Motor rubbing/not turning smoothly? Possible rusted bearing?

I went for a ride over the weekend for the first time in a week or so as it was the first sunny day we’d had all last week. I noticed when I got home that one of my motors had started to make a slight squeaking/rubbing noise as it goes through a certain RPM range but at the time I wasn’t too concerned about it.

Yesterday morning I went to take my board for another ride while the weather was still nice and found that the squeaking had got significantly worse over night.

I’m assuming that one of the motor bearings is either rubbing on something in the motor or otherwise it’s started to rust?I’ve been using these motors for a month or two now. I’m surprised that rust would be an issue because, although the motors do get the odd splash, it’s never been an issue before, even with my old 6374 motor which I’ve had since near the beginning of the year.

I’m currently waiting to hear back from @chaka but I’m curious as to what you guys think. Has anyone else had this sort of issue with one of their motors before? Do you think it’s a rusted bearing or potentially something else?

I’ve had it happen to two Ollin motors, the bearings just needs to be cleaned out, or you can just ride with it a while and it might go away.

So it’s likely just dust that’s gotten into the bearings you reckon? Any tips for cleaning it out? I’ve never opened a bearing before

yea, dust or dirt most likely. it could be rust too depending if they got wet or not. easy to clean once you get the bearing out. pop off the c clip, take off the shield, and rinse in paint thinner or other cleaning solution, then dry and lube.

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You could have gotten some small rocks lodged in your motors. Happens to me occasionally. That would cause a lot of scraping noise. If you got your bearings wet, then I would just replace them. Motor bearings are easy to get and not very expensive. eBay has been a good source for me for quality NSK bearings.They’re made in Japan and imo there about the best for small electric motors. The bearings will have a number stamped on them making it easy to order the right size.

I am not to sure that it is the bearings, sounds like something is binding. If you want to send it back we can repair or replace it.

Would you have any issues with me opening the motor up to see if I can see anything obvious?

Be careful not to lose the spacer if you do :wink:

I pulled the motor apart last night and couldn’t see anything particularly obvious, was actually surprised that it wasn’t more dusty.

I’m not sure how many bearings there are in total in the motor but the one at each end of the stator seemed to spin without any obvious resistance. The metal spacer makes a little bit of noise when turned on the shaft though so I’m wondering if that’s where the noise could possibly be coming from? I decided to give the spacer a quick wipe down with a clean paper towel just to try and remove any little bits of grit/dust.

I’ve put the motor back together and spun it up again a few times and although it seems to be a little better, it still makes a similar noise, although the noise isn’t as noticeable when turning the motor by hand now.

@chaka I might look at holding onto the motor for now and check how it’s sounding after a few more rides and hopefully it’ll sort itself out, otherwise if it does end up getting worse I’ll let you know then work out what to do from there?

maybe a slightly longer edge of the rotor is hitting the mounting plate. seems that kind of noise and it looks close. maybe needs another spacer

You could add a “speed ring” to the spacer stack inside the motor and see if the extra clearance eliminates the issue.

I have several different spacers in stock and will be happy to send them if this solves it.

That would be excellent if you could? What does a “speed ring” actually look like, is it essentially just a small washer?

Most skate trucks come with a set of “speed rings”. They are the little shims we use to keep the wheel bearings from rubbing on the mating surfaces. Try it out and if it fixes it I’ll send you a few.

Ah I thought that might be it. Ok I’ll test it out when I get home from work then get back to you.

I tried adding a speed ring to the spacer this evening, actually tried it with 2 and 3 rings as well but no luck either way unfortunately, didn’t really seem to make any difference to the noise.

I noticed that the bearing you can see behind the sensor board is able to slide back and forth freely by about a mm or so. Not sure if that’s normal so thought I’d mention it.

The weather’s supposed to be nicer over the weekend so I’ll try and go for a few test rides and see if the motor seems to be making any noticeable difference.

Chaka do you know how many bearings these motors have ?

…maybe he should have added a little oil to the bearings while open ?

Those bearings are doubled up on that side. It did not sound like there is a problem with the bearings. If all else fails send it back and we will switch it out since it doesn’t look like it has taken any hits.

Is there any evidence of rubbing on the edge of the pcb?

That’s something I didn’t actually look at too closely. I’ll open the motor up again after work and have a look then get back to you.

Opened up the motor again and there were no obvious signs of rubbing on the PCB, I tried looking at the edges of the PCB while the motor was spinning as well and it doesn’t look as though any part of the PCB touches the can at all.

I had a closer look at the magnets and I’ve noticed that a group of several magnets seem to show that there’s a slight scrape on each one that runs perpendicular to the length of the magnets. Each scrape is about 1mm thick and a few mm’s long at the most.

The scrape on each magnet is pretty much perfectly in line with the others, each being about 1.5cm from the magnet edge closest to open side of the can. I think the first photo that I posted of the inside of the can shows one of the magnets with a scrape to the left of the shaft. There doesn’t seem to be any indication of scrapes on the stator though from what I can see.

Here’s a video that hopefully shows what I’m talking about, they’re pretty hard to see though. (If the quality’s no good, try downloading the video and playing it. For me, Chrome would only play the video at 360p instead of 1080p).

How much clearance is there between the magnets? Considering that the issue occurs only when the motor is spinning at low RPM’s, I’m wondering if there’s possibly a small amount of rubbing between the stator and several magnets that’s possibly a result of the can spinning with a tiny amount of wobble?