First mounting of mavic ust road

paucom

Hello,
I've just bought a pair of mavic cosmic elite ust; they are the first tubeless wheels for me.
I've mounted them following the instructions but, after a day (and without using them) they have losed a pretty amount of air. In 24 hours, the air pressure decreased from 6 to 3 bars.
Some questions:
- Without putting sealant, are the wheels suposed to be hermetic?
- It is normal that, with the sealant in, they keep losing air? Should I put more sealant?
- Do you think it is a failure of my unit and I should return them?
Thank you very much in advance for you answers!

prowlbass

Tubeless does generally lose pressure faster than a butyl tube (usually on a par with latex) - some tires more than others. The first 24 hours does usually result in a faster loss than usual while the sealant plugs all the tiny leaks. Giving the wheel a good long spin after you inflate should help a bit (distributes the sealant).

- without sealant they're unlikely to stay up long at all (depends on the tire as to how quickly they'll go down - if they've previously had sealant in and are well sealed, they'll stay up until punctured, however)
- yes, it's normal. If you have the suggested amount of sealant in, don't add more (until it dries out or you lose a lot through cuts)
- doubt it

orlok

paucom wrote:

Hello,
I've just bought a pair of mavic cosmic elite ust; they are the first tubeless wheels for me.
I've mounted them following the instructions but, after a day (and without using them) they have losed a pretty amount of air. In 24 hours, the air pressure decreased from 6 to 3 bars.
Some questions:
- Without putting sealant, are the wheels suposed to be hermetic?
- It is normal that, with the sealant in, they keep losing air? Should I put more sealant?
- Do you think it is a failure of my unit and I should return them?
Thank you very much in advance for you answers!

Mounted with tubeless tires they must be hermetic, but will lose some air in several weeks
Mounted with tubeless ready tires they need sealant to be hermetic, but will lose also some air in several weeks
If the tire lose air pressure in 24 hours from 6 to 3 bar there is something wrong. You can check air-lose with some soapwater but most of all it's the tubeless valve witch isn't fix tight enough in the rim.!

S_J_P

I went Mavic tubeless last summer and haven’t looked back, here’s my advice....

Make sure the valve core is tight.
Overinflate the tyre until it “pops” into the rim hooks, then partially deflate to your desired pressure.
Take 20 to 30psi off your original tubed-setup pressure.
With a brand-new tubeless setup, take the wheel out of the bike and after adding the sealant spin the wheel slowly whilst holding the axel, tilting it left and right to distribute the sealant all around the internal surfaces, this will ensure any minor leaks are sealed.
Leave the bike overnight before adding more air if necessary and then go ride and enjoy tubelessness!

Do bear in mind that Mavic’s Yksion Pro’s are not the most durable tyres around, so I suggest you get a pack of wired mushroom tubeless patches to repair those holes which the sealant can’t. Also, once you’ve used up the Mavic sealant, I suggest you try some MTB sealant with beads in it, this seems to plug larger holes more effectively.

StillGoing

I'm the same. Yksion UST Tubeless on Cosmic Pro Carbon rims with 30-40ml of Stans and losing lots of air overnight. Tyres had popped when inflated so are up against the sides of the rim. Mavic have advised they need a minimum of 40ml of sealant so will be topping them up.

zefs

It's normal that they lose air without sealant. After you add 30ml and inflate them you can rotate the wheel on all axis by hand or go for a short spin. After that they don't lose much air over night (better than latex but worse than butyl tubes).
By the way you don't need to overtighten the rings because it may pull the valve and damage it.

Andymaxy

I've got ust tires with the comete, the first couple days I pumped it up it lost a lot of pressure, it got better over time. I use orange seal, but honestly I don't think sealant would slow down air pressure loss.

Orange seal stays at the bottom of the tire, it's quite thin and doesn't coat the tire. So I'm guessing it wouldn't help.

zefs

Yes it does since it goes everywhere and if there is a leak it seals it.

cycleclinic

Without sealant tubeless tyres only sometimes hold air that you includes UST.

Andymaxy

zefs wrote:

Yes it does since it goes everywhere and if there is a leak it seals it.

Not the case with orange seal, it stays at the bottom and it flows like water, not jam, as soon as you rotate the tire, the section that was just covered by the sealant becomes dry. I know not all sealant is like this, but with orange seal, it stays dead at the bottom.

paucom

Thank you very much for your answers.
If you think that a loss of air the first days is normal then I'll keep them and try. I just was wondering if it was a problem of my unit.
Given that I am new on tubeless, some more questions:
- some of you suggested to use a sealant different that mavic's. Which one is the best for you? I am lookind for endurance.
- if the mavics yksion pro are not very resistants as someone said: is it posible to use with the mavic wheels diffent tyres? Which one would you suggest?
Thanks again!

zefs

Andymaxy wrote:

zefs wrote:

Yes it does since it goes everywhere and if there is a leak it seals it.

Not the case with orange seal, it stays at the bottom and it flows like water, not jam, as soon as you rotate the tire, the section that was just covered by the sealant becomes dry. I know not all sealant is like this, but with orange seal, it stays dead at the bottom.

All sealants do like that (maybe except caffelatex which bubbles). The liquid is not what helps with the seal or puncture, it's the particles in it (latex etc) that move by the internal pressure that is created.

paucom wrote:

Thank you very much for your answers.
- some of you suggested to use a sealant different that mavic's. Which one is the best for you? I am lookind for endurance.
- if the mavics yksion pro are not very resistants as someone said: is it posible to use with the mavic wheels diffent tyres? Which one would you suggest?
Thanks again!

It depends on the roads and conditions you are riding, for good roads the Yksions are fine and also different tires are not guaranteed to fit the Mavic wheels (couldn't fit Schwalbe Ones on Ksyrium UST).
If you commute and ride in the rain etc maybe a more robust tire is needed).

boondog

funnily enough I just bought some, the rear wheel doesn't lose any air at all without sealant, but the front is leaking a lot around the valve.
I thought they were hermatically sealed, I called the shop and the guy was dumbstruck I'd even try to do this without sealant.
I'm not riding them, I just wanted to test them before I put sealant in. I've taken the tyre off and reseated the valve twice, but it leaks every time.

zefs

Mine both leaked air overnight without, but with sealant they are solid (even if it dries).
Maybe if you do a ride down the road it helps them seat better even without the sealant, or putting a tube in but haven't tried.

Vino'sGhost

Tubeless road still sucks