Talk:Weight transfer

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A fact from Weight transfer appeared on Wikipedia's Main Page in the Did you know column on 29 September 2004. The text of the entry was as follows:

Did you know... that weight transfer causes the traction of tires on a car to vary?

A record of the entry may be seen at Wikipedia:Recent additions/2004/September.

Wikipedia

Untitled

Should the shifting of weight in the first paragraph be described as "imaginary"? The article implies that the effects are real and recognized by car designers. Is the issue that weight (mass * gravity) is not actually shifted, but the acceleration makes it look like weight is being shifted? Perhaps a better word would be "apparent", "perceived", "so-called", etc? -- Jacius 23:54, 28 Sep 2004 (UTC)

The emphasis of this article is crazy. Weight transfer is far less important than load transfer for most cars and so on. Does the paragraph I added help to explain why? Greglocock 02:04, 18 February 2006 (UTC)[reply]

It seems to me, also, that "Weight transfer" is not a very good word here. Load transfer might be a better name, with a redirect. That is, the center of gravity doesn't move much. The change in load comes from centrical force or braking or acceleration reaction (inertia). On the other hand, I think "weight transfer" is the common idiom. David R. Ingham 07:17, 18 February 2006 (UTC)[reply]

I agree entirely. None of the hand calculation methods I have seen even considers the change in CG location during a manouevre as being worth calculating. I see no benefit in including an article that perpetuates the problem. If we were to kill this article and make it a redirect to load transfer, explain the problem in terminology there, and then include the bulk of this article in the load transfer article, it would be better. Greglocock 11:12, 18 February 2006 (UTC)[reply]

I sort of think "weight transfer" is what people will most easily recognize. "Normal force" might make them try to figure out what an "abnormal" force was. I guess the sense of "weight transfer" must be that the total normal force is still (about) equal to the weight but transfers from wheel to wheel. David R. Ingham 19:14, 18 February 2006 (UTC)[reply]

Hmm, but if common terminology is WRONG, as it is in this case, surely it would be wise to correct it. FWIW Vehicle Dynamics Engineers may talk loosely about weight transfer, but when we write papers we use load transfer. For instance, here are the headers on SAE's definitions of * transfer

9.5 Tire Load Transfer 9.5.1 TIRE LATERAL LOAD TRANSFER 9.5.2 TIRE LATERAL LOAD TRANSFER DISTRIBUTION 9.5.3 TIRE LONGITUDINAL LOAD TRANSFER

OK, how about we keep weight transfer as the main article, redirect load transfer over here, and then have a para explaining why the common terminology is wrong? Greglocock 21:22, 18 February 2006 (UTC)[reply]

The state of this article July 2009

It is wrong abysmal and misleading. I am going to cut all the stuff that is definitely wrong, please consider that the ONLY mechanism by which weight transfer as defined in this article can occur is if masses in the vehicle move with respect to the vehicle. Greglocock (talk) 01:53, 5 August 2009 (UTC)[reply]

Moment arm?

Hi, Regular.Stormy, good article. Only thing is I am not quite with you what a 'load transfer moment arm' is (5th para). Do you think you could make that a bit plainer for us simple folk? Thanks. Dieter Simon 00:18, 23 Jan 2005 (UTC)

What should this redistribution of normal force due to inertia be called?

I get about equal numbers of Google hits for "load transfer" and "weight transfer" but the first few for "weight transfer" are about car performance, while the first few for "load transfer" are not. So I suggest that this article be merged with "Weight transfer". We still need to say that the main effect is due to inertia but there is some secondary change in the center of gravity. "Load transfer" sounds a bit as though it meant the cargo (people, lugage and gasoline, in a car) shifting.

Anyway, we should keep trying to make it more quickly understandable to a larger readership because that will save lives. Whatever the effect is called, it does kill a lot of people each year. David R. Ingham 19:39, 18 February 2006 (UTC)[reply]

I've always referred to it as weight transfer, and so does every car enthusiast I've talked to. I've never heard of it being referred to as load transfer before. I did a quick google search and dug this page up which could be of some use: http://www.ozebiz.com.au/racetech/theory/wttrans.html Leedeth 12:47, 29 August 2007 (UTC)[reply]

These published references all call it load transfer:

Tyre and Vehicle Dynamics by Hans B. Pacejka
Motorcycle Dynamics by Vittore Cossalter
Motorcycle Handling and Chassis Design by Tony Foale

In fact, Tony Foale is quite explicite:

This is normally referred to as wight transfer, but that is really a misnomer. [long sentence about what weight is] Neither acceleration nor braking can cause this weight to transfer elsewhere. As a result the use of the term 'load transfer' is preferable.

