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, Tue, 5 Jun 2012 10:00:45
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Reposted #2 because the formulas are unclear with the copy/paste glitch. Can't Word fix this with some option? Scott/Mods, you can delete the other two.
I wasn't trying to get the max rear axle load. That is marked on each vehicle. I'm trying to get the load limit at 50/50 weight distribution which might produce a number lower than the actual max axle load.
Is there any reason one can't use this: to determine load distribution, use P x L / Wb = Wr and P - Wr = Wf . Where P is the load (passenger(s), luggage in luggage compartment/ overhead shelf, and any optional equipment or accessories not included in the unloaded vehicle weight), L is the distance from the center of gravity of the load to the front axle centerline, Wb is the wheelbase, Wr is the resulting weight of the load on the rear axle and Wf is the resulting weight of the load on the front axle. (Sourced from: http://www.ntea.com/WorkArea/linkit.aspx?LinkIdentifier=id&ItemID=12472)
I disagree about the driver issue. A driver is necessary to operate a vehicle and is thus part of GWR (literally, the weight of the vehicle at any point). If you do the math your way, the driver would have to come out of the equation on the other side. Otherwise, wouldn't you be saying GVWR=curb weight=unloaded weight (http://www.fmcsa.dot.gov/rules-regulations/administration/fmcsr/fmcsrruletext.aspx?reg=571.3)?
(154 lb x 4) + 218 lb = 834 lb. The 9-5 is rated for at least 920 lb GVWR based upon calculations and some online sources suggesting a 920 lb permissible load not including the driver. By your math, 86 lb is then still available for a child or a heavier driver or more luggage. Or alternatively, if the driver is 154 lb, the car can carry 766 lb. The amended luggage capacity doesn't indicate that the 80 kg limit is with 4/5 passengers. Perhaps it was added (along with the WIS changes) to try to account for the suspension design problem rather than fix the cars. The 9-5 cannot carry the 920 lb (or 834 lb or 766 lb) rating without major suspension issues that are permanent and lasting after the load is removed. Steel is yielding.
When the OM says "Permissible load (in addition to driver) = GVW minus curb weight" Saab is essentially labeling GVWR, otherwise not listed in the OM, as permissible load. It was Saab's decision to exclude the driver, likely on the above reasoning that a non-robotic car without a driver is useless for driving. Either way, it's unlikely that any driver weight up front is causing the problems with the rear of the vehicle. Given the underdesign at the rear, it makes sense to look for similar problems up front first before concluding that this is a typo in the manual.
Perhaps the designers failed to account for dynamic loading and that the springs are yielding during such loading. GVWR/permissible load is the weight at which a vehicle can be safely operated. Increased wear is perhaps acceptable on wear items such as tires, brakes, etc. Suspension failure from steel parts yielding (as opposed to premature wear on items such as dampers) isn't acceptable. And it's not only the loaded rear that is failing, but the front springs too.
It's common to see 9-5s with 4 passengers and luggage sagging considerably. Yet, these passengers and luggage are not exceeding the loads we're talking about.
An 80kg luggage compartment load is unreasonable for a 9-5. I wouldn't have bought mine if I knew that in advance. Airlines used to and some still do allow two and even three 32kg suitcases per person on international flights (some allow even more). It doesn't seem reasonable for a 9-5 to be unable to carry two adults and their 128 kg (2 x 2 x 32kg) of luggage to the airport. For comparison (the only one I can clearly find), a Smart fortwo can carry 50kg (http://www.smartfortwo.no/manual-cars/ba/smart/451/en/in-depth/d827e41267.shtml). This is a much smaller car with an 825-895 kg curb weight.
It also makes no sense that the towing tongue limit is 165 lb is the trunk can carry only 176 lb.
Owners were left high and dry with these murky suspension issues. This was going on well before the bankruptcy. Can we blame GM? I've got another GM vehicle I've loaded and towed with and there have been no permanent issues. The car is junk in many respects. The suspension is permanently failing after a little loading. It's got the original suspension despite being older and higher mileage. The GM2900 chassis likely has some issues GM hasn't disclosed. It seems too unlikely that the springs were underdesigned on all of these cars.
posted by 98.116.5...
, Tue, 5 Jun 2012 09:49:16, Tue, 5 Jun 2012 10:00:45
, Mon, 4 Jun 2012 13:07:26
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