bearings in stock motors
 

What is the main reason why bearings are not allowed in stock motors?
As far as I can tell, there really is no performance difference between a well lubricated bush and a bearing.
If it is designed to keep the costs down, I find it more expensive to replace armatures then bearings.
At our local track, we are permitted to run bearings at club days but not at sanctioned events. The difference in wear is very noticable.
I put a brand new monster based stock motor in on the weekend with bushings, cleaned and oiled it after every race and after 5 races I found noticable grooving on the shaft. Compared to other stock motors we run with bearings, no wear is visible after 20 races.
I find the logic behind this rule hard to understand.

Cost is one factor, performance is another. I believe it forces the engineers at the major motor manufactures to devise more exotic and cunning means of aquiring speed and efficiency. One thing you could do is remove the bushings from the motor, hone them to provide less resistance, and let them soak in a light oil solution for a day or so. This will increse the performance of the bushings.

Another reason could relate to the old day stock motors. The stock motors of yesteryears were throw away units, with endbells that were locked onto the can by means of 2 "flaps" on the can. These were bent over the endbell to secure it. To install bushings in a motor that was meant to be thrown away is a waste of money. Not to mention the fact that there was no effective way to clean them.

BJL,

There is no good reason anymore. Even $20 budget mods include bearings these days. But it's hard to change a rule like this when there are guys who want to run their existing motors.

I must also say that if you are seeing significant wear after 5 races, something is wrong. Maybe the bushings aren't seated properly or something. Is there usually dirt caked on the bushing and shaft after a run? If so you may have too much oil.

Thanks for the info guys, I'll give the honing and soaking a go.
Bodido, I think you're right about the wear, there was a significant dust buildup. I'll take it a little more easy on the oil.

If you spray just the endbell with WD40 the dirt will have a tougher time sticking. I do this to the front suspension and tires on my Mini-T when we do 30 minute races at our track. If I don't the tires will "snowball" after about 5 laps and I really have a hard time cornering. I spray the front suspension to help keep the grit away from the shocks and hingpins.

I'm a stock motor fanatic.....But occationally I run in the 19 turn class just for a little more speed and excitement. But, I don't run a 19 turn motor....just a MHP arm stuffed into a MVP can witha japanese motor "torque ring" and an GM3 endbell w/ bearings top and bottom. It will keep up with anything!

For the most in preformance....just make sure your bearings are reamed and polished to a mirror shine....as well as the arm shafts....polish the living shintz out of them. This will lower the overall friction.

I have a lot of "people" in japan, so I can get those cut bushings....where they're all cut down and there's minimal material that is in contact with the shaft.

The key to stock motors is cutting down on the friction and resistance. After that, center the arm....brush face tuning...then spring tensions.

Stock motors would also cost less with bushings. If you have to put bearings in a stocker from the factory, you could easily add on 10 bucks to the price of your motor!

It's another one of those stupid,counter-productive,out dated rules that ROAR refuses to update.If your club allows bearings,do it-it makes no difference in power but a big difference in "hassle".I have seen here and on some other forums that the Monsters seem to be worse about wear on the shaft and I don't know why-maybe because of the higher rpm.Using a thicker lube may help your problem.Polishing the shafts and bushings will help.Use a cotton swab & polishing compound in a drill for the bushings-don't do too much or you will get too much clearance.Chuck the arm in a drill and use polishing compound and a rag or super fine steel wool(0000).If the bushings are out of line they will ride on the edges and only reaming will fix it.

I have a hybrid stock motor that works really well also,an MVP can and endbell with bearings and a P2K2 arm with 767 brush on the pos and 766 on the neg.Gear it up like a 19 turn and it will keep up with any stock motor but the brushes and comm last forever.

There is no advantage to Bearings in a Stock Motor except for longevity.

As it has already been said here already,bushings are from when stock motors were sealed and meant to be thrown away, but as this is not the case anymore due to re-buildable stock motors. I feel that bearings should be included. yeah it might cost more for the motor but the motor is not thrown away anymore so this is not a problem! most clubs i race at have no problem with doing this to stockers but when it comes to a title race the bushing motor has to come back out.

We've allowed bearings in stock motors up here (Qld, Australia) for ages, it simply makes more sense.

Bearings offer as good - if not better performance - with the benfit of less maintenance!

I would rather pay an extra few dollars for a bearing-equipped stock motor than spend forever mucking about with polishing bushings and having to oil them all the time :nod:

:confused: How would you get a GM3 endbell on an MVP can? GM3s have flat sides and the MVP is round???

One of the other reasons could be that it would hurt small motor tuning companys. Reaming and polishing the bushings and polishing the armature are some of the most important things done by tuning companys. That leaves aligning the brush hoods and zapping the magnets as the major things that people can't or dont want to do to their motors. I think it would just make life easier if you could use bearings. I could see ROAR putting rules to limit the quality, like no ceramics or really high grade expensive stuff.

A good bushing with proper oil (teflon) will take more abuse and tolerate dirt better then a bearing and the performance difference is almost nothing.