Triangulated four bar rear suspension

[meangreen]

Hackerbilt and James C. - George's (fluidfloyd) description is correct (above). Whether there is room under a Bucket for a truck arm system would depend on the length of the frame and, more specifically, the distance from the rear axle to the forward mounting point (usually at or near the transmission crossmember). I have truck arm style rear suspension under my coupe. I have attached an early construction pic of it so you can see the configuration. Mine are considerably shorter than original Chevy truck arms, but the car still rides and handles great. Mine are rubber mounted at the rear so the suspension can move without flexing the arms or twisting the axle housing. In most Buckets, the engine is too close to the rear end to make it practical. However, if you run them straight forward and attach them under the frame rails, they work great. In that configuration they are usually called "lift bars". Smokeyco is building a set of them on his thread "My First T Build". Take a look at them.

 

[meangreen]

Bucketman - Why are you so adamantly against using a Panhard bar? Not that it's right or wrong, I'm just curious. If it's a matter of appearance, I have Panhard bars on both ends of both my hotrods and they are out of sight unless you crawl under... Anyway, I'm glad to see you got rid of that bridge. Welding it where you had it could have caused serious distortion of the rear axle housing.

One more thing, as long as you are mocking things up, you might try running the short rods straight back inboard of the frame and spreading the long lower arms out at the bottom (just the opposite of how you have it in the pictures). The reason? Body clearance - the lower arms are below the body and you might not have to cut clearance slots in the body. If you leave it as you have it now you may have to cut some sizeable slots in the body.

 

[bobs66440]

Before you start making stuff do a full mockup to make sure you have all the necessary room you need for a bridge structure over the diff.
I really think you are making a load of work/complication for yourself, and the end result will handle no better than a simple parallel setup.
My car has race style ladder bars right under the body and while I could see me changing that for parallel 4 bars to enable a drop in ride height...I wouldn't even consider the change to triangulated.
I see nothing there that would be an advantage...and on top of that my frame height is already close to the axle AND my gas tank is at a height I like. Theres no real room to fudge these little cars around like you can with a later car.
You move one thing and a lot of other things in plain sight need to move too.
Try to plan at least 4 things ahead as you go...

I totally agree.
I know it's fun to design different suspensions, and if that's what you want to do, then more power to ya. But for these cars, I think the old standard hairpins/panhard rod design is more than sufficient. My car drives like a dream and is as simple as it gets. I've driven many types of circle track & road race vehicles/cars and I know what poor handling is. I just don't see the point in making it so complicated...unless that's what you enjoy of course. Myself, I like drivin' em, so I like to get through the building process quickly...

 

[Zandoz]

View attachment 10484

Sorry about the two same pictures. This is the one I meant to post.

I could be wrong, but it looks like you do not have sufficient angle on the upper links. They should be a minimum of 30 degrees from the center line.

Also, I suggest downloading one of the 4-link calculator spreadsheets out there...they give an easy way to experiment with link lengths and mounting points.

 

[Hackerbilt]

I'm confused...I seem to be getting pulled into some discussion on truck arms as if I'm disagreeing about something or other...and I'm not even sure what!?!? LoL
This, my very first comment on them, is that they work really well.
I'm familiar with them and have built a pair myself from 2x4 tube (split lengthwise and joined back to back like OEM) but I really think they are a bit overkill for most T buckets and they still require a Panhard bar or some other version of side control, which the OP has stated he doesn't want to use for some reason.

When all requirements are considered for the OP's "wants" on this build, the one suspension design that comes to mind for me is 1/4 Elliptic style using the springs as 2 of the 4 control arms.
Mounted correctly, the 1/4 elliptic springs won't require a Panhard or the like and everything can be parallel to the frame for space saving.
It will also be more compliant than regular hairpins or ladder bars.

Having said that...in my opinion there is still nothing wrong with traditional ladder bars/hairpins on an open drive T bucket.
On heavier vehicles they can bind and eventually give trouble, but on a lightweight little bucket it's not a huge worry. (IMHO)

 

[fluidfloyd]

I'm confused...I seem to be getting pulled into some discussion on truck arms as if I'm disagreeing about something or other...and I'm not even sure what!?!? LoL
This, my very first comment on them, is that they work really well.
(IMHO)

Hackerbilt...

