Brand new MBS tyres deflate without puncture


a few months ago i bought 4x MBS tubes + 4x tyres. I now can finally use them but i noticed that almost all 4 of them loose Air over time, so that they basically are unrideable. Brand new and never saw the street.

If i fill up a bucket with water, pump up the tubes and hold it under the Water then there are absolutely no bubbles. Nothing visibly escapes the tires, yet they are flat in the next morning.

Has anyone else had this Problem?

Try tightening the vale.

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not sure about skateboard tires, but for road bikes that I ride, we lose 5-8 PSI per day with tires that are pumped to 110psi. If I don’t ride my bike for a few weeks it’s almost flat.

Sadly, the mbs tires haven’t held up well at all for me.

These are a hidden gem:

They’re just like mbs but much more durable without sacrificing ride comfort. I’ve been running them HARD on road and off and there is barely any wear.

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I’ll have a look thanks.

But brand new and multiple tubes is kinda weird

Found this in cycling forum about air loss at 100+ PSI so don’t know how relevant it is to small tires/tubes

“Air permeates through rubber. The more pressure under which this air is trapped inside the tube, the faster it will escape. Air also escapes through the valve. Again higher pressure tubes will let out air faster through the valves. Of course there will be minor variation depending on the quality of the tube and valve”

If you are using rockstar II hubs. Make sure all the bolts on the hubs are tight. Mine lose air pretty quick if the hubs are not tight.

Yes the bolts are tight

But shouldn’t it be visible underwater? Except if its soooo little at a time.

that kind of “natural” leak is not visible in water unless you set up a video recording and do a playback. How long does your leak take? I have trampa 6.5" wheels and haven’t noticed any change in over a month

Basically over night. I pump them up a fair bit and on the next day they are as flat as if somebody intentionally let the air out so you can’t drive.

But absolutely no visible leakage.

I’ll try to make a video of it. Tonight full and tomorrow empty

something is definitely wrong then. I assume you are not over inflating? all four tires are leaking sounds like a user error or batch issue

No, they aren’t fully inflated. I just pump a few times with my bike pump until its firm but not rock hard.

EDIT : I just checked two of the 4 wheels. They are still inflated like they should

Looks like they should be inflated to 50-80 psi. check pressure. submerge in water with value tightly and see fit there’s a leak. If you are looking all most of the air overnight something has to be leaking

Yes the tyre states 50 psi. I’ll check it and let you know tomorrow if you want.

Try taking the valve stems out and inspect the o-rings. If they are dried out or slightly brittle, replace them.

After I bolted down the hubs, it doesn’t deflate… I have no idea about your situation tho. Also make sure there are no gap between hubs.