Experienced it last weekend on a 4 day trip. Coincidentally, just had new Pilot Road 5's put on, and had a few hundred miles on them at the time. Conditions were: 2017 Multi S touring, about 3000 miles on it, with factory panniers, trunk, and Ducati touring screen. Bike is stock, air was clean. My height/weight, 6' 1" 260lbs. Bike was in sport mode, factory settings(going to double check that), preload 2 up (24) with bags, because I'm heavy and had luggage for trip. Nothing strapped externally. Riding with two other new GS1200's, friends of mine. One buddy decided to run me from a roll and was coming up, we stayed in it and somewhere just over 100mph my bike went into a wobble that was BAD. It kept oscillating worse and worse, I thought I was dead. I did not chop throttle, gently rolled it back and did not touch brakes. Seriously BAD, almost a tank slapper. Shook me up big time. Tires are balanced(new), pressures were F36 R42psi. I am so disappointed, I sold an S1000XR that also had a speed wobble, it began exactly at 120mph. I am not sure what speed the Multi was at, I am scared to duplicate it, and was not looking at speedo. Friend thought just over 100mph. I wasn't even out of 4th IIRC, stock gearing. it baffles me when the GS's have SQUARE panniers and trunk, with zero aerodynamics, and they are rock steady. I have ridden my bike with JUST the tail bag and stock tires before this, and I am sure I must have gone this fast. It had not wobbled before. It is either the new tires, or the fact it had panniers on and was loaded with gear. Definitely when accelerating hard, and front starts getting light, it triggers it. I love to wheelie too! Argh! Was in uphill passing lane pulling my friends just before that, road was irregular and front tire rose maybe 1" off pavement on a rise, did a minor wobble but not bad. Didn't thnk much of it, probably 80-90 mph I'd guess.