confused with vibration

i have a vibration that normally hits at about 55 and settles down between 60 - 65 now i know your probly going to say wheel balance but heres the best part for the whole drive to work to day nothing, not a single vibration for 15 miles, yesterday it vibrated, why nothing today and why dose it stop on long left hand turns and long right hand turns.plus thers no shaking in the steering wheel and no shaking while braking

have you had these tires on for a while? Tires can throw a belt and sometimes poor balancing comes and goes too

Maybe hub bearings?If it stops on turns it sounds like a bearing problem,or just crap tires,jack er up and shake down the front end for loose parts.

Mine does that too and I know I have a bad upper ball joint.

Checked the upper/lower joints or the control arm bushings?

all above and if the lower track bar end is moving around that could do it too