Rear control arm bushings
- Thread starter BuickMike
- Start date
Hi BuickMike,
The reason why I ask is that tires with a short, stiff sidewall seem to reveal any bushing non-linearities (up to and including the point of stiction, should it exist,) far more pronouncedly than tires with a tall, soft sidewall.
In general, since the tire represents compliance in both a vertical and horizontal sense, a soft tire can mask any ill effects with the rear suspension behavior better than can a stiff one.
The combination of short, stiff-sidewalled tires, PU bushings, boxed arms, and the towering rear roll center height engineered by GM, is a very poor one, in my opinion.
Best regards,
MAP
The reason why I ask is that tires with a short, stiff sidewall seem to reveal any bushing non-linearities (up to and including the point of stiction, should it exist,) far more pronouncedly than tires with a tall, soft sidewall.
In general, since the tire represents compliance in both a vertical and horizontal sense, a soft tire can mask any ill effects with the rear suspension behavior better than can a stiff one.
The combination of short, stiff-sidewalled tires, PU bushings, boxed arms, and the towering rear roll center height engineered by GM, is a very poor one, in my opinion.
Best regards,
MAP
HRpartsNstuff
Member
- Joined
- May 27, 2001
True, the high roll center height is far from optimum, but stiffer sidewall tires and OUR poly bushings & boxed arms (or new HR arms) makes it handle WAY better. Add our rear Sway/Anti-Roll Bar setup and you will forget that you are in an 18+ year old car!
Sorry if that sounds like an HR "plug", but I have felt the difference myself & go by the feedback we constantly receive. The older G-body platform can be made to handle & drag race great, using the right upgrades. Optimum compared to other cars out there, probably not. Extremely better than GM ever thought possible, YEP!
Hi HR,
Wow! Fast-forwarding 5-1/2 years...
I agree with a lot of what you said, and especially that, "Extremely better than GM ever thought possible." But - and promise I'm not trying to be difficult or argumentative by any means - taking the rear suspension and making everything stiffer is certainly not the best way to go - you've got to leave a source of transverse compliance in the system somewhere (and I would argue that the best place is the tires,) so that in the high-frequency, mass-controlled region of operation of the suspension, the tire can "permit" the suspension to migrate from side to side in a manner dictacted by, or constrained by, that very high roll center. If the tire is too stiff transversely, then the majority of the tire's traction can be taken-up simply in the course of taking-up difference-mode bumps and dips (i.e., those irregularities that would tend to induce roll in the suspension) in the road surface, leaving less remaining to negotiate curves well or to accelerate the car forward or backward.
So here's what tends to happen: if you make everything stiff, then the car will probably handle better in a variety of metrics on a perfectly flat surface. But add bumps to the mix, and the rear will get skittish and difficult to control for sure because of the towering RCH problem.
If you must have everything stiff, then lower the RCH. That's what I'm doing currently in my project to convert to a 3-L Panhard rod geometry.
Best,
MAP
Wow! Fast-forwarding 5-1/2 years...
I agree with a lot of what you said, and especially that, "Extremely better than GM ever thought possible." But - and promise I'm not trying to be difficult or argumentative by any means - taking the rear suspension and making everything stiffer is certainly not the best way to go - you've got to leave a source of transverse compliance in the system somewhere (and I would argue that the best place is the tires,) so that in the high-frequency, mass-controlled region of operation of the suspension, the tire can "permit" the suspension to migrate from side to side in a manner dictacted by, or constrained by, that very high roll center. If the tire is too stiff transversely, then the majority of the tire's traction can be taken-up simply in the course of taking-up difference-mode bumps and dips (i.e., those irregularities that would tend to induce roll in the suspension) in the road surface, leaving less remaining to negotiate curves well or to accelerate the car forward or backward.
So here's what tends to happen: if you make everything stiff, then the car will probably handle better in a variety of metrics on a perfectly flat surface. But add bumps to the mix, and the rear will get skittish and difficult to control for sure because of the towering RCH problem.
