Ericoschmitt

I was wondering if it would be possible to seal the spoke wholes to run tubeless, as motor-bikers do on their wheels, instead of using a rim tape? I suppose that the extra volume of the rim above the bead would be beneficial in many ways, specially in deeper rims. What do you think? Has anyone done/seen that?

frankenmike 

pdoege

Yoeleo's SAT wheels have a continuous (no holes!) tire bed. https://www.yoeleobike.com/tubeless-road-carbon-wheels-sat-c50-60-road.html

wschruba

Get ready for a new level of pain if you ever need to replace a nipple because a spoke broke off in it/re-build a wheel.

Ask any mechanic who's worked on Fulcrum wheels.

smashndash

I think there was something called veloplugs? Lighter too. But I don't think they play nice with tubes, which is something to consider if you get a flat.

well biked

Veloplugs are used in place of conventional rim tape (protection of the inner tube from the spoke hole), they aren't for tubeless applications.

wesmamyke

My limited understanding of current tubeless tech on bikes makes me think it probably won't help much. I think many rim/tire combinations require the tubeless tape to take up space and push the bead up as much as they also seal the rim. Have heard road tubeless often requires two layers of tape to account for the high pressure.

I do recall from experience the early MAVIC tubeless mountain wheels would spit tires off at anything above 40lbs. They had/have spoke bed with no holes, spokes thread into inserts from the hub side like mentioned above. I think tires have gotten way better recently, but it's still a trial and error thing to some degree depending on that specific rim and tire combination. I'm willing to bet many people run MAVIC wheels with no tape and just sealant, but it doesn't always work from what I've seen.

rm -rf

The tubeless rim tape is extremely thin and lightweight, even using two layers. (And two layers are necessary, even if using tubes.)

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Your proposal is to seal the spoke nipples, so that the air volume within the whole rim would be usable? Interesting, but I can't think of a good way to seal the nipple base and still let it turn to true the wheel. Maybe sealant would do this? But it would be difficult to periodically clean out dried up tubeless sealant that's down inside the rim body.

Ericoschmitt

I think others didn't quite understand, but this is the goal, to get extra air volume from the space between the bead and the nipples. How to get it done is something that could be learned from motor bikers probably, but maybe tiny rubber/plastic washers would seal it and still let you turn the nipple to true the wheel.

And then you wouldn't need the bead to be mostly closed with wholes for the nipples, but instead have some kind of truss just to keep the side walls from opening. But that's a second step, which would relieve some weight and make cleaning dry sealant easier. If sealing the nipples is possible, you can always drill more holes on the bead of a common rim to shave those extra grams.

This extra air volume seems that would be mostly beneficial for road tubeless with deep section aero wheels, as the rim probably has several times more air volume than the tire, so such a mod (or rim design) could give more time for the sealant to seal punctures before your tire pressure becomes too low.

One big disadvantage of not having a proper bead is that you can't just add an inner tube if everything goes wrong - unless you have some rim tape with you. But then maybe one can just carry a spare tire anyway - which weights just a bit more than a pair of inner tubes - and a CO2 catridge to put it in place on the road side.

ThermionicScott 

Ericoschmitt

I guess ride quality wouldn't change much (for a mtb), that is related to casing suppleness and pressure, and the volume increase is proportionally smaller, unless you use deeper section wheels too.

But then on a road tire whenever you hit a bump the tire compresses there and I suppose the pressure goes up in the rest of the tire as the air has nowhere to go. With added rim volume probably this pressure would be more evenly distibuted, not rising so much, and damping a bit better the vibrations. That's theory anyway...

I might try doing that one day!