Passenger backrest vibration

[Bull Durham]

Question, see if anyone else has this problem and what they did to fix it.

I have the stock passenger backrest on my 2005 Nomad. It vibrates enough to drive my wife crazy where she has to stop and scratch her back. At first I thought she was nuts, but she lifted up her shirt and her back was all red from being itchy. Yes, the backrest is bolted tight, it's just the vibration from the engine.

Same thing happens when my boy rides back there, and he's not a little boy either.

The only way my wife can take it for more than a mile or two, is to put a small pillow under her coat so it doesn't cause itching.

Anyone else's passengers experience this? I've seen some other comments on the web about the Nomad and passenger backrest causing itching.

If you had this problem, what did your passenger do to stop the problem?