Talk:Corvette leaf spring/Archive 1

Corvette Spring Pic
Why was the picture deleted? —Preceding unsigned comment added by 24.126.190.8 (talk) 02:13, 13 November 2007 (UTC)

Coil Over Springs
This section says that people upgrade to Penske springs. Penske makes shocks. What the poster must have meant was that people upgrade to a coilover kits that have Penske shocks because a common kit includes a Penske single adjustable shocks with Hypercoil springs. Leaftye 06:07, 15 December 2006 (UTC)

Quarter Elliptic Spring
There's a line in there about quarter elliptic springs. It was added by an unregistered user. I have no idea if it's right. Please check it, and the article in general, for accuracy if this is your area of expertise. Thanks, Dave Indech 10:50, 8 December 2006 (UTC)

Clarification Needed
Exactly how does a transverse leaf spring also act as an anti-roll bar? If anything, it should actually increase the vehicle's tendency to roll. Think of it this way - If one wheel is pushed up the other end of the spring will want to push the opposite wheel down. This is, of course, assuming that the spring is pivoted and not rigidly mounted at the center to the chassis.

Response
Addressed to an extent. The double mounts are supposed to stop it acting as any kind of bar, but in certain implementations with a chassis that isn't stiff, suspension movement on one side of the car could conceivable affect the other.

The problem is, this isn't really Corvette-specific, and it's largely anecdotal evidence that suggests it could happen with this car. Further, I had trouble deciding if the article should address ONLY the Corvette's implementation, or transverse leafs in general. There is no separate article for transverse leafs. Dave Indech, 5/20

This has been addressed largely to my satisfaction in the most recent revision. Dave Indech, 6/2

Harmonics
I can't provide a source on harmonics, or at least not one specific to leaf springs. I do believe that because of the nature of the mounts and fact that the spring is a solid piece, vibrations of various periods (harmonics) from one side will affect the other. The question is to what extent. If the mounts are so loose that the bar can act in an anti-roll capacity, they're certainly capable of allowing vibration to transmit from one side to the other. The wording I chose in the last revision is suitably noncomittal with respect to the Corvette, but the basic fact is correct, so I think it should still be included.

If you like, you may Google 'harmonics' and provide a counterargument. I'm certainly amendable if it turns out the connection is tenuous. Dave Indech, 6/2

Sorry, I originally posted in the talk section, not this one so I didn't see these posts: Harmonics: Certainly there are harmonics in the springs. This is true of all springs, not just the least springs. However, consider that compared to a coil spring the leaf spring is shorter and stiffer. Both raise the natural frequency of the spring system. The spring is of composite construction. Composite constructions are naturally better damped when compared to homogeneous constructions (metal coil springs). The rubber spring mounts are flexible much like a rubber suspension bushing. They are stiff and don't flex easily. They certainly would damp higher frequency vibrations. Finally, consider that most cars have front and rear anti-roll bars. Those bars are long metal springs. They do tie the two sides of the car together thus left and right are not truly independent. They also could be susceptible to the same vibrations a leaf spring could see.

'Roll Issue'
I don't have to provide a link, I spent a half hour going over this with two mechanical engineers, and you can visualize it yourself. The whole point of the section is that the mount configuration has a HUGE impact on how the leaf spring functions. A loose single mount offers no isolation from one side to the other; the leaf is already pre-tensed, and lifting one side increases the tension further, forcing the other wheel down.

C3 Roll: As a mechanical engineer with almost a decade of experience including suspension design, yes I can see what you are attempting to describe. However, the issue is not significant enough for mention nor is the general principle unique to the leaf spring suspension. In the C3 the spring is mounted to the rear dif housing. You will see more movement of the rear dif housing relative to the chassis that of the spring relative to the dif housing. The amounts of movement you are referring to are small enough to fall in the range of chassis flex. While we can make the argument that everything flexes to some degree under any load the amount of deflection in this case is not significant. As such it may be misleading to mention it in the entry because it suggests an issue that isn’t there in practice.

