# Confused about this forum.



## dms (Jun 27, 2005)

I have not been active in this forum mostly due to the lack of participation it has. I recieved an email stating that this forum has been updated. So I thought I would visit it again.

I must admit, I am alittle dissapointed. Not bragging, but I think I am one of the most knowlegable guys out there on GTO suspension issues. Being a new car dealer, understanding the GTO, and klnowing the significant amount of failures of the GTO OEM suspension, made me go and seek out and become the first pedders distirbutor in the nation. But looking at this section, I really do not see a lot of discussion about suspension concerns. I do not participate in the "other" larger GTO forum to sell Pedders. But I participate in the forums to help GTO owners fix multiple problems with the GTO. This forum does not seem to be very active in suspension issues. Knowing the car like I do, this section of the forum should be riddled with discussion. Why is it that it is not?

mike
dms


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## TR GTO (Mar 17, 2007)

If the questions were being asked, there would be topics for discussion for you to answer questions. Some people might not even realize the suspension problems inherent to the GTO. I would say it wouldn't be a bad idea to work up a thread of suspension information and recommendations that could be used as a sticky for the forum. I've got to say I haven't posted in a long time on here, but I get bored and check back from time to time.


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## dms (Jun 27, 2005)

TR GTO said:


> If the questions were being asked, there would be topics for discussion for you to answer questions. Some people might not even realize the suspension problems inherent to the GTO. I would say it wouldn't be a bad idea to work up a thread of suspension information and recommendations that could be used as a sticky for the forum. I've got to say I haven't posted in a long time on here, but I get bored and check back from time to time.


There are lots of issues of abnormal tire wear front and rea, ride height issues, tire cupping, strut rub and the list goes on. there are not issues that I havestarted, but they are issues that there are known solutions for. Why would we not see the discussion of this on this sight? that is what I was trying to say

mike
dms


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## Jeffs386 (Nov 1, 2005)

I haven't had any suspension issues with the car


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## GTOJon (Jan 25, 2005)

I am not one to claim much knowledge at all in regards to the GTO suspension. Either I'm oblivious to issues with the GTO (or my car), but I didn't even replace my STOCK tires until 40k. I am aware of the 'potential issues' (such as tire wear, strut rub - I know nothing of the 'riding height' problem that you mentioned), but I guess it does not involve ALL GTO's. Correct me if I am wrong, please.


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## GM4life (Mar 18, 2007)

dms said:


> I have not been active in this forum mostly due to the lack of participation it has. I recieved an email stating that this forum has been updated. So I thought I would visit it again.
> 
> I must admit, I am alittle dissapointed. Not bragging, but I think I am one of the most knowlegable guys out there on GTO suspension issues. Being a new car dealer, understanding the GTO, and klnowing the significant amount of failures of the GTO OEM suspension, made me go and seek out and become the first pedders distirbutor in the nation. But looking at this section, I really do not see a lot of discussion about suspension concerns. I do not participate in the "other" larger GTO forum to sell Pedders. But I participate in the forums to help GTO owners fix multiple problems with the GTO. This forum does not seem to be very active in suspension issues. Knowing the car like I do, this section of the forum should be riddled with discussion. Why is it that it is not?
> 
> ...


Mike, I know that you're the one to come to when I have suspension issues. I've PM'ed you in the past on the other forum for advice I trust your knowlage. The thing is I hear so many conflicting responses from other members(not on this forum) on the suspension issues with this car its not even funny. So maybe you can come up with a list of problems and solutions and ask the mods to make it a sticky. Because when I have to look for a solution to the problem to get a better grasp I have to sift through alot of bull just to find the answer I want. Also reading through your post it sounds like the GTO should have problems with the suspension. From what I've gathered this was cause by the car being straped down on a boat for months, and wider than Aus tire size correct me if I'm wrong. Also I think you said in the past was to prevent some of these problems was to make sure that the tire pressure was in limits, have the alignment checked, and if the alignment can't be fixed it is caused by failed bushings. It sounds like GM, NHTSA brushed the problem off about the strut rub problems why is that? Is it because it happen to a small percentage and/or money/politics?
I currently don't have suspension problems, but I do want the car to handle better but keep the same ride quality. Also when I bought the car I had the front suspension alignment checked because I was not confterble with the tire so close to the strut, they said it was fine.

Thanks for your concern Mike.


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## Wing_Nut (Mar 6, 2005)

dms said:


> I have not been active in this forum mostly due to the lack of participation it has. I recieved an email stating that this forum has been updated. So I thought I would visit it again.
> 
> I must admit, I am alittle dissapointed. Not bragging, but I think I am one of the most knowlegable guys out there on GTO suspension issues. Being a new car dealer, understanding the GTO, and klnowing the significant amount of failures of the GTO OEM suspension, made me go and seek out and become the first pedders distirbutor in the nation. But looking at this section, I really do not see a lot of discussion about suspension concerns. I do not participate in the "other" larger GTO forum to sell Pedders. But I participate in the forums to help GTO owners fix multiple problems with the GTO. This forum does not seem to be very active in suspension issues. Knowing the car like I do, this section of the forum should be riddled with discussion. Why is it that it is not?
> 
> ...


