So, based on the above, using an iPhone on a Harley should be fine.
If it has the rubber engine isolation. Pretty much the last place I would mount a phone is on a handlebar mount. Safety of the phone aside, if I took the time to read something on the screen or make an adjustment, around here the traffic would flatten the rider.
Out west where the roads are straight as far as the eye can see…….maybe.
Hoping for safety for those that watch their phone while they ride.
OM