Further edit: I think I see where the confusion is coming from based on your recent edit. I was considering the C2 and C3 rear suspension to be a single fixed mount. It is actually two closely spaced mounts but the intent is to hold the center of the spring and prevent motion from one side from moving the other. Prior to the wide spacing used on the C4 the spring was not able to provide any anti roll. See the leaf spring article in the external link for more details.

Update
http://www.corvetteforum.net/c3/juliet/bef_springdiff.jpg

This is brief because your edit to this page swallowed mine (or something of that nature), but I discovered this from a 1970 Corvette. I cross-checked through various other sources, and there no was mention of any changes from 1963 to 1970. Prior to '63, the C1 had a solid rear axle. I was working on an incorrect assumption, and I did not consider chassis flex. Corrected, though it may need to be proofed further.

Nurburgring
Funny, both the F430 and newer Lambos are slower on the Nurburgring than the Z06, however the Ford GT is actually faster than the vaunted Z06, 7:42 (as indicated by Octane magazine, 11/05) . CJ DUB 18:26, 15 January 2007 (UTC)


 * It's no surprise the Z06 is faster than the exotics. The F430 is short on power and torque, and the Lamborghini weighs too much. Nor is it any surprise the GT is faster; it's balanced better, it handles better, and it makes 515 HP at the wheels on a dyno. What is surprising is that the Z06 is less than a second slower. The so-called 'Blue Devil' should be a sight to behold.
 * Dave Indech 06:31, 7 February 2007 (UTC)

Delete?
Why is this page here? What does it offer that isn't in the general leaf spring article? I'm not so sure that wikipedia should include suspension tuning advice for particular models... 81.178.104.81

A feel good for people who feel people like Jeremy Clarkson were unfair to the car is about it. --220.253.14.72 04:52, 13 September 2007 (UTC)

You are absolutely correct, it should be removed. I added a Motor Trend reference article about the significant disadvantages of the leaf spring in the Corvette and anonymous vandals remove it right away because in 'their' personal opinion, Motor Trend is 'wrong'. --Autostream (talk) 01:32, 20 March 2008 (UTC)

The article provides a useful level of understanding and clarification of the suspension design used on the Corvette. I have repeatedly removed the reference to the MT article because it is an opinion piece. You have cited it to back opinions (ride quality, handling) yet neither you nor the article shows how the use of the leaf spring affects the other. The car may in fact ride badly and handle badly but no evidence was presented illustrating WHY the leaf spring would be to blame. That was part of the reason why it was removed.

It was also removed because it contained two factual errors. The leaf spring is a fiberglass structure, not carbon fiber. Also, the spring is not does not "rigidly" connect the wheels together. The ends of the spring are in fact not rigidly connected to the suspension arms at all. They are connected trough short pull links. Given the errors in the Motor Trend article, all of which can be shown to be incorrect by other sources, the article was removed. Please do not refer to the edits as "vandalism". —Preceding unsigned comment added by 68.209.216.200 (talk) 04:22, 20 March 2008 (UTC)

Motor Trend explains what they meant
Autostream had posted a request on the MT Forums for additional explanation regarding the magazine's claim that the leaf spring makes the rear suspension behave "a bit like a rigid axle".

Here is the response he received from tech writer Frank Markus:


 * They are composite springs, and yes they may be fiberglass reinforced instead of carbon-fiber reinforced. Some people use Composite and Carbon Fiber a bit too interchangeably and I should probably have changed that. Lots of other people just call them plastic which is certainly generic enough to avoid mile-long Wiki argument strings.


 * As for the handling reference, the point is that when an impact drives one end of the transverse leaf spring up, the other end is at least to some extent driven down, and vice versa. It is this side-to-side linking of forces that is in some ways akin to a live or solid axle, whereas in independent suspensions without a transverse leaf spring there is less force transmitted from an impact on one side of the suspension on the other. Motor Trend Thread

The first point by the author admits the spring material was wrong.

