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Close Call

Update on repair progress..
Had to Sawzall both sides of the axle to get the front wheel out. That took some effort. And 4 blades.
Then had to put the wheel into a press to get the axle out of the wheel.
Luckily the races did not spin, no damage to the wheel.
One bearing went way south and really bound up in there.
Damaged one of the tophats getting it apart, waiting on that and then planning on reassemble the whole thing.
The end of the axle with the hole in it, opposite the nut, turned a bit in the fork leg and buggered that up a bit. Going to hone it with a brake slave cylinder hone.

Happy Holidays!
Nick
1978 R-80
 
Nick,

What a nightmare. Good news is; this didn't result in a serious injury. But I'm curious about the cause of the failure. The tapered roller bearings are a robust assembly and with proper maintenance and adjustment should perform past the life of our bikes.

I have a PM message in to you, would love to hear the details about what you found inside the hub assembly, inner collar, wedding band, hub shoulders, etc. These are pretty common bearings to my knowledge and should be available at your local auto parts store. I have in my notes: BMW PN 07119985005, 30203 (NKE) tapered roller bearing. Take notes with sketches in regards to your wrenching, & removal process.

Give me a holler if you know what the approximate size your wedding band needs to be, I have quite an assortment in my parts bin. I'm happy to send you one if you're having trouble sourcing them. But let's get you back on the road with some confidence after some close examination and diagnostics, if we can so we can share it with the Forum. This can be very important information for all of us and those performing bearing work. You have my contact information, happy to help in any way I can.

Sorry I've been out of the loop. It's been a tough few years with some health issues that are now behind me. And, now that I retired in October of last year I'm looking forward to joining back in on the education, knowledge, and camaraderie the Forum provides. I think I have one more cross country tour left in me. Hopefully when it happens we can make that connection we missed the last time I made it through Telluride.

-Mike V. / San Diego
78 R100/7
81 R65
 
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Almost certainly over preloaded. Check the spacers. Tapered roller bearings are very durable. Could the red bearing grease be a contributor?
 
Gents
So after I got the wheel off the bike and taken apart I found there were no spacers or wedding bands or shims between the bearings. Not good.
So I've been working with Engle Motors in KC, great staff by the way, to get me the proper parts.
So far I've got new bearings and seals and the large internal spacer, waiting on a wedding band and shims.
Nick
1978 R-80
 
Gents
So after I got the wheel off the bike and taken apart I found there were no spacers or wedding bands or shims between the bearings. Not good.
So I've been working with Engle Motors in KC, great staff by the way, to get me the proper parts.
So far I've got new bearings and seals and the large internal spacer, waiting on a wedding band and shims.
Nick
1978 R-80

Excellent. Engles has been "my dealer" since 1983 and has always provides excellent, friendly help and service.
 
Nick,

Seems like the challenge moving forward, even though minor; is going to be what size wedding band to start with. Especially if you don't have an assortment to work with. From what you report ... you have no baseline to start with. I have a few ideas of how to accomplish this as a start point but not sure if I can put it in words. My guess is it's going to be somewhere between 6.40mm & 7.20mm. Doesn't sound like a lot but that can be miles for preload. Just trying to limit your trial and error. I may just lend you all my bands which are close to that range the last I checked. Having my bands will be a big help to have trials to work with. What we're after is a wedding band thickness that equals the difference in distance of the inner face to inner face of the inner bearing cage when installed in your hub to the difference in length of your inner collar.

My personal recommendation is to accomplish the final preload with wedding band only and no 0.05mm shims. Just my personal preference. You can do as you please. I have several of the 0.05mm shims I can send along for you if you wish.

I also have take-up collars that are precisely turned on a lathe. Without an accurate take-up collar, with your stack under a load you can experience radial stepping during rotation which can make preload determination difficult, erroneous, if not impossible. The closer to perpendicular the ends of your take-up collar is to the axle bore the better.

Lets talk, at your need and convenience.

-Mike V.
 
Nick,

Seems like the challenge moving forward, even though minor; is going to be what size wedding band to start with. Especially if you don't have an assortment to work with. From what you report ... you have no baseline to start with. I have a few ideas of how to accomplish this as a start point but not sure if I can put it in words. My guess is it's going to be somewhere between 6.40mm & 7.20mm. Doesn't sound like a lot but that can be miles for preload. Just trying to limit your trial and error. I may just lend you all my bands which are close to that range the last I checked. Having my bands will be a big help to have trials to work with. What we're after is a wedding band thickness that equals the difference in distance of the inner face to inner face of the inner bearing cage when installed in your hub to the difference in length of your inner collar.

My personal recommendation is to accomplish the final preload with wedding band only and no 0.05mm shims. Just my personal preference. You can do as you please. I have several of the 0.05mm shims I can send along for you if you wish.

I also have take-up collars that are precisely turned on a lathe. Without an accurate take-up collar, with your stack under a load you can experience radial stepping during rotation which can make preload determination difficult, erroneous, if not impossible. The closer to perpendicular the ends of your take-up collar is to the axle bore the better.

Lets talk, at your need and convenience.

-Mike V.
Whatever you do, don't over preload these bearings! If you make a new wedding band spacer in yr lathe, be sure there's no run out in the spacer thickness. Best would be to machine face sides in one chucking (i. e. cut from bar stock and then bore the ID). It would be better to leave the bearings slightly too loose than too tight.
 
I just love this early 20th century bearing design. This style of bearing was fundamentally obsolete by the end of WWII.
 
Tapered roller bearings for industrial and transportation applications are not anywhere near obsolete now. New ones are about $10.
 
Tapered roller bearings for industrial and transportation applications are not anywhere near obsolete now. New ones are about $10.

Indeed! Correct! But the specific fitment on Airheads with wedding bands and inner spacers and grinding or milling a thousandth here or there is obsolete. The '85 and later Airheads, and the K bikes had modern sealed bearings without the early Airhead micky mouse and as an engineer (I think) you know that darn well to be true.
 
Happy Ending update.
5 months later got the 1978 R80/7 out for a spin today.
Special thanks to Mike V. from San Diego for some parts and support.
Ride safe in 2012
Nick
 
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