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wtf is this thread for
 

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aww whyfore the delete?! makes me wanna go get post out of browser cache ;p
 

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Can I get a woot woot for 2-piece rotors :D
 

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Well I have to agree that you can improve speed by reducing un-sprung mass and I have done it - and won quite a few races by running on only 3 wheels.

Any of you guys have boys that ever were in Cub Scouts? Ever build and race Pinewood Derby cars?
Well my two younger boys and I have -
You take one of the front axles/nails and bend it up so the wheel does not contact the track.


Old Indy style cars the first two we built. These finished 4th and 5th place out of 35- 40 cars in the pack.

Then we came the next year with the Lamborghini and the Lotus - the Yellow Lambo took 2nd place and the Red Lotus took 4th

The boys wanted Mustangs so we built a couple 05 GTs with custom body kits - got 4th and 5th with these Stangs

My middle son was done and It was just Chandler (who can't accept anything but first place) and he wanted nothing but speed - no fancy bodies so we built the bullet.

Note how the Front wheel is slightly elevated - 25% un-sprung mass reduction - and sealed us in for a Second place.

Then the last year we built another wedge car and took the track record and 1st place.



I can't recommend this for your daily driver but for Pinewood Derby racing - it definitely works.
 

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Joe ... guess what came in the mail today! (let me go out to the garage and photo them ... give me a sec...)
waiting patiently.......
 

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^^ Sure, I need me some pics :D
 

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Nice looking rotors, screw you un-sprung weight. Btw your white balance is set to "indoor".

Here's some fun I had not too long ago --> LINKY
 

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Indeed, I am lusting after some lighter wheels, can you say monoblock HRE's...
 

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"Unsprung weight includes the mass of the tires, brakes, suspension linkages and other components that move in unison with the wheels. These components are on the roadway side of the springs and therefore react to roadway irregularities with no damping, other than the pneumatic resilience of the tires. The rest of the mass is on the vehicle side of the springs and therefore comprises the sprung weight. Disturbances from the road are filtered by the suspension system and as a result are not fully experienced by the sprung weight. The ratio between sprung and unsprung weight is one of the most important components of vehicle ride and handling characteristics."

Add to that the rotational forces that accumulate with the wheels/tires/rotors { F = ma }, and anyone with high school physics can see why it's so important to reduce the mass of these componants as much as economically possible to get a great handling car.


More detailed analysis here: http://www.proteanelectric.com/wp-content/uploads/2011/12/protean-Services3.pdf
Did you read the attachment? The study did not conclude substantial degradation due to increased unsprung mass.

While perceptible differences emerge with
increased unsprung mass, on the whole they are small
and unlikely to be apparent to an average driver. The
nature and magnitude of the changes appears to be
nothing that cannot be overcome by the application of
normal engineering processes within a product
development cycle.
 

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Joe,

Was looking at my new rotors and found these "clips" inserted into the cooling vanes on some of them. One ring had two clips, two had one clip each, and one had none.
Have you any idea what they are???? They were inserted onto the vanes from the hub side -- so they would not have "flung-out" under speed. They are just like heavy-duty paper clips so I can't imagine they would effect balance.... Sent an email to Frank Derks -- he thinks they might have been used during painting ... but doesn't know.


bummer -- I just realized one of the clips is A LOT HEAVIER than the others -- maybe they are for balancing the rotors! major bummer!
Weird. I never seen those clips on rotors before, very odd.
 

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Petew actually I'm very interested in this topic. I cannot find in your statements any opinion you have made about unsprung mass, more like hints of suggestions.
Is it your opinion that less unsprung mass (keeping total mass constant) provides you with more speed performance? Obviously less total mass is better for speed, but that's not the issue.

From what I read in the linked research, they tested a controlled unsprung mass vs an increased unsprung mass. For each they tested on normal road vs a rough road. Finally they used an expert driver to try to tell the difference, vs sensors and computers logging what it could feel.

Along the way, and in the final conclusion section, the author stated that the differences from increased unsprung mass were negligible, when compared to differences due to the rough road.

I'm not sure whether you're agreeing with him or stating something else entirely.

Yes, I have spacers, and the negative handling difference is negligible, while the look difference is quite effective.

Please clarify! I'm no physicist, so could stand to learn from anyone.
 
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