Rubbing/grinding sound from KS18XL while weight is on one side

[svenomous]

Hi all, I've had my KS18XL, my first wheel, for about two weeks now.  About 50 total miles on it so far, and I'm still in learning mode.  From the first day I've noticed something odd, and I'd like to ask about it: when I ride, if the chassis gets pushed by the right leg, there is a loud grinding/rubbing sound.  So, as I put more weight on the right foot than on the left, forcing my right leg to push the chassis leftward to compensate, and forcing the wheel to tilt left to keep center of gravity so the wheel continues to travel in a straight line, the louder the sound becomes.  Here's a short video where you can hear that a slight rubbing sound is almost always present, but as soon as I start lifting my left foot off its pedal, transferring weight onto the right foot, the sound intensifies greatly.  I'm not complaining that I can't lift my left foot off for tricks or anything like that, but naturally while riding the CG forces change, and the rubbing is always there.  I hear it if I mount the wheel with right foot first, and during turns, and even when going straight and making very small CG adjustments.  It's annoying, and possibly something is grinding together that shouldn't be and is wearing down as a result.  So...any thoughts?

 

[Electric Dexterity]

I’ve had my KS18XL for two months with over 150 miles on it and I’ve never heard it sound like that. My 18XL is very quiet and smooth regardless of turning, mounting, etc.

I’m not an expert but I’d say something is definitely wrong with the wheel. Can you reach out to your dealer and see what they say about that video?

[Preston Palmer]

For sure something is goofy. Mine is silent. Even on 1 foot.

[TomOnWheels]

This noise is definitely not normal...

[meepmeepmayer]

That seems to be the shell flexing and physically rubbing against the motor. Happened on some flimsier built wheels. But that shouldn't happen on the 18XL. Can you have a look inside the wheel well, maybe you see anything?

If there's nothing obvious there, contact your seller.

Edited May 10, 2019 by meepmeepmayer

[NylahTay]

@svenomous I have the same thing!!! I just got mine in last week (Tuesday April 30), I think ours are part of the same batch. I just thought it was normal for a big wheel. I get it all the time when adjusting one of my feet during a ride. 

[NylahTay]

Mine is not as bad at in the video, but basically the same sound. However, it only happens when I have weight on one side. It mostly happens when I have my left foot on and adjusting my right foot. 

[meepmeepmayer]

Maybe the 18L's battery casing is structural, and since the 18XL is missing it, the shell flexes enough to rub when ridden one-footed?

How heavy are you guys?

I'm not aware of any other reports for this, but maybe it is a general issue? Or as you say an issue with one batch? (Not sure how exactly that would work, but @Jason McNeil will know.)

[NylahTay]

I'm just under 200lbs/90kgs. For me it feels like the top of the wheel is rubbing the edge of the casing, but I don't know what the inside looks like. I've learned to simply not ride with one foot. I use mine as my main mode of transportation and have already put over 500kms on it. Since I average 40-50kmh, I don't ride with one foot off very much  

[NylahTay]

@erk1024 are you having any issues with your wheel like this? I believe yours was also from the same batch.

Edited May 10, 2019 by NylahTay
Grammar fixes

[Jason McNeil]

10 hours ago, svenomous said:

So, as I put more weight on the right foot than on the left, forcing my right leg to push the chassis leftward to compensate, and forcing the wheel to tilt left to keep center of gravity so the wheel continues to travel in a straight line, the louder the sound becomes.

The clearance between the innershell & the tire is pretty tight. Factors that can influence this are 1) tire pressure, 2) rider weight, 3) position of the foot on the pedal, a stance further out will exert greater inward pressure & flex in the shell body.   

[meepmeepmayer]

You could try deflating the tire and reseating it (rotate it in the rim a little bit so there's no tension or torsion anywhere). Maybe it's a bit asymmetrical and it can be fixed this way?

[Marty Backe]

My XL sounds like that too whenever it's leaning over a bit when most of my weight is on one leg. This usually happens when stopping and starting. So I try and keep the wheel more vertical when starting/stopping to avoid this. I never have any rubbing while riding the wheel normally.

If you bought the wheel in the hopes of doing a lot of one-legged riding, I'm afraid you made a poor choice with the XL.

So yeah, I think the XL shell, with the extra batteries, is a bit on the flimsy side.

[travsformation]

I've never had any issues of this type with mine. Received it in January (European distributor). I'm about 78 kg with equipment.

To me it sounds like something is definitely wrong...

