How wide should tubless tape be?

I helped my brother set up his stock wheels on OnOne Scandal as tubeless.

We used two wraps of some 3M Tesa tape I bought for some narrower WTB KOM i25 rims and whilst it covered he spoke holes and rim bed fine it didn’t make it onto the shoulders of the rim.

The tyre went up easily with a track pump and has stayed at 30psi overnight.

So is that it, job done? Or is the rim tape extending and covering the shoulders of the rim (ie. to the base of the vertical hooks) critical for some reason?

If it’s gone up fine I’d leave it. Optimally I like to about equal the inner width, but the main reason for me is that you then won’t catch the edge removing a tyre, which I’ve had a couple of times leading to replacing the tape.

Tesa tape is good strong stuff though. I don’t recall having any of that fail.

Too narrow and you’re relying on the tapes adhesive keeping the air/sealant in rather than the bead on tape interface.
Could be fine, might not last that long.

WTB recommend internal rim width +5mm. That way the tape covers the rim joint and, in some rims, holes that are there as part of the manufacturing process. It also means that the bead of the tyre seals against the tape and not the rim, helping to hold the edges of the tape down.

I reckon this is the best way if you’re not regularly changing tyres. Some folk reckon it’s easier to damage the wider tape when removing tyres so I can see why those folk use narrower tape.

as per @BearBack if the tyre bead is sitting on the alloy of the rim – the pressure inside will begin to push sealant under the tape.

The tyre bead should be sealed against the tape itself.

Sound like you might have it like the top, when really it needs to be like the bottom. Leave it, if you find they go down, re-tape them going right to the edge.

I just taped up my 729s with 32mm Tesa. Front is holding fine after sloshing the sealant about, it’s a very fine fit width wise but it seems okay. Will see how it does in the real world in due course.

Rear has an iffy hole in the sidewall, will see about that later when I can be bothered.

I go with the external width. By the time you’ve pushed the tape into the well it’s “narrowed” to the effective internal width. We’ve just done a wheel for my wife, internal width is 35mm, supplied tape is 37mm.

I just do a few wraps of electrical tape to cover over any holes and the full width of the rim. Seems to have been working for the last 6 or 7 years. This year I might splurge out with 1 inch Gorilla Tape. Never had a problem on any bikes I’ve set up for people, although personally I prefer ghetto tubeless with a split BMX tube

Tesa tape I always us is 25mm wide and all the rims I’ve ever used it in have been wider and I’m still here to tell the story 😂

The main thing with welded rims is, if the tape doesn’t go under the tyre, but does go onto the edge of the rim, then when you push the tyre off it’s likely to damage the tape (since rather than sliding over it, it’s sliding into it and pushing it right off). IME it’s not any better or worse for actually sealing the wheel up but it’s more likely to have future issues.

(with unwelded rims, the rim join itself might not be airtight so it’s sometimes essential to have the tape going right under the tyre)

Then again, if the tyre’s on the rim for a long time or the sealant dries up it’ll tend to stick to the tape and damage it when you remove the tyre anyway.

i25 might be just too narrow for this, but, ime, for wider rims it’s best not to tape the edges at all. If it’s wide enough, you can just tape the rim bed (ie the hollow in the middle). This works best of all, because it means the tyre isn’t interacting with the tape. When you remove the tyre there’s no risk of damaging the tape at all so your taping can be basically permanent. I’ve done this with my i29s and it worked well but 4mm might be all the difference it needs to be too narrow.

snotrag
Full Member

as per @BearBack if the tyre bead is sitting on the alloy of the rim – the pressure inside will begin to push sealant under the tape.

I tape all wider rims so that the tyre sits on the rim not the metal and they seal perfectly, no sealant under the tape. I guess it’s possible but I’m not doing anything fancy and it doesn’t happen at all for me- not with Tesa, roval or electric tape.

As Northwind says, some rims are far from airtight at the join so wider tape will help. Narrower tape will work fine but might be more liable to peel at the more exposed edge, however there’s no guarantee either way. If the tape is well stuck down then the width shouldn’t matter

Thanks all and impressed with @snotrag sketching skills and yes suspect the width of tape results in top image.

It has held pressure well for 24hrs now and sounds like no fundamental problem so will wait and see and try wider if this doesn’t hold up. Thanks all.

You want it as wide as you can for coverage, but if it climbs up the side of the rims too much or can stop the tyre seating and make fitment difficult.

Just up to the vertical wall of the rim has always been fine for me.

I had some rims with narrow tape that worked just fine until I left them in a car on a warm day and the adhesive softened enough for the tape to lift. Always go for full width now.