Are there definitive references that call it weight transfer? -AndrewDressel (talk) 14:39, 8 August 2009 (UTC)[reply]

Yes, Gillespie 'fundamentals of vehicle dynamics'. He calls it weight transfer, and doesn't mention load transfer. I'd say the obvious difference is that gillespie is a car and truck dynamicist, where load transfer is far more important than weight transfer, but we all call it weight transfer, except for the SAE who are up themselves. I agree it is a misnomer, but wiki should represent the real world usage, not pedanticisms, I'd have thunk. Greglocock (talk) 00:35, 9 August 2009 (UTC)[reply]

Imaginary?

Please explain how load transfer is "imaginary". If it were truly imaginary, why is it even worth discussing? As written, I don't think this subject is really separate from weight transfer. At any rate, it's not using the correct terminology to try to distinguish the two and may reflect a lack of understanding on the part of the author. Ham Pastrami 04:36, 4 October 2007 (UTC)[reply]

The word "imaginary" has been removed. -AndrewDressel (talk) 14:49, 8 August 2009 (UTC)[reply]

Merge proposal

It appears that the auto industry (with references) uses weight transfer, while the motorcycle industry (with references) uses load transfer to describe the same phenomona: the measurable change of load borne by different wheels during acceleration. For this reason, we propose the intro paragraph should read something like:

Weight transfer and load transfer are two expressions used somewhat confusingly to describe two distinct effects:^[1] the change in load borne by different wheels of even perfectly rigid vehicles during acceleration, and the change in center of mass (CoM) location relative to the wheels because of suspension complience or cargo shifting or sloshing. In the automobile industry, weight transfer customarily refers to the change in load borne by different wheels during acceleration.^[2] This is more properly referred to as load transfer,^[3] and that is the expression used in the motorcycle industry,^[4] while weight transfer on motorcycles, to a lesser extent on automobiles, and cargo movement on either is due to a change in the CoM location relative to the wheels.

^ Foale, Tony (2006). Motorcycle Handling and Chassis Design (Second ed.). Tony Foale Designs. pp. 9–1. ISBN 978-84-933286-3-4.
^ Gillespie, Thomas D. (1992). Fundamentals of Vehicle Dynamics. SAE International. ISBN 978-1560911999.
^ Pacejka, Hans B. (2006). Tyre and vehicle dynamics (Second ed.). SAE International. pp. 14–15. ISBN 978-0768017021. Retrieved 2009-03-31.
^ Cossalter, Vittore (2006). Motorcycle Dynamics (Second ed.). Lulu.com. pp. 84–85. ISBN 978-1-4303-0861-4.

Comments? -Greglocock (talk) and AndrewDressel (talk) 13:03, 10 August 2009 (UTC),[reply]

Done. -AndrewDressel (talk) 20:15, 18 March 2010 (UTC)[reply]

New Section Edited B Stead (talk) 11:12, 21 October 2011 (UTC)[reply]

Example calculation seems incorrect

"Center of mass" section has an example "in a 0.9g turn, a car with a track of 1650 mm and a CoM height of 550 mm will see a load transfer of 30% of the vehicle weight", which according to my calculation is correct, but then it goes on to say this means "the outer wheels will see 30% more load than before, and the inners 30% less". This seems wrong - is 30% of vehicle weight is transferred, this should mean outer wheels (which normally receive 50% of vehicle weight) now receive 50%+30% = 80% of vehicle weight, i.e. 60% more load than before (not 30% as the article claims).

I am however not an expert on the subject and am therefore doubting myself too much to correct the article myself.

Ahtih (talk) 14:24, 22 December 2011 (UTC)[reply]

[Foale-1] Foale, Tony (2006). Motorcycle Handling and Chassis Design (Second ed.). Tony Foale Designs. pp. 9–1. ISBN 978-84-933286-3-4.

[2] Gillespie, Thomas D. (1992). Fundamentals of Vehicle Dynamics. SAE International. ISBN 978-1560911999.

[3] Pacejka, Hans B. (2006). Tyre and vehicle dynamics (Second ed.). SAE International. pp. 14–15. ISBN 978-0768017021. Retrieved 2009-03-31.

[Cossalter-4] Cossalter, Vittore (2006). Motorcycle Dynamics (Second ed.). Lulu.com. pp. 84–85. ISBN 978-1-4303-0861-4.

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