The Rodding Roundtable

Motorhead Message Central => Rodder's Roundtable => Topic started by: enjenjo on April 14, 2009, 07:06:54 PM

Title: rear suspension geometry
Post by: enjenjo on April 14, 2009, 07:06:54 PM
I have been doing some reading, updating myself on suspension theory. Any one want to give some input on rear bar length? I found some good info here  http://home.earthlink.net/~whshope/
Title: rear suspension geometry
Post by: Crosley.In.AZ on April 14, 2009, 10:32:22 PM
I would  think you know 'whose" pages those are?

:idea:
Title: rear suspension geometry
Post by: enjenjo on April 15, 2009, 11:43:50 AM
No, I don't.
Title: rear suspension geometry
Post by: Crosley.In.AZ on April 15, 2009, 11:54:30 PM
Bill Shope


Ramchargers drag racers  were quite successful in the 60's

Bill is a purty good suspension  engineer
Title: rear suspension geometry
Post by: enjenjo on April 16, 2009, 12:32:54 AM
OK. Seems to know what he is talking about.
Title: rear suspension geometry
Post by: GPster on April 16, 2009, 10:04:20 AM
It's a good thing Linda is out of town. I'll have to print this so I can sit down and read it. I hope she put ink in the printer.It's been days since I checked this site so I am pleased that there is some subjects appearing here. I wonder if this is a book? GPster
Title: Re: rear suspension geometry
Post by: unklian on May 05, 2009, 02:53:33 PM
Quote from: "enjenjo"I have been doing some reading, updating myself on suspension theory. Any one want to give some input on rear bar length? I found some good info here  http://home.earthlink.net/~whshope/



The available space will limit the maximum length of the bars.
Especially on such a small car.
Adjustable front mounts would allow changes in geometry.
Title: rear suspension geometry
Post by: enjenjo on May 05, 2009, 05:00:16 PM
Since this might have a big motor, or a small motor, both the front and rear of the bars will be adjustable. What I am finding says the lower bars should be from 20 to 24 inches, and the upper bars at 70 percent of that. so that's where we'll start.
Title: rear suspension geometry
Post by: Crosley.In.AZ on May 05, 2009, 09:52:44 PM
Quote from: "enjenjo"Since this might have a big motor, or a small motor, both the front and rear of the bars will be adjustable. What I am finding says the lower bars should be from 20 to 24 inches, and the upper bars at 70 percent of that. so that's where we'll start.


I am guessing that 20 - 24 inch measurement is from center to center of the  heim joint ?
Title: rear suspension geometry
Post by: enjenjo on May 06, 2009, 07:56:38 AM
Quote from: "Crosley"
Quote from: "enjenjo"Since this might have a big motor, or a small motor, both the front and rear of the bars will be adjustable. What I am finding says the lower bars should be from 20 to 24 inches, and the upper bars at 70 percent of that. so that's where we'll start.


I am guessing that 20 - 24 inch measurement is from center to center of the  heim joint ?

yes. and 24" is preferred to 20"
Title: rear suspension geometry
Post by: GPster on May 06, 2009, 10:37:33 AM
Are you thinking the bottom bars will be straight front to back paralell with the centerline of the chassis or will they have to angle in from the rear end to find a mounting place on a narrow frame? If they are mounted at very much of an angle then the length of the bars will be longer than the radius that they are arcing in. Don't know how tight those measurements are to a theory but that might make a difference. GPster
Title: rear suspension geometry
Post by: enjenjo on May 06, 2009, 10:44:13 AM
The arms will be parallel. Lowers and uppers. I think a watts linkage for side to side control.
Title: rear suspension geometry
Post by: Crosley.In.AZ on May 09, 2009, 01:05:03 PM
so , we are talking a parallel 4 bar set up , than a drag race 4 link set up?

I've been doing some reading on basic  drag race 4 link systems..  the length of bars seems to be all over the paper... even the length difference from top to bottom bars.

I am looking at the 1 1/4" diameter  bar set up from Chris Alston chassis works for my Morris project.  Many seem to use the 1 diameter tubes for direct threading for the hiem joints
Title: rear suspension geometry
Post by: enjenjo on May 09, 2009, 01:51:06 PM
No, it will be a drag race setup, parallel side to side, but not top to bottom.
Title: rear suspension geometry
Post by: Crosley.In.AZ on May 25, 2009, 03:04:12 PM
we had a 66 Chevelle  drag car in the shop.  A Lucas oil sponsored car.

the 4 link bars on it were the 1 inch diameter stuff., direct  threaded tubes..  

Measured  about 23.0 inches from rod eye to  rod eye on it.

i took some photos of it too
Title: rear suspension geometry
Post by: enjenjo on May 25, 2009, 03:10:54 PM
Cool, post some photos.

I was looking at some back half kits at the swap meet this weekend, I got some ideas.
Title: rear suspension geometry
Post by: GPster on May 26, 2009, 09:09:02 AM
I'm sure this is far above our spending limit at this time but there has been a guy advertising a new  back-half drag/pro-street 4 link set-up in our local  Bargin Shopper. It comes with a narrowed 9" reinforced housing with Moser 35 spline axels. He's also got a spool and bearing kit. Adding it all together he's got a price of $2,140.00 but the add has been running for over a month so who knows? He's got an Email address if anybody wants it but I'm uncomfortable even typing an amount that big. GPster
Title: rear suspension geometry
Post by: Crosley.In.AZ on May 27, 2009, 09:25:46 PM
a few photos of 4 link suspension.

clik on them for a larger view
Title: rear suspension geometry
Post by: Fat Cat on May 31, 2009, 08:26:31 PM
Here is a jpeg of the design that was discussed over the weekend at the Build Day.
Title: rear suspension geometry
Post by: Crosley.In.AZ on June 05, 2009, 10:42:15 PM
Quote from: "Fat Cat"Here is a jpeg of the design that was discussed over the weekend at the Build Day.

Instant center looks a little too high.

8)
Title: rear suspension geometry
Post by: enjenjo on June 05, 2009, 11:12:04 PM
For the sake of making the brackets, we used an instant center of 24" high. this can be adjusted in the build.