Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site watdaisy.UUCP Path: utzoo!watmath!watnot!watdaisy!gvcormack From: gvcormack@watdaisy.UUCP (Gordon V. Cormack) Newsgroups: net.auto Subject: Re: Additional weight transfer myths Message-ID: <7283@watdaisy.UUCP> Date: Thu, 30-May-85 17:26:47 EDT Article-I.D.: watdaisy.7283 Posted: Thu May 30 17:26:47 1985 Date-Received: Fri, 31-May-85 02:32:28 EDT References: <191@twitch.UUCP> <194@twitch.UUCP> <7275@watdaisy.UUCP> <196@twitch.UUCP> Distribution: net Organization: U of Waterloo, Ontario Lines: 55 > > First, the relative front-to-rear roll stiffness (which certainly IS > > affected by sway bars etc.) has a great effect on how much of the > > total weight transfer is borne by the front vs. rear wheels. > > -- > > Gordon V. Cormack CS Department, University of Waterloo > > The transfer of weight from rear to front is also a fallacy. > In other words, the sum of the load on the rear tires > is the same when the car is parked as it is when > the car is cornering at a constant velocity. > Guido Bertocci > AT&T Bell Labs > Holmdel, NJ > > ...!ihnp4!houxm!twitch!guido The latter is true, but in no way contradicts what I said. Weight transfer is not a fallacy; it is real. What is fallacy is that stiff suspension can alter (significantly) the amount of weight transfer for a given lateral acceleration. What I said is that the LATERAL weight transfer (that is caused by cornering) can be distributed to the front and rear wheels using anti-roll bars. Let me give an example. Suppose a car weighs 2000 lb. and is perfectly balanced front/rear and side/side. Each wheel bears 500 lb. static weight. Suppose further that the car is cornering left at such a rate as to incur 100 lb. lateral weight transfer. That means that the right side gets 100 lb. "heavier" and the left side gets 100 lb. "lighter". If roll stiffness rates of the front and rear are equal, the weight distribution is: front left: 450 front right: 550 rear left: 450 rear right: 550 On the other hand, if the rear roll stiffness is made infinite, the weight distribution is: front left: 500 front right: 500 rear left: 400 rear right: 600 The total weight of the car is still 2000 lb. and the lateral weight transfer is still 100 lb. But the weight transfer is borne by the rear wheels. It is easy to see that if, in the second case, the weight transfer were 500 lb., the left rear wheel would lift from the ground. Even with a wheel off the ground, the car is not in particular danger of rolling over (assuming that there is, in fact, some roll stiffness in the front). It would take 1000 lb. weight transfer (twice the current cornering force) to roll the car. -- Gordon V. Cormack CS Department, University of Waterloo gvcormack@watdaisy.uucp gvcormack%watdaisy@waterloo.csnet