 How flexible do you think a stock, trailing arm is |
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| ChrisFoley |
 Dec 16 2005, 06:19 PM
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I am Tangerine Racing  Group: Members Posts: 7,968 Joined: 29-January 03 From: Bolton, CT Member No.: 209 Region Association: None 
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Specifically I am looking for rotational stiffness (ie. twist) of the trailing arm due to the tire contact patch resisting sideways sliding of the car. I'm only interested in forces greater than 1G during cornering.
I already know what happens but go ahead and take a guess. (IMG:style_emoticons/default/biggrin.gif) I'll post pictures of my test fixture shortly. |
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| Thorshammer |
Dec 17 2005, 10:49 AM
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Senior Member Group: Members Posts: 749 Joined: 11-November 03 Member No.: 1,335 |
I have'nt seen this thread until this morning, but wanted to add some comments.
Chris and I started talking about this because som eof the info we have found for 914's seems at times to be untrue. People have done things for different reasons and many are not known. Such as The outer (stock) pick up point piece is extremely flexible, Chris has a stronger piece, I used it it works well. Why some people use a trailing arm stiffening kit and others do not. Here are the things we want to know: -How much does a standard trailing arm twist in degrees of deflection when we load it near max load that we might see with slick under racing conditions. . Only flaw I can see in Chris's methodology is maybe we have under or over estimated the load at the wheels. It also has a lever that would act upon the trailing arm, the Wheel. 11.75inches from the centerline. So we really need to make sure we've thought that through. -How much lateral deformation when a max cornering load is applied. Meaning doe the arm bend thowards the transmission when we load it and if so how much. -Where does it bend or Twist -How does a trailing arm that is stiffened using the typical weld on plates perform to the same tests. -Where can the arm be properly strengthend while adding minimal weight. Keeping in mind that some bending can be advantageous in gaining car "feel" at the limit. Same with Chassis twist, if its too stiff it looks good on paper but does not give the driver any feel and therefore be difficult to drive at the limit. These are the problems we (Chris) are trying to solve. Erik Madsen |
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Posts in this topic
Racer Chris How flexible do you think a stock, trailing arm is Dec 16 2005, 06:19 PM
TimT Chris the trailing arm appears to be a pretty sto... Dec 16 2005, 06:25 PM J P Stein WAG:
1 deg @500 lbs.
I'm assuming you're ... Dec 16 2005, 06:26 PM airsix What exactly do you mean by "1G". I'm sure you... Dec 16 2005, 07:09 PM ppickerell Chris,
Do you intend to test before and after boxi... Dec 16 2005, 07:41 PM Dave_Darling I'm guessing that most of the flex happens in ... Dec 16 2005, 07:54 PM spare time toys My guess is it has flex designed into it at an amo... Dec 16 2005, 08:08 PM Racer Chris So far JP is the only one really on the right trac... Dec 16 2005, 08:24 PM Racer Chris Then I attached a 5ft piece of structural tubing t... Dec 16 2005, 08:26 PM Racer Chris by putting a 200lb man's weight at the end of ... Dec 16 2005, 08:32 PM Racer Chris I had a friend sit on the end of the tube and saw ... Dec 16 2005, 08:34 PM Racer Chris I have several more tests planned already.
1) meas... Dec 16 2005, 08:40 PM TimT Put the level on the trailing arm, not the lever
... Dec 16 2005, 08:41 PM TimT and yes I see the angle you have welded on the bo... Dec 16 2005, 08:42 PM SpecialK ....go on.... http://www.914wor... Dec 16 2005, 08:43 PM andys Chris,
This is exactly the kind of testing requir... Dec 16 2005, 08:57 PM goose2 If you mount the level in various locations on the... Dec 16 2005, 09:06 PM TimT 