It would appear that I did in fact pull you into this on post 34 and I apologize as I meant to respond to James C. Sometimes my eyes mess with my intents and you can see the results. My fault and I will take the bullet!

George

 

[Bucketman]

Fluidfloyd made some comments that it wouldn't make any difference which rod I used where so I decided to try it. If it doesn't work I'll try something different.
Zandor, I agree, a 30, 60 ,90 would be perfect, but any angle will work. Its all based on a triangle. The smaller the angle the more force it puts on the pivot point.
Meangreen, I have nothing against the pan hard bar, I just wanted to see if I could eliminate it. I like doing things different. If it doesn't work, I'll know why, and then I'll try something else. As you can all see there is more than one way to skin a cat. Four or five different suspension systems on this thread alone. If this doesn't work or I get tired of it I would like to try the half a leaf spring in combo with a radius rod. Thank you all for the input and information. I'll keep this thread updated.

 

[Hackerbilt]

It's all cool George...I was just wondering what was going on and figured it had to be a simple mix up.
I love threads like this! They cover a lot of very interesting ground for sure.

Bucketman...you have the perfect Hot Rodder attitude for sure!

 

[meangreen]

Everyone - My apologies for stealing the discussion. Suspension is my favorite part of building a hotrod and I get a bit over-enthusiastic when the subject comes up. I don't mean to step on anyone's toes.

Bucketman - I have quarter-elliptic springs ("half a leaf spring") on the back of my roadster. The great thing about this type of suspension is you can tune the ride stiffness by adding or deleting leaves. It can also be done economically; I used boat trailer springs from ACE Hardware ($26 each) and cut them off in my chop saw. I can furnish details and pictures if you decide to go that way.

 

[James C]

Hackerbilt and James C. - George's (fluidfloyd) description is correct (above). Whether there is room under a Bucket for a truck arm system would depend on the length of the frame and, more specifically, the distance from the rear axle to the forward mounting point (usually at or near the transmission crossmember). I have truck arm style rear suspension under my coupe. I have attached an early construction pic of it so you can see the configuration. Mine are considerably shorter than original Chevy truck arms, but the car still rides and handles great. Mine are rubber mounted at the rear so the suspension can move without flexing the arms or twisting the axle housing. In most Buckets, the engine is too close to the rear end to make it practical. However, if you run them straight forward and attach them under the frame rails, they work great. In that configuration they are usually called "lift bars". Smokeyco is building a set of them on his thread "My First T Build". Take a look at them.
View attachment 10485

Yeah I'm quite familiar with truck arms. I used to help a buddy with his 66 c10 back in highschool and the truck arm suspension really helped his launch times. I just didn't see anyway for them to fit under the car and wanted to see an example. Lift bars are cool but they are not the same thing. The Truck arms work closer to the center of gravity for the vehicle. You can also raise the mounts on the front end of the bars (on a c10 by flipping them, on race cars they have adjustable mounts) to adjust them. They cause very little pinion angle movement and transfer power very well. That is why they are so popular with NASCAR.

 

[Bucketman]

No apology needed. At my age I listen more than I talk. Trying to balance things out from when I was younger. Everyone has been very helpful to me. The ideas I've gotten from this forum are great.
I saw this triangular rear suspension offered on a T-bucket frame in a Speedway catalog. I liked the way it looked and the theory of how it worked. It is better than a pan hard bar because the pan hard travels in an arc. I know it would have to travel up or down quite a bit to make a noticeable difference but .......... That is how this all started. Speedway doesn't sell a triangulated rear suspension kit ( from now on a TRS) for a t-bucket. I found a pretty cheap one for a 32. Any way I got the dimensions of the TRS from Speedways completed t-bucket frame. Now all I have to do is fabricate some mounting brackets, shorten the bars and put it together. That is when I wondered if I could make it work without shortening the bars. It is also when I joined this forum and asked my question that started this thread. Fluidfloyd's response got me thinking, and after that well, you can read all the great responses I got.
Zandoz, Sorry about the Zandor name mistake.

Meangreen, I would like to see more pics of the quarter elliptical spring set up. The price sure sounds better than coil overs with radius rods.

Got a bunch of welding and grinding to do, I'll post more pictures (and ask more questions) when the perimeter frame is ready to start adding mounts n brackets. Thanks again to all of you.

