Tire Weight: How much does it matter to you?

I'm looking at a few different tires. I like the Duratrac RT, Wildpeak AT4W, and a few others. Both of them are the same weight according to tirerack.com.
At what point would you consider a weight difference "too much"? 5, 7, 10, more #/tire? Obviously bigger tires are going to be heavier, but at what point do you say “No, the tire is too heavy.” or “That much of an increase in weight is going to take its toll on the fuel economy.”
I also understand there's a difference between static and rotating mass. At what weight difference do you consider a tire to be too much over your current tire?

 

A 50 pound tire makes a large difference over a 40 pound tire.

If you're considering weight, stay in the SL category. 90% of people that "absolutely positively NEED" an LT, in fact, don't need an LT.

 

Function of the tire comes first. If you need a specific type tire for use, you may suffer the penalty of weight. Some of that can be offset with a lighter wheel.

I'd wager a massive majority of users here buy for looks and tell themselves they might need that function sometime. And we see piles of threads about wheels where weight isn't a thought, at least not mentioned. (some do) Most are more concerned about following the black wheel lemmings with a style they like.

An example. On my autox car I wanted light and sticky, yet street legal (for classing). I wanted the wheel/tire package the same or less weight than stock, and I was using a larger wheel/tire.

The lightest tire I could find with the grip and size I wanted was heavier than my goal, so I picked a wheel that was lighter to 'offset'. The total package wound up less weight than OE, larger sized, excellent grip, street legal. And my wallet was lighter too.

A taller package changes the effective gear ratio as well, one reason you see folks spending lots 'o bucks to regear.

Every choice is a compromise of something else.

Does a couple of lbs matter? Mathematically it all matters. How much practically? That's hard to make a specific line.

Letting the goal be to stay light and meet your functional need will give the best result.

Good for you for thinking!

 

Depends on how much you are able to lift if your spare in on a tire swing or you have to life it in to a truck bed

 

To me performance matters more than weight. The 35s I'm running are such a massive increase in capability over smaller tires, that I'm happy to put up with their 65-lb weight in daily driving.

 

You're right about that. Getting that 35 onto the swingout was more difficult than I had anticipated. I'm glad my rims are shaped in such a way that I can get a good grip on em.

 

Great example, and exactly what I was trying to explain. You understood your functional need, the compromise going to that size/type/weight, and made your choice.

 

I just went from 255/85/16 Cooper ST Maxx to 265/75/16 Cooper Road + Trail. The Maxxs were 54lb and the Road + Trails are 40lbs. There is a HUGE difference in performance, especially with a 4 cyl. This was also a change from Load Range E to SL.

 

Tires/rims are "unsprung weight" adding weight to those levers (A arms/Rear Member) has a greater impact then the tire or rim's weight difference suggests.

 

Might want to start training if you can't lift a 100 lb spare into the bed

 

I recently have run 45lb KO2s, 51 lb KO2s, and 61lb Falken AT3W. Surprisingly the mpg is fairly similar. I get around 280 miles out of a tank. I would have thought I’d see a bigger difference in mpg but I didn’t. I’d say I have about 25 percent stop and go traffic in my driving.
Running 285 70 17 C load