Remove spare tire, how much mpg gain?

I added a 30lb hitch, and I didn't notice any difference, but my wife lost 20lbs., so that kind of makes up for the hitch.lol

 

I took out spare, front seat, top part of back seat and did lithium battery upgrade. AND running around town near empty drops the weight 180 lbs total. Basically converted the Gen 2 to an NEV, except for occasional trip. I always carry a pump and tire plug kit and have always been able to plug and fill..or get to Walmart for repair before going flat in 50 years on the road. And for around town I could walk home so not a problem for me in small town. Will be interested to see mileage on highway though on next road trip with the lower weight, and since I use it for camping I have to make up for carrying a few extra items on such trips.

 

Yep not enough weight to make any significant different. My 2021 AWD Prius did not come with a spare so she has one in the back, now. Roadside assistance is great if you have 2-3 hours of spare time on your hands.
I recently finished a bathroom renovation in my house and had about 150 pounds of unused stuff to return to Lowes. (A 50 pound back of mortar and four boxes of tile was the bulk of the weight) It was in my car for a couple days and I didn't notice a significant drop in MPG on the gauges...maybe 3-4.
A gallon of gas weighs about 6 pounds so if you only filled up halfway (5 gallons) you could save 30 pounds there.
I've heard we need to do the "pulse and glide" method to get the most MPGs available. When starting, get the car up to speed quickly, then glide as much as you can after that....really works! The goal is to get the ICE running as little as possible and it won't kick on unless you floor it or the traction batteries are low.