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Thread: Airhead wheels

  1. #31
    Registered User stanley83's Avatar
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    Modern Tubeless Spoked Rims

    Quote Originally Posted by Darryl Cainey View Post
    Is it possible to buy just the BMW rim and spoke kit that has the spokes on the outside?
    Then have it laced to the hubs on your bike.
    This is a question for which I like to hear an answer. Does anyone manufacture tubeless rims of the correct diameter, width and number of spokes that could be laced to stock hubs? If so, has anyone built up a such a a set of wheels for their Airhead?
    Justin in Somerville, MA
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  2. #32
    . AntonLargiader's Avatar
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    Cross-spoke rims of a useful width are used by BMW in 17", 18", 19" and 21". The problem is that the spoke angle is much greater and the hub drilling won't match. Well, that's ONE problem. Might be others. But these problems are solvable by wheel building experts like Buchanan's and Woody's.
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  3. #33
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    Quote Originally Posted by 20774 View Post
    Not sure what you mean by "it couldn't be done". Probably you're talking about the idea of newer tubless-style rims on an older Airhead. I myself thought there wasn't a way to do that for various reasons...an other reason were suggested.

    But now I see that if one really wants to work for it, it might be possible. I agree with Kent...at what cost and will there be an affect on the handling of the bike. But I suppose it's worth an experiment.

    I hear a lot about how people have run snowflakes with out tubes. It is a fact that the rim design for tubeless tires and tube-type tires are different...and the snowflake doesn't fall into the tubeless tire category. Therefore, it shouldn't be done. People do it, haven't had a problem (dare I say yet! ) but that doesn't make it right or totally safe. There are enough issues with tubes, tires, etc., that for me, I would not want to add another variable that could put me on the ground. That's my choice...but the rims are not correct for running tubeless...that's a fact.
    Tell me EXACTLY what is the difference?

    I am not saying that there isn't a difference - one example: the density of the rim material and ability to hold pressure. But this has been done by so many for so long that one can't argue that it has worked.

    Do y have ANY examples of it working and THEN failing?

    The fact is, is that often things are engineered for one purpose but later can be perfectly adequate to serve another - happens all the time - in virtually all industries.

    Show me the FACTS. If it has been done successfully then it CAN be done.

  4. #34
    Administrator 20774's Avatar
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    Quote Originally Posted by jimmylee View Post
    Show me the FACTS. If it has been done successfully then it CAN be done.
    Just because it has been done, doesn't mean that it was designed for either/or or that that it is a totally safe thing to do. Snowbum has a good discussion about the rim shapes here, in addition to all his caveats.

    http://bmwmotorcycletech.info/section6.htm

    Even he says there is no 100% clear-cut answer. But I contend why introduce an possible variation that is not in your favor?? On the plus side, it seems to be said that punctions from a tubeless situation end up being slower leaks but possibly a faster leak with the tube installed. On the negative side, if you get to a low air situation on a tubeless, bead retention is going to be an issue.

    And we're not the only ones having this discussion:

    http://www.advrider.com/forums/showthread.php?t=786130

    Basically, it can be done, not recommended by the manufacturer, there's no definitive answer...it ends up being a personal decision.
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  5. #35
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    Quote Originally Posted by 20774 View Post
    Just because it has been done, doesn't mean that it was designed for either/or or that that it is a totally safe thing to do.

    Even he says there is no 100% clear-cut answer. But I contend why introduce an possible variation that is not in your favor?? On the plus side, it seems to be said that punctions from a tubeless situation end up being slower leaks but possibly a faster leak with the tube installed. On the negative side, if you get to a low air situation on a tubeless, bead retention is going to be an issue.

    And we're not the only ones having this discussion:

    Basically, it can be done, not recommended by the manufacturer, there's no definitive answer...it ends up being a personal decision.
    What I object to is the immediate answer by someone who cites "engineers didn't design it that way" and THEN assume (or state) that it can't be done.

    This thread has shown that it CAN be done and done successfully and safely.

    I agree that one is on his own, but on a 35 year old motorcycle, ANY change is "on your own."

    I personally wouldn't do it as it seems to me to be a lot of work for very little benefit.

    I, having worked as an engineer (though honestly I do not have an engineering degree - just years of design experience) have seen literally hundreds of "designed" applications that later COULD be used for some other purpose perfectly OK, but some older "engineer" would say "it can't be done" as it wasn't designed for that!

