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Re: Confirm formulae? Posted by Larry West [Email]  (#1140)  [Profile/Gallery]
(more from Larry West) on Tue, 5 Jun 2012 09:49:16
In Reply to: Confirm formulae?, steve, Mon, 4 Jun 2012 09:25:21 Members do not see ads below this line. - Help Keep This Site Online - Signup |
Max. Axle Load is NOT necessarily 50% of GVWR. Your owner's manual, or the data plate on the B pillar has the exact #. For MY 2000, the max axle loads indicated in the OM are:
Front: 2500lbs (1135 kg)
Rear (sedan): 2310 (1050)
Rear (wagon): 2480 (1125)
The only way to know the exact weight distribution of a particular car is to use scales, though the OM does indicate that at curb weight it is 60/40.
Assuming a 4480 GVWR (again, from the OM), if you max out the rear on a sedan to 2310, that puts only 2170 on the front, a load distribution of 48/52...
If your curb weight is 3470 (bottom of the scale...), then 60/40 puts 2082 over the front wheels, and 1,388 over the rear wheels. So you could, in effect, put over 900 lbs in the rear.
Of course, the load doesn't all go over the rear, some does transfer to the front, but lacking a weight & balance sheet for the car (like you would have with an airplane), it is difficult to calculate, and much easier to just measure.
What the scales cannot take into account is the dynamics of the load, or the dynamic effect on the cars performance. As you correctly note, if you spread the load over more area (back seat plus trunk), some of it is transferred to the front, though most stays over the rear.
Dynamically, you could end up with poor handling if you placed, say, a 100 lb load at the very rear of the luggage compartment, vs on the floor behind the front seats. At the back of the luggage compartment, you effectively multiply the weight by the distance from the rear axle. So 100 lbs 3 feet past the rear axle might act - dynamically - like 350-450lbs centered over the rear axle! Railroad tracks and speed bumps would take on a whole new character, even though you are technically within the load spec for the luggage bay. And let/s not even mention what rain-soaked roads could be like!
While I haven't loaded any of my 9-5s down that much, I have loaded down a Classic 900, and it wasn't really fun. Weight distribution is meaningless, as you're overtaxing the shocks and springs. Careful driving is a must. You really need to plan turns and stops well in advance. One time, I was moving stuff between states, including a coin collection (placed on the floor, behind the front seats), the other time was a complete C900 motor & trans, loaded over the rear axle. I'd do it again, if I had to, but I'd really rather use a trailer or a better-suited vehicle for the weight.
_______________________________________ Current: 2002 9-5 Aero Kombi Cosmic Blue 2000 9-5 SE sedan, Imola Red 1990 900S Rose Quartz, Auto Past: 1999 9-5 LPT Combi 1999 9-5 LPT sedan 2002 9-5 Arc 1990 900 5-speed 1986 900 turbo Convertible 1991 9000 turbo 1980 99 GLi 1986 900 turbo 1986 900 S 1991 900 turbo 1984 900 turbo 1976 99 GL
, Tue, 5 Jun 2012 09:49:16 <-- Viewing This Message, Tue, 5 Jun 2012 10:00:45
, Mon, 4 Jun 2012 13:07:26
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