Edited May 10, 2019 by travsformation

[kasenutty]

Mine doesn't do this at all, and I'm 215 lbs. It sounds like something is wrong. I think deflating completely and reinflating just in case the tire is slight off on the rim might be worth a shot like Meep said. Mine is virtually silent, no creaks or rubbing at all. I do run pressure on the lower side compared to some of you, if that makes a difference in rubbing. It's far from flat though. I don't ride one legged, but this Svenomous isn't riding one legged in the video, he's just turning. 

[mrelwood]

Yep, the shell flexes to rub on the tire. My new tire for the MSX is a bit wider than original, so I get a bit of this too.

To confirm: Ride a bit on dirt/gravel road to get your tire dusty. Then lean to make the sound for a while, and stop to inspect the tire. The part that rubs against the shell should be clearly darker than the rest of the tire.

Since it rubs for the whole rotation of the tire, and only on one side, re-seating the tire will probably not help much. What should help is to re-seat the shell:

- Check the tire clearance on front and the rear, and make note if the clearance is narrower on front or back. That probably means that the rubbing spot is not at the center of the shell.

- Loosen the six screws that attach the shell to the pedal hangers/brackets on both sides, for a few full rotations.

- Pull and push the wheel from the handle to make sure there is some movement between the shell and the motor assembly.

- Lean, twist or push the wheel in a way that pulls the tire away from the shell at the spot where it rubs. For example, if the tire rubs when riding on your right leg, let the wheel lean  against the wall on it’s left side, and push the wheel against the wall at the axle. Or put your left leg on the pedal and push against the shell with your leg, as if you were riding one-legged.

- While you keep doing the above, tighten the 6 screws on both sides. It might be difficult to do them at the same time, so an extra pair of hands could be helpful.

If the issue remains, one/some/all of the 6 screw holes on the shell might be badly aligned. I did have to carve with a knife a bit on a few holes on my 16S to make the screws go in smoothly.

Edited May 10, 2019 by mrelwood

[erk1024]

1 hour ago, NylahTay said:

are you having any issues with your wheel like this? I believe yours was also from the same batch.

I haven't tried balancing on one foot yet. I'm heavier than both of you. I'll keep an ear out for it.

[svenomous]

Thanks all for info and advice. Especially @mrelwood for the detailed shell realignment attempt instructions. I’m 205lbs (that’s 93kg) btw. In the video I was riding straight and intentionally shifting the bulk of my weight onto the right foot, to the point the left foot was starting to come off it’s pedal. I have no desire to ride one-legged, this was just a way to exaggerate the problem so it could be heard clearly in the video. In normal writing, what I am hearing is a slight rhythmic rubbing sound all the time, except when I lean left (it goes away then).  When I lean right, on the other hand, or mount with the right foot first, or dismount onto the left foot, or in general shift weight to the right for any reason, the rubbing intensifies as you can hear in the video  

My conclusion from the replies is that the wheel is rubbing the inside of the shell, and that this is not an immediate safety concern.  It is also probably not a serious manufacturing defect requiring an actual repair or part replacement , so much as a misalignment aggravated by very tight clearance of this design. Hence, I’m going out for one last neighborhood training ride right now, despite the rubbing. This is because the weather is great, I have about two hours of sunlight left, and I want to get one last session in before tomorrow’s acid test on a populated trail.  This evening I will take the wheel into the house and perform the realignment attempt. I will report back!

Thanks again, all. 

[erk1024]

10 minutes ago, svenomous said:

This evening I will take the wheel into the house and perform the realignment attempt.

Good luck! Doesn't sound too involved. 

[Marty Backe]

22 minutes ago, svenomous said:

Thanks all for info and advice. Especially @mrelwood for the detailed shell realignment attempt instructions. I’m 205lbs (that’s 93kg) btw. In the video I was riding straight and intentionally shifting the bulk of my weight onto the right foot, to the point the left foot was starting to come off it’s pedal. I have no desire to ride one-legged, this was just a way to exaggerate the problem so it could be heard clearly in the video. In normal writing, what I am hearing is a slight rhythmic rubbing sound all the time, except when I lean left (it goes away then).  When I lean right, on the other hand, or mount with the right foot first, or dismount onto the left foot, or in general shift weight to the right for any reason, the rubbing intensifies as you can hear in the video  

My conclusion from the replies is that the wheel is rubbing the inside of the shell, and that this is not an immediate safety concern.  It is also probably not a serious manufacturing defect requiring an actual repair or part replacement , so much as a misalignment aggravated by very tight clearance of this design. Hence, I’m going out for one last neighborhood training ride right now, despite the rubbing. This is because the weather is great, I have about two hours of sunlight left, and I want to get one last session in before tomorrow’s acid test on a populated trail.  This evening I will take the wheel into the house and perform the realignment attempt. I will report back!

