Motor bearings question for spec motor classses

I am continuing a conversation that started in another thread and have a question. I have two motors that I run in 1/10 Scale boats that are on the list of approved motors to run in NAMBA for that class. The rules are specific as to what can be done to a motor as far as connectors and flat spot on the shaft etc. I'm wondering what a guy does about bearings if they are going bad. Is there a specific type of bearing that you can replace them with? Do guys just have to buy a new motor when bearings wear out. Are there bearings that cannot be used? I don't know if there are better bearings out there, but with Nats coming up, I'm sure guys want there stuff running as well as possible within the rules.

There was a guy on the other thread who has made accusations of cheating , I assume against guys he's raced against that changed their bearings in order to gain an advantage, but I'm not sure. Is your only option to buy a new motor or does anyone have any insight as to what is legal and what is not as far as bearings go? I'm sure no one wants to be embarrassed by being called out for using a replacement bearing that's not legal. It's a tech issue, so maybe some of the folks who are familiar with running in NAMBA sanctioned events can help us out here. What do we need to know if we want to maintain our equipment and stay legal? I've got some pretty old motors that still run well. It would be nice to get old bearings out of there and not have to buy new motors if I don't have to. We all want to have our stuff running as well as we can before Nats, but what's legal to do with bearings, or is it just considered regular maintenance to replace them? Up until now, I hadn't thought about it.

As the rules are presently written, Mitch, I'd say that it's really an un-techable situation. The rule specifically states the following:

28.E.7.d.ii: "No Modifications may be made to the motor. Except for normal wear, drive flats or keys, electrical connectors and water cooling, it must be run as shipped from the manufacturer."

Reading that a couple of times, it's a very poorly worded pair of sentences. However, taken at word value, it is saying the following:

'Outside of the normal wear that occurs from running the motor, the only modifications you can make are to make flats/keys for your coupler, change electrical contacts, and add/remove/modify the water cooling.'

From that other thread, it sounds like there may be people "enhancing" the "normal wear" by 'honing"?? Whatever. These people are operating at the WRONG end of the boat if they are trying to gain any kind of competitive advantage, so worrying about whether or not they are cheating is really a waste of time. They clearly don't understand what actually makes these boats "fast".

I see nothing in the rules that lets you replace the bearings with anything other than factory supplied replacement bearings. That's the ONLY way to satisfy the "as shipped from the manufacturer" part. HOWEVER, since there is really NO way to confirm/detect/verify exactly what these bearings are, I'd conclude that it's an un-techable situation.

One could easily pop one of the particular motors on this list apart and replace the bearings without anyone knowing it had been tampered with. Sorry, that's just a fact that has to be dealt with. It's not in the SPIRIT of the rule, but it's tough to enforce "SPIRIT".

Not sure what you want to do about it. Personally, it wouldn't be something I'd spend a lot of time worrying about. You guys already are hyper-rules-oriented on paint shades, decals, details, etc... Worrying about a few RPM difference because of a set of replacement bearings is really energy better spent elsewhere.

Just my opinion.

The rules says no changes. Impossible to tech. I've seen several different bearings shipped in new motors as they went through production batches.

If you use bearings with rubber or teflon seals, you'll probably get called on it. If you decide to put $60 worth of ceramic bearings in a $70 motor, you've already missed the point and probably aren't in the hunt anyway.

Like Darin said, the spinney thing at the other end of the driveshaft is far more important.

I agree completely with Darin and Brian, but cheating accusations get me all fired up. Something like bearings shouldn't be a reason to buy a new motor if you're not sure what to replace them with. The way the rules are written now, one could argue that bearings are a normal wear and tear item that should be able to be replaced. I don't see where that is going to be the big difference maker in performance. Most, if not all, of the performance improvements I've found are in what you stick on the wet end of the drive shaft, how you drive and what's between your ears. I don't know much about the fancy things folks might do with the motors other than what I've read about in threads, but part of tech could be to plug a motor into a simple Kv meter, set an allowance window and call it good if the motor falls within that window. I bought one of those meters, but haven't even taken it out of the box. I read the instructions and it's super easy to do at the lake. If guys are that worried, include a station for that as part of tech and mark a motor somehow to show it's been teched and passed. I hate to think that's necessary, but the guy on the other thread got under my skin and .... you know! Thanks for the input guys. Can't wait to go racing with you again.

