Rear Spring Replacement
 

Ok. I have read about 201 threads about the different composite springs and shocks and combos and etc, etc, etc. I hope this is an easier question. For a daily driver, keeping the car for a long time, and am budget minded; is replacing the rear spring with a composite worth it? The spring in there is in terrible shape and needs to be replaced. Is it worth replacing steel for steel and a good set of shocks a good idea or keep the car off the road for a longer time and go composite. For the wife ride quality is more important than road racing 78 L82

Hi C,
What are you seeing or feeling that makes you think the spring is in such bad shape?
Might it just be the shocks that need to be replaced to improve the ride?
Regards,
Alan

Spring clamps missing and springs spread out like a deck of cards. Never had seen that before

Sweet......! Let's see a pic of that !
:willy:

In my opinion getting the better upgrade for the long haul and having to wait a bit for it is much better a choice than just throwing something on there for the time being. Get a set of good shocks, Bilstein sports if possible if not get the ones at autozone like these:

http://www.autozone.com/autozone/par...258137_0_7413_

I put these on my old chevy silverado and have been happy so far.

Big upgrade will be the rear spring. VB&P:

http://www.vbandp.com/C2-C3-Corvette...y-1963-82.html

The spring is an easy install and will soften the ride a lot but here's the deal. The cheapy shocks may not do well with the new spring. This spring is designed to run with a good quality shock. But the cheapy ones will get you by for now. So in short if you can get the rear spring and the new good quality shocks at the same time.

hth,

Sully

Got a friend with an 81 or 82 with the fiberglass spring? Take a ride. You will notice the difference.

:thumbs:

Original or stock springs had no clamps. You have other problems.

Hi C,
The top 3 leafs are straight.
Might that be what you're seeing?
Regards,
Alan

http://i218.photobucket.com/albums/c...G_0001-1-1.jpg

When you said "fanned out like a deck of cards" I was thinking sideways, as in not in line with each other. So I thought you must have broken one of the four bolts that held the spring to the diff.
Hopefully you meant like what Alan is talking about and they are fanned up/down

As for the spring, I've had a TRW one on my 72 for ever and with a decent set of delco shocks (just changed this winter to KYB so don't know about those yet) I was very happy with the ride, 99% of the time boulevard crawler.
My $.02
Mooser

Hi m,
You could be right.... that would allow the leaves to 'fan' out and make Cam wonder about 'clamps'.
Regards,
Alan

The VBP #330 spring with the specifically designed VBP218 shocks is a nice combo. It works very well for me for just driving.

http://www.vbandp.com/C2-C3-Corvette...ear-Shock.html

http://img.photobucket.com/albums/v1...ingbolt3-1.jpg

Installing the fiberglass rear spring was possibly the best upgrade I ever made to my '79. There is nothing else you can do that will improve the ride and handling of a C3 as much as that spring!

My '75 had the HD spring (7 leaf), was a daily driver for 6 years, and my wife hated the harsh ride. My '80 has the composite spring (upgraded by previous owner) and it is a noticeable improvement. Having driven both I would recommend the composite spring. If you are changing it yourself, do some research on the shielding required to protect it from exhaust heat.

I'll crawl back under again this evening. Yes, fanned out sideways not up and down as Alan suggested. I'll try to find out what the problem is and will start looking for the composite spring. Now I remember why I haven't had a corvette in 25 years.....

The usual cause of the leafs fanning sideways is a mismatch of spring and diff rear cover, or missing spacers. Look for a big gap in the pocket where the spring sits in the cover.

Ok. Composite spring and Bilsteins....after I run a tap thru the brake caliper bracket I tried to cross thread last night. Frustrating but it is fun in its own weird way

Same here. :thumbs:

And same here. :thumbs:

I've had mine (330lb VBP with KYB GR2 shocks valved for composite springs) for about a month. Its the main reason why my car is fun to drive again.

I agree. It was one of the best mods on my 1974. People like the Bilsteins, and they may be very good, but they are twice the price and not necessarily tuned for the VBP spring. I believe VBP has some engineering expertise. Those specialty shocks come from Japan (not China) but what the heck. I'm happy with the mods in 2011. They work very well.

And driving just some 50 miles in 2012 all seems fine.

