If you look at the picture I have attached you can see the radius rod is not paralell with the frame. Is that a problem? Should I move my hole in the frame up to fix it? Anyone have any ideas why it's like that and what I should do to correct it?
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If you look at the picture I have attached you can see the radius rod is not paralell with the frame. Is that a problem? Should I move my hole in the frame up to fix it? Anyone have any ideas why it's like that and what I should do to correct it?
It would have been easier to cut front off and move frame down. I know I have NEVER seen anything like that.
You've got to raise the mount point up, ain't gonna work like that at all.
Your talking about where the rod bolts to frame?
I'm afraid if I would remove that kickup and run the frame straight out I'll be setting way too high.
OK-----like i said before--cut it off around the fire wall area--your frame rails are too low--on my buildsI have a fixture that I use so I can mock up the top edge of framerails at c/l of crankshaft--this fixture is made up of three pieces of 6 inch channel iron where the middle piece is welded back to back with the ends---the ends are referance for frame rail tops and middle just goes under bare engine block with out crankshaft or main caps---
This seems to work pretty good ---it will bring up your frame rails and then your wish bones will be right.
Bearcamp, take a look at Speedway's T-Bucket frames T Bucket Frame - Speedway Motors, America's Oldest Speed Shop The low stance is achieved by the kickup in the back and the spring mount in the front and the drop in the axle. Not saying buy a new frame, but like Jerry says, that front "Z" needs some serious attention.
Ok I don't like the way the frame looks.................. but it Ain't my ride. With that said, the radius rods do NOT need to be parallel with the frame rails. Your main concern will be having the proper ammout of caster in the front axle 4 to 7 degrees. That is the king pins angled with top of king pin angled towards rear of car 4 to 7 degrees. Your front spring perch should have a similar angle, so the spring will not bind when you set the correct caster. As long as you have the correct caster your present setup should work fine.
The problem I see is that with unequal links on the top & bottom bar of the radius rods they will describe different arcs as the suspension moves, which is going to tend to shift the caster more than having them equal length. I'd be concerned with that contributing to some potential squirrely handling. As much as the bad geometry, they just look wrong to my eye. That said, like was said above, "...it ain't my ride."Quote:
Originally Posted by dlotraf33
Roger he has hairpins, I think you are talking about 4 links--
In suspension issues(other than what it looks like) should be referanced to the ground(mother earth)
If the links are parallel to the groung it doesn't matter what the frame looks like--If you look at the 32 ford pics in my gallery of the header build pics you can see where the block/top of frame is--keep in mind that that is a mock up block and there is no oil pan on it so its easy to see the height of engine(crank centerline) to the frame rails, which are basicly parallel to ground---and yes that one is a ifs , non an I beam axle but engine height to frame is what I'm referring to---
This subject car WILL have frame and suspension pieces bottoming out on ground as its laid out
Jerry,Quote:
Originally Posted by jerry clayton
Yeah, I recognize the hairpins, but they're sitting at maybe 30" top, 28" bottom which will rotate around the fixed mount on the frame describing different arcs. As the axle goes up in compression it will tend to reduce caster a bit (bottom travels shorter arc), and when it rebounds down through the static point it will increase caster. Granted the change is not going to be huge, and I understand that caster changes a little with equal length bars on the hairpins, but with equal lengths it tends to increase caster on spring compression and decrease on rebound. Seems to me this setup will create an opposite situation unless my mental math is bad....
And I think you're right about bottoming out.
By looking at the length of the motor mounts, it's obvious the front of the frame is way to low, as Jerry said. Any kind of 'band-aid' fix is going to leave a front end with terrible geometry problems and a car that will bottom out-with potentially lethal results!
Jerry's right, only way to salvage the thing is to get the frame rails at a height equal to the crankshaft centerline, then start on where the front end should be mounted.
Maybe not what you wanted to hear, Bearcamp. But it's the only way to salvage a very poorly designed chassis.....
I looked back at early posts looking for a pic of whole vehicle to get a VIEW that entailed the whole side picture--IF, this is cut off at the forewall area and rerouted the frame rails, they could also be narrowed as the go forward-- could be a very good looking vehicle---
Roger----with hairpins-----the axle does not rotate----it swivels up and down as a unit-- the hairpin is and works as a single solid piece,---
With hairpins, there is quite a bit of binding with the travel either end of the axle because the original suspension design was a triangular arrangement this didn't occur but splitting the wishbone and moving the arms out to lower the cars caused a severe binding---the use of surplas aircraft heims helped some(at least the quit breaking off the mounts)
The use of parallel 4 bars helped this but didn't solve it.
Remember that as a person looks at suspension , you have to keep in mind that the wheel does not go up and down , but the vehicle does--
with that being said----camber doesn't change on a beam axle---
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Right now my camber is a 7 to 8 degrees at both wheels and the tires that are going on it are 2 1/4" taller so ground clearance will be greater than what it looks. Hey,,,,,,when I first started this project I came to you guys for help and most said to replace the whole front axle so that's what I did. So it's all of you guiding me in the right direction cause without the info from here, I don't think I could figure it out.
