Originally Posted by Airhead Wrangler
I'd consider it a yearly maintenance item unless you ride in the rain or off road a LOT. It's probably not necessary yearly, but with a grease gun and the right tip it's a 5 minute affair, so why not? Just pump grease through the pivot pins until you see clean new grease coming out past the seals. Wipe up what came out and you're done.
I could never work out how to get the seals/bearing out. Mind you I don't recall asking either. The seals are basically levered off. Anyway, that prevented me from properly greasing the bearings on the few occasions that the swing arm has been out of the bike.
Now, it is a five minute job to grease them.
The swing arm bearing from bmw is wider than a standard30203
30203 outer race is approx 10.5mm. Inner race I'm not sure as I threw it out.
bmw swing arm bearing with fitted seals outer race is approx 13.5 from memory. It is wider because it has a groove which holds the inner race cage in place.
The inner race on the bmw bearing is wider @ 17.25mm. The roller bearings are the same, but the inner part which holds the rollers is longer, so as to also hold the seals....
Good opportunity for a photo...
I used the original pins from my bike as the NTN bearings are the same physical size as oe. No need to change pins, and no spacers needed.
If a standard 30203 is used to replace the oe bmw bearing, a 3mm approx spacer is needed to make it the same width as oe.
The spacer will need to have a 17mm id. The pin will pre-load? on this spacer so a sloppy fit (17.5mm or so) will be unsatisfactory.