Greg Bender

http://www.thisoldtractor.com/gtbender

Tires - tubeless conversion

DISCLAIMER: DO NOT ATTEMPT THIS MODIFICATION. DESCRIPTION IS PROVIDED HERE FOR ENTERTAINMENT PURPOSES ONLY.

My conversion

Inspired by Greg Field's write-up in the MGNOC newsletter about his tubeless conversion on his Eldorado, I decided to make the same modification to my Ambassador. Here is what I did:

  1. Used a hand file to dress any gouges in the rim...particularly where the tire bead will seal.
  2. Cleaned the rim with a heavy duty wire wheel on my high horse power bench grinder. This did the lion's share of the work.
  3. Cleaned the rim with a light duty wire wheel on my low horse power bench grinder. This got in a little better around each spoke.
  4. Used a cup-style wire wheel on my dremel tool to clean around each spoke nipple. This finished up the clean up.
  5. Scrubbed down the entire rim with rubbing alcohol.
  6. Let the rim dry.
  7. Applied standard, normal, everyday silicone to each nipple hole...a light first coating. (I used General Electric Silicone II Aluminum & Metal 100% Silicone Sealant; stock number GE5050; P-1285)
  8. Let dry for 24 hours.
  9. Applied standard, normal, everyday silicone to each nipple hole...a second finish coating.
  10. Let dry for 24 hours.
  11. Vigorously scrubbed clean a rim strip with soap and water. Then I wiped it down with rubbing alcohol and let it dry.
  12. Applied standard, normal, everyday silicone to the entire "well" area where the spokes are located. Then I fit the cleaned rim strip to this area and made sure it was fully siliconed in place.
  13. Let dry for 24 hours.
  14. Fit another rim strip on top. The purpose of this second rim strip is to protect the sealed silicone area from accidental contact with the tire or tire irons. Since it is on there without any silicone, it is able to move and slide around a bit. I think it is a very good thing.
  15. Fit a valve stem from Drag Specialities, part number VS-1218R. The nice thing about this valve stem is that it does not require enlargement of the hole in the rim.
  16. Fit tire and inflate.
  17. Ride.

Greg Field's conversion

Thanks to Greg Field for posting this information on the Wildgoose Chase forum. In Greg's own words:

For those who want to try it, here's an easier way to make your Borranis tubeless


The key is surface prep. Wire wheel the drop center to get all scmutz and corrossion off of the metal. Then take a conical dremel wire wheel and thoroughly clean each spoke dimple. Blow out all dirt with compressed air. Then clean the drop center and dimples with solvent. Blow thoroughly around the niples with compressed air.


First sealing step is to smoosh a little RTV thoroughly into each dimple. Let this cure overnight, and then repeat. This is the ehart of the seal, so do it like your life depends on it.


Then fit a 16-inch scooter tube, and note how much rubber you need to leave in the center to fill to the edges of the drop shoulder. Cut the tube to this width, leaving in the valve stem. Mask off all but the drop center, and then thoroughly clean both sides of the tube with soapy water and then solvent. Get off all the wax and powder, so the RTV will stick well. Then scuff the rubber with sandpaper. When the tube is ready and dry, smear on a light layer of RTV all the way around the drop center. Squeeze out a bunch of extra RTV around the valve stem because this area will be held proud of the drop center by the valve-stem reinforcements in the tube. You want to fill in entirely that area with RTV. Then fit the tube, and use you finger to work out all the bubbles. When this is done the tube will look like a shrink fit into the dropcenter and will conform even down inside the spoke dimples.


Then, fair in RTV around the edges of the tube, and let it cure.


Remove the masking and fit a tire. Test for leakage. If no leaks, then you're done. It usually takes less than one 3-ounce tube of silicone. If you are using more, it's likely too much.

Pay to have it done

Alternatively, have Wheel Works do it for you.