scaling question

[57m]

hi just got a quick question when scaling a car for setting the overall bite say you want 90 lbs of bite should the driver be in the car for the 90 lbs or should that be just as it sits.

[RacerX10]

adding driver will increase your LR, so scale acordingly

[TheJet-09]

A long, long time ago, when I was much, much younger, I asked a wise man the same question. His reply was simple: "That depends if you plan on driving the car from the seat or from the pits" (I did say he was "wise"). Most every chassis manufacturer I am aware of sets ride heights, front end settings, weight, etc. with the weight of the driver in the seat. Think of how much things would change by placing a 200 lb. driver in the seat of a car that was set-up "empty" with a 200# LR spring versus a 250# LR spring. Same goes for fuel, fluids (oil, coolant), etc. Get it as close to race trim as possible.

[AmickRacing]

I have 2 views on this.

I completely agree with TheJet, generally the driver is in the car when it's racing, so that's the best way.

However, if you're mostly a one man show (like myself), and using grain scales to boot (like me), that can be a very difficult chore. I typically weigh the car out with me in it once, bug some friends to stop over. Once I have those weights, I can get out and get the weights. Now I have a baseline to go from, and for the most part I can weigh the car out myself, with out the driver, but will know what it'll do with me in it.

I think the most important thing when weighing the car out is consistency. Make sure you do it the same every time, that way any changes you make are easily documented
.

[zeroracing]

I put my weight equivalent in the seat, with say 25 lb at the pedals and 25 halfway between pedals and seat.

The main thing is do it the same every time.

[fastford]

I bought 4 50lbs bags of play sand and put in seat of car when scaling, this worked best for me, and there not hard to get out when done.

[FlatTire]

Do what your chassis builder tells you. Mine tells me to scale without the driver and their LR weight is based on an average size driver.

It can be done with or with out the driver or his simulated weight.

You will be adjusting your car based on how it feels, not by what the scales say. ;-) I've never worried too much about it.

[LM14]

FlatTire hit it right on the head. What does your chassis builder say?

Most people get so tied up in the scaling experience that they forget what they are actually doing. All you want is the baseline for the car. That way when you make a change and it works, you can have a new baseline. If it doesn't work, you can get back to square one and start over. It's not magic, it's a way of returning to a common base when you wreck, change or experiment.

Every car I have had, except one, the chassis builder said to scale without driver. It's more repeatable and they are already compensating for the weight of the driver (ask what weight they base their numbers on and how to best adjust to fit your driver's weight) and take that into account for percentages, bar angles, bite, etc. If you are lighter/heavier than the driver they based everything on, ask where to make changes to suit your weight for the baseline and create that new baseline for your weight.

It's more about repeating the procedure the same every time so you can return to square one than it is to getting the magic bullet.

SPark