If you must have everything stiff, then lower the RCH. That's what I'm doing currently in my project to convert to a 3-L Panhard rod geometry.
Best,
MAP
Turbo6Smackdown
Well-Known Member
- Joined
- Dec 31, 2005
Ok. Good thread, but lets get to the nitty gritty. WHERE do we get bushings from. I want FACTORY STOCK bushings for all 8 points. No 1LE's, no police bushings, no steel, no poly, nothing from outer space. Just plain old bushings. Every one of them. Where do I go.
Hi,
Good question - someone else will have to help. New or NOS stock parts like these are getting harder amnd harder to find - maybe GM parts direct?
Stock bushings work great wtih stock tires, springs, sway bars, and shocks.
But if you set-up the car to hug corners on a par with some of the better sports cars on the road today, then the stock suspension and body bushings will be revealed in al of their inglorious shortcomings, so be forewarned if this is your intention. But for everything else (short of curing wheelhop, however,) the OEM bushings should be fine.
Best,
MAP
Good question - someone else will have to help. New or NOS stock parts like these are getting harder amnd harder to find - maybe GM parts direct?
Stock bushings work great wtih stock tires, springs, sway bars, and shocks.
But if you set-up the car to hug corners on a par with some of the better sports cars on the road today, then the stock suspension and body bushings will be revealed in al of their inglorious shortcomings, so be forewarned if this is your intention. But for everything else (short of curing wheelhop, however,) the OEM bushings should be fine.
Best,
MAP
I cannot believe I am replying to this old thread its been 5 years since I posted here.
Despite what you think, you will not want replacement stock bushings. I had some legitimate 1LE bushings from the dealer a few years ago and also some Moog stock replacments. They are identical. I would bet money they are in fact made in the same factory. The 1LE are not harsh in any way, the car will drive very nicely. Do not use polyurethane, that is a serious mistake especially in the upper rear arms, see my post above. The factory bushings are from a different era, handling was not in the equation. On my Buick I rebuilt the complete front and rear suspensions used Moog stock replacement bushings after much thought and the difference was huge. The car was extremely tight, firm, and modern feeling, no longer grandpa's Buick. You will also want carefully selected springs to complete the job. The stock sway bars are actually pretty good.
Turbo6Smackdown
Well-Known Member
- Joined
- Dec 31, 2005
I run a 1 & 3/8ths rear sway, with bilstein shocks and air bags. Though, my tires will be a 28x10.5 et drag, with boxed control arms. This will be a street car. I don't want any bind. And to be honest, with the Radial t/a's that are on the car now, it rode pretty nice. I don't really have any complaints to be honest. I run the stock bar up front, with poly bushings and end link bushings. Bilsteins up front as well. My car handles very nicely I think. Zero complaints. I just want more straight line traction that's all.
RmvBfrFlght
Well-Known Member
- Joined
- Sep 28, 2007
I used standard rubber replacement MOOG bushings in another vehicle (not the boosted one). I had boxed the stock trailing arms and put poly's in, hated it.
So kept the boxed trailing arms and replaced the poly bushings with MOOG rubber. This worked out and gives a good ride with good handling.
Note that the poly bushings I had used were a common off the shelf brand, not H&R's.
RemoveBeforeFlight
Turbo6Smackdown
Well-Known Member
- Joined
- Dec 31, 2005
anyone? any place that sells ALL of them?
RmvBfrFlght
Well-Known Member
- Joined
- Sep 28, 2007
The local CarQuest had the Moog rubber bushings in stock. And the trailing arms I put them in are the same as the lowers used on g-body's.
RemoveBeforeFlight
87Turbo-TWE4
Member
- Joined
- May 9, 2008
Try Rock Auto
Turbo6Smackdown
Well-Known Member
- Joined
- Dec 31, 2005
Ok, there are 8 bushings for our control/trailing arms. I think there's two styles, correct? The all rubber deals, and then the ones that have that steel sleeve. Is this correct? Between the 8, how many of them are identical? So basically what I'm asking is, how many different and separate part numbers are there? 2, 4, 6, 8?
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