Heat shielding is highly recommended by VBP. In fact its absence voids the warranty.

http://img.photobucket.com/albums/v1...pension005.jpg

I just got a Hyperco composite 330 rate and Bilstein sport shocks yesterday from Van Steel.

Let us now know how you enjoy that combination! Sounds like a good one.

I ended up ordering the 330# spring and shocks from VB&P. Hopefully the car will be on the road before July!!!

:iagree:
And you MUST use the heat shield, you might be suprised how warm the shield feels after idling the car for 15 minutes.

Of course not requiered with side pipes.

You might also consider a stock rate fiberglass spring. Hyperco makes a 200 lb spring and sells it through Van Steel and Eckler's.

I agree with Paul , I installed quite a few of these and what a difference , on my 80 I got a 360lbs with Munro gas shocks , no need to waste money on expensive stuff if you don't track it . Ron

I just got a 72 vette and I'm pretty sure it is need of a rear spring and shocks. So I'm definitely enjoying the thread. How should I go about determining the spring rate I'd like? I'd like it to ride smooth (I live in MI and the roads are Sh&$) However, I always find I push my cars and want performance. 330#?

Thanks

78 L-82 4 speed with the OEM gymkhana 7 leaf sport spring and replaced it in 1986 with a VBP 360 mono spring back then with KYB Gas A just shocks-was way too bouncy. In the early 2000's replaced the Gas A Just with Bilstein Heavy Duties-gigantic improvement but still too bouncy for my liking. Sold the bilstein HD's to a forum member with about 2,000 miles on them and replaced them the rears only with Bilstein Sports (30% stiffer than the Hd's) about 5 years ago and the ride is perfect. Recently took a neighbor for a ride who owns a Lexus LS430 and he could not believe how good my car rode for a C3. It really is that good with the 360 spring and the Bilstein Sports. No heat shield except the factory one right under the spring where it mounts to the diff-zero issues. Don't waste your money on KYB's/Monroes/Delcos etc with a mono spring. Go for the Bilsteins!-They will never wear out! Last shock you will ever have to buy. They are that good and worth the money!

I would not use a mono spring rated less than 330 lbs/in-200 is way too soft for these cars and it will ride and handle like a 70's cadillac with that marshmallow spring!

I'm in the same boat as many with choosing between the 330 and the 360. I haven't driven or riden in a Vette with either so any additional advise to the best bet for a weekend cruiser 1971 big block 4 speed convertable would be appreciated.

Question for paul 74 and/or others who went with the VBP #330 and the VBP shocks. Did you go with longer spring bolts or stick with the stock length? I remember hearing about the car sitting high after the install. Definately don't want that. I want to maintain current height. I have thought about doing this for a long time, but have not due to those (horror?) stories.
Dale

Its been a few months, so I hope I remember correctly, but it seems like I ordered the VBP 330lb spring in a "kit" that included all mounting hardware (longer bolts). I have no problems with ride height whatsoever. Also note that my spring bolts don't hang down dangerously close to the rear tires like many of the pictures that we see on here from time to time. My setup looks just like Paul74's picture above.

I just installed the VBP Performance plus suspension. I called VBP before I ordered my kit and told them that I want my spring rate for just street and I wanted a nice ride. I have the #260 lb rear spring and a #630 front spring. The Performance Plus kit has the adjustable spring rate and works out great with these spring rates for me.
I had the F7 gymkhana suspension from the factory and my new suspension is a bit stiffer than what I had with the F7. Check out my album picture # 12 . The system
Lowered my whole car, front lowered by 6 inches and the rear by 4 inches:thumbs:
VBP can make any rates spring for your needs.

I used the 8" bolts that came with the VBP spring kit. As you can see they do not hang down below the wheel rim.

http://img.photobucket.com/albums/v1...onrear-001.jpg

As to ride height I do not see a problem. The 235-60 tires (rather than stock 225-70) do allow for some air to show in the wheel wells but the car looks and drives fine.

http://img.photobucket.com/albums/v1...ngisland27.jpg

http://img.photobucket.com/albums/v1...rs2012-001.jpg

When I was younger I had a '63 with standard suspension. A number of my friends had similar C2's. All were real stiff in the rear and we just thought it normal to come to something close to a full stop whenever we crossed railroad tracks. The point is, this was my baseline for Corvette suspension stiffness.

