Trailer arm?

[macawlover70]

I need the steel tube that connects from the rear axle on both sides to the body that acts as a stabilzer for the rear axle. I think it's called the trailer arm. I need the one on the driver side for an 81 spider. Anyone have one that they would care to part with. Need ASAP.

[v6spider]

I believe you are looking for a trailing arm. The spider has a four link rear suspension. There are two short trailing arms that connect the top of the axle to the body. And two longer thicker trailing arms that attach the bottom of the axle to the body. the one that runs from one side to the other across the back side of the axle is the panhard rod. Its purpose is to stop the axle from traveling side to side.

Is the trailing arm broken or cracked? or are the bushes worn out? Just curious it is a common problem... :)If the arm is broken it can be welded rather easily if it is just broken or cracked if it is rusted through you may end up replaceing it if it can't be welded. to my knowledge the bushes are replaceable.

rob

[Zmatt]

what spider has a multilink suspension? Ive only seen solid rear axles with panhard rods. If its a solid axle, than that bark is called the panhard rod.

[maytag]

what spider has a multilink suspension? Ive only seen solid rear axles with panhard rods. If its a solid axle, than that bark is called the panhard rod.

Zmatt, you are both correct. the "4-link" described above and in use on (all?) Fiat Spiders is not the traditional 4-link that many of us think of, but it certainly fits the description, as there are, indeed, 4 links locating the axle front / rear. The Panhard bar that is ALSO in use on (all?) Spiders is there to keep the axle located left / right.

[v6spider]

Boys,

Four-link rear suspension is defined as follows:
"A four-link rear suspension uses four longitudinal links to locate the axle fore and aft, and to control the axle torque loads due to acceleration and braking. Lateral location of the rear axle is controlled by the use of a pan-hard bar, a Watt's linkage or similar device..."

This quote is from a great Chassis And Suspension Design book called "Chassis Engineering" by Herb Adams, a well known automotive design engineer who once worked for GM and now owns his own automotive consulting business, and the spider's rear suspension fits this description. I bought this book years ago when I built my first V6 Spider. It totally demystified the basis of suspension design what works and what doesn't. I highly recommend it to those that are interested suspension design and theory. From basic-ness of terms most of the designs are explained up to udder mind-boggling theory. I am no theory expert, but I do know enough to get me by. In most cases I always refer to the book. It is my suspension theory bible.. LOL

BTW I purchased the book on Amazon... another good one is 'Engineer to Win' by Carol Smith.

Cheers!
Rob

[maytag]

Boys,
Four-link rear suspension is defined as follows:
"A four-link rear suspension uses four longitudinal links to locate the axle fore and aft, and to control the axle torque loads due to acceleration and braking. Lateral location of the rear axle is controlled by the use of a pan-hard bar, a Watt's linkage or similar device..."
Rob

"boys"? doooood......

Rob: as I said in my post above, the Spider certainly fits the definition of a 4-link, but it is NOT what most of us think of when we talk about a 4-link. (at least in the hot-rodding world I grew-up in, and then the road-racing world I grew-old in). In those two worlds, a "Four-Link" (aka '4-link') is there to provide near-infinite tunability in the way the power meets the ground. Yes, it is still comprised of four links, just like our Spiders. But with oh so much more to it than our Spiders have. It is very common (in classes that allow it) to ADD a 4-link setup to cars that were not so equipped, in order to find that tunability. The 4-link on our Spiders, as designed, offers none of those benefits.

So I was merely clarifying, assuming that's what Zmatt was looking for when you said "4-link".

But thanks for taking us all to school.... Dad.

[v6spider]

Maytag:

At no point was racing ever mentioned in this post, not even by you:

Zmatt, you are both correct. the "4-link" described above and in use on (all?) Fiat Spiders is not the traditional 4-link that many of us think of, but it certainly fits the description, as there are, indeed, 4 links locating the axle front / rear. The Panhard bar that is ALSO in use on (all?) Spiders is there to keep the axle located left / right.

It is all about interpretation right? I said " boys" which meant to me that I that persons I was referring to were male and not meant to be an insult by ANY means. You said "traditional" which you meant as a reference to the four-link adjustable rear suspension that is commonly used in drag racing. In my Opinion, the term four-link does not refer to adjust-ability. I think just about every type of rear suspension can be setup with some form of adjust-ability, including the four-link type. Some of the types I am aware of are: 4 Link, 3 link, Torque arm, Independent.....

So, you can see how both of us misinterpreted what the other said which has led us to this point. Offending someone is NEVER my intention when I post on this forum, but it does happen because of how the information was perceived on the other end.

The references to the books I mentioned were merely mentioned to be shared as references...something to back up what I said. Not as a belittling session.

We all know what we know, I guess the clearer we can be when we post the better...

No Worries!
Rob

[maytag]

dooood....... SOOOOOO not offended!!!!!

[Zmatt]

Boys,

Four-link rear suspension is defined as follows:
"A four-link rear suspension uses four longitudinal links to locate the axle fore and aft, and to control the axle torque loads due to acceleration and braking. Lateral location of the rear axle is controlled by the use of a pan-hard bar, a Watt's linkage or similar device..."

This quote is from a great Chassis And Suspension Design book called "Chassis Engineering" by Herb Adams, a well known automotive design engineer who once worked for GM and now owns his own automotive consulting business, and the spider's rear suspension fits this description. I bought this book years ago when I built my first V6 Spider. It totally demystified the basis of suspension design what works and what doesn't. I highly recommend it to those that are interested suspension design and theory. From basic-ness of terms most of the designs are explained up to udder mind-boggling theory. I am no theory expert, but I do know enough to get me by. In most cases I always refer to the book. It is my suspension theory bible.. LOL

BTW I purchased the book on Amazon... another good one is 'Engineer to Win' by Carol Smith.

Cheers!
Rob

my bad, when I read 4-link I thought "multilink" as in an independent rear suspension with half shafts.

[seabeelt]

Ahhhhh, but the real question is have we helped the original poster identify the part they need and where to get one. Great discussion btw.

[maytag]

Good point Seabeelt:

I need the steel tube that connects from the rear axle on both sides to the body that acts as a stabilzer for the rear axle. I think it's called the trailer arm. I need the one on the driver side for an 81 spider. Anyone have one that they would care to part with. Need ASAP.

Based on this description, I think macawlover70 is looking for a 'trailing-arm' for the driver side. Question: long or short? But I'd presume the long one.

Can anyone confirm interchangeability between '79 and '81? I know at some point they changed, but not sure when. I have one from a '79 I could part with for macawlover70.

[MNspiderman]

Seems you boys scared the fellow away with all of your high tech confusion. Now he will never come back

[wbsterritt]

It appears to me that things changed for the rear suspension between 1978 and 1979. Looks like you can just replace the bushings on 1978's and prior. Need to change the whole assemblies for 1979 and later. One good site-among many others-is called spiderroadster.com out of Texas.