Proper tubular tire installation I'm trying to install a new tubular tire once again. The problem is every time I do this I always get it wrong because I always have this area (let's say 10-15cm each way) around the tire's valve that kinda extends a bit so when I ride after the installation I always have this wobbling, which you barely notice when you ride slow but when you speed up it's getting kinda annoying and a bit scary.

I watched A LOT of videos on youtube, I used different kinds of cements, tape and ways of installation, but I can't get it right for some reason. Maybe it's because I use cheap tires or I need to do something after the tire is settled on the rim?

Please tell me what am I missing here?
If you have got a loose area of tyre next to the valve, you need to 'distribute' this looseness to some other part of the rim.

Put a screw-driver across the rim under the tyre, and roll it around the rim away from the valve.   The screwdriver will slip on the metal rim, but grip the tyre, so it will revolve.

Do this for both loose areas, each side of the valve, before you blow the tyre up.   Once up to pressure, the tyre should run true, and be well stuck.
Cheers...  Pete