| Author | Message | ||
     Hughlysses |
http://www.badweatherbikers.com/buell/messages/290 431/395448.html?1222099706 Interesting. If I read one guy's post correctly, he says the Koyo's may not be that great and SKF's are the way to go. | ||
| Michael1 |
I've worked for SKF, Koyo and now NSK, all as an Application Engineer and spent my time working with various powersports manufacturer's. So each one has it's place in each industry. All bearings made follow certain specifications, that make all the mfg's equal in form, fit and basic funstion. ie... ABMA, JIS, DIN etc. So brg's with the same number are made to the same spec's between mfg's. Yes, the spec's for internal clearance are different between mfg's, but it so small (we're talking microns here) that it will not matter in the applcation. Bearings have different "feel" to them when they are out of a machine, but once installed operate on the same levels. You cannot judge a bearing truely by "feel" in your hand. And by suggesting to change the internal clearance from a C3 to a std clearance, bearing... BAD IDEA. When the bearing is pressed into the wheel housing, the internal clearance is reduced. It needs this for longevity (lubrication, loading and misalignment). Bearing fits, tend to follow strict rules based on application, speed, loading, impact loading, heat etc... A lot of time and number crunching goes into picking a bearing fit. Yes, I would agree, the seal on the SKF's are better at water intrusion...if you get the right seal. Most bearing manufacturer's make over 5 different seal designs per bearing size. And yes, water intrusion is most likely the cause. But I also think that running our bikes in the dirt and off road a bit, tends to add more uncertantity to that as well along with the higher belt loads that a Uly has. The NTN bearings that are stock are just fine. They are high quality and made to NTN specs on NTN machines. The main factor with over seas production is the labor costs. Bearings are a funny animal... lot's of myth's and lot's of "personal experience" that turns into interesting word of mouth. I've trained maintanence personel doing their job for 30+ years and tried to correct their methods to increase bearing life...they won't do it, because some bodies cousin's uncle's twice removed sister said something to them back when they were a journeyman. The bearing world...it's a crazy profession...and I tried to get out...but it sucked me back in. | ||
| Court |
Very interesting and informative. I am watching this closely and monitoring bearings frequently. As a bearing guy . . . what would you suggest as "the best"? I'm not giving up on the stock ones. Just interested in your thoughts/ | ||
| Hughlysses |
This has been an interesting topic for a long time and it seems like we're finally getting some reasonable factual information after a lot of pure speculation. I sure wish we could put it to bed once and for all. I hate the thought of getting halfway into a 1000+ mile trip (especially two-up) and having a bearing go out. I'd like to KNOW I've corrected the problem by using the right bearing (if such a thing exists). Mike- I always remember a brief introduction to bearing manufacture/application one of my mechanical engineering professors gave ~30-some years ago. He waxed eloquently about how roller bearings are manufactured to the highest standards, with the most stringent quality control, the bearing is carefully handled in near-sterile conditions and carefully packaged and sealed to prevent contamination by even the slightest dust particles. Then that bearing is shipped to an auto mechanic in some backwoods town, who unwraps it, accidentally drops it in the dirt, washes it out in a bucket of kerosene, shoves some grease back in it, and installs it on a customer's car.  Back on topic- one of the other threads is reporting that at least some of the 09 bikes have black seals on the bearings (a change from the orange seals used from ~2004 to now) so maybe the new improved OEM bearings are in production and being used. (Message edited by hughlysses on September 23, 2008) | ||
| Michael1 |
In my professional opinion, the following needs to be done: Move the bearings inboard and add an external double or triple lip seal. This will seal the water, dust contaminates out. It should only increase the loading a bit (less than 20% on the bearings due to less center to center distance). If the bearings are designed right to the ragged edge (which more than likely they are not), then it's a very viable option. Except, the wheel casting would have to change, the spacer dimension would change and a procurement of another seal would have to happen. But with what it sounds like, Buell is heading in the right direction by procurring a new seal. This new seal should be some sort of heavy lip contact in a two or three lip design. More than likely it'll involve different machining on the seal groove to make it a deeper groove, which then the seal will set into the groove. So in therory when water trys to enter the seal would press against the side of the seal groove and prevent any water from getting in making a tighter seal. With the bearings that are presently out on the market we will still have to watch them closely...until we figure out what is the TRUE failure mode. Mine still have the OEM NTN Tawian (from when my Uly originally failed) with a set of Koyo's in the wing. I've been trying to get an SKF with their automotive type seal, but they don't make them in the 6006 size. What you have to also take into consideration is the 6006 is not "really a common" bearing. Yes it's used in electric motors and other applications, a 63xx or 62xx is quite more common in the automotive or agriculuture (which have the heavy duty seals). Hughlysses - Yes, you are quite correct. A human hand will never touch a mass produced radial ball bearing. But what the end user does with it, the factories cannot control. I also rememeber in my Mechanical Design class. It was a 20 minute intro into bearings. The prof said...here is a ball bearing, here is a roller bearing, here is a plain bearing.. Questions? Nope? Good. | ||
| Teeps |
Michael1 Posted on Tuesday, September 23, 2008 In my professional opinion, the following needs to be done: Move the bearings inboard and add an external double or triple lip seal. +100 the double/tripple lip seal is the only way to go. The Japanese have done it that way for ever... So, what are your thoughts about removing the seal from the bearing and adding grease helps, hurts, placebo? | ||
| Michael1 |
If I have grease of the same thickener, I'll add it. Most of the time, it's a pull and fully clean and then regrease. Bearings on like about 25% ~ 35% fill of grease. Any more and you run the risk of premature failure due to heat. THe nice thing is that with our bearing seals exposed to the elements, they'll purge the excess grease until it finds the happy median amount. Usually when I teach, I'll tell the people that when they think they have enough grease in the bearing, they already have too much. |