We now know what the author was thinking when using the rigid axle reference. The description is not consistent with the suspension used on the C5 and C6. The description talks about a seesaw effect. For this effect to occur the spring must be centrally mounted. This effect likely did occur in the C2-C4 rear ends (not the C4 front) to some degree due to flexing of the mounts and shifting of the dif housing with respect to the chassis.

This description is not correct with respect to the later cars nor the C4 front suspension which used the leaf spring as an anti-roll bar. What the MT author describes would be the opposite of the anti-roll affect mentioned by Michael Lamm as well as in a number of patents I've found by searching transverse leaf spring in the google patent database.

Additionally, this finite element model of a transverse leaf spring with two widely spaced mounts shows that when one side of the spring is pulled up the other also goes up, not down.

It is now completely clear what the MT article meant. It is also clear that the information was entirely mistake and thus not suitable for the article. Future references should be removed. Springee (talk) 14:04, 30 April 2008 (UTC)

Frank Marcus did NOT write the Motor Trend article of interest.--24.46.144.102 (talk) 23:25, 30 April 2008 (UTC)

My bad Autostream, perhaps he wasn't the writer. However, the MT admin gave his response. I would assume you agree that his response would represent that of MT. It certainly would seem he was at least the person who contributed the particular morsel of information in the article to which you have clung. Any comments on the technical validity of what I have shown above? Springee (talk) 00:33, 1 May 2008 (UTC)
 * A followup on this: the Corvette ZR1 uses leaf springs similar to those of the Z06. Without exception, every publication that has reviewed that car has praised the ZR1's handling for a combination of around-town civility and at-the-limit behavior, including the aforementioned Clarkson. This, as opposed to the Z06's more skittish character. The advances of the ZR1 are Michelin PS2 tires and MR dampers, the former always a major factor in any sort of high-power, low-weight FR vehicle. If there's any question that MT was off-base in their characterization of the Corvette's composite monoleafs, the ZR1 should lay that doubt to rest.Alexdi (talk) 21:22, 23 November 2008 (UTC)

Some content removed
I removed the following content:

"Conventional Leaf Spring vs Corvette Suspension

Conventional leaf spring suspension performance is criticized with respect to independent suspension types for several reasons:

1. Friction between the individual leaves of the leaf spring impedes smooth articulation of the suspension. 2. Leaf springs can flex under lateral loads resulting in lateral shift of the axle with respect to the chassis. 3. High unsprung mass of the rigid axle reduces ride quality and suspension effectiveness. 4. Deflection of one wheel directly affects the angle of the opposite wheel which can negatively affect cornering quality uneven surfaces.

The above issues do not apply to the Corvette suspension for the reasons listed below:

1. The monoleaf spring is not comprised of individual elements sliding across each other and thus does not suffer from internal friction. 2. The suspension uses rigid A-arms to support lateral loads. The leaf spring does not support lateral loads nor does it act as a suspension link. In this way it acts exactly like a coil spring and unlike a conventional leaf spring suspension system. 3. The Corvette suspension has the same sprung and unsprung components as other independent suspension systems. It does not use an unsprung live axle thus does not have the extra weight of the live axle. 4. The wheels of the Corvette are free to move relative to each other. As with all independent suspension systems, the movement of one wheel does not force a movement of another."

Point 1 of the first set was actually an issue with the circa-1960s Corvette leaf suspension, which did in fact have multiple leafs. Points 2, 3, and 4 are more aptly characterized as criticisms of a solid rear axle.

Point 1 of the second set is repeated elsewhere, as is point 2 and point 4. Point 3 is again about axles. Like most of these points, there isn't adequate differentiation between the facets of suspension design that are covered in greater depth elsewhere in this article. Alexdi (talk) 22:51, 15 August 2008 (UTC)

Hotchkiss Suspension is the correct, though rarely used term that describes the traditional leaf spring suspension.  —Preceding unsigned comment added by 129.59.79.27 (talk) 18:54, 5 September 2008 (UTC)