The Pantour hub does help to reduce vibration in the handlebars a bit, and I liked it enough to take the trouble to restore it! To check the bearings for play, just push the rim from side to side and watch for movement between the rotating part and the fixed centre. Even with brand new bearings there will be a small movement of maybe a couple of millimetres measured at the rim. To check the elastomer, simply stand astride the bike and then press down as hard as you can on the handlebars whilst watching the rim adjacent to the brake blocks. You should easily detect the movement, and when you release the pressure, you should see the rim spring back up in relation to the brake blocks. If there's no movement, it means the elastomer has solidified and needs replacement. To check the main frame hinge, set the seat height so that you can sit on it with legs apart and your feet flat on the ground. Then press down alternately on each side of the handlebars while looking down at the hinge joint. If you can clearly see movement between the hinge parts, you'll have to make a decision about whether it's at an acceptable level or not. Best thing is to ride it up a hill which requires you to put some serious pressure on the pedals and see how "squirrelly" it feels. All folding bikes with long seat and handle posts flex a lot from side to side under heavy pedalling, so you just have to decide how much flex you can tolerate. If there aren't any hills where you test the bike, you could shift into a higher gear than you normally would and press harder on the pedals to try and generate the flex.