• This topic has 21 replies, 14 voices, and was last updated 6 days ago by kaiser.
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  • Fatbike tubeless issues (Jumbo Jim’s)
  • Premier Icon sbtouring
    Free Member

    Anyone had issues with going tubeless on the fatbike? Especially with Jumbo Jim tyres?

    Fitted some to my Surly ICT and went tubeless for the first time. But they keep loosing pressure when riding. If I ran them as soft as I would with inner tubes (Don’thave pressure gauge, just go off feel) they just kept getting gradually softer.

    When pumped up harder (probably too hard) they seemed fine, but if I take a big hit they seem to loose all the air straight away, then just keep going down.

    They seem fully seated on the rim (they are Surly My Other Brother Darryl 80mm rims) with the tubeless kit fitted, I inflated them with compressor to get them fully sealed, then let pressure back out.

    I can see a small amount of sealant come out on part of the rim and tyre wall, but not massive amounts, nothing compared to my mtb or cross tyres when I’ve burped one of those tyres, but they have always reseated and never had further issues. Can’t see anywhere else where the sealant is coming out.

    Any useful tips to get them to seal fully? And how much sealant do you use for fatbike tyres?

    Cheers

    Premier Icon honourablegeorge
    Full Member

    ” can see a small amount of sealant come out on part of the rim” – you mean between tyre and rim, or somewhere on the rim itself, like spoke holes? Latter would suggest problems with the tapw

    Premier Icon sbtouring
    Free Member

    Yes, between tyre and rim. Like I have burped the tyre. But it is only a very small amount of sealant, and doesn’t seem all that much compared to the amount of air lost.

    Premier Icon scotroutes
    Full Member

    Fill a spray bottle with a wee bit of washing up liquid diluted with lots of water. Then spray it around your wheels – rims, nipples, rim cut-outs and valves. It’ll bubble up wherever you are losing air.

    The problem I had with my (DT Swiss) fatbike rims was caused by the valves not sealing well on the single-wall rim. This was fixed by using Super P-nuts. FWIW, I’m just using insulating tape as tubeless tape.

    Premier Icon sbtouring
    Free Member

    Scotroutes, I already bought the super P nuts following issues with tubeless on other bikes, but compared to double wall rims the valves don’t seem to sit the best on the single walls. Will give your idea a try cheers.

    Premier Icon Painey
    Full Member

    I’ve had JJ’s on Mulefut 80 rims and now also DT Swiss. All setup tubeless and all without any issues whatsoever. I usually run them around 6-8psi and they don’t lose air. I got them onto the rim with a compressor and left them inflated at a high pressure for roughly a day in the garage before reducing to how I’d ride them

    I setup the rims the same each time using gorilla tape on top of the standard rim tape that goes over the cutout holes/spoke holes. Not always the preferred method but for me it was fit-and-forget. Cut the smallest hole you can in tape to get the valve through and do it up as tight as it will go.

    I hope you can resolve the issues but what I did worked a treat. What I can say is that it’s not the tyres that are causing the problem for you. If air continues to leak then maybe try what I’ve done? I hope it helps.

    Premier Icon monkeyboyjc
    Full Member

    When I had JJ’s I just couldn’t get them to go tubeless – i think I had that kinda rim / tyre combo that just wouldn’t let them sync at the time.

    Had several different rims since, but changed to Nate’s and had zero issues going tubeless they’ve gone up with a track pump, every time.

    Premier Icon J-R
    Full Member

    To be sure where it’s leaking I found that putting the wheel and tyre in a bath half full of water always works. Rotating the wheel very slowly lets you spot even the tinyest leak – such as from the valve/rim interface or around spokes.

    One other thing I found helpful to seal fatbike tyres after first inflation is:
    – ensure they are inflated to the maximum pressure allowed
    – hold the wheel nearly horizontally and rotate it slowly while shaking it back and forth, to ensure sealant contacts all the joints between the rim and tyre
    – then leave the wheel overnight still at maximum pressure
    – next day deflate the tyre to the pressure you want to run it at

    Premier Icon rickmeister
    Full Member

    All of the above and I echo the not the tyre, it’s something else comments. JJ’s and FBF/FBR have been the most reliable tubeless set up.

