Suspension free for all
 

:swordfight:
:party:

Rather than comment in Fcracker's thread why don't we all have a good ol debate about suspension designs in it's own thread?

Roy's questioning the "equal lengthers" got me to thinking about this topic, as it's one i've studied copiously not only since I got into buggies, but also through all of my years involved with cars, magazines and racing, even my mountain bikes.

Primary comments I'll make are just a couple.
A. -- One must always remember that suspension design ALWAYS involves a compromise.
B. -- There is no one design that's right over all others.
C. -- suspension design should be based on the intended riding usage/type.

Personally, I enjoy all schools of thought and approach. I went with an equal length arm design that allows me to alter the upper arm's length and the distance between the arms at the hub end (thus making them even more unequal if desired) for the very reasons that were brought up. When building mine, I took my ideas to a person responsible for suspension design at the uppermost racing levels -- his comments regarding my intent to keep everything parallel and equal length were basically that it was a non-issue worry-wise given my desire to have little camber change and bump steer over very rough and rocky terrain. (my far end of the scale use isn't rock crawling per-se, but darn near as you'll want to get to it in a buggy and the setup doesn't impact everyday moderate riding enough to bother me) He basically indicated that i'd have a successful design as long as I left an "out" to work in some adjustibility at a later time if i wished. (heims and spindle mount spacers.) Anyway, that's my "why I built what I built" statement.

Your primary comments pretty much wrap it up!
I feel equal or not depends on where your from. The guy who states equal is the way has never been in the desert. and the guy who hypes un- equal has never rode a tight east coast mountain trail. There's places where both shine! and both have limitations. Unequals are great for precise camber, scrub and Ackerman. If I were building a road racer for pavement thats the way I would go but for my intentions it's wasted time, expense and defeats my objective. I use equals because I like yerfs. I don't have a huge budget, sponsorship and the latest and greatest in fabrication equipment. I am a hobbyist so like most of us, we use what we got! I enjoy the challenge of reworking the original yerf design into a functioning system while still retaining the original concept. And all the while keeping it practical and serviceable also!
I will never feel a little scrub while I'm on loose surface trail. Yea I got some bump steer too but it occurs beyond the limits of my shock travel so it's irrelevant.
My whole feeing on the matter is the only place you'll find that perfect suspension is in that perfect world
Use what ever you have to work with! Don't worry about it, have fun with it! Enjoy your hobby.

I dont get why it maters were someone rides.Scrub is a big factor, for people that do not know,look at the spindle mounts to the top and bottom aarms.Draw a line from top to bottom through the mounting points and it should point to the center of the tire.When it points to the ground beside the tire thats a lot of scrub.When built this way on ruff ground bumps are felt in the steering wheel,sometimes a lot.with out scrub you dont feel them and can drive the same places that jerked the wheel(with scrub) with one finger and a thumb.
Camber change makes a buggy or car handle better,thats why they have it.Look at atvs it there utvs yup there to.IT cost the same to build it one way as the other so why settle?
I was new to this when I built the first buggy and I made it from a carter 150(the one in my avatar).I had no help just the links Ive posted.
If I can do it anyone can.Look at this aarm set up(not mine) its done right and can be short travel and 45'' if you want.Do what a winning car builder does to have a good handling and driving car.

Just so every one knows that Im not saying thats it wrong to build equal aarms,just not the best for handling.If you think they are the best drive someones buggy set up like IM talking about or build yours this way and see.
This place is here to help and not every one thinks the same and by reading peoples post is how we learn what we want.If nobody tells what we have learned then this site will not grow and every ones buggys will have equal aarms.LOL

How does every design have compromise?

I agree with x-bird & ckau 100% and the reasons "why" we build what we build- nearly always boils down to $$$$'s
I've stated that the reason behind my use of even A-arms are simplicity,ease of set-up and ease of maintenance. They "even A-arms" from what I've experienced are very forgiving when it relates to driveability from a less than perfect fabrication.

