Broken Varishock

[dhutton]

Hit a dip in the road today and one of the Varishocks on my G-Bar blew apart. What a mess, I'll need to cut the spring to get it out of there. I put in a longer spring due to the original spring bending and hitting the shock body. I know some are very happy with this setup but I've not been too impressed. I may be doing something wrong but at ride height the shock length is as specified. This setup has roughly 500 miles on it.

It looks like they have reduced the angle of the shock on the G-Link so I'm thinking that may have something to do with all this. It appears that the springs might be under pressure to bend due to the angle of the shock relative to the suspension travel.

I can't decide if I will try a pair of Shockwaves, a different brand of coilovers or just go full out and get an AME tri four bar setup and be done with it.

Hard to take a picture but here's one:

[ProdigyCustoms]

Where did you get the red springs? I need some installed height pics.

[dhutton]

The red springs are Eibach springs that I installed when the original springs were bending and hitting the shock body. They cured the bending but I guess the stress that caused the bending was still there.

Like I said I know a lot of people are happy with this setup. Todd kicks butt with his. Maybe I installed it wrong but I don't see how. There was no binding through the whole supsension travel. I checked it many times.

Here's a ride height pic.

Thanks,
Don

[ProdigyCustoms]

You have something going on we have not seen in hundreds of G bar sales. Looks like too long springs? Need more information on the springs and would like to see a under body shot of the installed suspension.

[Rhino]

Looks like too long springs?

As someone who is going through a decisioning process with coilovers this got my interest. Could you elaborate on the ramifications of too long of a spring? I don't think I would have imagined this outcome. Ignoring the differences in preload, I would feel the big difference between setups would be the longer spring would attain coil bind sooner, however the load would still be applied evenly.

[MrQuick]

Each shock will have a specific spring length. To go out of its bounds (operating limits) will cause problems with over leverage or bottoming out. Both are bad to suspension components.


I'd like to see a picture of the shock and spring at ride height.

Vince

[69sponge]

I run those springs on my sand car.The specs are printed on the coil 14"-- 2.5 dia --and 165 wt.I also run a g-bar on my 69 camaro and i know the coils are shorter than 14".

[dhutton]

It says above in my first that I put in the longer springs in an attempt to solve a problem with the spring bowing and hitting the shock body. This was done at the recommendation of one of the forum suspension gurus. This may have caused this failure but I somehow doubt it and it does not address the original issue of the spring bowing.

Interestingly enough here is a thread with someone having the same bowing issue with a G-Bar and QA-1 springs:

https://www.pro-touring.com/forum/sh...ad.php?t=69408

I know it will be easy to dismiss this as an installation error or the use of the wrong spring but 30 years of design engineering has taught me to never dismiss a failure without a thorough understanding of what caused the failure.

I also crunched some numbers on replacing this with an AME setup and it got costly considering I am likely looking at modifying my exhaust and new brakes if I go this way. I think I will look into replacing them with a higher end coilover, maybe one of the new ridetech pieces. I am still a little concerned about the angle of these shocks though.

[ProdigyCustoms]

It says above in my first that I put in the longer springs in an attempt to solve a problem with the spring bowing and hitting the shock body. This was done at the recommendation of one of the forum suspension gurus.

Now don't you know advice on the internet is dangerous!, LOL!

The other poster has to soft a spring at only 150LB. His spring is almost in bind trying to hold the car up. 200LB is the normal spring on your suspension. And it is only supposed to be a 12" spring.
If you have a 14" spring with a 165LB spring rate trying to support a car that requires a 200LB, that could cause a issue.
I have to be honest, I never tried what you did (longer spring, softer rate), so I am not sure what the effects would be, but I think I am learning right now.

[ProdigyCustoms]

Here ya go

http://cachassisworks.com/p-1057-var...-2-1-2-id.aspx

[dhutton]

My G-Bar came with 175 pound springs. That other poster doesn't know what he has. First he says 250 and then when I asked him if they really are that high he says maybe they are 150's. I'm guessing they are 250's.

My G-Bar was a relatively early one. Did they make a change from 175 to 200 pound springs?

The advice didn't come on the internet, I talked to him on the phone...

I don't think the longer spring caused this failure. Fact is the springs that came with my G-Bar were bowing from day one.

[ProdigyCustoms]

175s are the lightest spring that will hold the lightest cars. We use 200s on 95% of the cars we sell and install.

