Today, while commuting to work, I was on a paved riverbed trail that I take all the time. I sat up and rode with no hands for a bit, which I also do all the time. Something different happened this time though. The handle bars and front wheel started wobbling back and forth and the more I rode it got progressively worse. I only rode like that for about 5 seconds as it happened almost immediately.

I attribute it to my rear rack being extra loaded down today as I had some extra stuff back there that I don't normally carry around.

I usually just throw my clothes in a bag on the rack and I am good to go. Today it was clothes, lunch, drinks(3 12 oz sodas and 2 16 oz bottles of Vitamin water), water proof deck boots and a medley of fruit. I had a good few extra pounds in the back.

The bag was centered on the top of the rack so a weight imbalance side to side was not an issue.

Sound like I just moved too much weight to the back and gave the front wheel an opportunity to get "light" or am I crazy to keep riding??

If you keep your hands on the bars you will be OK in a straight line, but severe weight imbalance can definitely compromise handling in an emergency. The weight being high and in the rear is the issue, not whether it is centered. You created an updisde dwon pendulum which accentuated any instability already present -which can come from a variety of causes, and the low weight on the front also accentuated the effect. Get some of the load in the front or at least lower on the rear using panniers.

I'd check the tire pressures first thing (wobbles that dont' want to "go away" are often a sign of low tire pressures). But yes, an over-loaded rear rack could be the real culprit (cargo weight should be carried high up front, in the "center" of the frame, and down low in the back).

Ya, today was more of a fluke for now and panniers are in the works. The load was so high I actually had to take my saddle bag off because my other bag was right up under my seat.

Tire pressures are good. I'll figure it was the weight since that is what has really changed and is out of the ordinary. I just wanted to make sure this would not be a symptom of a failing wheel or other such up front components that I need to worry about. I'll keep an eye out for it to occur again with less weight.

Thanks.

could be all the cliff bars and hot tamales..... (inside joke)

So the extra weight isn't my rack but it is my gut? Perhaps!!

felt a bit of swaying, with each pedal stroke, on my loaded touring bike,
load is on the end of a lever.. the rear rack.
adding to the frame tube's flexibility.