R100 Big Tube swingarm questions

I just put NTN 32203 bearings in my big swing arm.
They are 40 x 17 x 17.25 basically the same size as oe.
I was able to use the original outer dirt seal from the previous bearings. It isn't a perfect seal, but at least the bearings can now be greased via the pivot bolts.
How much of an issue is greasing the bearings?......perhaps not too much as my bearings were 31 years old. They were stuffed, but still quite serviceable.

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.

So with 32203 bearing did you use the earlier pivot bolts and/or spacer?

I was also curious about people who've tried the 30203 bearings, which seem to be the most readily available (read: cheap)

It's been a while but I believe it is the inner race that is longer. I have had trusted reports that they do make a difference. I did the front axle trick on my LS and I am sure it made a difference. All the little stuff adds up. (You machine the big part of the axle back so that both sides of the other slider pinch on the axle versus just one side of it.)

Personally, I wouldn't worry about that drive shaft spring. Sure they rarely fail but so does everything. Of course, the solid ones are lighter! I have seen the spring in the transmission fail at least five to one more times. I think that's what the spring on the drive shaft is suppose to be saving. They beefed the trannies up a lot there around '86? Good luck!

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.

What are you doing for the rear brake switch?

I have a large maglite with a red theater gel lens that I can shine over my shoulder when braking.

No, I found the rear brake conversion tutorial on your website and plan on putting in an order with you for the spacer you mention (though I don't see it on your website).

Sorry about that Rear Brake Switch Cap

Oh wait. I forgot which swingarms have closed off ends where the bearing seats are and some don't. Some swingarms you can just pump grease through the pins until it oozes out past the seals. Others are open on the inboard side of the bearing, so you can't grease them that way. Check yours before you pump your swingarm full of grease.

All good for greasing on my swing arm. Driveshaft side is closed off, and the other side has an oe tin plate that sits under the bearing, effectively closing off that side as well.

So I got the big tube swingarm and the NTN 32203 bearings. Only problem is I'm missing the seals. The parts fiches (which, as mentioned before, have been known to suck) don't seem to show the grease seals shown here:



Am I missing them in the fiche? Anyone know where I can get them?

I just got new swingarm bearings a couple months ago and the seals came as part of the bearing. They aren't listed separately as far as I know. I ordered the BMW part though, not an equivalant.

I think you're right. Well, crap. So much for saving money with the equivalent non-OEM bearing.

Re-use the old seals. They look straight and in good shape. If there is enough grease in the bearing you should be fine.

Nah, those aren't mine. That was just an example pic from earlier in the thread. I tossed the old ones -- hopefully into the unused parts bin and NOT in the trash.

Go look in that bin brocktoon, you'll want those old seals. They're not a perfect fit as such however they will assist in keeping the crap out.
From what I've found it will be easy to grease the bearings through the 6mm allen key hole in the centre of the swing arm pivot pin, then just push the seal back into place. I reckon the grease will hold the seal in place quite well.
I only used the larger outer seal.

So, those who've made the switch to a big tube swingarm: did you also switch to the later driveshaft boot and clamps? Having trouble getting mine to fit.

All of the driveshaft boots are the same. There is no early or late. make sure you have it installed ib the proper direction.

So they are. I assumed since the /5 swingarm had a rectangular-ish driveshaft opening, whereas the big tube swingarm has a completely circular driveshaft opening, that they would've modified the boot to fit. Looks like the tension clasps were the only parts that changed -- probably lengthened. I'll get some longer clasps.

I have a new to me big swing arm for my 77 r100/7
Just trying to get the right parts on order
What bearings should I be getting ?

Thanx

Big bearings and new seals and use old pins seems to be the trick I think