfectly! It took only 5 minutes or so.... and oh yeah- it was free! Can't thank you enough for taking the time to post your findings! :)
Doug by Doug on 7/7/2012
That's great to hear Steph!

Just an update to my post... my treadmill is still working great ever since I made the motor belt tighter 2+ years ago! And so far, I haven't had to retighten anything... ;)
anonymous by Clayton on 10/27/2012
Thanks. Worked great.
anonymous by Noah on 11/7/2012
On mine, there were two bolts on top and one long bolt across the bottom that was hard to reach. I unscrewed the top two and pried against the bottom with a pry bar. It pushed the motor up and I was able to tighten it up. Thanks for the help!
anonymous by Lisa on 12/3/2012
Thank you so much for posting! This worked for my old ProForm model and saved me from spending big bucks on a replacement :-)
anonymous by Nate on 1/21/2013
Many thanks. This was exactly my problem
anonymous by Joe on 4/7/2013
Thanks an awful lot, Doug! Three years after posting this article, it's still helping many of us. Just replaced the rear roller on my wife's Proform 8.5 and did the standard adjustments to the rear bolts per instructions but to no joy. After much Googling, came across this article - did as you said and voila - perfection! You ARE the MAN! :)
Doug by Doug on 4/7/2013
Awesome Joe! Great to hear you were finally able to get your treadmill working correctly again!
anonymous by Isis on 5/9/2013
Super helpful!!! Thank you for saving me a ton of money. I was this close to buying a new treadmill or a bunch of expensive parts. Thanks again for the very thorough instructions!
anonymous by Eric on 5/16/2013
Doug, I thank you so much!! you saved me a lot of money and gave me a sense of pride after fixing my treadmill. You are a superhero...Super Dougo!
anonymous by Damon on 11/19/2013
Worked for me too! Thanks!
anonymous by Anali on 12/2/2013
Thank you so much for this information. I was about to order a brand new belt and waste $80 for nothing. Thanks again!
anonymous by Christy Lou on 12/4/2013
I am so excited I found your information!! Thank you for sharing and saving me $100.00. Happy Holidays!!
anonymous by Kevin H on 1/18/2014
Thanks so much for this tip! I'm usually mechanically inclined, but this had me stumped. I tried to tighten the rear tensioner as much as possible, but it barely fixed it. After I realized I had shavings all over my treadmill it occurred to me the drive belt was probably the issue. I had my wife push down quite hard while I tightened the bolts and it works like a charm now. I could bring the rear tensioners almost all the way back in and it still didn't slip. Thanks for saving me a ton of cash!
anonymous by Caleb on 11/24/2014

Works!!! Thanks!

anonymous by Steve on 10/19/2015

It worked for me also, thanks so much.

anonymous by dean on 2/19/2016

at last! its sorted. thank you!!

anonymous by Ben M. Midland Park, NJ on 4/1/2016

Thanks Doug,
You are awesome and a life saver. it worked perfectly and easy to do.
Ben M.

Doug by Doug on 4/1/2016

Great to hear Ben M.

My Proform treadmill is still going strong...

It actually out lasted a Nordic Track X9i Incline Trainer which I got to do incline training, but a weld broke on it that held up the track base 1 1/2 years after I purchased it. Luckily, I never sold my Proform treadmill (just stuck it in a corner), and the X9i was still covered under a 2 year warranty when it broke, so I was able to get a full refund after sending the incline trainer back to Nordic Track.

anonymous by Jan on 3/21/2020

I have a proform 355 I'm going to try that.

anonymous by logdog on 4/30/2020

My wife has a Weslo treadmill that was jerking so bad that she hurt herself. I tried spraying and adjusting the belt but no fix. We were just about ready to give up on this 5 year old treadmill when I ran across your fix. I loosened the motor, moved it up and down a few times and re tightened it. It didn't seem like it did anything to change the tension on the motor belt but my wife says the treadmill now runs like new. It's quieter and no more jerking. Thank you so much for posting.You saved me a bundle.

anonymous by HT on 7/29/2021

OMG, this tip worked 10 years after it was posted

The tread on my 17 year old proform 995 SEL was slipping quite a bit. I was 30 seconds from buying a new treadmill and randomly found this tread and bang, 10 minutes later it's like new again. Thank you.

Doug by Doug on 7/29/2021
Hey HT, great to hear it! Glad I could save you some money!

It's actually been 11 years now since I first published this post, and I still have and use my 995 SEL treadmill. And I've never had to re-adjust the belt, since fixing it.

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