Topic starter
I spent north of one hundred earth pounds on a Bontrager Air Charge a couple of years ago thinking this will work a treat and to a certain extent it has.
Trying to seat 50mm GravelKings today, and a fair portion of yesterday and it's no Bueno. I don't know what's going on to be honest.
The pre charge feels the same but when you release the hounds it's more of a damp squib, it seems the air is escaping at the valve before it gets in. It should be 200 psi ISH blasting into the tyre.
I've only used it 6-8 times, I hoped it might last a bit longer before I had to replace the head.
I'm basically asking what you use or recommend as mine no Bueno.
Posted : 15/04/2025 8:06 pm
you've taken out the valve core ??
Posted : 15/04/2025 8:17 pm
Topic starter
Yes, yes I have.
I'm thinking it's a valve/pump head issue to be honest. I tried some PTFE tape on the valve stem to beef the interface up but no dice.
Posted : 15/04/2025 8:20 pm
... and valve stem definitely not clogged ?
(after that, I've got nothing)
Posted : 15/04/2025 8:31 pm
Could well be the tyre. I’ve had no end of trouble in the past getting gravelkings setup. They’re just way too baggy on the rim. They also seem quite flat when you unpack them, rather than tyre shaped if that makes sense?
Have you tried inflating using a tube to get the beads locked in, then carefully undo one side to get the tube out without disturbing the other, then hit it with the air blaster doofer.
Posted : 15/04/2025 8:32 pm
oldnick reacted
I've had some tubeless valves which were really narrow and couldn't mount the tyres. You could try drilling the valve to make the hole larger at the rim end.
Posted : 15/04/2025 8:42 pm
Topic starter
Some good suggestions there. I'm glad I asked.
I will go back and try again.
Posted : 15/04/2025 8:44 pm
Topic starter
Right. Just back in and thanks to a combination of the above, drilling the valve and getting one side on with a tube the score so far is frustrated guy in the garage 1 Bastard GravelKings 0
This is, if course till I go out tomorrow morning and find it flat.
Posted : 15/04/2025 10:46 pm
cerrado-tu-ruido and Tom83 reacted
If not new valves then try pushing a piece of wire through, they do gunk up on the rim end with whatever sealant you are using.
Posted : 16/04/2025 6:48 am
Ahhh Gravelkings, put a pair on last year using a compressor, had to call in the bike shop cavalry for one of them . Had an ongoing issue with the front one recently, wouldn't stay up no matter what .
Thought right stick a new one on yesterday, compressor is at mates house he's not around , Didn't hold out much hope but it popped into place using my track pump ! Having said that haven't looked this morning 😔
Got a bit of a theory FWIW Old pair without realising one was the plus version the other wasn't , the new one is a plus . With that extra reinforcement would that make them " shape and seat" better ?
Posted : 16/04/2025 7:02 am
They will almost certainly go down overnight, but just top up the pressure and go for a decent ride. Once they're on and happy, they'll be fine.
Posted : 16/04/2025 9:18 am
It's messy but ensuring there is some sealant all around the bead works for me on baggy tyres.
Posted : 17/04/2025 8:52 am
