Tubes & Rim Locks

Discussion in 'Trials' started by motojunky, Jun 5, 2013.

  1. motojunky

    motojunky Professional Idiot

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    My brother has a 1986 Yamaha TY350. The rear tire has been on the bike since he purchased it and was overdue for a change. I started a tire change last night and found that it had two rim locks. The TY350 came with tube-type tires and has a traditional tube-type rim. Are the rim locks necessary? Maybe just one?

    When I bought my Scorpa, it had a tube installed with no rim locks. I rode it for several months that way without issue.

    Thanks!
    #1
  2. nwcycle

    nwcycle Long timer

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    The chance of slipping and spinning the tube ( Or Valve ) will be greatly reduced therefor ending your riding day early, Not sure if the scorpa is tubeless or not, but tubeless tires are very soft and stretch more than spin on rims,
    If you are interested , there are some nice plastic rim locks out there now that we use in our enduros, better than the clunky old rubber and alum. ones....
    Best set up is to use a Heavy duty rear tube also,IRC makes the most affordable at $18 ( IRC92 )
    #2
  3. Sting32

    Sting32 Trials Evangelist

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    To the point...

    The older bike has tube type rim, rim locks (times 2) used on trials bikes because of sub 6lbs of air, usually like riding a flat tire, wheel can slip, rip valve stems in an instant, on these bikes. the tires don't grip the rim at all, only the air pressure of tube holds tire to rim.

    Your Scorpa, has "tubeless" rim, which fit tighter to "tubeless tires..." that yea, you can & I have used tubes in. FWIW, tubeless is like your car, lip tightly seals to rim, when you air them up with or without a tube, you hear the bead/seal seat with a loud POP (usually takes 50lbs of air or more).

    Plus with Tube-Less, IT WILL usually take a "bead/seal breaking" device just to get tire loose off rim,whereas with tube type rims, just letting air out lets the tire come loose from rim's lip, 98.6% of the time.

    Could you get away with just 1? probably, but only other thing to think about is, weigh OUT OF BALANCE with one in vs 2 offset to each other.
    #3
  4. motojunky

    motojunky Professional Idiot

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    Thanks. I knew all that but apparently temporarily shelved the information. :D

    Feeling a little bit like a moron at the moment...
    #4
  5. Sting32

    Sting32 Trials Evangelist

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    Don't feel that way. We've all forgotten things and that's why the forums are so cool!

    Sent from my SCH-I535 using Tapatalk 2
    #5
  6. Monty348

    Monty348 Adventurer

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    My old 348 Cota had a single rim lock and akront rim. I ran the Dunlop 803 on it and it never "slipped" on the rim but did "creep". That's like the difference between a stop and a pause. :wink:
    When first mounted the 803 it would slip back into the center of the rim at low pressure so I kept it well inflated for a day or so then it stayed in place when the pressure was dropped.
    Front tire had a rim lock also and it would creep also from braking pressure. Imagine that, with Spanish drum brakes. :1drink
    #6
  7. buls4evr

    buls4evr No Marks....

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    Or just go to the "Tubliss" system and do away with rim locks altogether.....One big rimlock! And run a tubeless tire:clap.
    #7
  8. JRAM

    JRAM sherpa

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    I switched to the Motion Pro liteloc rimlocks on my Bultacos and it made a big difference. They are much better than the old rubber rimlocks. The tires don't slip on the rims and tear out the valve stem. If you don't use the 2nd rim lock I would plug the hole with silicone or something to keep the muck out. I used to have trouble more on the front tire slipping than the rear, I guess I brake hard on the front. Keep an eye on the valve stem- if it isn't straight up deflate your tire and rotate the tire on the rim so the stem points up again. I see this a lot on bicycles too from running too low tire pressure.
    #8