BMW R69S motorcycle wheel rebuilding – help needed.

[Walter_Middie]

I bought a 1969 R69S BMW motorcycle that I know has a few non original parts on it. The motorcycle needs a complete restoration, and I am starting on rebuilding the wheels. The rear wheel has some rust on it, so I purchased another rim on ebay that was supposed to be for a /2, but it is not the same spoke pattern as the rims that came on my bike. My question is: what motorcycle is the rim I purchased from?

I purchased new spokes from Buchanan Spoke and Rim and am starting to rebuild the wheels using the hub that came on my motorcycle and the new rim. Here’s a picture of the first side of the rim with half the new spokes installed.



When I turned the wheel over, I realized that the original hub and new rim do not match. Here’s a picture of the original rim on top, and the new rim on the bottom with half the spokes installed.



Notice that every other hole has a spoke in it, and the remaining unused holes point in opposite directions. Where the original rim has holes that point to the left, the new rim has holes that point to the right. My original hub will not work with the new rim.

What rim did I buy from ebay? Are my original rims from an R69S? Any help would be appreciated.

[stomachmonkey]

Am I missing something or can't you just flip the top rim over and things will line up?

[Walter_Middie]

Am I missing something or can't you just flip the top rim over and things will line up?

If it were only that easy. You can see from the 2nd picture that the empty holes are pointed in the wrong direction on the bottom / new rim. The holes need to be oriented like the top rim to line up with the holes in the hub.

I'd like to know what motorcycle the new rim is from?

[Joeaksa]

Does either have a part number on it? There are several options and do not forget that they had different rims at times for bikes with sidecars on them as well.

[67R69S]

Rex, that rim looks like a /5 rim; that is a no-go on a /2 hub. The chrome rim looks to be original /2. I just started rounding up the parts in my workshop to build a pair of /2 wheels; we can compare notes! I'm trying to get my old R69s up and running, it is in many pieces right now.

Cheers, Gunther

ps: any pics of the bike?

[Walter_Middie]

Joe - I couldn't find any part numbers on any of my wheels. My bike did come with a sidecar, an Earles Court front end, and the front and back wheel are exactly the same (I think the rear rim is supposed to be wider than the front).

Gunther - I have been using this excellent site for help, including wheel building:
BMW Motorcycle Wheelbuilding, wheel, Lacing, spokeing, respoking, truing, trueing, /2 slash 2, R60, R50, R69, R50/2, R60/2, R69S

I'm at work right now and don't have any pictures of my bike - I'll add some tonight - but here's a picture of a similar bike with the same sidecar that I have. Please note that the picture is of a completed bike, and mine is far from it.

[67R69S]

Thanks for the link, that is a good write up on the /2 wheels. If you do end up getting another set of rims, make sure they match the hubs. The early bikes, '55, '56, and I think some '57's, had a different spoke pattern than the later bikes. Those rims and hubs are not very common but I got caught by that so just a head's up. There should be a date stamp somewhere around the valve hole. The wider rear sidecar rim is also quite rare; it would be a nice find.

I just did the preload setting on my hub and I'm ready to start spoking. I'll try to get pics up later tonight.

Cheers, Gunther

[Walter_Middie]

Here's a picture of the poor thing just after I uncovered it after a 3 year rest in someone's front yard.



And a picture of it finally out of the weather in my garage where I can assess the complete damage.

[Chocaholic]

Don't know the answer...but looks like a very worthwhile project. Pls keep us posted on progress. Would love to find such a bike to tinker with on rainy days.

[67R69S]

That looks like a worthy project! There seems to be some stuff on the front and top of the engine that one does not normally see; do you have any pics of that area? The engine appears to be an R50 or R60, judging by the valve covers and air filter housing. Please keep us updated on this, it should be a good build.

[Walter_Middie]

Engine is supposed to be from a Mescherschmit bubble car, but I can't find any information to back that up. The engine has an electric starter motor in addition to the kick starter on the trans.

Progress so far is to strip the bike and rebuild the transmission. Now I'm working on the wheels. I still need to get parts for the carburetors and one of the exhaust pipes is badly dented.

