wheel weight

[rjscustom]

how much does wheel weight affect really affect performance? I have a set of 7in. chrome stockies that weigh 54lb.s each with tires.

[Squirmn German]

Any added weight to a car has adverse effects on performance. Of course a lighter car will be quicker than a heavy car. It also takes more torque/HP to turn a heavier wheel than a lighter wheel. The only positive to wheel weight is that its evenly distributed around the car as opposed to say, battery weight or driver weight which is off centered weight.

[Bruce Tweddle]

The only positive to wheel weight is that its evenly distributed around the car as opposed to say, battery weight or driver weight which is off centered weight.

There's nothing positive about heavy wheels in a drag car.

Your wheels have a double effect at slowing you down.  Not only do you have to accelerate that 108 lbs of dead weight down the track, you also have to accelerate those big flywheels bolted to your drums.  Those flywheels are doing their best effort to resist the acceleration.

With a pie plate wheel and a light slick, you can easily remove 30 lbs from each wheel.  Doing this will have much more effect at reducing your ETs than removing 60lbs from anywhere else on the car.

[Jason Foster]

  Wheel weight is "unsprung weight" and anytime you reduce unsprung weight you will reap benefits.  Such as better acceleration better handling and less wheel hop

The sprung weight of a wheel controls: a trade-off between a wheel's bump-following ability and its vibration isolation. Bumps and surface imperfections in the road cause tire compression—which induces a force on the unsprung weight. In time, the unsprung weight then responds to this force with movement of its own. The amount of movement is inversely proportional to the weight - a lighter wheel which readily moves in response to road bumps will have more grip when tracking over an imperfect road. For this reason, lighter wheels are often sought for high-performance applications. In contrast, a heavier wheel which moves less will not absorb as much vibration; the irregularities of the road surface will transfer to the cabin through the geometry of the suspension and hence ride quality is deteriorated.

Pneumatic or elastic tires help by providing some springing for most of the (otherwise) unsprung mass, but the damping that can be included in the tires is limited by considerations of fuel economy and overheating. The shock absorbers, if any, damp the spring motion also and must be less stiff than would optimally damp the wheel bounce. So the wheels execute some vibrations after each bump before coming to rest. On dirt roads and perhaps on some softly paved roads, these motions form small bumps, known as corrugations, washboarding or "corduroy" because they resemble smaller versions of the bumps in roads made of logs. These cause sustained wheel bounce in subsequent vehicles, enlarging the bumps.

High unsprung weight also exacerbates wheel control under hard acceleration or braking.[clarification needed] If the vehicle does not have adequate wheel location in the vertical plane (such as a rear-wheel drive car with Hotchkiss drive, a live axle supported by simple leaf springs), vertical forces exerted by acceleration or hard braking combined with high unsprung mass can lead to severe wheel hop, compromising traction and steering control.

[martin]

You can really feel the extra weight in the heavy steering and swing axle rebound when driving on the street. It's a tradeoff for wider wheels, bigger brakes, etc. For reference a stock rim is 15 pounds, and with stock tire about 35 pounds.