Granite How important is ABEC rating in a motor bearing?

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I have, but they are out of stock and have been for quite some time.


I did contact Boca about these bearings. The speed limit is 25,600 rpm, so they do not recommend these bearings in these motors - the bearing in my original post is what Boca recommends, but they are ABEC 1.

abec357.com sells a very similar orange shield bearing for a little less, but they state that the speed limit is 26,500 rpm.

TRBRC bearings seem to top out at 35,000 rpm, which is again too low.

So I just ordered these: https://www.bocabearings.com/products/smr626c-2os-7-nb2-18200 same bearing you mentioned different size. I called bocca to confirm they are ok for a motor and was told they are. Mike who I talked to couldn't find the exact rating for that bearing but told me he believes its 50-55k rpm and should be fine for a brushless motor. Im so confused!
 
My 2 cents is to get some basic rubber sealed bearings and create a routine that you service them (clean and re-oil/grease) after X number of hours or battery packs.
That's my plan, but want X to be as big as possible while using a bearing that meets all specs.
 
So I just ordered these: https://www.bocabearings.com/products/smr626c-2os-7-nb2-18200 same bearing you mentioned different size. I called bocca to confirm they are ok for a motor and was told they are. Mike who I talked to couldn't find the exact rating for that bearing but told me he believes its 50-55k rpm and should be fine for a brushless motor. Im so confused!

They don't seem to have included the data sheet for that particular bearing size. The one I looked was this:

https://www.bocabearings.com/products/smr625c-2os-7-nb2-18172

It looks like the same bearing, just a smaller diameter. If you go to the "Downloads" tab and select "Technical Image" you'll see the Max Speed is 25600 rpm. I contacted Boca by email and while they didn't explicitly confirm that this bearing was not suitable, this is how they (Michael) responded:

Thank you for your email. The bearings we recommend for your motor would be our Ceramic Hybrid Metal Shielded type. The metal shields will not cause any additional drag like the rubber sealed bearing would. This series would be able to handle the RPM of your motor. I have enclosed the links below to the bearing sizes you mentioned. Feel free to contact me with any other questions.

https://www.bocabearings.com/products/smr625c-yzz-5-nb2-18740
https://www.bocabearings.com/products/smr695c-yzz-5-af2-15474


Now that I look more closely at what they recommended, the speed is still a bit low at 36,000 rpm, but still better.
 
That's my plan, but want X to be as big as possible while using a bearing that meets all specs.


Problem is your x range cant be determined, you have an offroad rig, with a open power module.. your x range will vary under every environment run.. sandy silt = less x... indoor carpet= more x...

In my opinion there is way to much thought being put into this.. heck, the cheap factory steel bearings would live if they were cared for and never saw dirt.. I would highly doubt you are going to see any difference between junk steel or ceramic in a basher, the concern should be rubber sealed for the open module and that's pretty much it imo...unless your trying for land speed records...
 
In my opinion there is way to much thought being put into this..

Problem is I'm an engineer - it's in my nature to mitigate the crap out of everything. What I want is a bearing rated for the speed this motor can spin (40k+) with the tolerances to support those speeds, i.e. not ABEC 1 or even 3. I'm now coming to the conclusion that this unicorn may not exist, at least not in the RC world.
 
That's the one I was looking at. Maximum RPM is 25,600, so not high enough for these motors as Boca confirmed. Boca's recommendations are in my original post.
But they list it under their "brushless motor bearings". Another person recommended them on this forum as well. I'm inclined to agree with Camaroboy, main thing is rubber sealed so they don't get junk in them and crap out again. We'll see how they work out.

As for ABEC rating, in my experience with inline skates, for "dirty" uses, low ABEC rating is actually better. As others have said, they tolerate dirt better. With tight tolerances, any dirt will seize the bearing. For a Granite (or any basher), you're not looking for ultra high performance, you want durability and low maintenance.
 
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But they list it under their "brushless motor bearings".

They do. I was about to buy them, but then found the spec sheet and sent Boca an email to confirm. They responded by recommending a different bearing with a higher speed rating.

As for ABEC rating, in my experience with inline skates, for "dirty" uses, low ABEC rating is actually better.

Very true ABEC rating is almost meaningless when it comes to inline skates, scooters and skateboards, unless you ride fast enough to approach the bearing's speed limit (200-300 mph). Tolerances become more critical in determining bearing life as you approach the bearing's speed limit. Brushless motors push the bearings to their limits.
 
abec357.com sells the same orange seal bearings as Boca, but as a pair: https://www.abec357.com/ProductDetails.asp?ProductCode=CC1512-SMR625C-2OS-A7-NB2&CartID=1

They confirmed the same speed limit, but instead of recommending a different bearing, they recommended removing the seals, de-greasing the bearings, lightly oiling them and running them without the seals.

I am curious to see how the orange seal bearings work out. My guess is that the speed limit has more to do with the seals than the rest of the bearing.
 
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They confirmed the same speed limit, but instead of recommending a different bearing, they recommended removing the seals, de-greasing the bearings, lightly oiling them and running them without the seals.
Defeats the purpose for me. Jim's Bearings has metal shielded motor bearings in stock. I don't know the specs. If rubber sealed is not your priority, you may want to check.
 
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