Viewing 22 posts - 1 through 22 (of 22 total)
  • Toobless Noob question
  • Premier Icon mark90
    Free Member

    My first go at setting a rim up tubeless.

    Superstar XX27 rim taped with two wraps of 25mm tesa 4289. Appears well stuck down, was done in the warm house to help it stick. The rim ‘well’ is fully covered but the tape doesn’t quite reach ‘wall to wall’.

    Small x cut in the tape and a stans valve fitted.

    Tyre fitted to rim, logos aligned with valve, bead of tyre lightly lubed with weak baby shampoo solution (as used for helitape fitting).

    Tyre inflated ok with small compressor and bead seats well.

    I did all this without adding sealant (stans) as I wanted to make sure the tyre would seat in case I had to revert to using a tube for initial seating of the new folded tyre.

    Now air is leaking from the base of the valve stem, done up pretty snuggly, and also from the rim joint.

    Are these likely to seal with sealant or do I need to go back to step one, or something else?

    Premier Icon mikedabear
    Free Member

    Yes mate. Put your sealant in blow tyre up and spin the wheel.

    Premier Icon jamesoz
    Full Member

    Worth checking if there are any holes in the rim either side of the join.

    Premier Icon jonnyboi
    Full Member

    Don’t forget the glitter

    Premier Icon pdw
    Free Member

    Yep, whack some sealant in and give it a shake. It might be worth adding a little extra tape over the rim joint, but I’d expect the sealant to sort it anyway. Worth bearing in mind that air escaping from the valve hole and rim joint doesn’t mean that that’s where it’s getting past the rim bed: the rim is hollow, and nipples do a pretty decent job of sealing the spoke holes.

    Premier Icon mark90
    Free Member

    Thanks guys. I put a little extra tape across the rim joint, wall to wall. Added some sealant and re-inflated. Quick slosh and the leak from the valve stopped almost immediately with no sealant visible. Small amount of sealant visible from the rim joint (partially obscured by the stickers). Gave it a good slosh about and this appears to have sealed now with no noticeable air coming out. Will leave it at 30psi overnight and see how it is tomorrow.

    I wasn’t really expecting the rim joint to be a problem, is this normal?

    Oh, what colour glitter for 650b Shorty?

    Premier Icon jonnyboi
    Full Member

    Red obvs, and it wasn’t a joke.

    Does adding glitter to tire sealant really work?

    Premier Icon jonnyboi
    Full Member

    As to the rim joint, if it’s a pinned rim rather than welded then it’s to be expected. You want to encourage the sealant into the gap by sloshing it around a bit, but based on that pic it looks ok already.

    Premier Icon otsdr
    Free Member

    The rim joint shouldn’t matter and it should positively, definitively not leak.
    The two sealing surfaces are the rim tape and the tire, at the “middle” of the tire well, not on the sides. My suggestion would be thicker tape (or an extra wrap).

    L.E: If the rim is 25mm internal, 25mm tape clearly won’t cut it if installed centered. The tape must fill the center well and reach the flat sides of the rim in order to seal correctly:

    Premier Icon mark90
    Free Member

    Hmm so conflicting advice.

    Sloshed it about last night and left it at 30 psi. This morning it’s at 28psi and no more sealant coming out.

    I am wondering if I might now have more sealant in the rim than the tyre and if I should start again re-taping but making sure I get the tape right to the edges of the rim, as per otsdr’s picture

    Premier Icon martinhutch
    Full Member

    30 to 28 overnight is not a bad result, especially if you haven’t even ridden it yet (?). I normally expect to lose about 1psi in 24 hours just in normal use.

    If you’re curious about sealant levels, unseat a small section of bead and have a look.

    Unless the tyre is going flat overnight, or there is an obvious leak which won’t seal, I would just be riding it and topping it up where necessary.

    Premier Icon iainc
    Full Member

    30 to 28 overnight is not a bad result, especially if you haven’t even ridden it yet (?). I normally expect to lose about 1 psi in 24 hours just in normal use.

    ….really ? 😡

    I am about to go tubeless (first timer) on my FS, which may often sit in my garage for a fortnight between rides, especially in winter. Does this mean I will be having almost flat tyres before many rides ?

    Premier Icon martinhutch
    Full Member

    Does this mean I will be having almost flat tyres before many rides ?

    I doubt it. I don’t tend to leave it that long between rides, but occasionally need to top it up a few psi here and there. Even inner tubes will lose some pressure over time.

    Premier Icon cp
    Full Member

    For a first overnighter, 30->28 psi is good going. Take it for a couple of rides to really get the sealant sloshed around and those last few little air escapes will seal up. It’s normal for the sealant to take up some gaps on the first ride or two.

    I’ve a set of tubeless wheels, unused since August. The rear is still at what it was, the front has lost circa 10psi.

    Premier Icon richmtb
    Full Member

    Does this mean I will be having almost flat tyres before many rides ?

    Depends how good a job you do of setting them up tubeless!

    They won’t be flat after a fortnight if done correctly but they probably will need topped up

    Premier Icon pdw
    Free Member

    If the rim is 25mm internal, 25mm tape clearly won’t cut it if installed centered. The tape must fill the center well and reach the flat sides of the rim in order to seal correctly

    Actually, I’m not sure why it’s important to get the rim tape right to the edges, as long as the spoke holes are properly covered. Obviously if you don’t there’s a risk of leaking at the joint (if it’s pinned) but nowhere else on the rim.

    The only possible issue I can see is with the bead catching the edge of the tape when you unseat it, but I’ve not had this problem using a single wrap of tesa tape, even with really tight tyres.

    Premier Icon otsdr
    Free Member

    The bead should sit on the tape, if it goes outside the air will go under and out the whatever hole it can find.

    Premier Icon trusty
    Full Member

    I had the same problem with my xx27 rims, fixed with wider tape.

    Premier Icon jonnyboi
    Full Member

    Checked on superstar website and it’s a pinned rim not welded so as bit of seepage at the joint isn’t unlikely but it should seal fine. As above 30-28 psi overnight when first set up is pretty good. Go ride it!

    Premier Icon Poopscoop
    Full Member

    Like the glitter idea!

    Premier Icon whitestone
    Free Member

    I remember seeing a tubeless video/setup sequence that recommended using tape that was the external width of the rim. The reason being that when the tape was pressed down into the rim profile it would “pull in” to the correct point just inboard of the bead channel.

    As for pressure drop overnight/after a week: I’ve found this fairly common with *some* setups. As mentioned above a few rides to get the sealant everywhere sorts this out. If you leave the bike for a long while then pressure will drop but then even with tubes you’d check before going for a ride.

    Premier Icon mark90
    Free Member

    Well the tyre is still up. I’ve not had chance to ride it yet, and won’t before the weekend. I fully expected to lose a few psi, at least initially.

    I appreciate the point about wider taping and the tyre sealing on top of the tape, makes sense.

    As the tyre is staying up and there sounds like plenty of sealant sloshing around in the tyre I think I’ll run it as in for now. If I have any problem the will re-tape wider.

    Thanks all for input.

Viewing 22 posts - 1 through 22 (of 22 total)

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