79corvette

*Sorry, I guess "mono spring" means the one piece composite springs. I thought it was used for all rear springs, but then I thought about it and I guess there is a difference. Sorry for the mistake.

I was driving to work today, and my rear spring broke. Good thing I was only going about 25 in my neighborhood. Scary for a second. Tires barely cleared the fenders. Good thing my car still has the rubber bumpers on the chassis for the trailing arms, that's what it was riding on I think. Now is the time I should decide if I want fiberglass, or steel. What spring rates do you recomend, and vendors? Will a fiberglass be a worthwhile investment?


[Modified by 79corvette, 2:09 AM 7/6/2003]

Chris69

Wow! Which glass spring was it? :eek:

standup

I bought a VBP carbon fibre 330lb rear spring.....not too stiff......not too bouncy......much better than my 32 year old original steel spring, which was just taking up space in the rear end...and now is taking up space in my garage :)

Dk Met Grn 80 L82

WOW! What spring was in there that broke? Doesn't sound like fun... :nonod: :nonod: :nonod:

MIKER

It's hard to come with any statistically significant data showing the failure rate of composite mono-springs vs. steel leaf. Mostly just speculation. One thing for sure is that they have used a LOT of them in Corvettes over the past 20+ years.
I'm very satisfied with the ride improvement provided by my new 355 psi composite spring vs. my OLD, WORN OUT steel 9-leaf spring but I have no idea if a new steel leaf spring wouldn't have worked just as well.

composite pros and cons:
-light weight
-quick reacting.
-won't sag over time
-cost over two times as much as steel spring
-must be protected from excessive heat, chemical exposure, and mechanical damage.
-Several CorvetteForum members have found their new composite springs to have an excessive arch which causes the rear end to ride way too high. This requires longer end bolts to mask the problem. End bolts extending below your actual rim height can be dangerous if rear tire goes flat. (bolt could dig into pavement)
-specially valved (ie. expensive) shock absorbers required to control excessive bounce.

Steel spring pros and cons:
-relatively inexpensive
-old proven technology
-very heavy
-inexpensive shock absorbers can be adequately used
-very resistant to heat, chemical, and mechanical damage
-some aftermarket springs are over arched causing the rear end to ride way too high
-will sag over time

Lot's of stuff to consider. I Hope you are please with whichever one you choose.
:cheers:

79corvette

It was actually the stock 24year old spring that broke. I should've known it was coming. I didn't have enough time to check out exactly what happened since I had to get to work and got back at 11PM, but I did notice either end of the spring dragging on the ground.

I never knew that the composite spring requred special shocks. that'll be a deciding factor I think. I'll have to do some research, and inspect the car tomorrow.

1969Vette383

I believe the word you're looking for is "transverse rear spring" :thumbs:

I just bought a 360# fiberglass rear spring with KYB whites, amongst other parts, and they are on their way from FL. I bought my parts from Eckler's and this is the first massive order I've had with them, hopefully everything will be in great shape when it arrives. Both the KYB white and silvers are in the $40 each range.

I'll tell you how I like this combo when I get a chance to drive my car again, but you'll probably have resolved your issue before I can do that.
My steel spring wasn't broken per say, but another con I can add to the steel ones (and what happened to mine) is that the rubber sheets in between the steel can warp and get all bunched like a sock in a shoe. That and my steel spring is slowly starting to sag and show its age. I was also interested in more performance and with the higher spring rate in the rear (I also ordered 550# coil springs for the front) I'm sure I'll be able to grab a corner, put it in a headlock, noogie the heck out of it and spit it out of my exhaust :smash:


[Modified by 1969Vette350, 12:53 AM 7/6/2003]

Bearcat

:iagree:
I have the 550# front springs with the 340# TRW fiberglass rear spring. I liked the TRW design better because they're broader. It looks to me like they'd be more resistant to breakage, but that's just an intelligent guess.

It handles much better. With the old suspension, I couldn't believe how wallowy it felt. It handled horribly, even with the 50/50-ish weight distribution. But once I swapped in the springs, along with Bilstein high pressure gas shocks and urethane suspension bushings, the difference was unbelievable. Now the limiting factor is tires. You can't get enough rubber under a C3 to handle as well as that suspension combo is capable of. But you'll be hanging corners very impressively with that suspension.

I wish I would've gone with the TRW 355# spring though, but the 340# isn't bad. They're a little bouncy over rough roads, but the handling is very good.

1969Vette383

:lol: tell that to all four 295-50/15s under my car. I've got the rear fender flares and while my tires don't quite fill them out now, I'll be fixing that one of these years. The fronts stick out a little bit but I'll downsize them to 275 or so to cure that. These mods are further down the road when I actually I have my car drivable :cry

isosceles

Sorry to hear about your spring :sad: I guess you won't be making it to Immokalee this week? Check out Van Steel. You might even want to consider having them do the work if you don't want to do it yourself. They are about 122 miles from me, a little farther from you. But back in March my car was throwing belts because Bubba had the wrong P/S pump pulley on it ( I didn't know at the time). I had a poly front kit from Van Steel staring me in the face and figured if I couldn't even get the belts to stay on, there would be no chance I'd successfully install the front end kit.
I had AAA pick up the car and flat bed it to them. Only cost me $56 for the mileage over the 100 you get with the 'plus" plan. Anyway it might be something to look in to. If you want to do it yourself, buying the parts from them or Ecklers could save you some money and time in shipping.

Crash Dummy

79corvette,

If you are looking at installing a fiberglass monospring replacement it does not take any special shocks. Although, it would be best to put new ones on if your's are as old as the spring that broke. I've got the VBP 360lb fiberglass monospring and I like the idea that you can raise/lower your ride height with them. A bit pricy at $340.00 + the set of KYB shocks I had installed at the same time. Total bill a little over $500.00.

