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Thread: Tubeless

  1. #26
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    Quote Originally Posted by cxwrench View Post
    If 1-2 flats a year are 'too many' maybe these riders should take another sport.
    Or get more rugged tires AND watch where you are riding.

    Quote Originally Posted by cxwrench View Post
    Still convinced it's the only way to go for mountain bikes, but not for road.
    For my mountain bike, I use these:

    Bontrager Thorn Resistant Tube (700c, Presta Valve) - www.trekbicyclesuperstore.com

    Kenda Thornproof Tube - Outside Outfitters
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  2. #27
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    Quote Originally Posted by cxwrench View Post
    What is this magic rim you're talking about? Pretty much every tubeless compatible rim I've mounted tubeless tires on has been more difficult than most non-tubeless set-ups. Getting normal clinchers on the new tubeless Zipp alloy rims is a pain in the ass. For anyone. The whole idea is that they fit tightly so they seal well. If you have an 'easy' to mount tire/rim combo it's most likely not as safe.
    I don't agree with your assumption that ease of tire mounting (getting the tire beads in the rim channel) has an impact on tire safety. How easy it is to get the tire beads over the rim is purely a function of how deep and wide the rim's center channel is- the deeper it is the easier the tire is to mount. However once the tire is fully inflated, there are different factors that will determine how difficult it will be for that tire to come off (defined as the beads becoming unseated). These are:

    1) Bead shelf diameter- this is totally independent of the center channel diameter
    2) Does the bead shelf have a lip on it to keep the tire from going into the center channel
    3) Use of sealant which effectively glues the beads in place.

    IME the sealant "glues" the bead in place so well that I have to pry pretty hard to get the beads off the shelf and back into the center channel when I dismount a tire. In the event of a catastrophic flat, I have little doubt the beads would stay mounted in the bead seats long enough to come to stop. I recall Lennard Zinn writing that he once rode a completely flat tubeless tire for 1/4 mile without the tire becoming unseated.

    Of course this would not be the case with a ghetto tubeless setup.

  3. #28
    changingleaf
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    There is a learning curve and tubeless may not be for everybody. It is true, if you get a flat that wont seal you will get some sealant on you when you remove the tire and install a tube. Sealant isn't necessary for tubeless, but the tape has to be perfect and the tire and rim bead area has to be clean or a small amount of air can leak. I always use a lever to get the tire off, but not to put one on. There a few rims I've tried that work well and others that don't. Many do not work well. Not all rim designers seem to understand what a good tubeless ready rim should be shaped like. A tire doesn't have to fit tight to seal well because all tubeless road tire beads measure less than 622mm when slack. But, a tire that fits tight may inflate easier because it will not be excessively loose in the center channel of the rim. Few rim-brake rims have got this right. Pacenti's original SL23 rims were difficult to mount tires on because the the center channel of his rim had a diameter that was too large so there wasn't enough slack, but now the new ones have this solved.

    To mount a tire by hand on a tubeless rim it is by far easiest to begin the installation opposite the valve because the valve sits in the middle of the channel and will require the tire to have to stretch further to get around the rest of the rim. I'm sure this has been written about many times before. The tire bead needs to be pushed into the center of the rim and worked around to seat at the valve area last, and repeat with the other side. Remove the tire at the valve area first. The tire bead must be pushed to the center channel of the rim (unseated) on both sides before attempting to remove it from the rim. When inflating a tire make sure the tire is around the valve and the bead is not sitting on the valve.

    Regardless, here's two rim brake rims that I like because tires can be mounted by hand, tires inflate relatively easy, and they stay seated after being deflated.
    Easton R90SL, Pacenti Forza

    These rims work great tubeless, tires inflate relatively easy, and tires can be mounted by hand, but they don't have a wide enough bead seat, therefore the tire bead slips to the center of the rim when all the air is let out. Though, in my experience a small puncture does not deflate the tire enough to let ALL the air out so these generally keep the tire seated at very, very low pressure.
    Stan's Alpha 340, Boyd Altamont, DT Swiss R460.