You are searching the sands of the Sahara (not the casino) for water my friend. 

I've been hanging around since March 05 and suspension almost never comes up with the exception of the strut rub problem.

Most here are focused on creating HP & TQ rather than managing application of same towards forward motion of their car. Now if you had an answer for wheel hop at the drag strip, you could become a god, or at least a demi-god on this forum.

Here are the hot topics in no particular order

Dyno Tune
Supercharger / Turbocharger
Headers
Cold Air Intake
RWHP
Selling Price
Ricer kills on public roads
Mustang kills on public roads
I totalled my GTO today on public roads
What wax should I use
What tires should I buy
Ugly F-body paint jobs
Ugly aftermarket wheels
Gas prices
We also waste an appropriate amount of time solving the worlds social, economic, and political problems.

Where were you when my 05 had the cupping issue? I felt like Fred Flintstone. Ruined all four OEM tires.


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## 6QTS11OZ (Mar 27, 2005)

With me, I already know all about the problems with the GTO suspension so there really isn't a need for me to discuss it. When I have the cash I'm going to invest in one of your Pedders package. And honestly, your products are not necessarily inexpensive. I currently have Pedders "0" drop rear drag springs as well as drag bags. I don't have strut rub issues because I have aftermarket wheels with a 40 mm offset. And even with lower profile tires (235/35 fronts, 275/30 rears) I have never had any abnormal tire wear. Remember that not everyone have had problems their suspension. Some don't care to change their suspension because they are pleased with the current comfortable ride that the stock suspension provides. Plus I really don't NEED to change my suspension but if you knew me, you'd know that I am always looking to upgrade stock components if a better product is available no matter how much that product costs. That's why I'm $15K in to appearance and performance upgrades at this moment. Like gm4life said, provide us with information that you may have that will educate some members of the issues, concerns, fixes, etc. that will make them aware of something they may not know about. Include a Q & A section as well as a section describing the affects of your available individual components and complete packages. I am all for making that a sticky if you are willing to provide the information. :cheers


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## GTO JUDGE (May 14, 2005)

Perhaps you should monitor this section more often. If and when members have questions regarding suspensions, your knowledge and input would be greatly appreciated. Members offer assistance to the best of their knowledge. Most are limited on their knowledge however. Your insight to suspension issues would be valuable to those who seek answers to questions. If you are monitoring this site on a regular basis and others see your input to questions asked, perhaps more members would be inclined to post questions.

If you would list the issues related to the suspension with reasons why and corrective action, it will be made a sticky for all to view.


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## Rukee (Feb 8, 2007)

Yea, start a thread with known issues and the corrective upgrades and results.
Some people might not even know they have an issue unless you tell them how much better it can be.


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## GM4life (Mar 18, 2007)

Thanks Mike for taking the time to type all that out.:cheers


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## 6QTS11OZ (Mar 27, 2005)

Now that's what I'm talking about. Thanks!! :cheers


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## dms (Jun 27, 2005)

You know, many of you asked me to explain suspension cocnerns and I did. I spnet a considerable amount of time to help. It saddens me that one of you deleted the post. It was probably the best explanation of GTO suspension issues ever posted on the internet. IF YOU DID NOT WANT IT, THEN YOU MODERATORS SHOULD NOT HAVE ASKED ME TOP DO IT.

This will be my last post on this forum!
mike
dms


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## GTO JUDGE (May 14, 2005)

Mike, I have no idea what happened. Your post was one the best ever posts. I have sent a PM to Randy to see if that post can be retrieved. I have been searching for it and cannot find it.


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## GTO JUDGE (May 14, 2005)

dms posted a lengthy detailed post regarding suspension problems with reasons why and fixes. For an unknown reason that post was deleted. That post cannot be retrieved. If anyone would have by chance saved that post or printed it out, could you please post it so that information dms took so much time and effort to share can be shared with the group. Thanks


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## ELP_JC (Jan 9, 2007)

Wow!! This should be made a sticky. 
Thanks a lot for taking the time to write all that Mike; it was great. And pictures are better than a thousand words; saw them all. Now I understand much better how the suspension works on our cars. 

Hey, may I ask you a few questions, to continue the thread?

- How exactly causes the tire to rub against the strut body? They're supposed to move as a unit (at the same time), like all struts, no? Just curious.

- If a car doesn't have damage from shipping, are we home free? Or is there partial damage than progressively gets worse with miles? Did Holden changed their settings at some point, or ALL GTOs from beginning to end were shipped the same way? Mine was built the last week of production, but judging by all the problems I've had, they weren't made any better at the end. 

- How do we know if our bushings need replacement for sure? By the measurement system alone, or should we also look for a gap from the front tower to the plate? Or take the plates off and look if bolt is centered? Or try to rotate the top shaft like your little video (but how hard should we try)? Inquiring minds want to know. The reason I ask is because my car had 3 sides measure right at 600, but front left at 610; sounds strange, no? Could be the floor of my garage. 