Well, we definately suggested replacing that earlier setup. Some wanted you to cut all the way back to the fire wall, but you wanted the kick! While it's not what many here would build, It'll still be safer that the first go round. Try it if you've got the angle right and if you can live with it for now.. Do it. Then look at other examples and get some ideas and when you ready to make it even better, you'll have more knowledge in your back pocket! IMHO, FWIW, YADA YADA YADA...
OH, I can't tell from the picture, but make certain your using grade 8 hardware in your suspension.
Yeah I think what happened was the orignal build put the drive train to high and that is causing lots of problems.
Would any of you suggest coil overs, gas or reg oil shocks?
Deleted - no added value.
I think you're right Charlie, Roger, no added value? Hard to believe! 8-)
I believe you already have a transverse spring in the front. So you'll probably need very short oil shocks or friction shocks.
You mean Castor, Camber is not adjustable on your axle.
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I have found this article from R&C to be a good fallback in understanding the basic geometry of straight axle front suspension, the history of split bones, hairpins, why the parallel bar radius rod was introduced, why cross steering solved bump steer, etc, etc. Basic Suspension Geometry Lessons - Rod And Custom MagazineQuote:
Originally Posted by 34_40
They had a corresponding article on IFS that provides a lot of very good information, too Independent Front Suspension - Overview & Technical Specs - Rod and Custom Magazine
No--he means camber---its already built into the axle and is what it is from combo of axle ends and spindle angles---
Roger--seems to be something about my reply???
See Roger, I KNEW you had the goods! :LOL: All great data/info. He'll just need time to read and digest all this. But in the mean time, he needs to decide what style he's after! He'll get there.. we always do! :)
Bearcamp,
I went back and re-read my earlier post and realized that I typed "camber" when my brain was thinking "caster" :o I sincerely apologize for any confustion my typo caused in this discussion. "Caster" - the fore/aft tilt of the spindle, measured relative to the ground; and "Camber" - the in/out tilt of the spindle/wheel relative to a flat plane through the centerline of the vehicle. I corrected my statement, and again apologize for confusing the discussion.
Jerry, as noted above I made a terminology error. As I look at a scale sketch of a traditional hairpin setup and the arc's descrbed with axle movement it's clear to me that the caster increases/decreases with movement of the axle, but the change is relatively small because both the top and bottom mounts on the batwing follow the same arc radius. However, if the top bar is longer (let's say 2" longer for point of discussion) then the batwing mount points describe two different, parallel arc's, and the measured caster angle increases more on an upswing, and decreases more on a downswing than the change seen with equal length (or very nearly equal length) top/bottom bar lengths. In my head I looked at the angle of the line through the batwing as opposed to the actual caster line, and it muddled my brain a bit. When I did a sketch it became clear. Bottom line, I think referencing the R&C tech description provides a clear, concise path for Bearcamp, and he's getting good advice about re-working his frame.Quote:
Originally Posted by jerry clayton
Roger---not to get in a fight--but I think that you are maybe not realizing a couple of facts about these front ends and how we got there--now there is hardly anything similar between ifs and beam axles and only a very minute differance between wishbones, split wishbones, hairpins, and parallel 4 links---
ONE factor with any suspension is that the wheel/axle DOES NOT move up and down, but stays in contact with the ground
Wishbones were split in order to lower the cars back then---
In order to adjust castor beyond what they had (remember they wanted to go from a 40mph car to a 140-200 mph car) they cut a notch out of the arms to angle the axle where they wanted it
The guys wanting lighter weight and more at track adjustment went to tubing HAIRPINS with heims so they cutadjust caster plus set axle square with driveline of car.
A car with hairpins-----does not have any different arc(concentric/parallel) for the top or bottom tube--it works as a singular unit with the batwing on the axle---now a parallel 4 link is a different story.With 4link the caster of the axle has a better chance of staying constant thru out the travel
With the split wishbones, hairpins and parallel 4 links, there is considerable binding of the front on suspension travel and also a greater need to keep the axle centered, especially with anything other than the leaf springs/shackles.
Most of these older vehicles have a decent amount of camber which came about from wheel/tire size height etc and using wheels with different offsets upset the issues very quickly (death wobble)
Jerry,Quote:
Originally Posted by jerry clayton
As you said, not to get in a fight, but we disagree on a couple of points. First, when we mention movement of the suspension it is relative motion, the measurement of the wheel/axle regerenced to the frame. As you point out, the wheel stays grounded (we hope), but the relative motion of the frame to that wheel is the same whether the wheel & axle move up, or the frame moves down. I agree with your statement, but the relative motion is identical whether we say "...as the wheel moves up & down.." or as the suspension compresses and decompresses." It is common practice to raise the frame/body and then check travel and clearance by moving the axle assembly, right? Same motion, relative to one another - it's only terminology.
