Spring behind axle w/ wisbones-how do you do it?

OLD-TECH :

 

So, that spring perch is welded through the bone? Are they going to cut off what is sticking out, or does that attach to the steering arm, for excellent straight shot driving?

 

on shines and lukesters,
are those 2x2 5/16 bolts on each side strong enough?
I have a roach rod I'm slapping together,
with the same idea,
but with cheesy speedway hairpins,
and am not trustworthy of those bolts holding up
the whole front end.

does anyone drive far with this?

tp

 

Yeah the perch gets cut off! I am using an actual spring hager meant for a T bucket. The bolt is 5/8s OD. I like to err on the side of overkill if I can. Also, the way my shocks are mounted they would bottom out before the frame hit the ground in case of a catastrophic failure of the spring.

 

[ QUOTE ]
does anyone drive far with this?

[/ QUOTE ]
Last I heard,Jimmy Shine had 1000+ miles on Frankenshine.Which isn't a true test of durability,but it does work.
Even so,I think the design test the limits of the materials.The safty margins are not as large as some would like.
I doubt they are El Cheapo No Name brand ungraded mystery bolts.Good bolts will be at least 3 times as strong as cheap bolts.

 

This is great timing for this subject...gonna start making the frame for the jalopy next weekend! I know NOTHING about hot rod type suspension, so any and all info is going to be very useful.

 

[ QUOTE ]
and am not trustworthy of those bolts holding up
the whole front end.


[/ QUOTE ] I'm sure someone will correct me if I'm wrong:
The bolts are in double shear,so they shouldn't be a problem.
The clevises are the weak point as they are loaded largely in shear.
In nice round numbers,if the truck weighs 2600 lbs with 1200 pounds on the rear axle,
1400 on the front axle.
That gives you 700 lbs on each front tire.So each clevis has to support 350 lbs.
Now if you take the Minor Diameter of the thread,multiply by Pi to get the area,then multiply by 30,000 PSI yield strength you get the yield strength of the thread.Divide that by 350lbs to get the safety factor. Who has a calculator?
PS I've left braking torque out of this example for simplicity.

 

UI
sounds good...
tp

 

Why couldn't something like this be built? Put a longer perch like bolt through the bone and then build out a sort of C style mount that goes above and below the bone and axle. Then you mount the horizontal perch into it. It could even be welded onto the bones if you were worried about that setup being weak.

 

Does this setup use the original spring or one a little shorter? Looks good. Dave

 

Unkl Ian, multiply that 700 lb dead load x 80 MPH + a 3" pothole & you get a live load that would raise a little concern with me. The one problem I see is that by BOLTING the batwing to the axle Then putting a side load from the spring you are creating a Hinge effect ? Which would multiply the load on them clevise's Seems to me it would be stronger with the bat wing welded. I know that creates yet another dilema on a beam axle.
(my opinion applys to wishbones not stock bones)

Later, Mark

 

[ QUOTE ]
& you get a live load that would raise a little concern with me

[/ QUOTE ]
That is where the safety factor comes in.Carrol Smith talked about safety factors in one of his books,and gave values for racecar suspension,roll hoops,and compared these to production street cars.
Jimmy Shine might have made his own clevises from some fancy heat treated alloy.Or maybe he's just very brave.
Another solution might be to use the heavy steel parts from the front of a production wishbone,and weld your hairpins to this.If it was executed properly,it would look acceptable and be plenty strong.
How did people attatch hairpins before batwings were comercially available?

 

I understand your concern Mr Hawking...err I mean Unk But while we are debating this **** Jimmy is racking up the miles and laughing his *** off at us!!!! The way I see it we all have to build to our level of comfort. My setup has a little more beef engineered into it, that green T Bucket has quite a bit less!

I really enjoy this thread since I am knee-deep in this very thing right now. I will get some pics up as soon as mine gets together. Just waiting on a spring...hopefully tomorrow.

 

I went through a similar design problem with the Dumb **** Engineers(tm) where I was working.
To meet the safety code,the part I designed had to withstand 5 times the maximum working load without complete failure.
The Dumb **** Engineers(tm) told me the 5/8" cap screw wouldn't handle 3000 lbs in shear.I did the math,not good enough for them because I didn't use a computer.So I built a test fixture and proved that a 1/2" cap screw would handle over 10,000 lbs,without any visable distortion.
They still didn't like it. Clowns.

 

So my 5/8ths spring hanger going through 1/4" wall DOM that is welded double shear is OK? Thought so. I will post pics.