    Fails have been due to a split presta core rubber, valve not closing properly with a valve cap pushing on it, valve not seated inside the rim so that it seals, unseated bead due to no lube when setting up.

    Premier Icon sbtouring
    Free Member

    @rickmeister what lube do use use when setting up tubeless? I’ve never used any lube on my cross or mtb when setting up tubeless (didn’t know I was meant to).
    Is there anything specific that I need to use? Do I just put it around the whole.bead if the tyre? And does this just help the tyre bead seat to the rim?

    Glad it won’t be an issue with the tyre, especially due to the very high price of fatbike tyres!

    Premier Icon scotroutes
    Full Member

    That spray bottle of dilute washing up liquid should come in handy for setting the tyres into the beads too.

    Premier Icon sbtouring
    Free Member

    OK, so doesn’t need to be anything specific?

    Premier Icon Northwind
    Full Member

    Another “always been fine with JJs”, on DT 710s. (I had the same issue with the single wall rims but hadn’t seen the P Nuts, those are cool- I just used a brake washer to space it out but I might get the P Nuts now I’ve seen them). Actually fitting them was kind of a bollocks, they didn’t want to inflate at all, but once up they’ve been grand. Just with wide PVC tape.

    Premier Icon 40mpg
    Full Member

    Fattystrippers. Careful how you google that, but the most foolproof way I’ve found to set up fatbike tyres tubeless. Used them on all my fatbikes, even the ICT with bud and lou on clownshoes went up easily.

    Premier Icon kayak23
    Full Member

    Zero issues here with JJs on my Calibre Dune. Sorry.

    The first brand new JJ I fitted, I went a bit high with my compressor to seat the bead, it exploded off the rim and the tyre was stretched, deformed and ruined.

    Expensive mistake. 😂

    Premier Icon boltonjon
    Full Member

    For alloy rims, i always use the split inner tube gorilla technique

    Find a 20″ inner tube, cut it around the outside of the tube so you have a 80mm wide rim tape with a presta valve in the perfect place

    Been doing this since 2014 and its never let me down

    It’ll still be a B@astard to inflate mind!!

    Premier Icon kayak23
    Full Member

    For alloy rims, i always use the split inner tube technique

    Me too. Most reliable I find. I used 24″ tubes if I recall but importantly,I put some lightweight foam in the valley of the rim.

    It helps greatly not to lose your split tube behind the beads as the tubes are rarely wide enough to give you comfortable excess. The tyre moving around before you inflate it can push the split tube down, into the valley (The Skids™) without the foam.

    Pretty bombproof method really. Never had any issues with split tubes and saves any possibility of tape failing.

    Premier Icon big_scot_nanny
    Full Member

    Fattystrippers for me too

    Premier Icon cheekyget
    Free Member

    Always wanted to go tubeless on my fatty…question..how much “milk” do you put in each tyre.

    On my road bike I’ve got it tubeless…60ml of Stans in each tyre…18 months now and it’s been great…had about 6 punctures a d didn’t even know if it wasn’t for the white squiggles on the frame

    Premier Icon kayak23
    Full Member

    I roughly double up what I’d put in a regular mtb tyre I think. Couple of Stans cups.

    I don’t worry about being too exact or grams. Just stick a good lot in and shred…..hard.

    Premier Icon richardthird
    Full Member

    If it’s for the winter, get an FBF 4.8 for the front!

    Both those and JJs are literally the easiest ever tubeless for me on Bontrager Jackalopes.

    Premier Icon kaiser
    Free Member

    I’d add more sealant …with 4.8’s I put in 200ml iirc. You can add excess , spin it around an inflate hard , leave one side down on top of a bucket overnight then flip it over and do the other side . You can remove the extra / excess sealant once it’s airtight . Otherwise as above ..split tube method with foam underlay strip to take up any slack when seating . I had one tyre ( not a JJ ) that bubbled through the sidewalls for several days initially and kept deflating ..extra sealant and the process mentioned above eventually fixed it.

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