When I got my C3, I was surprised at how much softer was the ride. For me, I preferred stiffer. After some years I replaced the standard steel spring with a VBP 360 mono-leaf. I was familiar with all the posts regarding shock stiffness so I also installed QA-1 adjustables. I set the adjustment at something like 4-5. Way too bouncy! I upped the adjustment to an 8 and it's much better. I've considered taking it up to a 9 but haven't done so.

Recently I was doing some more work on the back end so I replaced the 360 lb spring with a 420 lb spring. No change to the shocks. It doesn't seem much different but I prefer the 420 all the same.

The C3 rides better now than it ever has - much better than stock. I am a big advocate of the mono-leaf spring and as you can tell, I'd err to the stiff side when making a choice.

Thanks Paul. I'm going to add spring replacement to my to do list.
Dale

Installation note: do NOT torque down the four bolts holding spring to differential until you have the weight of the car on the spring. You can crack the differential housing if you tighten the bolts with the wheels off the ground.

Since spring rates affect balance as well as bars, if you are just guessing between two rear springs IMCO the prudent move would be erring with the softer one. This may not seem important to anyone who doesn't ever plan on pushing the limits, but you never know when an unexpected situation could put you there. And, that's no time to find out whether or not you've taken rear roll stiffness too far and created an oversteer characteristic. My $.02

I am with gearhead74 with preferring a stiffer ride, so not knowing anything else about your BB 71, i would go with a 420 mono spring since it is a BB which tend to understeer much more than the small blocks. I intend someday if my 360 monospring ever wears out or breaks (installed in 1986), I will go with the 420 spring. You would not believe how good my car rides and handles-everything is poly including the control arm bushings and competition adjustable rear struts with heim joints. I have to laugh when I see the comments about poly and the effect on ride quality-not true.

The biggest problem with the C3's suspension is that it has way too much play in its design even with rubber components that are new. I have spent 25 years experimenting with many different setups and have concluded that you should do everything you can to tighten up the suspension components.

C3 member, Karol, recently rode in my 78 L-82 which originally had the gymkhana suspension and Karol's 78 L-82 does not have the sport suspension nor a composite spring (among many other differences) and he could not believe how much better my car rode, steered, and handled than his.

I just put a #300 vbp spring on and bilstein HD shocks, which should be softer than the #330-360 and bilstein Sport shocks that seems to be common here. I could tell you how it rides if only I could get my brakes bled properly so I can drive the damned thing. Argh.

A composite spring rated at 360 lbs will have very different ride and handling characteristics from a steel version of the same rated springs. This difference is the reason that my 78 with the 360 lb rated spring rides so much better than the much less rated OEM steel gymkhana spring and the reason that i mentioned in a prior post of potentially going to the 420 composite in the future. As long as the front and rear spring rates are compatible, you can go much higher in spring rate with a composite versus a steel rated spring. Last word on shocks with composites, don't waste your money on mass market shocks like KYB, Monroe, Delco-go Bilstein-they cost more because they are worth it!

Sorry to disagree with others here, but respectfully...

Despite notions to the contrary, IMOE it's quite easy to create a BB C3 that oversteers at the limits (where balance matters most). Thing is, BB C3's usually require more front spring relative to the rear than SB's - which translates to less (not more) rear spring requirement relative to the front - to achieve a good balance.

When I first swapped a BB into my '78 back in the day, due to my own SB based preconceptions I had missed that point, and was fortunate not to have crashed out while chasing my tail (pun intended) before Dick Guldstrand set me on the path to getting it fairly well sorted. FWIW, "only" an F41 rear spring here, and I'm on 860# fronts! Before you think that's whacked, Mr G ran a an even softer rear than that with 860's on his A Prod BB C3.

But, I digress. I'd really rather not completely derail the OP's central topic with all this. Suffice it to say, I'm not particularly speculating when I urge conservative steps rather than giant leaps here. You don't have to understand roll couple distribution theory to know that expensive noises often result from getting it wrong, even if pressing the limits on purpose isn't on one's menu.

OK, that's $.04. PayPal accepted. :D

Hi, new to the Corvette world, so dumb question time. When a guy goes to that spring, is there any kind of spacer for the differential cover that has to be ordered to make up the difference in thickness, or is it built in/included with the spring?

Everything comes with VBP spring kit.

