i got a question...

[fastball48]

I hear so many people talk about heavy rims and stuff, but i dont yet understand the exact setbacks that it causes to your car in terms of quarter mile time? handling? etc... and if you have a high horsepower car, can the weight of the rims still make as big of a difference than in a stock car???

[whiterps13]

Well Im not really the one to talk, look at my wheels. However, the reason people worry about wheel weight is cintrifigul force. When a wheel spins, physics mulitply the weight by some factor due to rotational mass. Adding 1 pound to a wheel would equal adding many more pounds to the car (I have no clue about the actual relationship). I understand the concept, but maybe someone with more knowledge can elaborate with more details, like actual numbers.

Another factor to consider is overall tire circumference, which can easily throw your gear ratios out of wack. A taller tire effectively changes your gear ratios, as would a smaller tire. Again, someone with more knowledge will need to give you some real time numbers.

[benemorius]

Adding weight to the tires adds to the rotational mass and unsprung weight. These negatively affect RWHP and the life of your suspension components, respectively. I'm not the one with the numbers, though.

I guess you could look at it like being the opposite of a lightweight aluminum flywheel if that helps you understand it.

[naed240sx]

Short and simple:

Heavy wheels have more inertia, and take more energy to accelerate. The heavier your wheels are, the slower your car will accelerate, and the slower it will brake.

They also affect handling. Heavy wheels don't conform to the road as well. When the hit a bump, the go over, but cannot return down to the road as fast as lighter wheels (vertical acceleration).

[Eddie]

the reason people worry about wheel weight is cintrifigul force.

Whiterps13 don't meen to burst your bubble,but centrifugal force does not exist only centripetal force. It's no big deal, but a lot of people don't know that. Inertia is the cause of the so called centrifugal force. When you are driving in a straight line and take a right turn, your body wants to go to the left. Your body is actually still going straight, but your vehicle is moving closer to your left side if that makes any sense. There is no force pushing you away and making your head hit the window.

[benemorius]

Well since we've opened up the bursting bubbles can, centrifugal force most certainly does exist. In modern days it is defined as the reactive force to centripetal force. Originally defined, it was considered a force. It has since been redefined as a reactive force. Following your example, the car exerts centripetal force on the occupant by changing direction, and the occupant exerts centrifugal force on the car due to its inertia and the centripetal force the car is exerting on it. And it's beside the point anyway. Neither centrifugal nor centripetal force are behind the mal effects of heavier wheels on acceleration. Inertia is.

And just so another smartass doesn't come along to try to burst my bubble, I'll state that technically the weight of the wheel is not what affects acceleration, but rather the mass of the wheel is.

[Eddie]

whiterps13 I was not trying to be a "smart ***" and I realize that my little tangent had really nothing to do with the topic of the post. I wasn't picking on you I just wanted to let you know about commonly missunderstood topic. No hard feelings.

Benemorius take a course in dynamics and then tell me if they ever mention centrifugal force as a real force.