My front wheel gets a “shimmy” when going downhill at 30+mph. The bike does not do this with my Neuvation wheels. I am wondering if they are not balanced properly or if I should run longer stems. I have taken them to 2 bike shops and they each said the wheels were in good shape and no issues. One shop did say to try longer stems. I have 60mm stems on so I think I may try 80mm to see if it makes a difference. A buddy said he had this problem with some Zipps and he had to actually had to add some lead to balance the wheel. Has anyone else had this issue?
Nope, mine are great. 30 mph going downhill is slow. I have hit 30 on a flat road with mine. Are you sure it isnt your handling skills/fears?
Being serious, not trying to put u down.
I have hit 50mph with mine going downhill with no problems. I am using 80mm stems, but I don’t see why that would make any difference.
Been riding mine every week as my daily training wheels for a year and a half and not a single problem. I am running Cosmic Carbone SL with a PT rear.
Greg
Send them to me. I’ll check 'em out for you. 
But seriously:
- Check to make sure your brake is tight.
- Do you have a bottle launcher on your seatpost? That gave my bike a death wobble.
- Play with the play on the front wheel. Put it in the fork and grab the rim and rock it side to side. Does it move? This might indicate the hubs are lose, but the LBS should have caught that.
No problem with my handling. They START the shimmy at around 30mph, at least that is when I first notice it. Above 40 and it is a little bothersome. I have no problems with my Neuvation wheels. The hubs are in good shape. the wheels only have about 500miles on them.