[Walter_Middie]

do you have any pics of that area?

[Joeaksa]

Thats really interesting...

[67R69S]

Ok, that just reached a new level of cool. I've never seen that engine before. A Messerschmidt/BMW!

I started spoking my wheel. Got the first row in

[Walter_Middie]

It's been 6 years, and this wheel issue is coming back to bite me again. The bike isn't as much of a mystery now, thanks to a motorcycle show I attended where BMW was the featured manufacturer. I talked with several experts and found that my bike is an R50/2, probably built in 1962, and the engine is from a BMW 700 sedan, also from 1962. The engine has an electric start called a Dynastart - a 1962 BMW with electric start! Very nice.

I had the frame straightened (it was run through a ditch before I got it), the Earles Forks straightened twice (the first one wasn't a quality job), rebuilt the engine with the clanking rod knock, and put new brakes and bearings on it. This is how it looks now along with it's newer garage mate:



My main problem is the front brake. If I brake hard, the front end shimmies and bounces. Make riding the bike nerve racking.

I took the front wheel off and readjusted the bearings - didn't help. However, I noticed that the front hub is not running true. I can look down at it while ridding, and watch it wobble. The wheel rim is true, but the hub is not. This must be what the front brake issue is.

I could have the brake portion of the hub re-cut true, but the hub itself would still wobble. The braking may be OK, but the hub would still wobble and I'd rather start with something straight.

There is also a technique where the inside of the hub is removed by a machinist, and re bushed true. But this is supposed to be pretty tricky - and the bearings may not fit correctly if it is not done exactly correct.

So now I'm looking for a good front wheel hub for a /2. I've read that a /5 hub could work, and they are about 1/4 of the cost - and I think I have a /5 wheel rim (see story above). But the axle may be a different size and some spacers might be needed - I can't find any information saying for sure how to do this.

I've tried eBay - and these things are rare. I'm on my way this morning to an independent BMW service to see if they have a front hub they would part with.

Anyone out there have a spare BMW /2 front hub they are willing to part with?

[67R69S]

Wow, that turned out great Rex! I had the same issue you are having with my front wheel and to a lesser degree with the back wheel. Turns out that when I spoked the wheels I distorted the hub. I took everything apart, spent some time with a hydraulic press and some hardwood blocks, and got the rims as flat as possible before I started lacing it. That made a huge difference. Maybe it's the actual braking surface that is damaged, in which case I believe replacements are available. Meyer BMW in Germany rings a bell for this, but I'm not sure. Finally got mine on the road too!

[Walter_Middie]

67R69S - Your bike looks great too!

I visited Valentine BMW Service here in Seattle today - an independent BMW motorcycle repair place.

vallantine motor works - Home

They are only a couple of miles from the main BMW dealer here, but at the dealer, you walk into the showroom and only talk to the salesman behind the counter. At Valentines, you walk into the door and are standing in the workshop between a couple of work stations with bikes on lifts and the two guys working away. That's my kind of place. I've done business with them before, and they are genuinely interested in helping you - rather than just getting your money and punching a time card.

They looked at the runout of my hub and it wasn't as bad as I thought. They showed me a good way to mount it in my vise and check for myself. The runout really doesn't look that bad. I'm now thinking I could get the brake drum portion turned, re-spoke the wheel, and try it again.

[LakeCleElum]

Originally Posted by Walter_Middie

Anyone out there have a spare BMW /2 front hub they are willing to part with?

Rex - Not willing to part with it, but if you need measurements, I have a '62 R27 basket case. Not sure if it's the same as a R50 wheel?

Vallantine's: In college, I lived at the house just one door north at 3915 Aurora.

Left me know if riding thru this summer, we missed connections by a day or so last year. Bob

[Walter_Middie]

Bob,

The neighborhood around Vallantine's sure has changed over the years - and not always in a good way.

I hope we can meet up sometime soon - I'd love to look at your R27 - I'm used to basket cases - even those that come without the basket.

[67R69S]

Sounds good Rex, good luck with it. If I recall correctly from my days of riding an R27, those wheels are 36 spoke as opposed to the 40 of the slash two.