What if I went tubeless but didn't...

Discussion in 'Dakar champion (950/990)' started by chevtech, Sep 28, 2017.

  1. chevtech

    chevtech Long timer

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    So as I contemplate a blow out on my bikes I have toyed with tubeless conversion (no interior bead retention so I no likey this option) what about doing a hack job with cheap tape (electrical or whatever) to seal the spokes, but still run a tube? Trapped air in the tire would expell from the valve stem slowly, when seating bead, and in the event of multiple tube failures you could o-ring the schrader valve stem and limp home on a shitty tubeless set-up?!? Explosive decompression unlikely, so best of both worlds? Am I missing something here? Just trying to mitigate risk.



    Update:

    I did in fact do this (two tires now), see post 55 quoted below:


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  2. AliveDK

    AliveDK Long timer

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    Can't see the drawbacks, only you would. We'd to decide if running TL or TT :-)
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  3. chevtech

    chevtech Long timer

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    I'm worried about the tube getting an air pocket between it and the tire because the schrader magically sealed metal to metal. I wouldn't think that would be possible though, but how would I know? Things that make you go hmmnnnnn....


    :confused :hmmmmm :dunno
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  4. KT MOTOMAN

    KT MOTOMAN Adventurer

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    Are you talking abut the Tubliss system that lots of dirt bike racers use? It has a high pressure small tube that seals and holds the bead. Over 100psi I think. Then the tire is open to be used for low pressure 8lb or so and can be plugged with a standard plug kit. Not sure if that's the application you are referring to but it works well.
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  5. DirtyADV

    DirtyADV Long timer

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    Kind of did this, seal rim with the 3M tape but the rubber i wanted to fit was a little to narrow for the wide adventure rim.

    So ended up fitting a tube to force the tire to seat on the rim but at some point I damaged the tube but rather then taking it all off I fitted a rubber seal from the bolt in place valve onto the valve stem on the tube and thightened the nut and all of a sudden it held pressure just fine.

    This was on the rear end have tried sealing a front also but would not do that if going any lower then street pressure.

    /Johan
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  6. chevtech

    chevtech Long timer

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    No. I don't like the added weight of tubliss, plus if you actually run as low a pressure as they recommend you would destroy rims.

    Just taping off the spoke holes to prevent the carnage instant decompression can cause in the event of tube failure. Think nice slow leak instead of flat as f@#$ in about what...2-10 seconds when it can leak out all the spoke holes? That's all, plus the ability to convert to emergency tubeless set-up as described in first post.
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  7. chevtech

    chevtech Long timer

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    So basically your tube is probably deflated in there and you are just running tubeless right? Means it would work in an emergency. Good to know. Wonder if there are any ramifications to having a flat tube in your tire? balancing issues I would think, but hell I dunno....
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  8. DirtyADV

    DirtyADV Long timer

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    Yes but had spooned on a paddle tire so was not to worried about balance issues.

    But try to avoid the tube all together if you do seal the rim, no point in still having that just unnecesary weight.

    /Johan
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  9. chevtech

    chevtech Long timer

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    I have debeaded 3 tubeless tires, and one tube tire off rims on MTBs One of those got me an ambulance ride. Super wary of not having the inner bead retention ring as a result.

    YRMV
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  10. DirtyADV

    DirtyADV Long timer

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    The rear you should have a hard time busting of the safety bead if you have any feel for when you start running low on pressure.

    Front on the other hand without a safety bead at some point if it goes low it will slip down into the valley of the rim and that would be instant zero pressure if running tubeless (would not go tubeless on the front if every bringing pressure below full street pressure) ...but maybe seal the front and have a limp home mode if tube fails.

    Just plugging the hole and a good pump and it might be possible to get the tire to seat enough to hold pressure.

    But for the rear dump the tube ...if riding remote bring a tube if plugging and pumping is not working.

    /Johan
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  11. chevtech

    chevtech Long timer

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    That makes sense. All of my catastrophic tubeless tire debeading episodes were on the frt tire!

    Good insight!
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  12. chevtech

    chevtech Long timer

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    As I thought about this again, I remembered that I have blown the rear bead (totally different animal on a motorcycle vs my MTB) 3 times and was able to ride it out, albeit not without destroying my rim as I power slid across the pavement, but the frt tire debead was catastrophic and the sole cause of my ambulance ride. Looking at the rear tire there really is no way to blow that bead unless you are already under ~10 PSI (probably more like 6 PSI) given the large flat portion it would have to slide over to completely debead. The frt however...yah I could debead that easily.

    Guess I am going tubeless in the back, and going to use tubeless as a safety measure up front!

    Thanks Johan!

    Cheers!


    Todd
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  13. Maoule

    Maoule Long timer Supporter

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    Out of curiousity, if you make a tt/tl hybrid and you need to change your tire, how do you get the air out of the tire? Or will the pressure inside the tire go down when you relieve the tube pressure?
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  14. chevtech

    chevtech Long timer

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    With no o-ring on the schrader valve stem, the tire shouldn't have any pressure (other than the force of the tube pushing against it) as it will leak out at the schrader stem hole. Just deflate tube, and go.
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  15. Maoule

    Maoule Long timer Supporter

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    So then, if the tube gets a flat...the tire will go flat as well?
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  16. DirtyADV

    DirtyADV Long timer

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    Yes a slow leak. But if you bring a rubber seal to add to the valve steam from a bolt in place valve that can be added to seal it up when you have plugged the tire.

    /Johan
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  17. Advadvadv

    Advadvadv Adventurer

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    I have contemplated this same project, I would love to go tubeless front and rear but defiantly the rear for sure. I figured if I seal the spoke holes like in the link below things should last well.

    Even on the front if I continue to run a tube I could run on it longer as the air would leak out much slower. I ordered all the glue for this and have it sitting in my tool box waiting for me to have the time to accomplish it properly.

    The other thing is that the lack of a safety bead on the front tire doesn't seriosly concern me because if the tube goes flat then there is nothing holding it on the bead anymore anyway so what is the difference, the tire can still slip down into the valley and cause some issues weather there is a tube in there or not. Just my two cents

    Read this:

    https://cyb.smugmug.com/Motorcycles/KTM/Tubeless/


    Ride safe everyone!!!!
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  18. Advadvadv

    Advadvadv Adventurer

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    Yes!

    This what you are thinking?

    IMG_2251.JPG
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  19. chevtech

    chevtech Long timer

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    Problem with the front (no tube), is that prior to getting down to a PSI that you notice the loss of air, the right hit, or maybe even the right corner with a pothole might take you from say 15PSI down to zero and cause a complete de-bead instantly. That can't happen with a tube Edit: in front. It is not the same animal as the rear. YRMV but actually they won't. It's just simple physics, and the harder you ride the more likely you can de-bead it. It is a gamble you will have to decide if you are willing to take. After an ambulance ride, concussion, and stitches (got knocked out cold) at 17 years old, from a frt de-bead, I KNOW what can happen.


    Todd


    Edit: The difference is, at say 15 PSI you might debead a small spot with or without the tube. With a tube, only the small spot will debead and you will still be running and it may even reseat itself. Without a tube it will "burp" all the air instantly and down you go.
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  20. chevtech

    chevtech Long timer

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    Shouldn't it have a radius to it to contour to the rim?
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