I’ve just stripped my tubeless tyres off my wheels and replaced the valves and I’m now trying to get things back together. I’ve got an Airshot to do the pressure dump and one wheel worked fine, it took a couple of goes, but then the tyre locked into place and all was good, the second one just isn’t playing.
I do the air dump into it and it inflates, does the appropriate pops and seats nicely, no leaks at all, but when I let the air out so I can remove the Airshock, once the pressure drops to about 10 psi there is a big pop and almost all the tyre unseats itself.
I’ve tried at least six times, sometimes letting all the air out at once, sometimes just cracking the seal on the valve and letting it leak out over 10 minutes, it doesn’t matter, every time the tyre jumps off.
I’ve not put any sealant in yet as the majority of videos I’ve seen suggest adding it last, and I didn’t need it with the first wheel.
When I deflated them earlier, the tyres stayed where they were and I had to work to get then off.
In case it matters, the wheels are Bontranger Paradigm and the tyre a Continental GP5000.
Anyone any suggestions on what to try or what could be going wrong?
Welcome to the fresh he11 that can be tubeless wheels. I have no advice at all but I do feel your pain. FYI, I was using an old floor pump that everyone who has ever used it complained about, except me, , until today Suffice it to say I’ll be getting something better to pump air in for next time. Good grief!!
Sounds like the tires and wheels have been used before going tubeless so maybe the trouble is being caused by some usage that resulted in some surface irregularities that are preventing a solid beading … Have you inspected the troublesome rim up close for dents and such? Have you wiped with some rubbing alcohol before applying the tape? Is the tape job well done? No gaps? Is the tire surface in good shape (especially the parts in contact with the rim).
Just some ideas… perhaps obvious. Maybe putting a bit of sealant in before adding the first air might be worth a try.
It was tubeless before with the same wheel and tyre. I haven’t touched the tape which was put on by a shop and looked perfect when I inspected it with the tyre off.
The reason I did all this is the sealant had been in for over a year and all the guides suggest changing it before then so I decided to give it a go, just to see if I could and to see how easy the tyre was to get on and off in case I ever had to at the road side.
There are no dints and the tyre locks on perfectly with no leakage until the pressure is released.
Still no luck, I’ve tried the following extra things:
Suspended the wheel off the floor - someone said that maybe the pressure of the tyre sitting on the floor was causing the problem. It didn’t work
I put sealant in - Just in case it helped, it didn’t, I’ve now got sealant sprayed around
Leaving the high pressure in - Unfortunately the adaptor on the Airshock has a tiny leak even when done up as tight as I can get it, so I can’t leave it at pressure for very long. I did manage to keep it there for over 15 minutes then from another room I heard the double pop of both sides of the tyre unseating themselves.
Pumping up with just the pump rather than the Airshot - that does nothing, the tyre isn’t seated even vaguely well enough for it to hold any air.
Repeatedly trying to put it on, just in the hope one time it sticks but it hasn’t.
Every time, the tyre seats perfectly, no leaks from it or the valve and then every time, when the pressure gets too low, both sides give a big bang and jump off the rim.
Off on holiday now for three days, luckily the bike isn’t going with me, so will have another go when I get back or might just give up and go to the bike shop.
Are you inspecting all around the bead edge on both sides when it’s popped in? I often find there is one tiny bit of the tyre that doesn’t fully seat even after its banged loudly into place. I have to keep pumping and sometimes pull the tyre over to get the last little bit to seat.
I’m going to take it to the friendly local shop and see what they say. Only problem is that they are now full of sealant so transporting it will be interesting!
I’m assuming you take out the valve core for the airshot. I have also had this same de seating of the tire happen when trying to get the valve core back in before it deflates. You just need to be faster with the airshot to valve core swap over.
Steps I’ll do
The “airshot” type device I have threads on to the valve w/o a core. You can use the pump again inline after you air shot it.
Attached airshot hit it with 120-140psi.
Pump the whole system back up to 70psi.
Turn off the airshot valve.
Tire now has 70psi.
Remove airshot.
Put finger over valve.
Insert valve core.
Reattach pump and inflate before it gets a chance to loose more air and de seat.
I gave something like that a try but didn’t do it quick enough so didn’t try again. I’ll give it another try.
If the tube is locked on the wheel as it should and I get a puncture bad enough the sealant can’t seal it would the tyre stay on? I know with the current setup it wouldn’t.
I took the wheel to the bike shop and they confirmed I’d done everything right and the tyre was seating correctly, they reckon the tyre is just so tight it will pop itself off regardless of what I try.
Their solution was the same as @Scott_Yarosh . It took two goes, the second time I closed the Airshot valve before removing it and I don’t know if it technically made a difference, but there was less air shooting around so made it easier to get my thumb on.
Once on, it lost 20 psi in a couple of hours so there is a small leak somewhere, I suspect I’ve done the valve up too tight, so going to stick it in a sink later and see if I can track it down.
A lot closer to a working wheel than I was before I went away.
My tubeless setup ALWAYS leaks around the valve. I’ve got asymmetric rims which is a pain. I ended up trying some different shaped rubber ends on the valve and an extra o-ring. Now sorted.
Didn’t get chance to put it in the sink today, but I did a 50 minute ride. Started with 65 psi and ended with 40 psi so definitely something leaking. Must be a gentle one as I can’t hear or feel anything.
The only thing that had changed in your setup is new valves, why did you replace them? Are they the same as the old ones? I’ve found Some brands have different shapes on the tyre side that can get in the way of the tyre seating properly.
I swapped out black Muc-Off for red ones. Exactly the same model, just the colour changed. Was planning to do the bar tape at the same time.
I took it to the bike shop and they think I didn’t clean it all properly as I didn’t realise I had to strip off all the old sealant. So I’ve now ordered some isopropyl alcohol and new tape and going to start from scratch, hopefully tomorrow when the bits arrive.
, until today 
Suffice it to say I’ll be getting something better to pump air in for next time. Good grief!!