Great.... a chance to practice a little engineering statics.... ;)
The passengers weight will be distributed between the front and rear
axles proportional to the distance from each axle to the CG of a person
in a seated position, which would be approximately the center of the
seat which is roughly 53" front & 33" so with 400 lbs of passengers,
the front should see ~247 lbs and the rear ~153 lbs added for ~100 more
to the front than rear which in a 2500 lb car will be a 4 point (+2%
rear, -2% front) rearward shift of the weight balance.
As example if you have 52/48 balance without passengers, you'll have
50/50 with two passengers in a Tiger.
Now looking at the gas level.... empty to full adds some 70 lbs (I
think) about 24" behind the rear axle. This actually lifts weight off
the front proportional to the ratio of the 24" vs the 86" wheebase, to
the tune 17 lbs.. which now are loaded on the rear along with the 70
lbs of gas to result in 87 lb weight added to the rear, or nearly the
same as two 200 lb passengers in the example above. Let's say it's just
a 3 point shift instead of 4.
Now the question is... under what conditions do you want to "balance"
the car?
Do you want it to always be on the same side of 50/50? or allow it to
transition from rear bias to front bias as loading varies. Generally
transitions from one side to the other is a indicator of instabilty, so
Let's aim to be 50/50 at the extreme load of full tanks and two 200lb
passengers. The shift to an empty tank and no passengers should move
the balance by have the calculated passenger shift (+/-2 point) plus
the gas shift (=/- 1.5) for a target of 53.5%/46.5% "empty" balance.
Can't "weight" to see the numbers Larry got on the scales.
Waybright
--- CoolVT@aol.com wrote:
> Another question might be...when a driver sits in the car does his
> weight
> add to the front weight of the car or the rear?
I know that each end will benefit from the driver's weight, I'm just
curious to know
> if anyone
> has calculated what portion of the weight ends up where.
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