    I personally believe that the design of the bead profile of the tire has probably more to do with any hesitation in trying the conversion than anything, and that on the new tubeless tires is (as I had examined a month or so ago) adequate (in my estimation) to do a "safe" and "workable" job on the older non-tubeless rims. The other main issue, I think, would be the porosity of the rim material (and especially the spoked rims where the spokes go through) that could allow air leakage, but that in terms of safety would probably be a "leak" that would be over a long period of time, allowing the owner to keep the pressure up, and check regularly. But even that can be overcome with the newer epoxies, sealers, etc.

    As much as I LOVE the BMW Motorcycle world, there are literally dozens of BMW designs that just weren't too good and had to be re-done - even some that BMW would not acknowledge.

    The Snowflake front rim is an example.

    The first electronic ignitions on the airheads was really problematic as I understand it.

    And the list can go on and on.

    I just object to someone jumping on a "neophyte" and giving dogmatic answers without backing up. If one cites "engineering" issues, then he/she should be able to back them up on a "engineering" level.

    I love Snowbum and he has a wealth of collected information gleaned from years of experience, but even he (though on this particular issue doesn't seem to be that much against converting to tubeless) is not an engineer. He is one I respect very much though.

    For example, yesterday at our BMW club breakfast, and subsequent ride, I asked a lot of "old-timers" this very question. I didn't receive ONE negative comment like "you can't do it." Several had known people who had done the conversion, and not one of them knew of any failure after it was properly done. In my world, when I get the "old timer's" opinions, I value that a lot more than some so-called "educated" engineers (if they are such!).

    Thanks though, as I also appreciate YOUR opinion also (though I may disagree!! hehehe).

  6. #36
    Administrator 20774's Avatar
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    Jimmy -

    I think you captured the essence of the whole thing. Yes it can be done, but there are risks that must be taken. Quantifying those risks are difficult to do...might be doable if one had $500K to spend and opened up a project with some engineering company. I suppose miles/years of rider experience goes part of the way to suggest a level of risk, but given the many variables involved by all those people, it can't be accepted as de facto proof. How do you prove a negative? So, each individual must decide what works for them. Just as they do for tires, oil, starters, etc.

    This discussion comes up from time to time. Just like those other threads that people are passionate about, there is no right answer, just the answer that works for them.
    Kurt -- Forum Administrator ---> Resources and Links Thread <---
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  7. #37
    Registered User amiles's Avatar
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    One or two thoughts of mine.

    1. The two flats that I have had in recent years (one on a snowflake & one on a Lester) were both due to the inner tubes splitting on a seam, no tire damage occurred. Tubeless = no flats for me.

    2. The older tires (pre tubeless rating) were much easier to mount & dismount from the rim. Those tubeless tires on my snowflakes have a much more tenacious grip to the rim. Many have given-up trying to mount these tires at home or on the road.

    3. I agree that the snowflakes are not rated for tubeless use, BUT what good does a deflated tube in the same situation keep the tire rimmed? I don't see how a deflated tube is any factor in this. I have yet to hear any lore that tells of an incident caused by going tubeless on a snowflake.

    4. I still use tubes..go figure.

    5. Reportedly when a tubeless tire is equipped with a tube the speed rating of the tire (V, H, or S for example) should be considered one level lower. Apparently this is due to greater heat build up/retention in a tubed tire.
    Last edited by amiles; 08-16-2013 at 02:01 PM. Reason: Added #5

  8. #38
    Sir Darby Darryl Cainey's Avatar
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    You hit the nail on the head!
    This is the 3rd season for my 1977 R100RS with running tubless Snowflakes.
    Took my advice from a fellow club member with over 300,000 miles on his Airhead running the same.

    I have watched how hard it is with a professional tire machine to take modern tires off the rim.
    No way it is coming off with a flat!

    I guess you just have weigh the risks and be happy with your decision.

    Forget the Nay-Sayers!
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  9. #39
    Vern 12907's Avatar
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    Shreader Valve Info

    Quote Originally Posted by Darryl Cainey View Post
    You have to buy a special Shreader Valve that fits the stock hole size.
    Can you give more info on this valve??? Where can it be had? Price? Inquiring minds want to know. I'm thinking about going over to the "Dark Side"
    Have fun & Ride safe, Anthony
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    As a former "engineer" working for 10+ years in research and development of a nationally know manufacturing firm - Just how much testing does it take to "prove" that something is possible? I would say over 300,000 miles ought to say something as well as the myriads of other people who have changed to tubeless on a tube-type rim with not one, I say not ONE documented failure.

    I just think there are nay-sayers who simply enjoy saying "It can't be done!!"

