What effect does a composit spring have

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Feb 5, 2019 | 08:21 PM

#21

69427

Tech Contributor

Joined: Jun 2004

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From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.

Quote:

Originally Posted by 08redrocket

Thanks 69427. I spoke to a race that I know and he agrees with you. So, I guess I'll put on the original rear bar and give it a go and then go to the newer 3/4 inch bar and see how that works. The racer told me of a place that has a skid pad so I'll try it.

I envy your opportunity to do some testing on a skid pad.

A 3/4" rear bar is a healthy size piece. You're wise to try it out first on the skid pad. Post some pictures of your car during the testing, if it's convenient.

Feb 5, 2019 | 08:49 PM

#22

1Cerberus4u

Pro

Joined: May 2017

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From: North East

Quote:

Originally Posted by Factoid

Hmm, I run a 360# composite spring on my ‘64 convertible with a 550# front spring, QA1 shocks and 1 1/8” front 3/4” rear sway bars. My tires are 245/45-17 all around. The ride is stiff, but not overly harsh. Where it really pays off is on the twisty back roads of the Texas hill country where the car is amazing.

Texas hills and twisty back roads......... an oxymoron if I ever heard one... Isn't your state just a big flat plate with straight roads? LOL!!! Texas... hilly.... twisty.... That needs to go into Kurmudgeon's Fridays Funnys

Feb 5, 2019 | 08:58 PM

#23

1Cerberus4u

Pro

Joined: May 2017

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From: North East

Quote:

Originally Posted by 69427

You need to rethink that. Adding/increasing the bar size will reduce the traction on that axle (while increasing traction on the opposite axle). Increasing the front bar size will increase understeer, and increasing the rear bar size will increase oversteer. (Recall, that's why GM put rear sway bars on big block cars, Big block cars are front heavy, and will normally understeer. A rear bar will loosen up the rear, allowing a more neutral handling car.) A bar is used for tuning, not increasing traction. For amusement, go look at a picture of a 911 Porsche (with a big front bar installed) during cornering. Because the old 911s used to oversteer so bad, the front bar size was frequently increased to add understeer to the car. If the car was equipped with sticky tires, the body lean of the car, combined with the stiff front sway bar, would actually lift the inner front tire off the ground (I've seen Corvettes do this also when the front bar was too big.)

Cliff note: If the car is understeering, increase the rear bar size. If the car is oversteering, increase the front bar size.

You mean like this.....?

And this was going into a flat corner ie, turn one at Limerock, CT

Jul 23, 2019 | 03:29 PM

#24

CorvetteMikeB

Melting Slicks

Joined: Dec 2017

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From: Michigan

2023 Restomod of the Year finalist

Quote:

Originally Posted by 69427

Nonsense. The factory multi-leaf springs, in addition to being heavy as hell, are saddled with an inherent negative aspect known as stiction. Composite springs are not. The interleaf friction causes the spring to be a solid unit over bumps until a large enough road disturbance can dislodge/overcome the stiction of the interleaf liner/interface. That's why a stock C2/C3 rides like a covered wagon, and later models with the composite spring do not.

For performance and ride quality, composite springs are far superior to steel multi-leaf units.

I know the most common composite rear leaf springs are rated as 315 lbs, 340 lbs, and 355 lbs ratings. Some can be found to be 300 lbs & 190 lbs rated. Zip's told me the lower the weight ratings, the smoother the ride.

Has anybody tried the 190 lbs & 300 lbs rear composite leaf springs??? If so, how did you like it?

Jul 23, 2019 | 03:54 PM

#25

FLYNAVY30

Le Mans Master

Joined: Sep 2002

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From: Redacted

Quote:

Originally Posted by 1Cerberus4u

Apologies for the off topic post, but being an Austin home owner, I felt obligated to educate the uninitiated

Central Texas hill country is drastically different than the West Texas you are imagining....

Jul 23, 2019 | 04:01 PM

#26

MelWff

Race Director

Joined: May 2006

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Soring rating

Quote:

Originally Posted by CorvetteMikeB

I have a 69 and have used the 300 lbs for decades, cannt imagine going down as low as 190. I have Koni adjustables and am quite satisfied with the ride.

Jul 24, 2019 | 09:12 AM

#27

CorvetteMikeB

Melting Slicks

Joined: Dec 2017

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From: Michigan

2023 Restomod of the Year finalist

Quote:

Originally Posted by MelWff

I have a 69 and have used the 300 lbs for decades, cannt imagine going down as low as 190. I have Koni adjustables and am quite satisfied with the ride.

Can you still get American Made rear composite leaf springs??? Zip's Corvette doesn't know, the sales guy told me you have to wait and see when you get it shipped and look for the sticker.

Jul 24, 2019 | 11:20 AM

#28

woodsdesign

Safety Car

Joined: Jan 2004

Posts: 4,270

Likes: 561

From: Macedonia Ohio

Quote:

Originally Posted by CorvetteMikeB

Can you still get American Made rear composite leaf springs??? Zip's Corvette doesn't know, the sales guy told me you have to wait and see when you get it shipped and look for the sticker.

One of the reasons that I bought a Muskegon Brake was because it was American Made. That was about 7-8 years ago.