So here's a little info that may be of interest. Back in my days of building Aveox motors for pylon racing, we used to change air gap to fine tune the kV to the limited number of props that were available, we had two options. I had eight rotors in .005" decreasing diameters to fine tune for prop/conditions.

Increasing air gap increases kV at the expense of torque, it has no effect on total power output. You actually lose a bit of efficiency. If they are honing out the stack ID, they cut the top of the stator teeth making an inefficient motor even worse. Back when you only had x447r, x450/3r and K props, increasing the kV had a performance advantage. Now that we have lots of prop options (more all the time), there's no real performance advantage to building a cheater motor.

This doesn't address the moral side of the cheating issue. I find it pretty pathetic, but consider the personalities involved.

You can definitely argue the wear item side of bearing replacement.

At the 1998 FE Nats in Los Angeles, as APBA FE Chairman I was in charge of teching the ROAR 05 stock motors used in several APBA FE classes. Back then the chief no-no was to re-wind the rotor with fewer turns of wire to increase the Kv. Back then with limited props and far less power from round cells a change in Kv and motor IR could give the boats a bit of an advantage - but that was only a part of any speed increase. As Brian states, the prop (as well as boat setup) were probably more important.

Back then teching was almost non-existent, and at the 1997 Nats (which I did not attend) one winning racer was accused of using 'cheater' motors because he was so much faster than the rest of the field. He was hounded so badly for months after the event that he finally quit the hobby. But since no one actually teched his motors, no one can say for certain if his motors were illegal. This was terribly unfair to him, but sore losers being who they are, they drove a great racer out. Because of this, I wanted the next Nats to be different.

I asked the ROAR Tech Director to help. It was announced in the race flyers that all ROAR motors may be torn down for inspection after the race. At the end of the last heat in the ROAR motor classes, the top four boats had their motors torn down. This meant that we opened the motors and destroyed them by unwinding the wire off the rotors, counting the number of turns. All the motors passed inspection.

We can't really do this with our Limited motors today, so we are forced to go with the honor system. The only real solution with today's motors is to hand them out to each racer at the start of each race day. This pretty much precludes making major mods to the motor, but.....


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Originally Posted by Coug90

I agree completely with Darin and Brian, but cheating accusations get me all fired up. Something like bearings shouldn't be a reason to buy a new motor if you're not sure what to replace them with. The way the rules are written now, one could argue that bearings are a normal wear and tear item that should be able to be replaced. I don't see where that is going to be the big difference maker in performance. Most, if not all, of the performance improvements I've found are in what you stick on the wet end of the drive shaft, how you drive and what's between your ears. I don't know much about the fancy things folks might do with the motors other than what I've read about in threads, but part of tech could be to plug a motor into a simple Kv meter, set an allowance window and call it good if the motor falls within that window. I bought one of those meters, but haven't even taken it out of the box. I read the instructions and it's super easy to do at the lake. If guys are that worried, include a station for that as part of tech and mark a motor somehow to show it's been teched and passed. I hate to think that's necessary, but the guy on the other thread got under my skin and .... you know! Thanks for the input guys. Can't wait to go racing with you again.

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mitch if this is me...and I was the one to make the accusations..being that I have seen it done first hand..i will leave it at that..you can be mad at me all you like..but I hate someone that cheats..win or not..its not in the best interest of our hobby..so if you want to call it an accusation so be it..but it pisses me off just like it does you..we can leave it at that.. if you would like to talk to me in person I will be at nats ..hope to see you there