Physics question about gearing + tires

As well all know, 4-bangers lack some muscle. A lot of people recommend regearing for going up to 33's, but is the need to regear due more to the weight of the tire or the diameter?

The reason I ask is, a lot of the 265/75/16 mud tires (or BFG ATs weigh right around 50-55 pounds, but I'm considering the Kuhmo Road Venture A/T in a 285/75/16 and it only weighs 52 pounds. When I upgrade tires I either want to get a mud tire in a 265, or the kuhmo A/T (which is my current tire and has aggresive tread for an AT) in 285, and my options generally weigh the same.

Thanks to all the physicists out there.

 

Both, but more for the diameter.

think of it like gears on a bicycle.

Example: http://en.wikipedia.org/wiki/File:Bicycle_mechanical_advantage.svg

 

well im no physicists but from what i have read its the weight, width, and turning radius (height) that effects the amount of power at the wheels. When making the jump to a 285 you may not be getting the weight factor with your choice of tires, but you are going to be creating more rolling resistance via the extra height of the tire and also more power is going to be needed to turn the tire due to the extra width.

another option is you could cut out one of the 3 issues (height, weight, width) and go with a skinnier tire such as a 255/75/16 or 255/70/17. Most of the reviews state that they almost ride like a 265. Something to consider if you dont mind skinnier tires.

hope that all made sense

 

Definitely has more to do with diameter.

 

The weight plays a big part too.

 

I know it plays a part.. Did your 4banger get a lot more sluggish after you put on your 33's?

 

Not a lot but yea

 

I'm not worried about a re gear. I drive about 100 miles a day and still do 90 everywhere I go. Just get about 17 mpg