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Tubless Setting Up Velocity A23 Off Set Rim

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Tubless Setting Up Velocity A23 Off Set Rim

Old 09-15-21, 09:34 AM
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soreribs
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Velocity A23 Off Set - Tubeless Set Up - Need Some Help

Iíve been checking in from time to time over the years but havenít posted since the site was updated.

Could use your help.

Iím having trouble getting a good seal around the valve of an off-set a23 rim. Setting up 3 other a23s was a breeze, however, the off-set rim is proving to be quite difficult.

All 4 rims have two layers of Stans tape. The tape condition is excellent and the hole created for the valve stem appears the same on all 4.

So far, Iíve attempted unsuccessfully, using both muc-off and cushcore stems. After filling with Orange Sealant I flipped and spun the wheel. In addition I allowed it to rest on itís side for 15 minutes, or so, with no luck. Maybe giving it more time by spinning and flipping it over a period of days would help, but, Iím a bit skeptical at this point.


Due to the off-set positioning of the stem hole the lock down nut isnít ale to fully seat against the rim surface. A few of the valve stem threads remain exposed on one side. The nut can be snugged down, but, just not flush to the rim surface. I believe this is the culprit, but, would like to know if anyone else running an off-set tubeless set up has experienced similar problems. And, if so, would you mind taking a few minutes to share successful management strategies?

Wheels will be used off road only.

Sorry if my font is too small. Rookie iPad user.

Last edited by soreribs; 09-15-21 at 10:17 AM. Reason: Title Typo
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Old 09-15-21, 09:45 AM
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With out a picture, it is sort of hard to tell exactly what is going on.

For clarity: The rubber portion of the stem is fully seated inside the rim, correct? This is where the seal is. The external nut only provides tension against the rubber seal so that it seals against the rim/tape.

Second: The stem sits squarely in the stem hole? Not that a bit of angularity should matter, the inside end has ample rubber, but not sitting squarely could make obtaining a complete seal at more difficult.

Thirdly: How is the rim tape at the valve hole? Nice & smooth? A seam or a wrinkle would/could provide an area the rubber seal of the stem can't accomodate.

Additional, how large is the bore of the valve stem? Larger bore valve stems flow much more air for initial inflation & getting the beads set.
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Old 09-15-21, 10:00 AM
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Thanks base 2.

Yes, the rubber portion of the stem was seated well. I tried the both the round and rectangular/squarish rubber grommet included with the muc ocffs. The cushcore only comes with a tapered grommet, as I'm sure you're aware.

Stem fits both squarely and snugg in the hole. Rim tape is smooth. Although after removing the tire I washed the offexcess sealant that I wasn't able to suck back into my syringe; then let things dry for awhile. Later on, I decided to throw a tube in there for now. When I picked up and manuvered the rim, I noticed some excess sealant run out on the floor. It most likely was trapped behind/underneath the tape. One thought is that the tape isn't snugg enough and the sealant was getting behind it then escaping from valve stem hole. The rest of the tire was seated perfectly.

However, the same tape job was done on the other 3 non off set rims with excellent results.

Last edited by soreribs; 09-15-21 at 10:05 AM.
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Old 09-15-21, 10:18 AM
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When you tape the rim with 2 layers of Stanís tape are you doing anything to get the tape to smoosh down and contour completely to the rim shelf?
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Old 09-15-21, 11:15 AM
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Another possibility, if not the stem is a tiny defect in the weld at the joint where the 2 ends of the extrusion come together. It might not be a bad idea to lay a piecs of tape crosswise across the seam from bead to bead before wrapping the rim tightly in the usual manner.

Pinned rims are the worst for this tubeless failure mode. Velocity rims tend to be really well on this front as they are both pinned & (chemically) welded, but nevertheless, however unlikely a tiny inconsistancy may be in the mating surfaces may be, it has been known to happen.

Failure of a perfect seal at the joint seam has no affect in the rims integrity nor is it a mark of a defective rim as the rim is held together by the spoke tension anyway.

Placing a piece of tape accross the joint seam is just good standard practice. Just one of those things a reputable shop would do & never mention to anyone to save themselves the hassle & cost of doing a tubeless job twice. Try it & let us know how it goes.

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Old 09-15-21, 12:52 PM
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You could give this a try:
https://pacenticycledesign.com/colle...air-50mm-alloy
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Old 09-15-21, 01:40 PM
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I can't quote your post regarding the pacenti stem, but it looks perfect. If you removed the rubber on it's lower side, you would get an idea of what my stem looked like before I tore the rim down.

Thanks everyone, for the feedback so far. As far taping the rims, I purchased them from Prowheelbuilder a few years ago. The tapework was well done. Great coverage, adhesion and smoothness. However, I think it's time to re-wrap the wheel. I ordered some Stans 21mm tape today and will give it a shot as soon as I can.

I'm hoping someone chimes in who's running this wheel tubeless and w/o the need for stems such as the pacentis. To me, w/o such stems it appears obtaining a good seal will be difficult. I would think a few bumps would slightly dislodge the stem enough to create a small leak.

I'll re-wrap and snap some pics when finished. Hopefully w/o sealant dripping from the base of the stem....
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