I've just had an utter pain in the garage trying to set up a lightly used Forekaster tubeless on a Dt Swiss rim. Previously I've been able to get this combination working with floor pump alone, but this time even the CO2 inflator could barely cut it. I was finally successful with the CO2 inflator at seating, but then when I put in the sealant, valve and tried again with the floor pump, I couldn't get air into the tyre again.
The tyre felt baggy and very easy to pop onto the rim. I wasted a fair amount of CO2 cartridges and sealant before giving up and fitting a new Forekaster on with no problems at all, proving it's an issue with the tyre.
Has the tyre been stretched out too far by the previous rim and then possibly expanded by being left in the garage (only for about a year)? Just confused as it had not been used much and I didn't expect to have any problems. Starting to understand the unexpected complexities of what being a bike mechanic must be like.
Not uncommon ime - new MTB tyres are ezpz, but used tyre on a different rim can cause issues. I guess the bead just gets a bit worn and doesn't seat as smoothly.
Compressor would sort this, although they're typically not needed on a MTB tyre. It very much is needed on some road or cyclocross setups, so is useful if you ride different bikes.
Maybe a few wraps of electrical tape over the rim tape, bulk it out a bit?Â
Read my tubeless woes on my thread 🙄 I had the opposite, part worn Magic Mary off my mate , went up straight away and had stayed up. Brand new Assegai pain in the bum ! Put a new valve on , nope ! Finally added extra sealant even though I'd put the same in as the MM finally 👍