Thanks again for your efforts. Am sure everybody who needs suspension will order from you. 
JC


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## GM4life (Mar 18, 2007)

WHAT!!! You've got to be kidding me! The most informatve and usefull post on this forum and it's gone. 
Why don't the useless childish bickering disappear like that.
Atleast I've got your number Mike when I'm ready to upgrade I'll be giving you a call.


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## JusticePete (Sep 15, 2004)

Mike is *D'MAN!*


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## 05GTO (Oct 6, 2004)

Let me explain what happened, I have access to the mod activity and have researched the mistake. Bare in mind this forum upgraded the forum software to a newer vBulletin® version which includes about 20 new and better features.

The post in question was to be moved to it's own thread and would have been made as a sticky. The mod who accidentally deleted this post was using good faith and found the information to be worthy of a sticky.

Unfortunately, he was using some of the new features of the forum for the first time. He did not realize that by checking certain features rather than starting a new thread it would delete the non-selected item which was this post he intended to separate for a new thread.

Mike/DMS, I can understand your frustration, I wish that I would have seen the post as the moderator has expressed how valuable the information is for our forum. But, it is gone and if you would indulge us, please start a new thread with this information. 

Thanks for your understanding,


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## PDQ GTO (Jun 21, 2007)

dms said:


> You know, many of you asked me to explain suspension cocnerns and I did. I spnet a considerable amount of time to help. It saddens me that one of you deleted the post. It was probably the best explanation of GTO suspension issues ever posted on the internet. IF YOU DID NOT WANT IT, THEN YOU MODERATORS SHOULD NOT HAVE ASKED ME TOP DO IT.
> 
> This will be my last post on this forum!
> mike
> dms


Mike,
Could you please re-post? It was just deleted by mistake, no bad feelings directed at you..


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## dms (Jun 27, 2005)

*The Definitive Explanation of GTO Suspension Concerns Part 1*

*FRONT SUSPENSION PART 1​*
last year, I posted a similiar post that defines the concerns of the GTO suspension and offered solution to the concerns. i was asked to do this by moderators. Somehow, an error occured, and one of the moderators deleted the post. I spent a serious amount of time on this and left this forum. Today I decided to visit the forum again because Rob at Wretched Motorsports is a Pedders sponsor here. So i decided to revisit and will repost an updated definition/solution base for the GTO. Wretched Motors can offer you support to resolve any issues listed below. If allowed I will assist you as well.

I am well known in the GTO community and go by DMS, which stands for "Doing Mike's ****" I have dedicated a very serious amount of time, energy and conflict on the GTO and will pass on knowledge that I have on it. This forum has very little information on the GTO, and I feel this community can benefit by this info, just if it generates questions. So here we go!

*The Definitive Explanation of GTO Suspension Concerns and Permanent Resolution Part One *​
This document was prepared to give the novice GTO owner a list of concerns common to the GTO suspension, and offer solutions to each problem.

*FRONT SUSPENSION ISSUES*​1. STRUT RUB
2. INSIDE TIRE WEAR AND CUPPING
3. NOISES
4. RIDE HEIGHT CONCERNS
5. BRAKING ISSUES
6 EXCESS SUSPENSION TRAVEL
7. EXCESS BODY ROLE
8. INSUFFICIENT NEGATIVE FRONT CAMBERS
9. POOR STRAIGHT LINE STABILITY
10. LOOSE STEERING FEEL
11. FRONT END NOT CENTERED TO THE BODY

*REAR SUSPENSION ISSUES*​1. INNER TIRE WEAR AND CUPPING
2. RIDE HEIGHT CONCERNS
3. POOR LAUNCHING AND EXCESS SUSPENSION TRAVEL
4. EXCESS WHEEL HOP
5. EXCESS TOE AND CAMBER CHANGE
6. EXCESS LATERAL SUSPENSION MOVEMENT

*
FRONT SUSPENSION SOLUTIONS
*​*1. STRUT RUB*. There are 2 kinds of strut rub on the GTO. When the GTO first came out, it was common to have strut rub, (tire to strut contact). In 2004 and early 2005, this was due to aggressive alignment settings for negative camber. Why was this a issue in the USA and not in Australia? Simple. GM added approximately 400lbs of structural support to the GTO so it would meed Federal criteria. Due to this, GM needed a larger capacity tire than the 235/45R17 used in Au. To try and increase tire life, GM went to a 245/45R17 tire which has a larger capacity rating, but is 10mm wider. The 235 has a load range of 1433lbs @ 44psi, and the 245 has a load range of 1521 @ 44psiWe initially saw strut to tire contact at the first rotation. GM was/is aware of this problem since the beginning but did not publish anything. If you called GM Technical assistance, they would tell you to put the front cambers to the positive end of specs, .2 camber. This strut rub would only cause a cosmetic issue, and is/was not destructive. This fixes the first style of strut contact, but severely reduced the handling. We have come up with a general spec to go negative on the cambers to the -.3 to -.4 range. At this range, you should be able to have at least a pencil width clearance between the tire and the strut. With that said, it is also CRITICAL to have your tire pressures at 35psi cold!!!. This fixes the first kind of strut rub, at least temporarily.

