Best place for weight on a road course?

Blue_Wahoo_Racing Saturday, 2/27/2021

Where should I be trying to get my center of gravity for a road course racer.  I have a mail in race coming up and don't have a road course to test on.  So i am just looking for some tips for center of gravity.  Should it be centered in the length of the car or should it be centered between the wheels?  I am sure each car is different but I need some general rules of thumb for adding weight to a downhill racer that will be used on a road course. Thanks in advance for helping a newb out. 


Discussion

View member profile
SpyDude 2/27/21

Speaking as a newb myself, I would say more or less centered between the front and rear axles, with bias towards the rear. Weighing the front too much will cause it to jam harder into any turns and not steer real well. Having the weight in the rear two-thirds of the car should do it.

View member profile
redlinederby 2/27/21
Site manager

The article linked in your question about weight has some tips about placing weight on road courses.

I'm not a road course racer at all...total noob when it comes to that but my hunch is a middle weight like Spy said is probably best. I think the key to open road courses is just not spinning out...in many ways, just outlasting your opponents. 

View member profile
CrazyEights 2/27/21

I'm kinda curious on this one. With the upcoming pro am how do you build a drag car that's good on fat track too. I know where some would like me to put the weight. Lol!

Good thing I'm in the amateur division. I'll hope my partner has experience in this.


  • The two cars that have performed best in the 8 Modders races at Psychedelic Speedway (the June track) had some added weight in the very front of the car, but not too much (read: one small tungsten cube), more or less directly above the front axle. The rest was in the center of the car, as low as possible, and tending toward the back (just in front of the rear axle). The reason given by those builders for putting a little extra weight in the nose was to have the weight forcing the front end down the slope of the banked curves, to keep the nose pointed forward coming out of the turn. For what that's worth. — GenX_VintageRacing
  • That's a good tip to know - thank you. I was considering doing this. — SpyDude
  • Cool. Thanks. — CrazyEights

Easy, inside the car!

#bazinga


  • Bwahahahaha! — CrazyEights
  • lol...well obviously....my question is what is best to use for weights — RKCTDiecast
  • Ha! — GoldenOwl
  • Literally anything that will fit in the car. I've used wheel weights, nuts and bolts, old keys, BB's, and professional tungsten weights. — SpyDude
View member profile
Rusty_Rod 12/15/21

Ok, I know everyone has their own tricks on what works for them,and that's cool,I'll tell you guys what I do that works for me for the most part. I try and find the center of the car by balancing it on a price of key stock,or anything that will hold the car off its wheels before I take it apart,After disassembly,add weight towards the rear of the chassis just enough to tip it backwards a little so the rear wheels just barely touch your work bench,that should be just enough to get you in the corners without too much front end crashing in the turns.that works pretty good for me.


  • Good tip, I like that. — SpyDude
  • Me too, thanks bro'! — G_ForceRacing
  • Great Idea! I use mostly .50 cal BlackPowder round Balls, Soft lead and pound to the shape you desire — Bent_Rod_Racing
View member profile
Guingoyo 4/28/22

This is how u do mines just a idea you can improve it youtu.be/f4P70j3TjyU

View member profile
Learnector 5/3/22

Wow! Weight bias answers are all over the place and I have no definitive answers, but will post the ideas I am working on. For drag racing it has been proven rear bias is best because the weight stays on the slope longer. For the road courses, most have slope the entire length, so handling become the issue. Entering and exiting the corners with a stiff suspension, one wheel comes off the track because of the difference in slopes under the wheels. With neutral and rear bias, this will be the front wheel. The car temporarily become a tricycle. On entry, with rear wheels dominate I think would drive the car straight ahead up the hill on the one front in contact. On exit. I think rear weight dominate slides down slope causing back end to drift out. The car rotating around the one front wheel in contact. So for my cars I am working on having some forward bias. The hypothesis being with front wheels dominate the car will sooner be dealing with the slope of the track that is ahead of it and this is better. I hope some day to be able to test this out scientifically with controlled experiments.

Thanks GenX, F1 cars had a front weight once, about 5% of total car weight, mounted with damper springs (think soft foam rubber for us). It was used to reduce front end vibrations.

Thanks Guingoyo, The aluminum mold is a great idea. I have a roll of lead wire, used to weight fishing nets. I just cut off lenghts that I need to fill space availabe using pliers to squish them square. Placing them side by side I use JB Weld to make a solid block. When I want to lock it into the chassis, I use it as the mold by waxing it first with Johnson's Floor Wax which become firm after the solvents in it evaporate. Then place the weights in the "mold" with the JB Weld. The wax always works to release epoxy, a trick I use often when I want separate parts.

to join the conversation or sign-up now