You have to add the heat shields. Instructions make this very clear.

http://img.photobucket.com/albums/v1...nsion005-1.jpg

Like to thank all that replied on the post. Opinions are great and I tried to listen and make an educated choice. Went ahead and ordered the 360 rear and to help the balance upgrading the front to the 550 SS from VBP. I hope this was the right way to go, guess we'll see.

That is the combo I run-you should be very happy with the balance-ride is persona preference. What kind of shocks are you using? I also use the OEM 1 1/8 inch bar with poly bushings and use a 3/4 rear OEM type bar with poly mounting bushings. Let us know.

Right now I have the basic KYBs. From what I gather I might need to go to an upgraded shock. Doesn't hurt to try what I have before upgrading. Great to know the solution before you experience the problem. I'll post back when I get it all installed.

Years ago I had KYB Gas A Just's, not the GR2's, and the ride was very bouncy on the highway. The Gas A Just did not properly damp the spring on my car. I run the Bilstein Sports in the rear with the 360 spring and Bilstein HD's in the front with the 550 coil springs.

Would you say the 360 is enough, or would you go a step up if you had the chance?

The short answer is I would go 420 on my car!

Here is my setup:

Front:

Blue Printed/rebuilt Gary Ramadei OEM steering box
Speed Direct spreader bar
Poly upper and Lower Control arm bushings
550 springs, 1 inch lower than stock
OEM 1 1/8 inch sway bar with Poly endlink and mounting bushings
255/45/17 ZR ultra High Performance Summer only tires
Bilstein HD shocks

Rear:

360 monospring with poly cushings
Competition adjustable strut rods with heim joints
3/4 OEM type sway bar with poly bushings
Bilstein Sport shocks
255/50/17 ZR tires like in the front

The car rides, steers, and handles better than 99% of the C3's I have been in. I still would stiffen the rear just a tade with a 420 spring.

Fellow forum member, Karol, recently rode in my 78 and he could not believe how much better my car rode than his 78 L-82 4 speed with the base suspension (including the base steel spring) and 255/60/15 tires! You would never think that reading and hearing some folks comments about poly control arm bushings, low profile Z rated tires, high composite spring rates etc. My car simply rides MUCH better than the OEM suspended cars, Gymkhana as well as base!

Just picked up my new rear 360 spring from VBP today. They were out of the standard size 360 for the next few weeks (a supply issue with the materials) but they had a shorter spring that was available. It is 1 inch shorter on each end than the standard 360 spring. The VBP tech (by the way nice people over there) said the shorter spring wouldn't make any difference in performance or the way it rides vs. the standard length spring. He said if I wasn't happy they'd exchange it no problem. Well I don't have experience with this spring so I wouldn't know the difference one way or another if the shorter was not performing like a regular length. Not my favorite past time swapping springs, so I rather not do it more than once. So, is there a draw back to the shorter spring even if it rates out at 360?

The shortened main leafs are SOP for gaining additional tire/wheel clearance, and don't adversely affect operation. Many of us have had them for years.

So what spring would you suggest with stock front springs on a 1980?

The right question is, what is it doing wrong (according to your own backside, and assuming it's sufficiently calibrated) when you press hard now? Unless your car is actually suffering from what you know to be moderate to severe understeer (mild understeer is actually preferrable on the street anyway), and you aren't planning to do anything else, I'd stick pretty close to the stock rear sping rate.

My stock spring is sagging. My vette mechanic says it needs to be replaced.

I just did the swap as you can read in this post and I think the 360 is just about right. My Vette is a BB but as far as weight in the rear not sure there is too much of a difference from a SB. It's Definately not stiff by any measure. Not sure if this helps you or not but calling the folks at VBP helped me make my choice.

Vehicle Dynamics 101...
 

FACT: If you stiffen the rear spring without stiffening the front (assuming no other significant issues are working against you), your balance WILL shift towards or into oversteer; how much so a matter of degree relative to how far you move the roll couple percentage towards the rear. It doesn't matter what are your purposes or how comfortable may be the ride (or not), that's just the way it is.


Seems I'm constantly trying to pound this point home, but an oversteering car will often feel spectacular right up to the point it bites you in the backside. ...and there's also a little surprise called TTO (trailing throttle oversteer) which can even occur in an otherwise mildly understeering car. So, with the potential costs of overstepping here being pretty high, on which side do you wish to err? Sorry, there's no perfect setup however many may claim to have found it.


.