chistech

I have flown RC for over 25+ years and have also been a machinery mechanic for longer. I have seen all brands of bearings have premature failures and it can run in cycles for manufacturers. My son races motorcross and he rides KTMs. The KTM 250 fourstroke motor is known to be the most bullet proof of all the racing fourstrokes. The japanese bikes can't even come close with the motor longetivity. In 06' the motor used all NTN bearings and had virtually no bearing failures. In 07' KTM switched to SKF and the bearing failures started with frequency. I know, both are Japanese bearings. So why do the Austrian bikes run longer? Better metalurgy in all areas. It leaves only the bearings as the weak spots and not the other areas such as rod, valves, head, crank, etc. We rebuilt his 07' with old stock NTNs and no more problems. I know this is not a motorcylce forum but just an experience with another bearing issue.
As far as machinery issues, I manage a large company that sells and repairs packaging machinery. In strapping equipment we use a lot of small bearings in the same sizes as some of our engines take. Some strappers are designed for the fishing industry so they are equipped with stainless bearings. I will tell you by experience that we end up replacing these bearings with standard steel bearings. They are by far stronger and if sheilded, will hold up to the tough envionment just fine. I have replaced bearings made in the following countries, Japan, Spain, Portugal, China, England, US, Indonesia, Israel, and I'm sure more that I have forgotten. They all break or fail!!
I have also bought the standard "cheap steel" bearings from RC Bearings for my engines and my machinery. When I buy bearings locally or from the machine manufacturer I end up paying too much and they don't last any longer than Paul's. I have rebuilt many OS, ASP, and Saitos with the plain steel bearings and have had zero problems with any of the motors. As a matter of fact, all my friends comment on how well my motors idle and run. I think a lot has to do with how lean you run your motor. If you run your motor too hot it will cause all aspects of problems. When dimensions change because of heat, stress occurs. I know motors are designed to get hot but not overheat. Overheating in any motor regardless of what type of motor it is will eventually cause problems. You can overheat a Toyota just a little and think you're fine. Then a week later your head gasket will start leaking because damage was started and took some time to show. Same thing can occur with our small engines. Another problems with bearing failure is improper assembly. If people have replaced their bearings but haven't got them completely seated it can cause premature failure. You can also not rule out improper component manufacture. It is not impossible for a engine case to be made out of spec or a bad crank. A engine with a previous bearing failure could have also spun the outside race in the case causing the new bearing to now also spin in the case. Rebuilding model engines is fun but it is not for everyone. People need to know what to look for and need to pay attention when they disassemble and reassemble.
This day and age I have to agree that most bearings are decent and comparable. I will always look for the cheaper cost from a reliable supplier who will stand behind his product. I can't see paying more for getting the same.