How many of you had not issues at at at the first tire rotation at 6,000 miles and the second one at 12,000 miles, but at the 3rd rotation at 18,000 miles the inner tire tread is destroyed, and there was evidence of strut to tire contact? You took it to the dealer and they said you must have hit something and knocked the front end out of alignment? Does this ring a bell to many of you?? Now i is true that you could have wacked something and knocked the front end out of alignment. But you also could have driven the GTO like a little old gramma going to Sunday school, and never hit a leaf in the road, and will still have the problem. Why? The strut bushing is damaged the moment it gets off the boat. To protect the front end, Holden installed front coil spacers to eliminate all front coil movement. Then they chained and cinched the car down really tight. The GTO was this way for over a month. This collapses the front strut bushing. But collapsing strut bushings is just the first issue, and by itself, is not that severe of a problem. But when collapsed, it weakens the rubber, and therefore the center of the bushing cannot stay centered in the bushing. This causes 2 issues. First it causes the strut shaft to migrate to towards the engine compartment, seriously increasing negative camber, as well as it will cause the camber to seriously change. The center of the strut bush, thus the strut shaft, will move all over the place, causing serious camber change, which ultimately causes serious toe change, which always screws up your tires. 

Now for some controversy: When the strut shaft moves in and out with respect to the engine, this movement is rapid. It will also cause the tires to have excess sidewall flex. Add the normal sidewall flex of turning, and you now have a lot of sidewall movement: enough sidewall movement to cause the tires to kiss the strut. I have seen and documented a severely worn strut bush, causing major inner tire wear, and strut contact, with 1/2 inch clearance from the strut to the tire. The strut contact issue, however, is again primarily cosmetic and not destructive. The tire wearm however, is severe and is often interpreted as contact wear from the strut

So the primary fix will be to replace the strut bush, and bearing, which will most likely come apart once the strut is dissassembled, then re-align the front end to get -.3 to -.4 negative camber. This usually will give you the pencil thickness clearance.

All of us have seen the reallllllly serious strut rub that destroys tires. It is my opinion that this strut rub is only caused by major impacts and bent parts. 

*2. INSIDE TIRE WEAR AND CUPPING*. The primary reason for inside tire wear is wear as a direct result of the strut bushing as previously mentioned. But there is another concern. You can see it by drivng your GTO 7-8mph then seriously jam on the brakes on. Observe the front wheels. It is not uncommon to see the front wheels kick back 2 inches. What this movement does is reduce braking action and brake pedal feel, but mostly causes major caster change, which again causes toe change. Toe gets toed out a lot. This again causes major tire wear, primarily on the inside and is a major contributor to tire cupping, which again is a major problem with the GTO. The cause of the excess movement is primarily the front OEM radius rod bushings that are fluid filled and often leaks, thus increasing the movement. The rear radius rod bushing also gets damaged and the washers bent due to the excess movement caused by the front radius rod bushing. the fix is to replace the front radius rod bushing with a firm urethane bushing like the Pedders EP9166. The other advantage using this bushing is your ability to get an addition 1.25 degrees caster. More on this later. The Pedders EP9019 inner radius rod bushing will add serious support for reducing caster and toe change, and reducing tire wear. There are other benefits that will be discussed later

*3.NOISES*. There have been a number of noise issues found on the GTO. Here is a list of things that I have seen at least 10 times or more: 
a. Front coil contact on parking lot manuevers creating a clicking noise. The repair to this is to reverse the OEM coils. There is a bulletin on this
b. Sway bar end link bushings and links get torn and bent easily. end links bend very easily with aftermarket sway bars. Replacing them with Pedders HD end links is a practical way of fixing this concern. The OEm bushings wear extremely rapidly. If it is just the bushings and the end link is not bent, then the end link bushes can be replaced. Note that the end link washers are dished, and the dish, if you will always goes away from the bushing. This is different than most vehicles.
c. Torn strut bushings, especially when the ferrule delaminates to the bush, can cause a knocking noise, on top of all kinds of other tire wear
d. Strut bearings can get lumpy and create a popping noise
e. 95% of all GTOs on the road that have OEm suspension have damaged front bump stops. They get torn due to excess suspension travel. This can create a knocking noise on a heavy jounce (compression of suspension)
f. Loose tie rod ends. The OEM tie rod ends are very prone to wear and can knock
g. Loose lower control arm bushing nuts and torn lower control arm bushings can easily cause a knocking or clicking type noise in the front
h. Front tires contacting the inner fender wells, especially the right front. You can either remove the portion of the inner fender well, or drill a couple of holes and use a large nylon tie strap and pull the fenderwell forward

*4. RIDE HEIGHT CONCERNS*. it is normal to have the front end 10 to 15mm low. This is primarily a function of collapsed and damaged strut bushings, and collapsing, under-sprung coils. Our Pedders coils are designed for performance and still maintain a very fine ride quality. Our coils, on average, have a 50% increase in sprung weight. Plus each is bench tested to 2MM tolerance. Also the GTO is a old body design and the acceptable tolerances of the body are significant. It is not uncommon to have as much as 1/2 inch height variation in the body totally due to the assembly and tolerance variations in the body. 5mm variations are more common and there is little you can do unless you have adjustable coil overs

