R100 Big Tube swingarm questions

[Jon-Lars]

The dimensions are listed on Max BMW's catalog page.

According to them, 3mm.

[bmweuro]

Originally Posted by Jon-Lars

The dimensions are listed on Max BMW's catalog page.

According to them, 3mm.

Interesting. Well bigger is better! I do like the seal set up on the later ones as well.

[xavier296]

So, BMWeuro, you used the original sized (larger) bearings of the "big tube" swingarm with the longer (earlier) pivot pins (my question seems redundant, but I am just making sure)?

Also, how do you test a swingarm bearing?

My swingarm bearing and seal setup doesn't really look like any of the ones from the microfiche.

[bmweuro]

So, BMWeuro, you used the original sized (larger) bearings of the "big tube" swingarm with the longer (earlier) pivot pins (my question seems redundant, but I am just making sure)?
I did use the wider bearing and the early shorter pivots. I got everything adjusted and torqued down tonight ans ran the swing arm through it's travel and it worked great

Also, how do you test a swingarm bearing?
I removed the bearing and the race, Cleaned everything very well and did a visual inspection.

My swingarm bearing and seal setup doesn't really look like any of the ones from the microfiche.
The info from the fishe sucks. I ordered a bunch up parts and most turned out to be wrong. The seal let up has seals that you can clean and reuse.

[brocktoon]

THREAD, RESURRECT!

So, a year on:

For those that have done the big tube conversion, have any issues arisen using the earlier style bearing, spacer, seal and pivot pin setup? I have a big tube swing arm for my /5 coming back from the powder coater on Thursday. Like others, I'm loath to kick down an extra $130+ for the exotic bearing setup. Is performance the only thing lost from using the earlier bearing setup?

[ME 109]

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.

[Airhead Wrangler]

Originally Posted by ME 109

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.

[brocktoon]

Originally Posted by ME 109

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.

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)

[supershaft]

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!

[ME 109]

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.

[bmweuro]

Originally Posted by brocktoon

THREAD, RESURRECT!

So, a year on:

For those that have done the big tube conversion, have any issues arisen using the earlier style bearing, spacer, seal and pivot pin setup? I have a big tube swing arm for my /5 coming back from the powder coater on Thursday. Like others, I'm loath to kick down an extra $130+ for the exotic bearing setup. Is performance the only thing lost from using the earlier bearing setup?

What are you doing for the rear brake switch?

[brocktoon]

Originally Posted by bmweuro

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).

[bmweuro]

Originally Posted by brocktoon

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

[Airhead Wrangler]

Originally Posted by ME 109

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.

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.

[ME 109]

Originally Posted by Airhead Wrangler

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.