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1969 Firebird, panhard bar with leafsprings?

12K views 56 replies 12 participants last post by  kso 
#1 ·
Would a panhard bar work with a sway bar and leaf springs on a 1969 firebird? How hard with this be to build and weld in myself?
 
#39 ·
Let me try to clear this up. Herb Adams is talking about a race car where rubber bushings are taboo because any compliance in the suspension cannot be easily controlled or have predictable behavior. Consequently, hard or solid bushings are used in the shackles, and as Herb points out, he recommends a spherical bearing on the forward eye to allow rotation. With that scenario, it is his opinion that a lateral locating device wouldn't usually be necessary. So far so good...

With a street car, those hard bushings and spherical bearings would transfer too much noise and vibration, not to mention that maintenance on those type of joints would not be practical. That is why OEM's use rubber. They want comfort first and performance second.

With rubber bushings comes compliance, and that can be okay until your clearances get tight (tire to fender for example) or you put on tires with more grip. You do all recall I'm sure how crappy tires were back in the late 1960's? With more grip comes larger forces and then you come up upon the weakest (most compliant) part of the suspension, the rubber bushings.

As we have covered very thoroughly I think, some rubber bushings are necessary, and some bushings can be upgraded for more precise control of the suspension. One can assume that most of the lateral movement in a leaf spring suspension comes from the rubber bushings in the shackles. It would also stand to reason that the longer the shackles, the more lateral movement. If you just had to install those trick polyurethane bushings, put them in the shackles and not in the front spring eye.

All I am saying is that if you want noise and vibration isolation AND more precise axle lateral locating, you can use a Panhard bar... The Panhard bar can also help to lower the roll center of the rear axle, but that is a whole other story...

Hope this helps make it more clear.
 
#40 ·
So when you start out to get max performance and handling out of your car,, Aren't you looking to make it a disguise race car for the street..:rolleyes: Or something like that.. When your trying to get every little bit of handling out of your car,, (And this is very little extra, If any) your not out to build a family car..:mwink:

I had a feeling you would throw in RACE CAR...:D I don't think he's asking to make it better to go to the store..:mwink:
 
#41 ·
There are race cars, and there are street cars. If you want some of the benefits of a race car (better handling, more power etc) you couldn't do it without looking to the racing world for answers. You just need to tone it down a bit for the technology to work on the street. You should know all about this NEW INTERIORS. Take for example the Pro-Street cars you like to build. It is all race car technology toned down for the street.

I'm sure your cars go well in a straight line and do fine around town. As fast as you seem to like to go in a straight line, I like to go that fast in around corners. I drag raced for years and then I went to road racing school. Then I traded my 11 second 57 Chevy for a 455cid, 4 speed 76 Trans-am and have never looked back. Instead of having fun 11 seconds at a time a few times an afternoon, you can have fun for hours! But as you like to say "that's just me".

To each his own, that is what makes the world an interesting place.
 
#44 ·
Never got into Autocross, but it is fun to watch. I built my '71 Camaro to be street driven, but handle well, and it does whatever I want, and usually more. I find I chicken out before the car has handling issues.
We like to take a drive in the summer up the windy Columbia River Gorge scenic highway, and push through the 10-20 mph curves as hard as our pucker factor will allow. :)
 
#46 · (Edited)
That is a great road, I have driven it many times myself. The next time you are out that way check out the road above the Maryhill Museum. SOVREN, the vintage road race guys, stage a hill climb there once a year. The road they run it on is the first paved road in Washington state and it is as curvy as a snake with a hunchback! I hope to run my Jeep on it sometime...

Maryhill Hill Climb
 
#45 ·
My test for cars was an exit off the freeway in my town that I took to go home. This exit is now gone, changed to new version of freeway exits (isn't that amazing how they are changing them all?).
Anyway this was one of those tight hairpin like corners that goes off to the right , up the hill of the overpass then back over the top of the overpass.

I use to take that exit off the freeway at 50+ keeping it at 50 all the way to the top of the corner at the overpass. :D That sucker really handles pretty good. Blown away a lot of high end sporty types I'll tell you that, hit a corner with them on your bumper and when you come out they are way back there, then with the good old Nailhead to the floor, you are gone. :D Fun stuff, it sort of replaced the stop light drag races I had as a kid all the time which of course are now long gone and I don't want them back actually. That was stupid as crap. But to hit a corner out somewhere that no one is at and all you hurt is you? What the heck, it's a good ride. And yes, I have hurt me. In that Gran Sport hitting a freeway entrance too hard, I apexed the corner hitting it hard and was over my head and blew over the curb with my new Goodyears and Roadwheels, bent the left front wheel all to heck, along with the tie rod end. As I was sliding sideways across the dirt I pushed the right rear tire right off the rim. :pain: I changed the tire on the side of the freeway and still made my date. :D Yep, a lot better than draggin down the street safety for others concerned.

I dig the autocross at the Goodguys events but it is a little slow for me, just a little faster would be a lot more entertaining but it still is damn fun to watch. I don't plan on getting out there, those guys are way too serious for me I wouldn't stand a chance.

Brian
 
#48 ·
Look at the cars in my photo album and my avatar. Those are not theoretical, and they did not build themselves. There are plenty more where they came from.

What I am trying to do on these forums is to present a very complex subject in a way that is informative but not too heavy. If that is all you got out of my comments regarding leaf spring bushings and suspension binding, then you missed the point completely. If that is because I didn't explain it well, then my bad, if it is because you just didn't understand it, well...I tried.

Have a good day.

Andy
 
#49 ·
Andy, you have explained things well enough for my brain to get a grasp. I am thinking that "someones" deflection angle is binding. :mwink:

Brian
 
#52 ·
Only thing I was trying to point out here is.. By adding the panhard bar to fix one problem, Does it also create another one ??? ;)

Weighing out the real true benefits with a leaf spring set up..

I know Andy has some knowledge in chassis's,, But in the end is it worth the trouble to gain very little...;)
 
#53 ·
Same here. I understood, just didn't agree. That's what these discussions should be about, not about a contest to see how many will attack or flame.
I still think that the normal travel of a panhard bar is an arc, and as such it will try to push/deflect the springs sideways as the rear travels up and down. It's just not something I'd ever put on any of my vehicles.
If it's done because clearances are at a minimum, then those clearances must be enoughh that the arc of the panhard bar's travel wont push or pull the axle and create a further clearance issue.
By the way Andy, your build cars are amazing!
 
#57 ·
Umm hmm, it's a good video. At a vantage point about 12-14" above the stock roll center, it illustrates the result of body roll and a little bushing squirm. If what you really want is for the tires to not move sideways in relation to the body, you could use a panhard rod or watts link to raise the roll center but then you're back to fighting the leaf springs again and it will get skittish over bad pavement on corners. A better solution for the car shown would be stiffer (or just new) spring bushings and more roll stiffness via swaybars or spring rate.

But anyhow, I think we're all tired of this one and I'm not going to get anywhere with it.

For the original poster, see some light-but-knowledgable discussion pro/con specific to the panhard bar issue here:

Panhard Rod on a Leaf Spring Car
 
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