 

to the guy wondering about his axel and spring being straight up and down,

you put the degree into the crossmember or whatever mount your using to hold the spring

tim

 

tman uses stock style spring perches.
these have 5/8" holes.

shine and lukesters use 5/16 I think bolts,
but two on each side.
I know that on the cheesy speedway kit I obtained,
(on a trade for krapwerk)
is advertised as being under 1800 lbs (I think)

that is on a stock set-up,
where the spring is attached to the axle,
NOT the hairpins.

Shine's and Lukesters setup,
mounts on reinforced HAIRPINS,
that rely on clevis + bolts.

I know that the shinemobile was a trailerqueen,
even in the early days of its showtime.
And even the pics in ROdders Journal
were obviously before it was running or finished.
(Driving it hard for occasional short distances
is different than daily driver/long distances)

Therefore I would have a trust issue with that set-up
(unless lukester can enlighten me/us)

Now I think the set-up on LENO"S tank car
it is a semi-elliptic hairpin straight axle.



the TWO half springs are mounted solid on the axle,
with no spring shackles either.

that looks unquestionably stronger
than a true suicide mount

I think I might try that one.

yawn,

tp aka zibo

 

This is way I did it on the Bleedster. It's kind of a hybrid
beetween a suicide and a traditional set up as I retained frame horns. I've never seen another one set up like this and I think it worked out well. We did the H-Bomb the same way.

Basicly used a 7/16 bolt welded to some tubing for the perch. (It was welded by Lukes****er the Welder*** so I know it was welded good.) That is put through the wishbone, which was strengthened with tubing.

The difference between this set up and the others is I used a conventional lower shock mount that mounts to the cut off perch through the axle. I flipped it around backwards to place the shock where I wanted it. This way there is no added stress on the wishbone and it looks pretty good too.

I figure if the spring mount was to break, the shock would hold it up, and if that was to break, the frame horn would land on the axle and still hold the car up.

I guess it is a suicide front end with some saftey catches built in.........

To be honest I don't think suicide type front ends look that good, so this was a way for me to slam the car and keep
a traditional (kinda) looking front frame/ crossmember.

 

Bleed, thanks for the pics...looks a lot like what I got going. A question though..........how far does that thing travel up and down?

 

Probably about an inch and a half. I spent a lot of time jumping on it and it takes alot to bottom out.
I'm going to add some small rubber stops to the bottom of the frame horns.

I think it will work out pretty good.

It's finally coming home from the interior guy this weekend so hopefully I'll be able to drive it soon and see how it all works.

 

Bob:Nice work.
Would it be possible to use dropped steering arms and run the tie rod behind the axle,under the 'bones?
There is probably a reason you didn't do this.
I want to avoid having the tierod out front if I can.

 

Dose it turn in the right directon????

 

I guess it don't turn in any direction yet.

 

How about this coupe at VLV 03? They have the spring way below the bones.

 

close up

 

Thats an interesting setup.Not too sure I like the looks of it.You know with the shocks out ther front and center.Even uses the axle as the lower shock mount.

 

Bob, That setup looks great. That puppy has come along fast since I saw it at the pileup. Can't wait to see it done.

I saw a 32 ch***is going togeather at a local shop that I really liked. The axel was under the front x-member that was flat and in the stock location. The the spring was mounted behind the x-member with a suicide style mount coming off the back of the x-member. The spring perches were built into the batwing. So it basicly left everything looking the same as a normal 32 front end but took the spring off the top of the axel. Also the frame didn't need the usual c-notch for the spring clearance. this perticular ch***is also used a dropped I beam. I'll try and get a pic.

 

HaHaHa I sure hope it steers the right way!

I think I could run dropped steering arms but the problem is the tie rod will end up going right under the spring, so the would have to be SUPER dropped. I have an issue with the steering arm being the lowest point on the front end as well....... It seems you definatly need to keep it above the scrub line.

Because the grill shell sits right behind the steering arm, I think it looks OK. I still might change some stuff around.

I've got some top secret ideas for My Coupe that will solve alot of these issues. It involves mounting the spring to the batwing. I can't wait to start on that one.

 

TMan: What did you order for a front spring ? From who ?
Posies seems to have the best selection,that I've seen,
but I don't like the big ugly dimples on the ends of the leaves.

 

Unk, you mean the spring I was hoping to get today!? I ordered the Mr Roadster Spring, reverse eye from Speedway. It was a little less money than the Posies spring but I REALLY got it because it dint have the dimples!!!! I talked to a guy today about spraying a teflon like coating on all my springs. He says it wont wear off and will work better than the other solutions out there.