I'v got a pair of stans olympic rims on my xc bike.
I use it for both xc and commuting, so i often swap tyres between knobblies and slicks.
I want to go tubeless for offroad but i'm a bit confused. If i use the stans yellow tape and olympic valve along with UST tyres, do i have to use the tyre sealant?
Cheers.

Probably not but I do

Thanks. I don't really want to go down the sealant route due to the mess when swapping between slicks and xc tyres.

You should be ok but it might be harder to inflate them, bung a stans rim strip in there (the rubber one) and youll have 0 issues tho. Not sure why your worried about the sealent tho, ive swapped tyres a few times without any issue, you just pull the tyre off and pour the sealant out the tyre into the new one, easy as!

It's just the extra hassle. Will be swapping tyres once or twice a week. And i have Mavic EX823 and XM819 rims without sealant for nearly 2 years now and only had 1 puncture when i let the pressure get too low.
At the moment, just can't justify a second set of wheels.
Thanks for the advice.