*5. BRAKING ISSUES.* With the exception of the 2004 brakes, the 05-06 work pretty well, However, there seems to be a detectable lag time in the brake application. To understand the solution, you need to understand the cause. When you jam on the brakes, if there is any looseness or softness in the suspension. Before you actually stop, the looseness must be absorbed first. This is primarily an excessively loose or soft bushing concern. Replacing the radius rod bushings seriously reduces the fore/aft suspension travel, thus causing the brakes to react faster. Also the coils are way too soft. Jam on the brakes hard, the front suspension collapses and the rear suspension grows, this reduces the effectiveness of the rear brakes and adds additional weight and stress to the front brakes, Adding upgraded coils and dampers seriously reduces this affect

*6. EXCESS SUSPENSION TRAVEL*. This is a function of collapsed and damaged coils, and weak shocks, especially the front oil only struts. Going with a Pedders coil and any one of the 6 or so damper options that Pedders offers will control this concern. The rear is the biggest concern. Watch a OEM GTO take off. Notice how the back end collapses, this also seriously increases negative camber, thus promoting tire wear as well as other negative handling issues.

One of the other issues with excess suspension travel is movement of the strut bushing, even on a new one. A great way to improve the control of the strut bushing is to install a Pedders strut tower brace.. Putting on th animal strut tower brace, I feel, does little but improve "impression ratio". He with the biggest, baddest strut tower brace wins" to be honest the OEM unit works just fine. So how why is the Pedders unit special and different? Pick up your GTO and look at the strut plate to see what it does, It moves down approximately 1/4 to 1/2 inch depending on the condition of the strut bush. Our Pedders strut tower brace eliminate this movement by the positioning of the mounting plate. It goes between the strut mount plate and the inner fender well. Thus eliminating the gap, and eliminating the movement. This makes the spring/strut more responsive and adds life to the strut mount bushing.

*7. EXCESS BODY ROLE*. Once shocks and coils and critical bushes are updated the sway bars are still under-rated. Now by replacing the sway bar end link bushes, and mounting bushes with our Pedders urethane bushes, will add approximately 10-15% improvements to the OEM controls. This is due to the poly bushes being more responsive. But also Pedders offers a very HD front and rear multi adjustable sway bar assembly that comes with HD end links and rear end link bushes. No other sway bar kit, like Hotchkis, comes with these components. The Pedders HD sway bar kit will offer more control improvement than all the other sway bar kits on the market

*8. INSUFFICIENT NEGATIVE FRONT CAMBERS.* This is a function of not having sufficient tire clearances and tires being very close to the strut. There are several ways to resolve or reduce this concern. One is to install our soon to be available eXtreme Xa Monotube 30 way adjustable coil overs, install upper strut adjustable mount bushings, or relocate the lower control arm, decrease wheel offsets. Pedders has tested and elected not to have an adjustable strut mount bushing due to what they feel is serious reliability issues especially in the strut upper shock seal. There is a serious increase in strut seal leakages due to this style of strut mount. Pedders has come up with an adjustable lower control arm bushing, that can add approximately .75 to 1 degree of additional negative camber without getting the tire any closer to the strut. Changes in offset wheels really add a lot of strut to tire clearances. There are very few wheels actually made for the GTO. Most are designed for a BMW, and relabeled for a GTO. 


*9. POOR STRAIGHT LINE STABILITY*. There is lots of looseness in the OEM front end, but eliminating the looseness, and increasing spring and damping rates is not enough. Increasing caster is required. Installing the Pedders EP9166 front radius rod bushing not only seriously reduces the caster/toe change by keeping the tire from kicking back to the rear, but it also allows you to add up to 1.25 degrees of positive caster. You can get the front caster to the 10.5 to 11.5 range. The GTO can handle this without any negative affects, as long as your power steering is functioning. Adding caster seriously adds straight line stability and adds steering feel to the driver.

*10. LOOSE STEERING FEEL*. Once all the excess looseness is eliminated by bushings, springs/dampers, and making sure the tie rods are OK, which are a real pattern failing component, the steering can still feel loose, slow, and lacking feel. Adding front caster improves the feel, but may not be enough for all performance drivers. The OEM gear has a 3 turn lock to lock ratio for the GTO. The Z06 has a 2.6 turn ratio. Pedders offers a very limited supply fast ratio steering gear that has a 2.4 turning ratio. That is more than a 1/2 turn difference from the OEM gear. This also gives you substantial feel improvements, It is most noticeable during aggressive mountain type driving. It feels really great

*11. FRONT END NOT CENTERED TO THE BODY*. The Monaro in Au requires a front and rear cradle alignment process and supply their Holden dealers with alignment fixtures. In the USA for the GTO, Pontiac only supplies its dealers with a rear cradle alignment tool and does not supply, like Holden, a front alignment tool. Pedders dealers are the only ones that have a front cradle tool. Pedders dealers also align the trans mount to have all 3 cradles perfectly in line


Most of the parts and problems described above, especially strut bushings, can be viewed by checking out my webshots site listed below

