Replaced Rim, weird behaviors... Need help

[Shad0z]

So, I took it upon myself to replace the rim on my Master Pro V2. Since the stock rim is made of butter and already dented. I got myself a reinforced version, one made for the V2 with the same reinforcemed design as on the V3. 

Everything essentially went smoothly. However, I've noticed a weird problem and narrowed it down to it only happening if I ride my wheel aggressively. 

It starts making a "tch tch" sound at every rotation, almost like the stators rub against the magnets or something. It does what feels like a few skips, and when testing it while trolleying slowly, it's like it briefly doesn't balance when stuck in one of those "skips". And there's a few of them. 

The issue is completely gone if I ride moderately, but appears as soon as I heat things up. So I suspect it emerges when the motor heats up.

 

Anyone got any clues what this might be or how to fix it? I haven't heard of anyone with similar issues, and I had a similar issue back when I replaced bearings on my OG sherman. 

[Funky]

I recommend checking out valve stem. It may be making noise as tire suppresses under your weight and moves valve stem. I had also a similar noise - i could not find anything.. I even dismantles whole wheel and opened motor. Still had the noise happening. Long story short - it was valve stem.. Yup - 1-2mm gap around (rim hole) had enough space to make that dam noise! I put simple heat shrink over valve stem - noise gone... As rim hole got filled in.

You riding over longer time would heat up tire - it gives more. That also can be possibility. (I didn't have that noise also at start.. One day it started to make it out of blue.) Still it would not explain that "skipping/balancing" issue...

At least you can rule out something simple maybe..

Edited October 5 by Funky

[alcatraz]

Did you open the motor to replace the rim or is it bolted on externally?

Check for clearance between valve/tire and shell. Touching should leave scratches or at least lack of dirt. It helps to have a dirty wheel when looking for contact. 

[Shad0z]

On 10/5/2024 at 7:41 PM, Funky said:

I recommend checking out valve stem. It may be making noise as tire suppresses under your weight and moves valve stem. I had also a similar noise - i could not find anything.. I even dismantles whole wheel and opened motor. Still had the noise happening. Long story short - it was valve stem.. Yup - 1-2mm gap around (rim hole) had enough space to make that dam noise! I put simple heat shrink over valve stem - noise gone... As rim hole got filled in.

You riding over longer time would heat up tire - it gives more. That also can be possibility. (I didn't have that noise also at start.. One day it started to make it out of blue.) Still it would not explain that "skipping/balancing" issue...

At least you can rule out something simple maybe..

I will check the valve stem, but I doubt valve stem would cause the obvious blips in the motor response itself when moving very slowly

[Shad0z]

On 10/6/2024 at 4:44 AM, alcatraz said:

Did you open the motor to replace the rim or is it bolted on externally?

Check for clearance between valve/tire and shell. Touching should leave scratches or at least lack of dirt. It helps to have a dirty wheel when looking for contact. 

Yes you have to open the motor, and remove the two side covers that together when tightened creates the necessary gap for the stators to move relative to the magnets.
I made sure no debris could get in.

[alcatraz]

That means that the bearing spacing could have been altered. Not necessarily by you but by the rotor change that the covers bolt onto. There shouldn't be any axial play after the covers are bolted. It is usually taken out by a shim between the bearings and the "axle". Behind the bearing that is.

Is it possible there was one and it fell off when you had the covers off?

It's the same diameter as the bearing inner diameter, and is sometimes very thin, much less than a millimeter. Like a disc basically. 

[alcatraz]

Is it possible you swapped the left/right covers? That could also be it. That they aren't identical.

[Shad0z]

On 10/9/2024 at 2:11 PM, alcatraz said:

Is it possible you swapped the left/right covers? That could also be it. That they aren't identical.

I didn't, as I only partially removed one cover

[Shad0z]

On 10/9/2024 at 2:10 PM, alcatraz said:

That means that the bearing spacing could have been altered. Not necessarily by you but by the rotor change that the covers bolt onto. There shouldn't be any axial play after the covers are bolted. It is usually taken out by a shim between the bearings and the "axle". Behind the bearing that is.

Is it possible there was one and it fell off when you had the covers off?

It's the same diameter as the bearing inner diameter, and is sometimes very thin, much less than a millimeter. Like a disc basically. 

That does remind me, that the bearings were stuck onto the side covers rather than being stuck on the axle. I don't know about any disc, I didn't notice anything.
Not possible for it to have fallen off without me noticing as I paid close attention to every step.
 

However I am thinking, maybe what could have happened is that since the bearings are friction stuck onto the side covers and axle very firmly, is that maybe I haven't properly knocked it all back into the original placements, so the covers could be a few mm off of unsymmetrically in place, and the bolts bent the outer ends of the cover to fit, meanwhile the center is under more tension and not completely pressed in as far as it could be.

It's hard to say, my current plan is to try and remove the bolts, knock on the covers with a big rubber hammer, and tighten the bolts again.
That would not require me to take it all apart again, which I very do not wish to do lmao.
So I sure hope it works.