Enkil

You can raise ane lower the ride height with any rear monoleaf spring by simply turning the nut on the bottom.

Also, I don't necessarily think it's the arch of the aftermarket spring that causes it to sit any higher -- the old monoleaf spring I had had just the same arch on it as the new spring did. Well, sorta, the old spring broke, so it was like half an arch. But that half curved the same! I think the new ride height has more to do with how strong the spring is, so perhaps if you got a spring rated the same as stock, or less, you wouldn't have the problem that I am (and several other members are.)

I would DEFINATELY go with a composite spring, they are much lighter and much easier to deal with when you're installing it, especially if you're doing it by yourself like I was. (8lbs vs. 50)

It is true, a longer bolt will solve the problem of the car sitting too high. But as stated before, you probably shouldn't go TOO long just in case you have a blowout and your car drags the bolt. The bolt could easily move out of the way, as it's not held in straight up or down, just sort of pivots around the cushion, but it would probably also damage the spring some.

Solution: Bigger rims! :D

If you do get the composite, I'd get it from Van Steel. 250 dollars, great service, 5% discount for being a member, and it comes with the spring (duh), new bolts/cushions/retainers/washers/nuts/cotter pins, and a new heat shield. You just might have that problem of it sitting up too high when the new spring's on.

MIKER

bgrice is correct. "it does not take any special shocks".
Any shock absorber that would actually fit the car before will still fit on the car after installing a fiberglass spring. However, the composite springs have a different rebound characteristic than the steel ones. Many Corvette owners have found that certain shock absorbers with stiffer rebound damping will control this bounce a lot better than others.The same method is used to raise/lower your ride height with either steel or composite springs.
I think we were both wrong in our terminology. Neither "excessive arch" nor "how strong" are exactly proper terms for describing spring specifications. Check out this link for defining spring related terms. http://www.eatonsprings.com/tech%20infro.htm
The manufactures/vendors are not taking care to build/sell us springs with the proper load rate for our cars. It's the one size fits all syndrome.
We shouldn't have to use >8" bolts to bring our ride height down to GM specs. By using longer bolts we are simply trying to compensate for poor spring selection and or inconsistent manufacturing.
Basically, we should be getting a better product for our money.

The information below has been copied from the EATON Detroit Spring, Inc. website http://www.eatonsprings.com/tech%20infro.htm
RATE is half the difference between the loads 1 inch above and 1 inch below a specified position. Put another way, rate is the amount of weight required to deflect the spring 1-inch.
The lower the rate, the softer the spring.

LOAD is the amount of weight the spring is designed to carry at a certain height. This is also called the Design Load or Load Rate.

LOAD RATE is not to be confused with Rate.
Load Rate is the amount of weight a spring is designed to carry at a certain height.
Let’s say a spring has a rate of 200 lbs. per inch and is designed for a 3-inch deflection when deflected 3-inches the spring is supporting 600 lbs Therefore the spring has a Load, or a Design Load, or a Load Rate of 600 lbs.,not a Rate of 600 lbs.

FREE ARCH is how much arch is in a leaf spring when there is no load on the spring.
To check the Free Arch draw a line through the center of the spring eyes.
Then measure from that line to the top of the main plate (the leaf with the eyes) next to the center bolt.
This measurement can be positive or negative.

LOAD HEIGHT is measured the same as Free Arch except the spring is under load.
Again this measurement can be positive or negative.

There is nothing wrong with a spring that has a reversed arch when under load. A spring is dumb, it will still flex with a positive or a negative arch.
If your vehicle sits good and rides good, who cares which way the arch is. In fact many springs are designed at the factory to have reverse arches when under load.

79corvette

I went to check to see what happened to my spring today. It turns out there was only 1 bolt holding the spring in :eek: :eek: :eek: . I ALWAYS ASSUMED THAT THERE WERE 4 BOLTS THERE :mad :mad. I think I am going to order the VB and P 360lbs composite spring. Both Van Steel and VB and P are around the same price, but as Enkil stated it offers a 5% discount. Also thinking about it I don't want deal with installing a 50lb spring. This gives me a good excuse to get better performance :D .
Thanks Miker for clearing up some of the definitions. :cheers:
Isosceles, I wish I could go to the track, but I don't think it would work to well with a broken spring :sad: :banghead: . Have fun there :auto: .

1969Vette383

Um, wow! I think my current spring is mounted upside down. I went to that Eaton site and saw that the longest leaf is supposed to be on the top. My longest leaf is on the bottom. This makes no difference now as I have a replacement fiberglass monospring and my car is down. But now the question arises, when I install my new spring do I mount it with the bend up or down?

Captain Morgan

79corvette and all others:
If you have an older vette, it is a good idea to crawl underneath periodically and check bolts, etc. I lost a bolt on my rear spring last year. I heard a "click" type noise coming from the rear when I was on my way to the track. I got there, paid my money, and headed to the pits. When I got in, I crawled underneath the car and found one of the spring bolts was missing. I didn't run that day, nor did I drive my car until I got it fixed. For some reason, the center spring bolts tend to come loose over time and may need to be re-torqued to avoid problems. When installing the spring, be sure to follow the proper torque procedure to avoid damaging the spring, or the rear diff cover. If you torque the bolts too much, or at the wrong time, you can break the diff cover.

Your spring should arch down, and the longest leaf is on the bottom. I haven't looked at the Eaton site to see what you are describing, but yours is in the correct position. When you put in the new monoleaf, it will also arch down. The best way I can show you without a picture is by using this symbol: ^


[Modified by Captain Morgan, 2:20 PM 7/21/2003]