Wisbone/Hair pin Angle?

I just tacked my rear suspension in place and in order to have proper clearances I had to weld my hair pin brackets a bit lower that I had planned. The hair pins are at a slight downward angle. Is that going to be a problem? This is my first time building a frame and designing suspension. Let me know what you think guys. I plan on driving this car alot and am trying my hardest to avoid a ch***is disaster down the road.

 

Here's a bad cell phone pic

 

cant tell the angle in that picture from above,
How about a picture from the side

The general idea is to have them close to level at ride height, if they are way out of level at ride height I would sugest you find a better place to mount your front braces/perches

 

They should be close to level at ride height. If they are angled they will pull the axle fore and aft as the suspension travels and something WILL break.

Case in point...We've got a T touring in the shop as we speak that someone split the front bones and angled them WAY up to the frame at about a 35* angle... it was only a matter of time before it pulled itself apart going down the road. Literally broke the wishbone off at the forging and shoved the remains through the splash apron. The owner is lucky to be ALIVE.

While you're at it, unless you're planning on gussetting it up, I would rethink your crossmember too. You've got a big long lever arm there for the rear suspension to pull on... Do you know anyone who is familiar with setting up a geometrically correct suspension that could give you a hand?

 

Thanks for the tips guys! Ill get a better pic in few minutes. I plan on making that crossmember the central part of a stout "X" member. Will that suffice?

 

Maybe it's your cellphone pic, bit the hairpins seen a tad close to the frame rails. It looks like, when the rear moves up & down, the hairpins will hit. Is there any reason you can't move the hairpin attachment points out side (or just under) the frame rails? This is normally where hairpins are attached. To me, your set up looks like a ladderbar configuration. Like I said, maybe I'm not looking at your pics correctly. It's not too late to get things straightened out...it's good to ask.

 

With how you have your geometry a stock radius rod will work better. More pics please and show more of your frame.

 

Heres a better pic of the angle

 

If it were me I would make them closer to horizontal.

 

Your experience is greatly appreciated harv. I only have a 110mig to weld with.but everything I weld is just for placement. Once my brackets are in place I am going to take the frame to a certified welded friend of mine.

 

Cool hairpins! Are those made for the rear? Or are you using front hairpins for rear axle duty?

 

That looks awful wrong to me.

 

That's not the right application for hairpins. You ch***is is a mess. Please believe me when I say I mean this for your own good and not to be mean. Stop now and don't spend another dime on that ch***is. You will just be disappointed. You need to spend some time with anyone that that has ch***is design experience, or use a ready made ch***is.

 

what he said, these people know.....

 

for sure, or find someone close to you to come point everything you've done wrong so you can learn something and ask questions.

those hairpins will fold up at the first hit of the throttle they are designed to used ont eh front axle with no torque applied. You need ladder bars for the rear.


AGAIN PUHLEASE find someone to help you before you get yourself and maybe innocents killed.

 

You've gotten some good advice on your hair pen application here..but as I look at the photo's provided it scares me that what I'm ***uming is your ****** mount or maybe it's strictly for you hair pins to mount to, is so low below the frame? I would think that the first sizable dip in the road, curb, speed bump etc. would take the whole mess out. Not trying to piss in your cheerios just concerned with what I see.

 

Would a torque tube make the hair pins usable? I like the looks of rear hairpins. Reminds me of the old sprint cars.... but I don't want to die in this car either I read a few threads regarding hairpins bolted to the outside of the frame rails and how that is doomed to fail. The solution I read was to trianglulate the hair pins? Thanks for all the tips. I need all I can get.

 

would you use oranges to make applesauce because you like the color better?

what your wanting to do isnt gonna work, you could crutch it with a torque arm but you would just be putting a bandaid on a ****ing chest wound.

use ladder bars or something else designed to be used as a rear suspension component.

 

Im not the first to use rear hairpins. Ladder bars seem more like a crutch to me. Originally model a's came with wishbones and a torque tube. How would this set up be any different?

 

The torque tube provided the rigidity to the rear end. The bones provided very little support and only prevented the axle from wandering. Your suspension may look cool, but is destined to have a good chance of hanging on a wrecker hook or roll-back bed. The geometry is wrong and the material are too weak. Instant disaster is lurking down the road.

 

model a a wishbones had much higher strength in each component, they were also full triagulated onto one another so that there would be no bind or added stress on the individual components as it rotated and or articulated.


I should also add that those components were all designed to work together and were not cobbled up by an admitted first time builder.


good luck. You need it.

 

Crossmember is waaay too low as well - listen to these guys above - they know of which they speak.

 

Not to be a smart a**; but listen to what these guys are saying, they are not busting your chops, they are trying to help. Look through some magazines, check some of the build threads on here, and check out the ch***is set ups on the cars at the local cruise night. I don't think you will find anything like you have going now. Lot easier to step back a little and get things going in the right direction now. FWIW I have used hairpins on the rear of several cars and have them on the car I'm working on now.
That said, I think the application is limited to certain type vehicles and they need to be constructed out of the proper materials. Of course that is only my opinion.

 

How to build an early hotrod frame

This is a great thread with tons of info.

 

So if I weld a torque arm to my setup im more or less replicating henry's design right?

 

If you can figure how to have all three elements articulate together. The Ford torque tube pivoted on the rear of the transmission and the bones were bolted to the torque tube. Everything rotated in the same plane. I commend you for asking the right questions and I trust that you will heed the suggestions from experienced HAMBers. Good luck

 

nope, henry's design had the bones and the torque tube as one piece, with one joint, yours has the hairpins split apart and that will change the way they handle stress and articulation.

hairpins also use a much smaller bushing/joint than a ladder bar which on the front end with no torque load is fine, not so on the rear end.

your hairpins have a very round shape where it attaches to the bushings, this rounded shape places the load stresses 90 degrees to the joint. that shape also reduces the amount of welded area as well as increasing the shear placed upon them.


the amount of drop in that crossmember is an area of concern as well but not nearly as much as the rest of the design.

but since you seem convinced that your gong to make this work, have a ball, dont worry about the laws of physics as they dont apply to you.

 

but since you seem convinced that your gong to make this work, have a ball, dont worry about the laws of physics as they dont apply to you.[/QUOTE

I will make it work. Not because physics dont apply to me, but because it has worked for many decades before me. You ignorantly stated that hair pins are not for rear suspension. Obviously you have never opened up a speedway catalog or seen any pics of pre1970's open wheel sprint car. I am simply gathering as much info as I can so I build this car with the styling i prefer and still have a safe reliable car.

 

race car stuff doesnt work all that well on the street, especially dirt car stuff, but your the expert.

good luck.

 

Not at all...Henrys design pivoted in one place with no bind. Your setup will be in a bind due to 3 seperate pivot points and something WILL break. Probably will be the hairpins as they look like they were intended for a front end application.
Problem is that if you go with a stronger hairpin, then the next weakest piece will break, and so on. Do yourself a favor and search for past threads dealing with rear split wishbones as this is basically the same thing and comes up often on the board. Lots of good information available, very little of it positive for this set-up.