We just did a install last week on Patrick's 68 Camaro and used 200s and the car sat at exactly the correct center to center shock position, at the correct ride height, with the correct amount of spring compression. And he DOES NOT have any stereo stuff or added weithg in the rear of the car except a stainless tank that is a bit heavy.

G bars do not have a very extreme shock angle, so I doubt the shock angle has anything to do with it.

Any chance you have any pictures of the shock and spring at ride height? Maybe jack up the broken side and shoot a pic of the good side? I really think you were in spring bind. 2" too long spring is a lot. And the fact there were to light meant they were already cranked up high. A 12" / 165LB spring would be close to spring bind on, let alone a 14".

Now how the spring bound and caused the shock to break? I dunno, but I feel pretty sure this is what happened.

[ProdigyCustoms]

The advice didn't come on the internet, I talked to him on the phone...

.

I was teasing because you have given some GREAT advice. I have been very impressed with the advice you have given. But not all internet advice is so good!

[ArtosDracon]

Assuming a 3400lb car, with 45% rear weight that would put 765lbs on each spring assuming 50/50 left and right weight. On a 200lb spring that should mean 3.825" of compression, which would take a 12" spring down to 8.175. On a 165lb spring it would be 4.64" of compression, taking a 14" spring down to 9.36". Given the G-bar varishocks are designed to operate with a 12" spring and retain full function through ~3" of vertical adjustment, 1.5" each direction of center, the spring length shouldn't hurt at static height. Where the issue might come in at heavy compression and re-bound, I can't speak to the shock travel depending on loads, but it could have tried to yank the rod out in re-bound. Given the diameter of the shaft, I almost can't believe this kind of damage, the load must have been huge.

[dhutton]

Assuming a 3400lb car, with 45% rear weight that would put 765lbs on each spring assuming 50/50 left and right weight. On a 200lb spring that should mean 3.825" of compression, which would take a 12" spring down to 8.175. On a 165lb spring it would be 4.64" of compression, taking a 14" spring down to 9.36". Given the G-bar varishocks are designed to operate with a 12" spring and retain full function through ~3" of vertical adjustment, 1.5" each direction of center, the spring length shouldn't hurt at static height. Where the issue might come in at heavy compression and re-bound, I can't speak to the shock travel depending on loads, but it could have tried to yank the rod out in re-bound. Given the diameter of the shaft, I almost can't believe this kind of damage, the load must have been huge.

Thanks for putting some math to this. Does this analysis take the angle of the shock into account?

The dip was fairly abrupt. I didn't go back for a good look but I think they trenched across the road and then didn't fill in it correctly. It was likely an abupt 2 inch drop followed by an abrupt 2 inch rise so the shock took a one two punch. Maybe I'll return to the scene of the crime to take a closer look.

The interesting this is my AME subframe with 500 pound springs rode through this like a walk in the park.

[dhutton]

I was teasing because you have given some GREAT advice. I have been very impressed with the advice you have given. But not all internet advice is so good!

Don't worry, no offense taken. But he is a guru... LOL...

[Rhino]

I have to be honest, I never tried what you did (longer spring, softer rate), so I am not sure what the effects would be, but I think I am learning right now.

I have no experience in this area either, but logic would dictate the ride to be a little stiffer (due to the 2 extra inches of preload), but ultimately bottom out easier once the preload was overcome.

Don, are the ends of these Eibachs any different than the original springs? I could see this happening if one side of the shock hits bind before the other.

[dhutton]

I have no experience in this area either, but logic would dictate the ride to be a little stiffer (due to the 2 extra inches of preload), but ultimately bottom out easier once the preload was overcome.

Don, are the ends of these Eibachs any different than the original springs? I could see this happening if one side of the shock hits bind before the other.

The ends are identical. The only visible difference was the length. The ride was a lot better with these springs. I also tried longer 185 pound Eibach springs but I thought the ride was a little harsh. I was trying to match the ride of my AME subframe to the G-Bar to give a balanced response to the road. Even with the 165 pound springs the rear suspension was considerably stiffer.

[Rhino]

Do you have any bump stops in the suspension? I'm wondering if you bottomed out the shock with considerable force due to the decreased spring rate. With no more travel, the force would have had to go somewhere.

[dhutton]

Do you have any bump stops in the suspension? I'm wondering if you bottomed out the shock with considerable force due to the decreased spring rate. With no more travel, the force would have had to go somewhere.

Nope, no bumpstops on a G-Bar setup. The shocks have internal bumpstops as far as I know.