  11. #41
    Sir Darby Darryl Cainey's Avatar
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    Quote Originally Posted by 12907 View Post
    Can you give more info on this valve??? Where can it be had? Price? Inquiring minds want to know. I'm thinking about going over to the "Dark Side"
    I can't remember where I bought it.

    The valve is bright chrome finish and the part fits the stock hole diameter so there is no drilling.

    It has a formed rubber washer on either side of the rim and a metal washer on the outside as well as a nut.

    I put a liberal amount of silicone on the inside and out before tightening the nut, let dry over night before mounting tires.

    I faithfully check my air pressure every week and I only have lost one pound of air.

    I did have my rims powder coated.
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    Ambassador BMW MOA Ontario Canada
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  12. #42
    Vern 12907's Avatar
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    Thanks....Thats a good looking wheel, I too powder coated mine. Yea, I'm definitely thinking about going tubeless on the snowflakes. Read all the pros and cons, and I figure it's a whole lot better when it comes to flat tires. It's all about choices. I'll keep a look out for that valve. Thanks again.
    Have fun & Ride safe, Anthony
    '83 R100RS
    '03 GL1800A
    '99 KLR 250

  13. #43
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    Quote Originally Posted by 12907 View Post
    Thanks....Thats a good looking wheel, I too powder coated mine. Yea, I'm definitely thinking about going tubeless on the snowflakes. Read all the pros and cons, and I figure it's a whole lot better when it comes to flat tires. It's all about choices. I'll keep a look out for that valve. Thanks again.
    you'll have a slightly easier time finding some if you look for a Schrader valve, rather than a Shreader valve. In general, they are the valve stems necessary to run a tubeless tire. Darryl described one of the manufactured options.
    Ride Safe, Ride Lots

  14. #44
    Registered User toooldtocare's Avatar
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    I have had my share of flats over the years, and with tubeless tires I was always able to ride home with a plug. On bikes with tubes, well that was a different story. When they went flat, they went flat very fast. After reading all the positive things about tubeless tires on snowflakes, I think if I had to do it again I would run them too. This is a photo of a friends tire that picked up a large nail. He said he heard a ping as though a rock flew out from under the tire while riding, that was all. Apparently the ping was the nail hitting the swing arm and breaking off, there was a notch in it too. He rode the bike home and did not notice the nail until the next day while he was doing his morning inspection. The nail did go through the sidewall inside by about 1/4 of an inch. Wonder how fast he would have lost pressure if they had tubes in them.
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  15. #45
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    Quote Originally Posted by Darryl Cainey View Post
    ....If you can live with BMW Snowflakes they can easily be switched to tubeless, I have been running them for 3 years now & a friend has over 300,000 miles on his conversion without any problems. You have to buy a special Shreader Valve that fits the stock hole size.
    Quote Originally Posted by jimmylee View Post
    ....Mr. Know-it-all above (the guy further up the thread, not the person who wrote this quote) said it just couldn't be done because the rims weren't "special" tubeless rims!! This quote proves that it can be done SAFELY! And LOTS of people have done it with literally THOUSANDS of miles....Guess the "expert" with his dogmatic advice was just blowing smoke...I think the snowflake wheels are perfect candidates for this switch.
    Beyond the facts, the issue here is how many angels can dance on the head of a pin.

    Question. Can tubeless tires be used on "tube" rims without a tube? Answer. Yes, if the rim will hold air (and anecdotes seem to support that BMW "snowflakes" will hold air, something easy for anyone to check in practice).

    Question. Is it safe to use tubeless tires on tube rims without a tube if the rim will hold air? Answer. Depends on your view of the world in which we live.

    The industry developed special rim profiles to help retain tire beads with the tire under load at very low pressures. The rim/bead retention design is one of the benefits of tubeless technology. I think the industry qualify as experts. The rim/bead design was not adopted on a whim. If you want all the benefits of tubeless technology, then the industry would say the answer is no.

    I am not aware of any robust scientific investigation which "settles" any debate. For example how does the response of a tubeless tire on a tube rim differ if used with a tube or without when punctured ? not easily determined in practice. However, anecdotal reports suggest that some of the benefits may be available. There are no end of these stories to believe, or dismiss, but no one is forcing anyone to run tires on tube rims without tubes.. Individual choice.
    Last edited by R100RT_Mark; 08-11-2013 at 12:49 AM.
    Mark

    Current - 1974 TR5T : 1993 R100R : 1994 R100RT ~ Past - 11# 1970s BSA/Triumph Singles & Twins : 2# 1970s CZ 125s : 1# 1985 BMW R65 : 1# 1976 Moby X7

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