Second, we can solve the differential length point easily. Draw a straight line on a piece of paper, and we'll say that's the centerline of the batwing and the back hairpin mount. Now with a compass move out say 3" and strike an arc ~45* above and below that line, and then move out to a 3.25" radius and strike another arc, parallel to the first. On your first arc define two points, say 0.25" above and below the line, representing your "correct" batwing connections. Easy to see that as the frame moves up & down those two points follow that arc, and while the caster changes a bit it is not too much. If you have cross steering bumpsteer is not an issue.
Now using that lower point on the inside arc, connect it to a new point 0.25" above the line, but on the outer arc. This is the batwing connection point for Bearcamp's setup shown - the batwing is effectively rotated on the axle, tilting forward. Now as you move the frame up & down you'll see that in order to stay on the outer line the batwing has to tilt farther back on the upswing - the caster increases faster the more the rods are out of equality in length. It's a simple graphic solution that explains the point.......Or we can just agree to disagree.:D
Roger===there is no movement up and down at the front--only at the back--and the caster will rotate relative to the ground at about 1 degree per inch of vertical frame travel at the rear hairpin mount point---( the old 1/60 rule)
You have a mental block about this or a misconception of the real facts of basic beam axle suspension---
I read your R & C story and it jumps around so much that I don't believe the aurthor understood himself and most likely any one reading it would be confused---
With a hairpin set up you need to forget about your dancing radai because they don't exist--it matters NOT what the batwing looks like as the action is no different from just being welded to the axle like the wishbones were---the batwing just gives the builder a means of setting caster without having to build it into the arms(and a slight adjustment for wheel base or offsets of the mounting points to frame--
Choosing to disagree or not isn't what we should do here but end up with agreement on the proper and correct facts of this so readers won't be mislead about some very basic principals of suspension / steering/alignment-----
Dang, it's warm in here! Getting a bit heated! :LOL:
Bearcamp, don't take it personnal! I'd suggest that sometimes other folks forget the we live in a world of compromises! :) You found a ride that you thought was cool and now want to make it more your own yet retain the concept(s) that you felt made it cool. No harm, No foul! :D
Again, I think at this point just try it out. Read / Learn get familiar with the concepts everyone else is discussing. I'm sure that in a season or two you'll get the itch to further refine your ride and then you'll be ready to really make a nice rod!
Again, IMHO, FWIW, Yada, Yada, Yada.... :D
Nicely put 30-40 and I'm learning alot from these posts. I'm keeping the kickup where it is FOR NOW,,,,,,,,,and going to make this thing a safe and reliable ride for the wife. My main concern is first safety and then along with that easy handling. But also on a time period to get er done. I'm just soaking all this up from you guys and it's helping alot figuring it out. I build several rods (some that made magazine covers) but they were Mustang ll front ends. Piece of cake. Now we have rat rods, which we love and with the straight axles it's a different story. By all means get me the positive along with the negative, I eat it up. But,,,,,,,,,,,,,,,,,,brainstorming is the best way to solve issues and aid to get it right. I want to thank all who is helping me with this and I'm positive we'll get it right. It's not just me building this thing but all of us. Thanks again and keep it coming. Oh and the worst part is,,,,,,,,,,,I'm only working part time making 7.25 and hr down from 22.00 so we have a bit of a $$$$$$$$ thing, And I'm on a bounce back. LOL
Got the door lettering done last week. I didn't have a problem with that. LOL
I like that sign!! What's your definition of "Toading" (seen several)?
I'm installing a tow truck boom on the back, actually cuttling it down just for looks. Towing,,,,toading. It's a witchy thing for the wife.
Here is one of my favorites local car.He did such a nice job and it all works:
http://i172.photobucket.com/albums/w...airwell218.jpg
http://i172.photobucket.com/albums/w...airwell219.jpg
Hey Bearcamp,
As I awoke this morning a little voice in my head was saying "...extend the radius to the axle..." My visual concept of changing caster was totally wrong, and I'm sorry for confusing the issue. All points are hard points from the radius rod pivot to the axle, so the axle indeed pivots around that one, common point and caster changes are relative to a vertical line through that arc. Other than looking "different" the unequal length top/bottom rods make no difference to your setup. Listen to Jerry, Dave, Mike, Charlie, and others who know the old rules of thumb much better than I, and I'll try to stay out of the design theory questions. I hope you get it sorted out where you're happy with it, and you keep mama safe too.
OK--next time coming thru Gardner, you can buy me coffee
Heck, I'll buy you a coffee about anytime you're coming through here, as long as your not stuck on some Double Mocha Hot Shot Latte stuff from Starbucks or somewhere. I'd likely even buy you a beer or two....long as you don't mind being around a redneck - actually more of a transplanted Ozark Hillbilly.Quote:
Originally Posted by jerry clayton
I don't go into Starbucks---reasons--too many people with I phones(apple execs 100+million bonus, 500,000 chinese jobs) drinking high doller drinks that just had prices raised cause coffee went up and cep S-burks getting $65million bonus PLUS 12 mill retension -----and the management wants cut of the tip jar????
So with all said, should the spring mount have 4-7 degrees added just like the spindles?