Thanks again, all. 

But during normal riding, the tire should never be bumping into the shell. If nothing else that's going to affect your gas mileage 

[svenomous]

Well, my attempt was a bust.  I started by taking a close look at the wheel/case, and indeed there is an asymmetry:

This is with the wheel tilted onto its back, looking at it from the front, with the camera lens as centered as I could make it.  Clearly there is less clearance on the right side of the wheel/case (the left side as seen in this image).

So, I proceeded with the right side first, removing the 17 (!!!) screws that hold the outer shell in place on that side, disconnecting the LED strips, and lifting off the shell.  Now I could see the battery pack, cables/connectors, and the pedal hanger screws I was aiming for:

For a moment I thought they weren't Phillips heads, but upon closer examination I concluded they were large Phillips with some stripping from poorly done tightening.  I got my biggest-head P2 screwdriver and got the first screw off (bottom right in the above image).  It wasn't easy to get the screwdriver to bite, but I got it done.  Then I tried the next screw (the second one from the right in the bottom row), and I just couldn't get the screwdriver to bite!  These screws are badly stripped!

 

As you can see, the bottom right screw is partially unscrewed.  The others show the damage already done to the heads, but not by me!  I only touched the bottom right and the one next to it.  My screwdriver never touched the other 4 screws.  Being unable to remove screw #2 I had to quit, so I re-tightened the screw I had managed to loosen, and proceeded with the very finnicky process of getting the outer shell fitted back on and tightened down, which took several attempts to get everything nicely aligned.  the short machine screws used for this are really short, and hard to get to grab on to the threads in the inner case.  I didn't even bother taking off the left side to see what things look like there.

Btw while the outer shell on the right side was off, the inner case was touching the tire so I could hear/feel the rubbing even just free-spinning the tire.  It was touching and rubbing right on the front right edge of the case.

So that's where I stand.  If anyone has a suggestion for how to get these screws off successfully, I will try again.  Maybe P2 is not the right screwdriver head size?  Also, if someone knows the precise screw size (#, thread pitch, and length), I'll probably head to the hardware store and get replacement screws for these damaged ones...but first I have to get these off!  I can of course also just take a screw with me to the store and find the right type.

Meanwhile the wheel is back in one piece, but it will have to continue to rub for now I guess.  This is annoying given that I paid over $2,000 for this machine.

[Marty Backe]

Those screws are sad. I really don't get why these companies are still using Phillips   The screws in my 18XL were fine (I had to remove my wheel to fix a flat).

The typical process for removing stripped screws is it drill them out. You use a large drill until the head pops off. Then you should be able to use some vise-grips to grab the shaft of the screw and unscrew it. There are also extractor tools that can be use which also involve some drilling into the screw head.

[svenomous]

Thanks @Marty Backe. I’m hoping not to have to drill out the screws, but will if I must. Maybe I can find hex bolts of the same size to replace them? Anything I should watch out for, to ensure safety, like material (steel, nickel, ...?). Any other tips from those with experienced at dealing with KS hardware?

[Seba]

1 hour ago, svenomous said:

So that's where I stand.  If anyone has a suggestion for how to get these screws off successfully, I will try again.  Maybe P2 is not the right screwdriver head size?  Also, if someone knows the precise screw size (#, thread pitch, and length), I'll probably head to the hardware store and get replacement screws for these damaged ones...but first I have to get these off!  I can of course also just take a screw with me to the store and find the right type.

It's metric M6x16 screw. 

1 hour ago, svenomous said:

Meanwhile the wheel is back in one piece, but it will have to continue to rub for now I guess.  This is annoying given that I paid over $2,000 for this machine.

You're right. This is why I replaced all the screws in both my KS-18L and KS-18XL to inox ones with allen key head. I advise you to do the same. It will allow you to easily disassemble your wheel multiple times. I advise to use following types as replacement:

• M6x16 ISO 7380 A2 (for pedal hanger)
• M3x6 DIN 912 A2 (for side covers)

[svenomous]

Thanks @Seba. The side covers each use 17 screws, of which 15 are very short and 2 are longer, if I remember correctly. Are the side cover hex screws you mentioned the short ones, and you just keep using the 2 longer Phillips screws?  What about Torx instead of Hex, since for hex you usually end up using a T or L key, while for Torx you generally use a more “normal” straight diver? Wondering which would be more convenient. I agree that Phillips is a bad idea for screws like these, especially the bigger higher-torque ones used for the pedal hangers. Stripped Phillips is something I see (and cause!) often.