OK, so this is my first attempt at tubeless and maybe I have just chosen the Devil’s combo?

I have some new 2021 Mavic Crossmax hookless rims and a Racing Ralph EVO tyre. Using Stan’s tubeless valves.

Having watched many vids I thought I’d see if the tyre will seat without tubeless liquid inside.

No chance, the bead on each side just sits in the trough in the middle of the rim.

I have tried to pull the bead across so it sits next to the rim but it is hard work and the bead will slip back on the tubeless tape.

There is a clearly no way that an even vaguely airtight seal is being created and so I am having a pause to consider the next approach. The most obvious next step seems to be to add Stan’s tubeless solution but I suspect I am simply going to have the same issue of the bead not being near the rim, but complicated by everything being covered in white gloop.

Apologies for the sounding off but does anyone have first-hand experience of how to make a Mavic UST hookless rim form a seal with a tyre (its basic job!).

Thanks in advance for any help.

Are you using a tubeless pump / compressor to get the necessary boost of air?

Fit the tyres with an inner tube first to get them to seat and then unseat one bead to remove the tube. If they are new tyres it’s worth doing this and leaving them over night to give the bead time to reshape from when it was folded up.

Tried washing up liquid? I use it diluted down.

Only rims I have ever had tubeless issues with were Mavic 819’s. They have a solid bed, rather than tape, but they were a right PITA

What are you using to inflate the tire?

Anyway, with the trickier ones I’ve worked with I’ve found a bit of soapy water (or watery soap) applied around the bead and rim bed helps get things moving when you start inflating. Taking the valve cores out until the beads are seated can help too.

Yeah tube overnight to stretch it out a bit then compressor fairy liquid magic. Some tyre and rim combos are interesting to get properly seated.

As above – washing up liquid + a blast of air are your friends.

One trick is to put a tube in, leave it overnight, then take it out carefully only removing one tyre bead, then soap up and blast it.

Some rim/tyre combos are the devils work though!

Your mistake is having both beads in the rim well. Pop a tube in, inflate and get both beads where they should be.

Remove the tube by only dislodging one side only.

“Apologies for the sounding off but does anyone have first-hand experience of how to make a Mavic UST hookless rim form a seal with a tyre (its basic job!).”

Yes i do, both MTB and gravel wheels.

Some tyres just don’t work with these rims despite claims of being tubeless ready. Panaracer Gravel Kings being a recent/good example. Just hang loose on the rim, no way will they seat on the rim tubeless

Ones that are no problem in my recent experience have been from Mavic or Specialized.

Four different variants onto two two wheel sets all gone up dry with just a track pump and little or no manipulation of the tyre.

CO2 cartridge to seat. Put goop in through the valve then reinflate using a normal track pump. It’s all i ever do now and works first time every time IME

When I am really struggling to get a tyre to seat I:

Start at the valve

Take tyre lever and use it to pull bead into place, gradually working your way round. Go slowly, or it will just fall off again. It’ll start to get really tight about half way. Do as much as you can.

Then, turn around and do the same on the other side going the opposite direction. Again, it will get super tight and you’ll not likely be able to do more than half. Now, you should be able to seat with a track pump without too much problem.

Good luck!

Assume that the Mavic USTs don’t need rimtape as there are no spoke holes on the inside?

You’ll hate me for saying this….defeats the object of UST, but maybe a lap of rimtape to create a better interface between tyre and rim. That’s how I have dealt with “baggies” before!

Hi all, thank you for the replies and tips. MilitantMandy, yes, I saw that approach on Youtube and have given it a go but the tyre bead doesn’t have an inclination to stay by the rim and slithers back to the middle again. I liked the approach as I don’t have a compressor or boost pump and it looked like the method would remove the need for such devices.

I’ll try an innertube and see how that goes – the only issue being that the tyre still has some latest inside so removing the tube again carefully so as not to disrupt one bead could a PITA.

Not tried it but sounds feasible. Put string/rope/tape around centre of outside of tyre to tighten the middle of the tyre down to the rim which pushes out the beads to the sides. Then inflate.

Panaracer Gravel Kings being a recent/good example. Just hang loose on the rim, no way will they seat on the rim tubeless

Conversely I got one of these to seat itself on a Hunt Gravel X-Wide with a standard track pump and a bit of effort, and without having to resort to putting a tube inside or anything like that. Which was just as well as I’d already added the sealant…

Hi all, thank you for the replies and tips. MilitantMandy, yes, I saw that approach on Youtube and have given it a go but the tyre bead doesn’t have an inclination to stay by the rim and slithers back to the middle again. I liked the approach as I don’t have a compressor or boost pump and it looked like the method would remove the need for such devices.

I’ll try an innertube and see how that goes – the only issue being that the tyre still has some latest inside so removing the tube again carefully so as not to disrupt one bead could a PITA.

Ah, that’s a shame. This must be a tricky set!

Just rounding back on this with the solution – just in case anyone else has the same issue.

Part of the solution is soapy water. The other part is buying an Airshot.

I could have made one myself as it’s a simple device, but I got one from Tredz with a £5 discount. A lot cheaper than buying a track pump (I have one anyway) which has a high pressure can.

What a great bit of kit, simple but effective. Two tyres seated and sealed with no fuss or drama. The soapy water undoubtedly played its part in getting the tyre beads to whizz in to place.

I’m very happy with the outcome, thanks again for the tips.