Mysterious noise in the back, a tale of mystery and imagination.....

Quote from BigDan12

Don't forget to take a water spray bottle with you when you're going to bring it home.

I am changing the belt myself.

Quote from FunCycle

Owners of Slingshot have learned that ALL DEALERS ARE NOT GOOD. Also it took quite a while for Polaris to admit that there was a problem. My dealer to start with would not even listen to what I had to say, now he asks my opinion on problems and how to fix them. As to the bearing problems, if we had not done the videos Polaris may have not admitted to the fact that there was even a problem. This is all I have to say on your problem, drive it until it quits and do not worry about it. Better yet sell it.

You made it clear that bearing issue was a problem 4 years ago with 2015 models. Since then there has been swing arm recalls and a hell of a lot more slingshots on the road. If bearings are still an issue then Polaris would act on it.

It is stupid for them to give me a replacement belt after reviewing several videos and hearing my detailed report on the issue if there is any chance it's bearing or axle related.

I will document the new belt install and then video any and all noises afterwards. IF that noise comes back ( and I know how to make it come back) then clearly Polaris just lost some money on a belt and I will be heading to the dealership to deal with a full up bearing and axle inspection/replacement.

I know all about dealer reputations. There is a dealership only 15 miles away from my house but I choose to go friggin 90 miles away because that's how much I don't trust them (scumbags).

And yup, at the end of next year, I expect to have at least 20k miles on it and it will be paid off so I will be selling it. I will be trading it in for an electric vanderhall (0-60 in 4 secs) no gas, no oil and no effing belt drive!!! I will be done with the slingshot!

Quote from Bigdog

We’ve all been caught in the rain and I’m very sure if that was causing the belt to make that funny noise we would all be very familiar with that sound.....we’re not ....so it’s something else.

You suspect it could be a defective belt?

If it’s not a defective belt....I’m sticking with something bent, misaligned or loose. NOT water.

if it's not a defective belt then it's something with the pulleys or axle. Just so you understand the situation....I drove the vehicle two days straight (40 miles) in dry conditions with no sound or issues, I then drive 5 miles on wet roadways and the sound comes back nice and loud, the next day I drive 30 miles in dry conditions and as expected the sound eventually fades away then disappears after enough time in the dry climate. This is an issue exacerbated by moisture pure and simple.

If you have ever walked on wet sneakers you know full well how loud wet rubber under pressure can sound. This is exactly the phenomenon I am seeing. The reason why it's not common is because there is something wrong with the belt or possibly some other rubber material associated with the pulley system.

Also while I had my sling lifted I rotated the rear tire and watched closely both pulleys and wheel/axle for any deformations during movement. I saw nothing wrong with them but did see the belt move off to center then back to left during rotation.

Quote from Bigdog

With 20,000 SS on the road 19,000 of us should have heard that noise on a regular Basis. We’ve all been wet. More than once. I’ve never heard that noise in 17,000 miles. I’ve been in heavy downpours. Many have way more miles.......anyone else heard that noise before?

Maybe it’s taking that long for lubrication to reach the squeaky part...or to expand from heat.

I don’t think it takes a long time for that belt to dry out with rotational friction and the angle drive heating up.

Are there any nicks, missing teeth, splits or cracks or frays on the belt?

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Again I repeat once more MY belt is warped, let me repeat my belt is warped. I visually confirmed this and I say again my belt is warped. This is why my belt is making the noise and yours and others are not. No one in my local group is hearing this noise because their belts are not warped.

because my belt is warped, Polaris has decided to send a replacement belt, I repeat because my belt is warped, polaris is sending me a replacement belt because my belt is warped.

This is why after 17000 miles you have not seen this issue because your belt is not warped.

I have looked at my belt during cleaning and as far as I can see there are no signs of any damage.

Here is another slingshot with a very similar sound.

