weight ? for Pinewood derby car builders

[Gone Dave]

This is my first time to build a car with my son, and I am looking for some rocket science here..
My question is this, after construction I need to add some ounces, does it make a speed change if I put it in the front, center mass, or rear??:confused:

[Zoomschwortz]

This is my first time to build a car with my son, and I am looking for some rocket science here..
My question is this, after construction I need to add some ounces, does it make a speed change if I put it in the front, center mass, or rear??:confused:

I always put it low and near the center to try and keep the weight on all 4 wheels equal.

Make sure you polish them axles and sand them wheels so the contact surface is kept to a minimum as well.

[dunng]

Here's some pointers.. http://www.abc-pinewood-derby.com/speed-secrets-book.htm

and http://entertainment.howstuffworks.com/question169.htm

:ss

[Thaplumbr]

Graphite does good on the wheel axles, Good luck, and please post some pics!!!

[Starscream]

Graphite does good on the wheel axles, Good luck, and please post some pics!!!

We want pics!

[Opusfxd]

You gotta work the wheels and axles to do anything. BTW, www.scoutstuff.org now has colored wheels.

Now back to the weight, you can go stupid on all the physics and engineering that goes into where the weight goes posted on the internet. I seem to put mine right in front of the rear axle and up a bit. It has to do with the profile of the track I've been running on.

Have fun and good luck.

[smitdavi]

lol...Pinewood derby was the reason I joined the Scouts. Can still remember the cars Dad and I built.

[St. Lou Stu]

Like others have said.... Polish the axles/nails and remove the burrs from the nail head. also.... machine down the head of the nail to the smallest diameter possible while it still holds the wheel on.
Weight should be about 1/4" forward of the center of gravity of the vehicle without weight installed. Max weight allowed is a MUST!
Also, install the axles at a slight upward angle into the body so that when the wheels are installed only the outer edge of the wheels touch the track. sand and smooth the wheels to a near mirror finish too.
I may be forgetting some.... but the interwebs are your friend.

Most important of all..... let Jr. do most of the work while you teach him why it is you are doing each of the above.

[jjirons69]

Like others have said.... Polish the axles/nails and remove the burrs from the nail head. also.... machine down the head of the nail to the smallest diameter possible while it still holds the wheel on.
Weight should be about 1/4" forward of the center of gravity of the vehicle without weight installed. Max weight allowed is a MUST!
Also, install the axles at a slight upward angle into the body so that when the wheels are installed only the outer edge of the wheels touch the track. sand and smooth the wheels to a near mirror finish too.
I may be forgetting some.... but the interwebs are your friend.

Most important of all..... let Jr. do most of the work while you teach him why it is you are doing each of the above.

Tim is the man!!

Don't forget the spoiler adjustments! :)

[Footbag]

Graphite does good on the wheel axles, Good luck, and please post some pics!!!
:tpd: Graphite does wonders!

[Seanohue]

lol...Pinewood derby was the reason I joined the Scouts. Can still remember the cars Dad and I built.

:tpd: still have my 1st place trophy from like 12 years ago :D

[smokeyandthebandit05]

Just asking what shape did u choose? I have found something like a slight wedge works amazing. I try and find one of my old cars

[beamish]

Did pretty good with the cars my son and I made,I remember reading the weight should go over the back wheels,also when the car sits if the 2 diagonal wheels touch only this should speed it up as the friction will be less keeping 2 wheels off the track ,also the weight should be I think its 5 ounces if I remember right,think we had 1 car at 4.9 and the other at 5 exactly,I drilled the back bumper area up over the back wheels and used the tubular shaped weights that most hobby shops sell.....good luck