Vintage BMW Motorcycle Owners

Who has experienced concern about tube valve stem length when using the snowflake wheels? I've seen pictures that show much more height than I have. Are you going tubeless? Do you remove the bottom nut? Thanks in advance!

Snowbum has a good discussion of snowflakes on this page...note I don't believe he is a fan of running tubeless, certainly BMW didn't try that.

https://bmwmotorcycletech.info/section6.htm

Near the bottom he talks about valve stems.

Thanks Kurt, If I'm going to read something from Snowbum, I'm going to have to wait till I have an hour or more uninterrupted. I read a couple years ago his discussion of tube vs no tube on those wheels. In the end I was no more sure of a course than before I started.

You asked about valve stems...go to section 20 if I recall. It's a personal choice if you want to use tubes or not. I figure the engineers know more than I do.

The motorcycle tubes I have purchased over the years come with two nuts I assume one for between the rim and tube the other on the outside of the rim. Together they would lock the stem tightly to the rim. While I didn't find SnowBum discussing the nut between the rim and tube I did catch that he said the outside nut shouldn't be used. My thought is if you don't use the outside nut I see no reason for the inside nut. If I remove both nuts the stem will protrude farther past the rim which was my goal. Growing up with trail bikes I always locked the stem to the rim. Going forward I think I will stop that practice unless I hear a counter argument.

I don't install my own tubes these days...I don't have a machine and with the stiffness of the bead, it's extremely difficult to mount tires with hands or the spoons in the tool kit. As you suggest, I don't see the reason for the nut on the inside of the rim. Tubes have a reinforced area where the stem come away from the tube itself...why put a nut in there...you want the tube to lie flat against the inside of the rim. As for the nut on the outside, Snowbum mentions several time to only use a nut for holding the tube in position while the tire is installed and mounted. After that, the nut is removed. Without the nut, the stem is free to move if it has to...it's not a good thing if the tube moves inside the rim, so if you see the stem at an angle to the rim, you know that it needs looking into. If the stem were locked to the rim, there's more of a chance the tube would tear if it did move. One thing that he does mention is running a nut up to lock the valve cap in place. I have knurled nuts on the outside and I've been doing that for years.

Snowbum does mention the use of the inner nut on this page...he has it in a HOW TO DO IT section about 2/3 down the page under Details #3.

https://bmwmotorcycletech.info/TireRepair.htm

It seems to be associated with using a tube in a tubeless rim because of the difference sizes of the rim hole that accepts the valve stem.

Many tubes are supplied with a curved washer and two nuts, the natural rubber tubes I use come this way. (you are using natural rubber tubes, right?)
Standard method is the curved washer resides between the inner tube and the rim; (protecting the stem bond with the tube) first nut is used to secure the tube in position during tire installation; (then backed off 1/4" or so, to monitor any tire slippage from hard braking or acceleration that would show as the stem leaning over) second nut is used to secure valve cap, as protection against loss. (it is thought that a weak valve stem spring will lose air pressure from the centrifugal force of the spinning wheel, and a valve cap, with its o-ring intact, would maintain pressure, or at least slow down air loss)

Motocross guys used to put one nut on the inside (between tube and rim) and the second one hard down on the outside, to clamp the tube to the rim, an effort at trying to prevent to prevent loss of the valve stem that could occur because they ran such low pressure the tire would shift about the rim.
I have no idea if this is still the practice, and don't feel it's good practice with the pressures we use.

More folks are starting to use tubeless tires on the older wheels, (snowflakes and spoked) for perceived better tire availability, the technology to retrofit is apparently here.
I have no need for higher performance than I have, and so I stick with the tube type tires, plus they're much easier to mount.
Best-
George

George, I like your reply!

I agree with what Kurt said regarding tubeless tires on the snowflake wheels, the BMW engineers didn't make the wheels to be tubeless.

Despite TIRES being made to run tubeless, and owners and some mechanics finding they could be run tubeless on BMW snowflake wheels, and since the vast majority of tires on the market now are tubeless, they of course eliminated the tube and saved a few bucks.

I won't go into that can of worms it has been hashed out for years in various forums. Again I agree with Kurt on it.

As for spoked wheels, well only until BMW redesigned the spoked wheel in the newer bikes to take and use actual tubeless tires, all of the old BMW spoked wheels need tubes to hold air. There is no getting around that.

The modern spoked wheels are also now on bikes designed to run radial tires not bias belted. Same for the modern cast wheels.

If there is a tire company making radial type tires for the classic or vintage BMW bikes, I am not aware of it. Regardless even if there is, these tires despite being called tubeless should have or will need to have tubes in them to fit the snowflake or spooked wheels on the classic or vintage bikes. Unless there is some specific disclaimer by the tire company to go against BMW's requirement. This applies only to the snowflake wheels as the spoked wheels won't hold air without a tube.

One comment I can make on the modern radial tubeless tires is they can be a royal B to mount and inflate even with modern Motorcycle tire machines. St.