Quote from BryanL

I hope a new belt fixes your problem, but watching both videos I can see the noise is happening in the same spot with each revolution of the wheel. That would put it at different locations on the belt canceling out the warped belt theory. The second video shows that better. Watch the lettering on the belt and the paint mark on the axle nut.

If you realigned your belt and it quit the noise, why not just run with it? As long as it's not rubbing on one side or the other, it doesn't matter if it's a little left or right.

Good observation, the problem with the right-sided alignment was that the belt was all the way up to the edge of the right side of the front pulley to the point where I had my fingers in there and I could feel the belt actually over the edge of the pulley. As you can imagine that is very risky because with the belt being warped it's possible it could run off the pulley at speed.

I still think it's belt related even thought the noise "hotspot" may not be precisely in one spot of the belt. If it was axle or bearings I would be hearing the popping sound or large creaking sound. Instead that noise that is on the video sounds like moist hard rubber rubbing. Besides, faulty bearings would get louder in drier conditions as the bearings heat up.

In this case it's the opposite, the obvious and obnoxious noise has been missing for these past two days of driving in dry conditions.

All I can hear is a faint cyclic sound from the belt. I drove over 80 miles today at high and low speeds and the sound did not return but as soon as I get that back area wet via wet roads or spraying it down with a hose that noise will return almost instantly. Bearings are not going to do that. Dirt on the belt does the opposite, as soon as the belt is wet the steady noise I have due to dirt build-up (as heard in the video below) goes away only to return once the belt is dry.

Below is a video showcasing the belt, keep in mind the noise is not as loud because the belt is not wet enough because I hadn't washed it yet where video that you see in my original post showcases the noise level after cleaning the belt. It's hard to see but the belt is moving to the center slightly during rotation which is my hint to warping along with the noise.

The clear case for warpring, is during occasional spot checks during driving after parking I will see the belt physically located dead-center of the pulley track then minutes later at another stop the belt will be positioned normally to the left of the pulley track as in the video below.

Quote from Bigdog

The first thing I want you to do when the new belt is installed is....wet the living shit out of it with a bucket of water and then see if it makes the same noise...

But when the installation is being performed everything that needs to be loosened and moved to install the belt will be the same things needed to adjust and realign the swing arm and pulleys and belt tension......so will you really know what the issue was? If any of those things are out of alignment now. Are they also inspecting the bearings and axle.

They might accidentally fix the issue without ever knowing what it was because hopefully they get everything into alignment when they are done.

Sounds like a catch 22....well we fixed the problem but we don’t know what it was.

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I hear you, I will be installing the belt myself. The dealership rep told me if I can do the alignment and tensions procedures then I should have no problems changing the belt.

To address your main point, because I have been dealing with this obnoxious noise for a while now, I have had the wonderful opportunity to go through the 25 step process for belt tension/alignment adjustment several times to the tune of many many hours in the garage. I am so good at it, I could probably do it blindfold and I have all the torque numbers damn near memorized for the 5 bolts in question. Keep in mind, this process is elaborate and must be completed in order. There is a step in the middle that actually has you torquing the main swing-arm bolt to 195 ft-lbs then immediately loosing completely. Yeah that's how elaborate it gets.

And you only get to set the belt tension once at the start (after loosening all bolts) and it's not a measured number, it's just you taking your hand and pressing down on the belt to lightly touch the swingarm surface with light tension. It has to just be touching the surface of the swingarm then you lock down the tension then after that you proceed with 15 more steps (including rolling the wheel 4 revolutions) then jack it down (then up and down) to make sure the belt is firmly in place with the pulleys then you roll the sling back and fourth a few times under load then and only then will you measure the tension with an instrument and if it's not exactly .4 inches of deflection guess what, you get to go all the way back to step 1 and do it all over again. Remember that's after torquing all the bolts down include the 195 ft-lbs bolt.

I have experimented with a looser tension setting of .65 inches which only quiets but not eliminate the noise in question and I have gone tighter to .3 inches to where I hear the bearings begin to overstress (popping/creaking) when moving the sling under load.