Hope this gives all of you some room for thought and explanation of why your GTO is the way it is.

thanks
mike
dms


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## dms (Jun 27, 2005)

*The Definitive Explanation of GTO Suspension Concerns Part 2*

*
REAR SUSPENSION PART 2​*1. INNER TIRE WEAR AND CUPPING
2. RIDE HEIGHT CONCERNS
3. POOR LAUNCHING AND EXCESS SUSPENSION TRAVEL
4. EXCESS WHEEL HOP
5. EXCESS TOE AND CAMBER CHANGE
6. EXCESS LATERAL SUSPENSION MOVEMENT

*REAR SUSPENSION SOLUTIONS*​
*1. INNER TIRE WEAR AND CUPPING*. This concern has multiple causes and resolutions for each cause. They are as follows:
a. collapsed rear coil springs as a direct result of the shipping process. I checked 30 brand new GTOs on the lot one day and literally had 100% of them showing collapsed rear springs. In fact, the best way to tell a GTO if it has OEM suspension or not is to look and see if the rear is lower than the front. Once the GTOs left the USA port in Benicia, Ca. to the dealers, all the rear springs were collapsed. When the GTO left Australia, the back end was higher than the front. It is very normal to have the rear coils collapsed 1 inch. When the coils collapse, negative camber increases. So with a low coil which has lost its rate, when you take off, you literally can bottom out the back end if you have some sticky tires. This causes 2 wears, inside tire wear due to excess negative cambers, and cupping, caused by excessive changes in camber, which changes toe, which causes inner tire wear and cupping. 
b. Excessive rear control arm bushing looseness. The outer lower control arm bushings are solid rubber bushings and can be improved, but are not a problem. it is the inner control arm bushing that is the problem. The voids in the bushing. Look at the left rear inner bushing. The majority of the OEM bushings have a problem with the left inner. Look at the bushing and you will see the bolt is not in the center of the bushing. This means that the bushing is so weak it cannot keep the bolt in the center of the bushing. Plus, when in a torque situation, it will allow the inner bushing to move back and forth, thus changing camber again, which will again cause changing toe and thus potential tire cupping and inner tire wear again. These bushes are also a major contributor to wheel hop. More on that later.
c. Rear shocks are far better than the fronts but still have barely enough control for the weak, and severely under-sprung and damaged OEM rear coils. Even our entry level Pedders comfort Gas rear shocks are light years ahead of the OEM rear shocks. the OEM rear shocks again allow way too much suspension travel for a lot of GTOs. Excess suspension travel causes excess changes in camber, which causes excess changes in toe, which causes inner tire wear and cupping

*2. RIDE HEIGHT CONCERNS*. This was covered in the review of tire wear in 1.a. But again the rear coils are damaged in shipment. The coils are made out of a lightweight alloy, and once collapsed, they loose a serious amount of spring weight capability. 99% of all GTOs in the USA with OEM suspension will have collapsed coils. If your back end is lower than your front, then your rear coils are collapsed

*3. POOR LAUNCHING AND EXCESS SUSPENSION TRAVEL*. This is a big concern for a lot of GTOs in OEM configuration. The solutions are covered in the above with the reasons in depth. The poor launching and high 60 foot times is a result of lack of ability to transfer torque. There is a lot of time wasted in "loading up" all the suspension components first, before torque can get transferred to the rear wheels. Weak rear coils and dampers, and the weak and excess moving lower control arm bushings really add to a lot of wasted energy and delayed transfer of torque. But there are 2 other components that add to this. The OEM rear cradle or Xmember bushings allow a lot of movement in the rear cradle, that supports the rear cradle assembly, which supports the entire rear suspension. The rear differential mount is the 3rd of 3 mounts that support and transfer torque to the body. The mount is bolted to the rear differential and the body itself. the issue with this bushing, is the massive amount of voids in this bushing. Having excess movement and weak 3 part contact bushings, transfering torque is slow and lots of torque s lost. 

The repair for the rear cradle is simple. PEDDERS and some other Au companies offer much harder dura solid bushings for the rear cradle or Xmember bushings. Pedders on some other Au companies offer inserts that press into the massive voids of the rear differential mount, seriously increasing the strength of this bushing. 

So to summarize, update weak bushings, improve the damping, and increase the spring rates.

There are 2 other issues and potential concerns that can be addressed. Due to irregularities in body tolerances, we can have a large variance in rear camber, and tracking. Rear camber is not adjustable on the GTO. But installing our Pedders 5403 or some other Australian bushings in the outer rear lower control arm bushing will allow you an approximate +/-.7 degrees camber change. Also the rear cradle can be mis-postioned into the body, There is a cradle alignment procedure for the rear cradle to body, that is extremely sensitive. . A fixture that attaches to 4 datum holes, 2 in the control arms and 2 in the body, when all are attached to the rear to the cradle fixture tool, will gaurantee extreme accuracy of the rear cradle to the body.


