Can someone school me on un-sprung weight and wheel types?

[Pauli33]

so i'm a little unclear about the issues with "un-sprung" weight... from the way everyone talks about it it's clearly worse than weight supported by the suspension, but i'm a little fuzzy about why. care to illuminated me?

this all came to me after hearing that RUF is producing the 17" CTR1 wheels again... i've always thought they were beautiful, but after hearing everyone complain about how heavy they are i'm not sure i can justify the extra expense over other wheel options...

second, can someone explain the pros and cons of various wheel types - cast, forged, 3-piece, etc... are some better for certain applications (track vs street)?

thanks in advance...

cheers,

Paul

[IROC]

Hold your arm out straight ahead of you. Which would you rather hold - a 5 lb dumbell or a 25 lb dumbell? Which would be easier to quickly move around? Just like the lighter dumbell, your suspension can much more quickly react to road imperfections, etc. with less tire and wheel mass out there (the lighter dumbell). This equates to better handling (and ride, for similar reasons).

As for the types - forging generally allows the strongest wheel using the least amount of material (again - the lightest dumbell). Three piece wheels allow for a multitude of offsets for a given wheel center. Forged, 3-piece wheels are often seen on track cars for this reason. On a street car, you can get by with less.

Mike

[Pauli33]

ahhhh, that clears things up for me... thanks for the explanation. makes perfect sense. unfortunately now i'm spooked about getting new wheels - all that cash and not knowing how it's going to feel/ride once they're on is a bit scary...

any recommendations for a nice looking 17" street/track wheel would be much appreciated!

[MT912RS]

Anything in the suspension system that moves relative to the chassis when the car is in motion is unsprung.

[Bill Verburg]

If the weight increase is <~10# you will never notice it, as long as the shocks are in good condition. Do watch out for changes in the overall height of the tire. Small differences there make for perceptible changes in the torque curve. Taller moves it right and down, shorter moves it up and to the left.

[Jack Olsen]

Lindsey Racing makes 17-inch wheels out of Fuchs centers. Surprisingly, they are lighter than the comparable-width Fuchs in 16-inch diameters.

Here's Pelicanite 81930's car with a set:



More Lindsey pictures here.

They are so light, it can be hard to keep the car down on all four wheels.

[Pauli33]

hmmm.... i must confess, i was kind of looking to get away from the factory look, but those Lindsey's look like they mean serious business! it's amazing what one extra inch of diameter does...

where can i find prices/dealers? a google search didn't turn up much.

[Bill Verburg]

There are real advantages to some of the aftermarkets(besides lite weight) like Kinesis and Fikse, namely caliper clearance and a more open design that promotes air flow across the rotors.

[Jack Olsen]

That's true. From a functional point of view, there's no beating the newer technology. But if you've got a soft spot for the look of Fuchs, the Lindseys are a good compromise.