Building Tubeless Spoked Wheels for the BMW - LONG post

[DesmoDrew]

   Let me first say I am not doing anything different than many others have posted in Youtube videos.  But I will answer questions with first hand experience, if anyone has any.

   My motivation for doing this was prompted by my RD250 AHRMA race bike.  After switching to the vintage Continental radial race tires (I had used Dunlop and Avon race tires), the last of the handling gremlins were gone from the RD.  The chatter under braking and mid corner, the front end push on corner exit.  These experiences are reinforced by other racers I know.
   So, I wanted to put the Continental Vintage Attack (not racing compound) radials on the BMW.  But...I did not want to use tubes.  Radials are not designed to run with tubes, as the tubes negate some of the benefits of the radial construction by resisting the flex in the radial sidewall.  Tubes also make the tire run hotter.
   I decided to build some new wheels using Buchanan's in-house manufactured Sun rims.  The PO of the BMW had already replaced the stock spokes with stainless Buchanan spokes.  The Sun rims are machined smooth on the inside after manufacturing and all Sun rims 2.15 and wider have a 'safety bead' (nice, but not a necessity).  The Sun rims are also non-dimpled and are drilled to order. 
  Steps:
*Ordered the Continental radials 100/80-19 Front 110/90-18 Rear
*Ordered the Sun rims from Buchanans pre-drilled for my application (1.85-19 front & 2.15-18 rear).
*Dismounted the tires on the bike, removed the spokes and rims, removed the bearings, vapor blasted the hubs, cleaned spokes and nipples,       
  re-assembled bearings with new grease and seals.
*Laced new rims to cleaned hubs and spokes.  Trued wheels.  Torqued spokes.  Beat on spokes with a dead-blow hammer periodically (to make sure
  everything was seated and stress relieved)
*Began sealing nipples (after a good cleaning with 50/50 mix alcohol & water) with 3M 5200 sealant.  They actually glue boats hulls (top and bottom) together with the stuff.  It sticks like nobody's business, but remains flexible.  I sealed about 10 spokes at a time and then let the sealer firm up a bit before moving to the next 10.
*Let the sealed wheel sit overnight to let the sealer cure.
*Cleaned the rim and sealer again with 50/50 alcohol and water mix.
*Began to Carefully and SLOWLY apply the 3M 4411n sealing tape.  I started applying the tape 4 spokes before the valve stem hole.  I held the tape in a
  'U' shape so it would make contact with the center of the rim and not make contact to the Sides of the center channel first, making it almost impossible to get a good adhesion to the very center of the rim. You must not stretch the tape and must make sure you are getting good contact with the rim and sealer 'blobs' WITHOUT STRETCHING the tape.  I jammed a piece of styrofoam between the rim and truing stand so the wheel would not rotate on it's own   
  making me get ahead of myself.  The green tape in the one picture is for the excess tape to stick to for easier removal.  The tape is Very sticky and almost ooey-gooey to the touch.  A small tire patch roller does a nice job of getting the tape stuck down, but not necessary (I don't have one).  You must take your time so as not to get any air bubbles trapped under the tape.  It is an extremely tedious process!!!!!
*Once the sealing tape is in place and 'bubble free' I overlapped the ends about 1/4".  Then I used a single edge razor blade to trim the excess width of the sealing tape (which hopefully was mostly on the green tape) for removal.  Then I used a #11 Xacto blade to cut open the valve stem hole.
*For the valve stem, I used one from NAPA auto parts.  It is metal and has an 8mm diameter.  That way I did not have to enlarge the valve stem hole, and if necessary, I can remove the stem and the hole will still fit a standard tube valve stem.
*Let the wheels sit overnight

*After that it was mount the tires and air them up.  Listen for any obvious leaks and let them sit overnight and check pressures again.  All Good !!!!

   It has now been 3 weeks and several rides. Tires hold pressure and the ride is what I expected.  Lively, but predictable handling along with a much more 'planted' feeling in the corners.   I am really happy with the decision to invest the time and money.  I doubt I will ever build another spoked rim vintage street or race motorcycle without using the Sun rims/Continental radial combination and going tubeless.

  No safety bead on the front is not an issue.  Most tube-type rims do not have a safety bead anyway.  A safety bead has nothing to do with holding an inflated tire on the rim.  It is supposed to keep a flat tire from 'walking' to the center of the rim. 
  So....If you run over a nail with a tube installed, you WILL have a flat tire in a few hundred feet.  If I run over a nail there is a possibility my tubeless front tire may go flat in a few hundred feet.  So in both scenarios I am in the same boat and the tire Might unseat from the bead and walk away from it.  But in reality, I probably will develop a slight leak which I can plug, long before the tire goes completely flat.

I have attached some pictures of the process.  They are not necessarily in order, but most of the steps are illustrated, as well as the NAPA valve stem.

https://ibb.co/album/N28cNT

https://i.ibb.co/16qhmpV/23-FD05-EF-1-DAB-4-A9-A-85-C1-5110-D3-CB4-CAA.jpg

[85RZwade]

Drew, that is a bold undertaking and my hat's off to you. How did the wheels balance out for you?

[DesmoDrew]

How did the wheels balance out for you?

  They are balanced fine with no extra weights needed.  Good enough for an old pokey BMW that rarely sees the +side of 70mph.  Usually on a street bike; tubed or 'proper' tubeless, I use Dyna balance beads.  I don't think I will use beads in these wheels because the edges of the sealing tape are so sticky that I fear the beads may randomly stick to the edge of the tape and not roll around like they are supposed to.  I may pull the wheels in a few weeks and give them a better balance using stick in weights.  But for now, they are holding air and rolling smooth!

[pdxjim]

To post pics on the forum, you need to add " after the pic url.

[pidjones]

Probably a good callbon the beads. I once had a GoldWing tire with beads and it never seemed right. When removed we discovered the beads clumped by excessive mounting lube.