    This rim has a nice bead seat that keeps the tire seated when the air is let out. It also has a deep center channel (smaller center diameter) which allows a tire to be mounted easily by hand, BUT the sides of the inner channel are too steep which causes tires to be difficult to inflate even with a compressor. The steep center channel makes it too hard for the air to push the tire out of the center of the rim. It's a major nuisance. The only way I was able to get a typical tubeless road tire on this rim was to take the valve core out and use a conical nozzle directed right into the valve hole. -Reynolds Assault tubeless ready rim.

    I can't go into every rim here I've tested and I haven't tried many wheels from Shimano, Fulcrum or Mavic, but they work on the same principal and some are better than others.

    Tire variation can play a role as well, but among tubeless specific road tires I've found them all to be fairly similar in size.

  4. #29
    So. Calif.
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    Quote Originally Posted by Hiro11 View Post
    Upsides:
    - significantly lower rolling resistance (apparently)
    I disagree, tubeless are almost always worse rolling resistance than a comparable clincher tire.

    One exception seems to be this tubeless "compatible", Vittoria Corsa Speed TLR tire.
    Blather 'bout Bikes: Holy Moly...Vittoria Corsa Speed TLR

    But it's a racing-specific tire, is quite thin, and probably not very durable.

  5. #30
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    Quote Originally Posted by tom_h View Post
    I disagree, tubeless are almost always worse rolling resistance than a comparable clincher tire.

    One exception seems to be this tubeless "compatible", Vittoria Corsa Speed TLR tire.
    Blather 'bout Bikes: Holy Moly...Vittoria Corsa Speed TLR

    But it's a racing-specific tire, is quite thin, and probably not very durable.
    I disagree with your disagreement. ;) It's true that rolling resistance is more brand dependent than tubed/tubeless setup dependent. However it's not true that tubeless tires "almost always" have higher rolling resistance. It's also not true that finding tubeless tires with low rolling resistance is difficult or that those tires are compromised in other ways. For example, the Schwalbe One Pro is likely the most widely used tubeless road tire and it has superb rolling resistance in a lab:
    Schwalbe Pro One Tubeless Rolling Resistance Review
    Note that several tubeless tires rank very highly in that site's ranking.

    Also, other tests have shown that holding brand / rubber composition constant, tubeless setups perform significantly better:
    Clinchers, tubulars and tubeless - which tyre system is the fastest? (video) - Cycling Weekly

    Note that they're using the Vittorias you reference in all three configurations.

    I tend to take all of this with a grain of salt. Suffice it to say that if you go with One Pros, you apparently are getting a very low rolling resistance setup.

  6. #31
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    Quote Originally Posted by tom_h View Post
    I disagree, tubeless are almost always worse rolling resistance than a comparable clincher tire.
    That's crazy talk! Tubeless rolls way better than tubes for a comparable tire.

  7. #32
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    rolling

    Quote Originally Posted by Stoneman View Post
    That's crazy talk! Tubeless rolls way better than tubes for a comparable tire.
    Hutchinson Fusion 5 Galactik TL Rolling Resistance Review
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  8. #33
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    Review: "Fusion 5 Galactik doesn't use an anti-puncture belt under the tread,.. the tubeless sealant should seal most small holes instantly."

    Relying on sealant alone is sketchy. When that doesn't work, you've got a gloppy mess on the roadside to remove tire & install a tube.

    So why not just use a Conti GP4000S-II clincher having same Crr, and IME can get amazing 3000+ miles tread wear on a rear tire? (165 lb rider) :
    Road Bike Tire Comparison: Continental Grand Prix 4000S II Latex Tube Vs Hutchinson Fusion 5 Galactik TL

    Or if all out speed is the goal, with lower puncture resistance, use a Vittoria Speed TLR clincher.

    Some parts of country might be better suited for tubeless, eg many small thorns on road.

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