rear four bar lengths?

[RatchetRob]

When I set the rear end where I want it the bars end up being short. Not knowing if they are to short I am turning to you experts to help me out. The top link would be around 9" and the bottom will be around 12" Of course the bottom could be shorter if keeping them closer to the same length is better. Also was thinking of attaching them to the outside of the frame rail rather than the inner side. I think I like the looks since all the other suspension parts are pretty much out in the open. This would put the mounts out further towards the axle ends if for no other reason than just looks better to me. Any thoughts?

 

[RatchetRob]

I like the rear tire a little further forward like Nick Conti's T-Bucket.

 

[RatchetRob]

Thinking now of doing the four bar like this. Ex-Junk what are the lengths of yours? I think your rear set's a little further back than what I am planning though.

 

[EX JUNK]

Thinking now of doing the four bar like this. Ex-Junk what are the lengths of yours? I think your rear set's a little further back than what I am planning though.
View attachment 10763

The length of my bars are 11 1/2" and 10". That is the measurement of the bars ONLY, not any of the rod end or exposed thread.

Jim

 

[baddawgcustoms]

If you don't have your 4 link mounts welded to the rear yet, I got Ron Pope to cut me some brackets that set the top bar 2" behind center of the axle. This allowed me to get my bars closer to the same length. Every chassis book I have read says the top should be at least 80 percent the length of the bottom bars and it should be fine as long as your pinion angle is perfect at curb weight. I have an extra set for 3" axle with the top bar and bottom bar 8 1/2 " apart like in the photo if you can use them they are yours. My bars are 10 1/2 and 12" eye to eye of the rod ends.

 

[baddawgcustoms]

Just on one other note, a 12" bar set level, will basicly move the rear forward almost 1/4" at 2" of travel. That's the reason I switched from buggy spring to coilover suspension. The rubber bushings in the shock have some give when the rear moves forward where a Buggy spring will try to twist and something's got to give. Yes the rear looks much better on a modified style (bobtail) rear with the axle pretty far up as in your pic. I got bobs66440 to measure how far behind the body his axle was, and if you ran a line straight down from the very top of the back of the body, it was right at 3" from center axle. His car looks fabulous so I just used his measurement.

 

[RatchetRob]

I have an S10 rear so the brackets will not work. the 9" and 12" bar lengths would be total width with ends. If I moved the top bar behind 2 inches I would definetly be in the 80 perecent rule.

 

[baddawgcustoms]

I have an S10 rear so the brackets will not work. the 9" and 12" bar lengths would be total width with ends. If I moved the top bar behind 2 inches I would definetly be in the 80 perecent rule.

I'm sure Ron has the scan of my brackets saved in his computer. I wound up with an s10 rear as well so the ones in the picture are exactly what you need. He did them very affordable and he can change them to fit your specs. If you can draw it he can make it. Mine are designed to weld to the rear of the axle.

 

[fluidfloyd]

Well since there is still another day off from work I'll give you several links to suspension designs and let you look at the various ways to get from A to B. Not doing it right could let you go from A to Z real quick. The easiest to install and package is the basic street parallel 4 bar with same or close to same length thrust tubes like EX Junk has. That set up he has shown you is about as clean and functional as you will get. Keep in mind that you don't want a real short upper link as it will cause pinion angle changes that might be big enough to cause rear u-joint issues. Hope this will give everyone something to think about. Good Luck.

George

http://www.how-to-build-hotrods.com/parallel-4-link.html

http://www.lateral-g.net/forums/showthread.php4?t=42568

http://www.dragstuff.com/techarticles/PB-4linktuning.html

 

[fluidfloyd]

Just on one other note, a 12" bar set level, will basicly move the rear forward almost 1/4" at 2" of travel. That's the reason I switched from buggy spring to coilover suspension. The rubber bushings in the shock have some give when the rear moves forward where a Buggy spring will try to twist and something's got to give. .

Dale...If I am reading you right I think you are referring to letting the shock eyes deflect linearly against the bolt in the long axis as the rear hosing moves up and down. If that's the case why not turn the upper shock eye 90 degrees so the through bolt is parallel to the rear axles. That would let you have unlimited articulation in both rear housing travel and body roll. If I misunderstood what you're saying just overlook my old age and cluttered mind then fire an internet bullet to my brain!

George

 

[baddawgcustoms]

Dale...If I am reading you right I think you are referring to letting the shock eyes deflect linearly against the bolt in the long axis as the rear hosing moves up and down. If that's the case why not turn the upper shock eye 90 degrees so the through bolt is parallel to the rear axles. That would let you have unlimited articulation in both rear housing travel and body roll. If I misunderstood what you're saying just overlook my old age and cluttered mind then fire an internet bullet to my brain!

George

Yes that's exactly the issue. I thought about mounting it as you suggested but since the shock will be fixed at the bottom it will still try to bind, unless both the top and bottom mounted horizontal to the axle. Then I would have to fab both top and bottom mounts at the proper angle as well. I think as little as the car will be driven the rubber bushings will hold up and will seldom see 2" of travel. I really wanted the model A crossmember and buggy spring for the old school look but didn't want to take the chance. I've seen really short bars with the buggy spring before, but I just didn't want to take the chance.

 

[Zandoz]

What about the possibility of using bearing end shocks. Though not as good ride -wise, they should minimize binding. Another option would be to use shocks with a stud end on the top, instead of eyelets. That route would require a bit of upper mount fab work, but nothing unreasonable.

On the short control arm issue, the Ford Fox body triangulated 4 link I'm going to use features short control arms...17.5" centers at about 11 degrees angle in on the lowers, 9.25" at 35 degrees angel out on the uppers.

 

[RatchetRob]

Thanks for all the input guys. I have decided to go with the lift bar design. I really like the rear tire tucked up to the body and after getting back and looking at it I noticed the rear end was to far back for my taste. Moving it forward only shortened the rod lengths down to 8 upper and 10 lower. Just think this is to short. I seen the lift bar design from another poster and after mocking it up like the overall looks better anyway. Thanks for all the great input and info.

 

[Zandoz]

I really like the rear tire tucked up to the body and after getting back and looking at it I noticed the rear end was to far back for my taste.

Seems we have similar tastes in that aspect...which should be very scary for you...LOL. I love the bobtail look. On mine I'me shooting for the rear edge of the body directly over the axle centerline. What width axle and wheel backspace are you using to get you clearance between the tires and body? I'm going with a 61.5" axle and 4" backspace wheels.