where to place weight

[big G]

Hi All,

I stumbled on your board a few weeks ago and i think I've read every post, and more than just a little tempted to participate in WIRL. My question is in regards to our BSA race, We have won 1st in our den and pack champion three years running but fail to even compete in district race. our tracks are very old rough wooden tracks. The tracks at district are nice smooth aluminum. I have always centered my weight in the car and have good axles and tires with dead on alignment. After reading all your posts we have moved our weight back to 1.5" in front of rear Axel. Now I'm starting to worry because of how rough our tracks are and not having the fronts weighted enough.Lets face it if we don't win in our pack the district race is mute. Since they impound our car moving weight isn't an option, we do get them back to take to district but are warned not to touch them. Any suggestions would be greatly appreciated.
Thanks
Big G

[ProQuest]

Welcome bigg:

You moved the weight back to 1.5" in front of the rear axle, but where did that put the balance point? If your balance point is 1.5" in front of the rear axle you'll be fine. Many of the builders who race here and in the other national leagues use a balance point less than 1" in front of the rear axle. A balance point of 1.5" is very conservative. My guess would be that if your car does not perform to your expectations at the Pack race, it will not be due to you having moved the weight back. Again, this assumes that when you say you moved the weight back to 1.5" in front of the rear axle, you actually mean you moved the balance point (or center of gravity) to 1.5" in front of the rear axles.

ProQuest/Steve H.

[big G]

proQuest,

Im sorry i didnt make that clear yes the balance point is at 1.5"in front of rear axle. Thanks for the comment our cars always run smooth on that track just dont want to be one of the many that fly off the track....that just can't be good for alignment

[Lucky 13]

Bigg, Welcome to the DerbyWorx board. I'm glad you decided to jump in. My boys and I have the same problem you do with differences between the Pack track and District track. Last year we decided to go aggressive on the weight placement and had the com at 3/4 of an inch in front of the axles. The car ended up running great for us. He won Den, Pack and went on to place 3rd at District, so setting the car up to perform well on both tracks is possible. Do you have your own scale ? If so, weigh the front end of the car and let us know how many grams it is. To do this place the rear wheels on a block the same height as the scale and set the front wheels on the scale. If your front end weighs in between 25-30 gram max., you should be good. Anything lighter and you might have some problems if the track is extremely rough.

Lucky 13

[docb]

With good alignment, I don't see any problem having your COM around 1 inch in front of rear axles, even on the wood track. I would agree with Proquest and Lucky, 1.5 is very conservative and that is probably your issue regarding districts.

[Parrot Racing]

Bigg, you are obviously not alone. Our pack track is an old wooden one with joints that can pop a car clear off the track. Our car had com of about 1.25, a little less agressive than the league cars I race. Looking back on our race last week, had I put the com at 2+, literally, I am sure we would have taken an easy first instead of third. As soon as I figure out how I am going to post a race or two for an example.
We should be fine at district with the 1.25.
Enrico

[big G]

Thanks for all the advice gents

We were able to get the wheight a little farther back today. the load on the front tires is 40.2 grams and the back is 101.9. I can not get it any lighter than that unless we drill out all the lead and replace it with tungsten maybe. I probably have 50 pounds of old tire weights that were given to me by the tire shop here in town to use for our cars.

[big G]

oh no parrot,

now im nervous again

[car guy]

3/4 to 1 inch in front of the rear axles is the best. 3/4 is pushing it though. We have used this in both our kids cars and out of 12 races we have 11 1st place awards. We jumped the track in one race and were disqualified we were at less than 3/4 on the balance point.

[scojo]

Is this dependent on the shape of the track? Last year was my son's first PWD and we weighted slightly in front of the rear axle. I was surprised to see that rather than a drop and a long flat, the track was one constant angle decline with very little flat. Does that change where we should put the COG?

[speedy]

Does the method of drilling 3/8" holes parallel in the body and in front of the axles work better?

Or are you better off carving space from under the car and adding the weight?

[beakerboysracing]

Dec 19, 2008 10:41:39 GMT -6 scojo said:

Is this dependent on the shape of the track? Last year was my son's first PWD and we weighted slightly in front of the rear axle. I was surprised to see that rather than a drop and a long flat, the track was one constant angle decline with very little flat. Does that change where we should put the COG?

Scojo,
In the case of the track you are describing, where you put the weight doesnt matter.

Does the method of drilling 3/8" holes parallel in the body and in front of the axles work better?

Or are you better off carving space from under the car and adding the weight?

Speedy,

You want your weight as low as possible. Also centered in the body far back. If running three wheels , make sure the weight falls in the triangulation of the 3 wheels touching.

Drilled holes or weight cavities really makes no difference, that is determined by the body style of car.

Scott

Beakerboys