Weights and balance.

[Michael Squier]

I just weighed and calculated the front to rear weight percentages of 11 cars, some good handling and fast and some not to see if there is a pattern. I found the best handling are all over 60% rear bias, the best over 65%. Two exceptions but theres always an exception right?
My plan is to attempt to balance some of the worst cars closer to the good ones. Has anyone else tried this at home?

[Redlynr]

Every proxy car I send out gets tuned f/r weight bias. 60-65% rear bias is the sweet spot for me and most proxy racers.

[Michael Squier]

Cool, I guess I’m the right track then. Now to figure out how to keep the weight low ( as in not heavy, but low down is good too ) but shifted to the right places.
I curious, on your proxy cars do you have a maximum weight you try to stay under? Or even a minimum? I like light cars myself.

[Aptosc6]

I could tell you but I'd have to kill you first : )
Most serious modern sports cars have 65% rear to front weight bias, just ask any Lotus you come across.

[Michael Squier]

I knew that about full sized cars, just wasn’t sure on the little ones, with that guide holding the front in place you know. A friend of mine races a GT-1 Camaro, big car big V8 up front, he’s at over 60% rear too.
Now, if I can just get my front motored L88 to hook up I’ll be happy.

[Kevan]

When checking a clubmates car I always balance the car across my index finger to find the balance point, I always tune mine so that balance point is to the rear of half-way point between the wheels. All my cars ride on 4 wheels.

[mattb]

When we raced at the commercial track I used to try to check the balance point of a good car and then copy that. Same with car weight. I found that the same parameters didn't always mean a car would run the same. It seems like each car is a little different and all these settings are just good starting points.

[Michael Squier]

I agree, just using this as a guide of sorts. Most of my good cars are in the mid 60% range, except one. A little Reprotec Cobra, it’s in the mid 50% rear, shouldn’t work well at all but it flys around the track. Not smooth at all, just quick. Kind of like a real Cobra.
Som many other variables to deal with though, balance is just one.

[RichD]

I know a number of people that check both the front/rear and the left/right weight balance. The car must be perfectly level or your readings will not be accurate.

[slowshoes]

How is the rear vs front weight measured?

Bill

[Michael Squier]

Here’s what I did. Using a digital kitchen scale I put rear tires on scale and front guide on some blocks off to side. Just eying it make sure car is level. I did the same for the front, had to block rear higher to make up for the guide. I used the guide as my front point because my cars rude on it and the wheels barely touch so for me that made sense, you could also use front tires to weigh from.
For the percentage calculation I called my GT1 racer friend and he helped me with that. It’s pretty simple. Add front and rear weights to get total. Divide 100 by the total to get X. Multiply the front and rear weights by X to get your front and rear %. I hope this makes sense.

[Wobble]

When I'm measuring the weight over the rear axle I have a block the same height as the scales that the front wheels sit on and it has a slot in it that the guide sits in. Dunno if that's the right thing to do or not but it works for me.

[mattb]

This type of weighing works fine. Basically just doing a comparison of front to rear. Actual real weight is not as important as the bias. I used to just place rear wheels on desk and fronts on scale. Then place front on desk and rears on scale. That was an easy way to compare to a good handling car. I finally quit all that scientific stuff and just started running cars and tuning as needed.

[Michael Squier]

Wobble thats what I did except I decided to use the guide as my front instead of the wheels. They barely touch on my cars. So long as you do them all the same way I guess the results are close enough.