*4. EXCESS WHEEL HOP*. Again, partially covered. But wheel hop is caused by looseness and a frequency generated in the chassis. the fix is to either remove the looseness and/or adding dampening. The looseness is improved by updating the rear cradle mount bushing, rear differential mount insert bushing, replacing lower control arm bushings, especially the inner, adding more rear damper control, increasing rear spring rate. These are the common areas to improve looseness. For 100hp at the wheel increases you may have to eliminate the 2 piece driveshaft to reduce flutter in the driveshaft by installing a 1 piece driveshaft. Other ways of reducing wheel hop is to add air bags in the coils. This does not eliminate any looseness but acts as a damper. There are negative effects of air bags. Traditionally they are connected to a single air supply port. Adding air to the bag, will lift the back end, dampen the wheel hop movement, bus also will act as a reverse sway bar in the rear. Not a good thing to have when going thru the twisties.


*5. EXCESS TOE AND CAMBER CHANGE. *Already covered but a problem non the less. Excess toe and camber change is a function weak and collapsed coils, under controlling dampers, , excess movement in the lower control arm bushings. 



*6. EXCESS LATERAL SUSPENSION MOVEMENT.* What this means is the body moves a certain amount when turning, but the rear suspension moves laterally even more than the body. This is a function of the cradle moving separately from the body. To repeat, there are 3 contact areas that mount the rear cradle to the body. There are 2 front cradle mount bushings, and a rear differential mount bushing. The OEM bushings allow a very large amount of movement laterally and up and down. Installing Pedders or other aftermarket cradle bushings will seriously improve this movement. Adding a Pedders differential insert bush is the 3rd part of a 3 part fixture that seriously supports the rear cradle in all directions. 

Most of the parts and problems described above, especially strut bushings, can be viewed by checking out my webshots site listed below

Hope this gives all of you some room for thought and explanation of why your GTO is the way it is.

thanks
mike
dms


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## WanaGTO (Sep 7, 2008)

Amazing! Im saving this! You are an amazing man mike!


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## GM4life (Mar 18, 2007)

Thanks again Mike for putting that together, the only person I look to for suspension advice.Stick around. :cheers


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## PDQ GTO (Jun 21, 2007)

gm4life said:


> Thanks again Mike for putting that together, the only person I look to for suspension advice.Stick around. :cheers


And Mike is just a town away from me, like 15 minutes. Just need a job and some $$$...


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## GM4life (Mar 18, 2007)

PDQ GTO said:


> And Mike is just a town away from me, like 15 minutes. Just need a job and some $$$...


I with you on the money part.


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## dms (Jun 27, 2005)

Thanks to all!. I have had a major love affair with the GTO. The GTO community is fantastic. However, I do wish there were not so many OEM issues. There are so many issues and Pontiacs lack of support on this car, makes it a challenge for a owner of one to deal with stuff.

It is interesting on my feelings why the GTO has issues, and why it is not supported well in the USA by the manufacturers. Now this is shear speculation, but working with GM for 35 years, I think there may be some truth to the statement I am about to make.

The GM engineering staff, in my opinion, are really quite fantastic. It ii breaks down in middle management accross the entire GM organization. I think John Wagner recognizes this. So what did he do? Knowing that GM is growing into a very large world organization, and knowing other products will be coming from outside the North America GM plants, I think he let the GTO in, knowing it will fail the internal structure, and it did. Middle management looked a the GTO as "not our car!" I think he best internal organization in GM is related to Buick. The Buick product is equal to Lexas quality. This is per JD Powers. If the Buick organization was in charge of the GTO, this would be quite a different quality vehicle for the better. Instead, a not my car attitude middle GM management took it, and did not care. They know there is a tire wear and spring issue and bushing problem. They know there is a strut contact issue, but they never published anything about it.

So the GTO was the experiment and process identifier for the ZETA platform vehicles (G8 and Camaro, and G8ST)

But with all this said, the GTO is a awesome ride. We can take it from awesome to specacular vaery easily.'

There are some exciting things happening at Pedders that will have nearly all GTO owners in need, VERY Happy. So stay tuned.

take care to all and drive safe

mike
dms


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## hsv (Jun 11, 2007)

Thanks Mike, these articles are great!


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## silversport (Mar 23, 2007)

WOW...thanks for the effort...nice read...
Bill


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## alsgto04 (Nov 21, 2007)

Great read Thanks alot.


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## [email protected] (Jun 9, 2008)

Thanks for posting that Mike, your words are much better than mine, as usual, lol


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## dms (Jun 27, 2005)

[email protected] said:


> Thanks for posting that Mike, your words are much better than mine, as usual, lol


Hey Rob,

I would not have known you were a sponsor if I did not see your heading at the top. You are not listed in the sponsor area where Frank is

thanks
mike
dms


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## [email protected] (Jun 9, 2008)

I am not a sponsor anymore, the banners just haven't been updated. I had your similar confusion but not the time to dedicate by myself to this site to do what needed to be done.


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## Tri-Power (Jan 10, 2008)

Great info. I didn't realize that the new GTOs had half of these problems. It's no wonder the big power guys swap everything.