Quote from FunCycle

According to him he already knows what is wrong but does not know what it is!

Why don't you look at my garage video there ace, then make that remark.

And good luck explaining how the bad axle or bad bearings decide to squeak every other rotation or so.

Quote from Bigdog

The video camera was very wiggly....can you mount it stationary and show the wheel and the pulley as you rotate them to see if there is a wobble....maybe a slightly bent pulley.

Have you jacked up the rear and put power to the wheel to make sure everything is tracking true? And without power physically shook the wheel from side to side (3-9 position and top to bottom 12-6) to check for play in the wheel or swing arm. Shake the wheel front to back.

Listening very closely can you actually pin point the noise location? Do you have a stethoscope?

I am too spent to do all those things right now. I did test the swing arm integrity and I did try my best to pinpoint the soundsource and it felt like it was around the rear pulley area and not the front. With my own eyes there was no sign of warping of the pulleys or wheel. Dealership saw no issues either.

Since I have the new belt incoming I will go ahead and install it. Best case, issue resolved, worst case, I get to clean out the pulley teeth and hopefully get rid of that beading sound but still have an issue with the cyclic sound (pulley issue) which I will have to deal with the dealership on that one. Thankfully that would be guaranteed to still be under warranty (expires after two years or 8k miles).

Quote from Bigdog

In The video of the other SS, the belt is not wet.....the road looks dry to me...

Look at my original video, road was dry too just washed the belt with water a few minutes before filming.

Odds are pretty good too that guy was troubleshooting his noise he probably cleaned the belt to rule out dirt build up as the cause of the noise.

Quote from BryanL

I hope a new belt fixes your problem, but watching both videos I can see the noise is happening in the same spot with each revolution of the wheel. That would put it at different locations on the belt canceling out the warped belt theory. The second video shows that better. Watch the lettering on the belt and the paint mark on the axle nut.

Even though I have a warped belt, looking at those two videos more carefully contrasting with my garage video, there are multiple things going on, clearly the belt is making a noise at a specific location of the belt but the other videos do show a consistent sound pattern within one wheel rotation.

Looks like I have two things going on here but clearly the noise generated within one wheel rotation is the main culprit not the noise from one belt rotation.

So tomorrow I am going to start with just getting a little isolated water on the belt to see if that starts up the noise after that test I am going to get the belt cleaned and the back-end soaked. Once I have the noise nice and loud, I am then going to revisit belt rotation while lifted both loaded and unloaded and see what I get.

Some assumptions:

-I still think if it was a bearing issue I would be hearing it loud and clear in dry conditions and not just wet.

-A rubber material with heavy friction would act up more in wet conditions than dry (wet sneaker).

One theory:

as the warped belt teeth is sliding across the teeth of the pulley (left to center than back to left) it could generate that noise especially when wet and silicone lubed.

Looking at the videos in question one full belt rotation is about two full wheel rotations. This is not exact when you watch the videos but roughly 1.5 to 2 wheel rotations per belt rotation. It's possible the belt is moving laterally to and fro per wheel rotation. Notice when rotation slows the noise stretches out like it would if the belt was making it.

As suggested I will see if I can get steady cam footage of the drive system on jacks spinning in first gear, this should allow me to rule out warped pulley axles which could be rubbing against something.

Finally here is a video that I made when I had inadvertently set the belt tension too tight (.2 inches). Notice you can hear three distinct noises.

1:the constant beading noise from dirt buildup in the pulley teeth

2:the squeaky wet rubber noise (main issue)

3:overstressed pulley bearings as a result of a belt that is too tight. That obviously went away once I had the belt back to normal tension.

This should quell any theories about pulley bearings. Could it be axle bearings only making noise on command when wet??? Aren't axle bearings packed and sealed?

Note: You can also make out the slight lateral movement of the belt. It wouldn't take much lateral movement to make that noise given the forces in play.