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So i've been trying to get a pair of gravel tires to set up tubeless for way too long, it's been a comedy of errors but a very good learning experience. Where I am currently at is that the gorilla tape i've been trying to use is just too thick, it is a struggle to get the tire to pop into the bead fully even with a tube. With a significant amount of soap and a few days of it sitting, i've gotten it to seat but it has created small tears in the tape while doing so which leads to leaking that sealent hasn't really been able to plug later on.

I used some Stans tape initially but the 21mm for a 19mm internal rim width (Bike shop said it would work and i was uneducated at that point). It did not work at all, but the tire seated easily with it. I was considering repurchasing that at a 25mm width. Unless there is other recommendations for a thinish tubeless tape that people have had success with. Any ideas?

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  • Just to clarify, are you using tubeless-ready rims and tires? My impression is that tubeless setups are finicky enough that "alternative" setups are risky.
    – Adam Rice
    May 26 '20 at 15:28
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    You shouldn't need a thick tape, at most two layers of standard tape should suffice. Are you using a compressor to inflate the tires ? If your using a track pump you'll need to pump really hard and quick to get a seal, soapy water around the bead will initially create a temp seal to get some air in the tire. More importantly your tires are tubeless ready ?
    – Dan K
    May 26 '20 at 15:28
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    @AdamRice The tires are tubeless ready. The rim does not have any tubeless ready designations on it, which is likely contributing to the issue.
    – Bobbygllh
    May 26 '20 at 19:21
  • BTW this is sometimes called "ghetto-tubeless" where not all parts of the system are rated/designed for tubeless use.
    – Criggie
    May 26 '20 at 21:18
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Your plan is correct. 21mm tubeless tape on a 19mm internal width rim is simply a mistake on their part. That won't create the contact needed between the bead and the tape. Hopefully they'll refund it.

On the bright side, you got some practice stretching the tape on, which might help you one-shot it next time.

What usually works is internal width plus 5-6mm. Going by outside width, i.e. holding up the roll of tape to the rim, you're looking for outside width plus 0-1mm on aluminum and minus maybe 1-2mm on carbon, since carbon sidewalls are usually thicker (that varies and I would always just use the internal width on a carbon rim, but I rarely do on al). It's a little bit of an experiment if you don't have a manufacturer telling you an exact number, but doing it this way will typically get you a width where the tape is just starting to kiss or ride up the inside of the sidewall, which is what you want. Plus 5-7mm works sometimes but not others; you can get in trouble with the tape wanting to curl over at the sidewall or get squished out of place by the tire if it's too wide.

If it's not clear, what's happening here is you want the tape to basically go from sidewall to sidewall, erring slightly on the wide side because you need the tire contact. The X factor is how much tape width gets eaten up by the rim well. Tubeless rim designs are mostly similar enough in this regard for the above rules of thumb to work. With practice one could probably learn to make corrections ahead of time based on seeing a flat versus upwards-angled rim shelf and other factors. But for the most part, +5-6mm gets you there. I'm somewhat copying this from WTB, who just say +5mm for all their rims and make rim tape to match these numbers. That works great for their rims but beyond that, one needs to know which direction to fudge things if an exact match isn't available.

One dynamic to this is that what shops really should be doing at this point is have something like the whole size run of bulk tapes from a couple different companies. For example, the shop I work at has almost every size of Stan's and WTB, except overlaps. Once you've got all the pluses and fats in there, it's like 12 or 15 rolls of tape. That buys high odds of being able to do any rim needed as a repair shop. But few if any shops would be able to have all those widths in retail size packs, and tubeless tape can't be resold from bulk without fouling it. So, walking in and knowing they'll have whatever size you need isn't a given. That said, the 24-25mm roll you need is common, so maybe it was out or someone was having a bad day.

In no case is there a need to get sealant involved until the tire is seated and holding air a while dry. Doing it all at once is fine when one has high confidence things are going to go smoothly, but that's almost entirely about saving time, not increasing efficacy. When things require experimentation, you should hold off until you've found a setup that works, then put your sealant in through the valve.

A final note is there are some rims out there with finishes that just don't play nice with Stan's-type tape. Some DT rims are the major example. DT makes a tape that works for these. We've successfully put it on at least one non-DT rim that wouldn't take Stans or WTB yellow tapes. The DT tape has a somewhat gummier, more flowy adhesive and that makes me suspect that Gorilla would also adhere, but I haven't tried it.

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  • Another option is Kapton tape. It's very thin and light, has a good stretch properties, and available in a variety of widths. Jan 18 at 22:25
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You don’t need 25mm tape on a 19mm rim. You don’t have to seal the bead on the tape, you just have to seal the spoke holes. I’ve been running 30mm tape on 30mm internal width rims for years and no issues. Also run 78mm tape on 80mm fat rims and had the same tape for 5 years and multiple tires.

Don’t waste your time with Gorilla tape. It seals but absorbs the sealant over time. More importantly, it leaves a terrible mess in residue when you remove it months later.

If you want to save money, buy the 8898 Scotch 3M strapping tape. It’s exactly the same tape as Stans and can be purchased on Amazon for pennies on the dollar when compared to Stans.

Do a thorough clean up with alcohol and pull/stretch that tape as hard as you can while applying. Mount the tire and valve with no sealant and inflate to max pressure overnight. This will force the tape to the rim and remove most of the bubbles before you add sealant.

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    Doing a bead-to-bead tape job ensures that there is a solid layer of plastic under the bead. If there’s no tape under the bead, you are solely relying on the adhesive to stop the wheel from leaking. Tolerances also mean that one may need tape under the bead to build up the rim diameter slightly for a better seal.
    – MaplePanda
    Jan 18 at 23:19
  • Great first answer - welcome to the site !
    – Criggie
    Jan 19 at 2:13
  • You don't actually need an adhesive tape at all, as today you have special non-adhesive tubeless rim tapes that use only elasticity to create a seal. The two I know of are Specialized 2Bliss Ready Rim Strip and the Newmen Tubeless Strip, which is supposedly better. If I had known this before taping my first tubeless wheel, I would have saved myself a lot of time and trouble.
    – Mick
    Jan 19 at 14:31

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