 

[T-Test]

IMHO--- Keeping it simple with a tried and true design is far more safer, cheaper and efficient than trying to make a design that belongs on a heavier vehicle. All designs can be bought cheaper than you can buy the material and build yourself. Check out the sponsors section and call them. Ride quality on these cars is mostly in the seating as well as softer springs, Short wheel base is the worst for bumps and such.

Pan Hard Bars are or should be mounted parallel with the rear housing or as close as possible to keep from pushing the axle sideways. To achieve this a mount needs to be high on the housing and low on the frame using weld on brackets. If you get more than 2 to 3 inches of suspension travel, it could hit the pumkin, and that's when you/I would need a Watts Link or you can bend the pan hard bar in an arch over the pumkin so as not to hit it when the frame goes down when weighted down or bounces. Material thickness is a must in this situation.

I hid my pan hard bar with license plate bracket and trailer hitch. Many ways to achieve this. To each his own and carry on the way you seem fit for it is your ride. No 2 are alike as well as ride quality when you go for 500 to 1000 mile trips, for you will find out what it will be like. Good luck and don't be mad at me for trying to give helpful constructive criticism.

 

[Zandoz]

No worries on the name...actually for some reason that is a pretty common mistake. Anything close is fine.

 

[meangreen]

Bucketman - Here is a link to the build thread on my track-style T. you may have to join the site in order to see the pictures, but it's free. Everything is explained in detail there, from material choices and basic metalurgy to mechanical parts, and there are lots of pictures. Just skip through the parts you aren't interested in. On my roadster I used classic Kurtis style radius rods and a Panhard bar to locate the rear end (and front axle) and I used quarter-elliptic springs with shackles to suspend the rear.
http://www.clubhotrod.com/hot-rod-talk/30400-another-build-thread-yep-my-track-style-t.html

If you are a competent welder, you can fabricate most chassis parts much cheaper than you can buy them. For example, Kurtis style radius rods in plain steel from Speedway are $159 ea. + clevises and rod ends. I build my own for about $110 per pair including rod ends. I've been doing this since 1968; if you have any questions about anything, feel free to pick my brain.

 

[Bucketman]

Got some welding done. Went a little faster than I had figured it would. Bought me some .035 mig wire. Sure fills in a big crack. LOL Got the coil over mounts welded on. Just stuck them on to see what they looked like and the approximate ride height. Here is my $18 dollar spring perch, and front cross member. 3" sq. .250 tube, with .250 3x5 angle iron, and .250 3" flat bar stock for braces. Heavy duty!
3"x .188 Rd. cost $48 for three feet. Spring perch in speedway catalog was $43 with shipping. Saved enough to buy a round for you guys. ;-)
Now for the fun part. Where is that grinder?

 

[Bucketman]

I could be wrong, but it looks like you do not have sufficient angle on the upper links. They should be a minimum of 30 degrees from the center line.

Also, I suggest downloading one of the 4-link calculator spreadsheets out there...they give an easy way to experiment with link lengths and mounting points.

Can you send a link to the calculator spreadsheet?

 

[bobs66440]

Nice looking welds there

 

[fluidfloyd]

Can you send a link to the calculator spreadsheet?

Bucketman,

Not sure if this link is still active or not but you can check it. Most all the free down load calculators are targeted toward rock climbers but they will run the number you put in them and should work just fine. Give a try and if it's toast I'll try and find something else. Good luck.

George

https://tbucketeers.com/threads/4-link-calculator.9088/

 

[RPM]

View attachment 10493


Got some welding done. Went a little faster than I had figured it would. Bought me some .035 mig wire. Sure fills in a big crack. LOL Got the coil over mounts welded on. Just stuck them on to see what they looked like and the approximate ride height.View attachment 10494 View attachment 10495 Here is my $18 dollar spring perch, and front cross member. 3" sq. .250 tube, with .250 3x5 angle iron, and .250 3" flat bar stock for braces. Heavy duty!
3"x .188 Rd. cost $48 for three feet. Spring perch in speedway catalog was $43 with shipping. Saved enough to buy a round for you guys. ;-)
Now for the fun part. Where is that grinder?

Wish you would have checked us out. Front perch is just $22.00 with all the holes in it already, and it is one piece, bent in a press brake. The round front tube we have for $25.00

 

[butch27]

Darn it Ron--You have it all. Why go anywhere else??