Front end vibration at deceleration

[Buster]

1941 WL I put together from parts 2,000 miles ago. Always had too much front-end vibration. 18" tires with new Shinko tires, new front hub ball bearings. Front fork head stock bearing is adjusted correctly. Front end vibrates badly upon deceleration. Gets worse the tighter the springer ride control is adjusted. Took wheels apart and retrued, changed from spoke balance weights to Dyna Beads. Front wheel spins free. Have tried 20 to 30 lbs. air pressure on front tire with no difference. I suspect possible problem could be with front Shinko tire (possibly bad tire with defective belt)., but have not had this problem on other bikes. Does anybody have idea of what could be causing problem. Any help appreciated.

[dukekleman]

What are the current Axial and Radial runout measurements?

[Architect]

I had a bad death wobble with my Shovel running Shinko's, went to Dunlop and she rides like a new bike. For me they are suspect at best.

[duffeycycles]

Customer bought stinko wide whites for his Shovel.Worst fricken tires ever

[Buster]

Probably get around to check runouts, neck bearing resistance, and alignment this weekend. Raised tire air pressure at both ends to 35lbs and vibration almost gone, but not quite perfect. I believe the 18" Shinkos will not handle the 20-24 lbs. low pressures many commonly run with ridge frame. I have run lower pressure in better brand tires on ridge with success. When I installed the Shinkos, I noted they were very flexible in sidewalls. Believe these tires suck. Probably upgrade them this winter to what I should have put on originally. . Thanks.