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## WanaGTO (Sep 7, 2008)

My first mod on my GTO will be replacing ALL the suspension parts that need to be done...I wana give my car a whole new platform because it is NOT lacking in power. What can pedders do for someone like me? Looking to just fix the car from the ground up


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## dms (Jun 27, 2005)

WanaGTO said:


> My first mod on my GTO will be replacing ALL the suspension parts that need to be done...I wana give my car a whole new platform because it is NOT lacking in power. What can pedders do for someone like me? Looking to just fix the car from the ground up


If I understand, you want to replace all the bushings and upgrade everything.
With that said, then Pedders track 2 will work for you and meet all your needs. Here s a Track II drop:
2275	GTO Front Coil 35mm Drop
2275	GTO Front Coil 35mm Drop
9433L	GTO lowered Coil Use GSR Strut Requires Use of 424211 End Link
9433R	GTO lowered Coil Use GSR Strut Requires Use of 424210 End Link
5030	GTO Strut Bearing.
5030	GTO Strut Bearing.
5851	GTO eXtreme Strut Mount
5851	GTO eXtreme Strut Mount
4358	GTO Bump Stop Front Requires 2 packages
4358	GTO Bump Stop Front Requires 2 packages
EP9019	GTO Urethane REAR Radius Rod Bush
EP9166	GTO Urethane Front Radius rod bushings and caster adjusters
EPC27	GTO Urethane Sway Bar D Bush of use with OE bar
EP6500	GTO Urethane FRONT LOWER Control Arm Bush
EP2105	GTO Steering Mount Rack
424210	GTO Double Ball Endlink RIGHT for use with the 9433R or E9433R
424211	GTO Double Ball Endlink LEFT for use with the 9433L or E9433L
4658	GTO Sports Ryder Tower Bar.
2643	GTO Rear Coil 20mm Drop
2643	GTO Rear Coil 20mm Drop
9195	GTO GSR Big Bore Performance Rear Shocks
9195	GTO GSR Big Bore Performance Rear Shocks
EP1145	GTO X Member Urethane Bush
EP1157	GTO Diff Mount Insert
EP1168	GTO Xmemb sub frame connector
5403	GTO Rear Eccentric Bushing Camber Kit, Install as outer bush
EP7023	GTO Rear Control Arm Inner and Outer bush
EP513	GTO End Link Rear Bush
EP613/17	GTO Urethane Sway Bar D Bush
Total Pedders Parts


PAGE 1






PAGE 2
TTY BOLTS AND NUTS
92138396	GTO TTY Front Cradle Bolts (4)
92138396	GTO TTY Front Cradle Bolts (4)
92138396	GTO TTY Front Cradle Bolts (4)
92138396	GTO TTY Front Cradle Bolts (4)
PDUSA5409	Pont GTO 5409 Replacement Front Radius Rod Nut. Gm P/N 11076363
PDUSA5409	Pont GTO 5409 Replacement Front Radius Rod Nut. Gm P/N 11076363
PDUSAEP1157	GTO TTY Bolt/Washer Kit for EP1157 Replaces Part # 92138390 Diff Insert
92038482	GTO TTY Rear Cradle Bolts X Member (2)
92038482	GTO TTY Rear Cradle Bolts X Member (2)
92019618	GTO TTY Radius Outer Control Arm Nut (2)
92019618	GTO TTY Radius Outer Control Arm Nut (2)
11094256	GTO FR/RR Control Arm TTY Nut replaces nut # 92138178 (2 FR & 4 REAR)
11094256	GTO FR/RR Control Arm TTY Nut replaces nut # 92138178 (2 FR & 4 REAR)
11094256	GTO FR/RR Control Arm TTY Nut replaces nut # 92138178 (2 FR & 4 REAR)
11094256	GTO FR/RR Control Arm TTY Nut replaces nut # 92138178 (2 FR & 4 REAR)
11094256	GTO FR/RR Control Arm TTY Nut replaces nut # 92138178 (2 FR & 4 REAR)
11094256	GTO FR/RR Control Arm TTY Nut replaces nut # 92138178 (2 FR & 4 REAR)

Add Pedders sway bars and you truly will have a screaming machine

mike
dms


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## bwiest (Nov 30, 2008)

not wanting to sound like a dumb newbie,

The man I bought mine from told me there was a recall or something on the suspension becuase of the strut rub. He took it in to the dealer and they redid the suspension to eliminate this. Does this sound familiar/correct?

Thanks,
Ben


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## dms (Jun 27, 2005)

bwiest said:


> not wanting to sound like a dumb newbie,
> 
> The man I bought mine from told me there was a recall or something on the suspension becuase of the strut rub. He took it in to the dealer and they redid the suspension to eliminate this. Does this sound familiar/correct?
> 
> ...


 There has not been a recall on any GTO suspension issue. There was a special policy that expired on leaking struts on early 2006 GTOs. There is a non circulated info within GM that when a dealer calls in abut strut rub, they will tell the dealer to put the front cambers to as high positive camber as you can get it, and still be within specs. Doing this, however, really changes the handling of the GTO.

mike
dms


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## bwiest (Nov 30, 2008)

That have been what he said he did. He did notice that the ride was different after having it serviced at the Pontiac dealer.

Thanks,
Ben


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