Boy-oh-boy,go to one of these sites or all and start the same thread and say that equal arms are best you will get laugh at.
http://www.minibuggy.net/forum/searc...7&pp=25&page=3
http://www.race-dezert.com/forum/
http://www.dtsfab.com/index/index.php

:dunno:If it comes down to money then unequal aarms are cheeped to build because there is not as much tube!!!

I AGREE 100%. it depends on your situation, your $$$ available, and your fabrication, or the lack of, skills. roy no disrespect but if we all had big bucks and all the fab tools we need, and all the ability to use them, and and and... in a perfect world. not disagreeing with you just saying not every one can do what you do. not saying i cant just saying most cant. happy buggying to all.

No, not true, the cost of retooling to fab a seperate shape far offsets the cost savings of a little less material. IE, making two jigs for 2 seperate a-arm shapes rather than making one jig for all. Time and labor is where the real cost is. -manufactureing 101

Please note that i use a lot of "qualifying" terms ... I'm no expert on suspension by any means .... :biggrin:

It's inherent. This is not a put-down of one design over another. Where does the compromise come in with an unequal arm design that causes more camber change through it's travel come in? Increased steering effort. cambering a wheel inward requires more force to make the inside wheel turn against the camber. No matter what you do with a rotating circular mass that you're trying to control the movement of through 2 or more planes of travel, altering one area affects another--unless one has access to a lot of spherical end bearing components capable of rotating equally large distance amounts in all planes ... ;)

When you look at the various designs there are pros and cons to them all.

Don't forget that the yerfs started with unequal arms and as reliability issues arose, they were modified and "improved" to the point that the final design ended up with equal arms. This isn't so much because the performance of one was better than the other, but because the target market was younger and the intended use was "light" terrain. Performance wise, it appears as if keeping their product light and inexpensive was also a goal. those 3/4 factors combined are a tough goal to meet -- in fact it's what really sank the company. The end-users who have converted their a-arms to heims in place of ball joints are in fact building adjustable equal/unequal arm suspensions. FWIW, the yerfs also are not the only buggy with equal arms--not a "this is better" comment, just a statement.

For my use, I absolutely, positively, most assuredly want my front wheel, when it impacts a very steep terrain change, to travel upward as close to dead on in the vertical plane with a large amount of caster to help it achieve this as I can get it to. While even metal feels that maybe the yerfs had too much built in caster, i wish i'd added a few degrees more. As that wheel--and this is from the view that only ONE wheel is going through this, is going up the face, i want camber to act as minimal a turning force on it as possible.

While the focus so far has been on the fronts, the rear suspension plays into the design process and performance of the fronts and is one of the main issues that drives what's going on handling-wise with the "china buggies". the live axle swing arm at the rear is a big trouble maker. It exists because it's simple and cheap. it causes more lousy handling, roll overs and frame damage than most realize since it severely limits proper weight transfer and eliminates predictable roll center and axis. it's also an oversteering pig of a setup. because of it the buggy frame is actually part of the suspension as a torsion element--not good. Once out get into IRS, then you can begin to take advantage of the features of other designs.

As far as what's out there on the internet, i've been on all of the sites and forums that you've linked and many more and participate on two because they cover the hobby pretty much from all aspects. I've used what i've seen here, there and everywhere else when deciding what to do with mine. the original source of what i decided to build was taken from the blueprints of the MG midget R-type of the early 1930s. Ideally, i'd prefer to create a lightweight version of Lancia's sliding pillar suspension, also of that era. Laugh if you wish, there isn't anything even remotely new under the sun about what we're talking about here ... :cheers: The only reason you don't see much of the latter (sliding pillar) was the manufacturing expense of it ... unless you look at the front end of a VW buggy or an odyssey--that's where the root design of those came from ...


Enjoying this, and we haven't even gotten into opinion's on Mr. Ackerman's ideas yet ...

You dont need two jigs. You need a second set of holes in the orig jig for a shorter arm. For slow trail riding, you likely wont know the diff. But any cornering at speed, un equal stomps egual all day. Any whoops at speed or any un even terrain period. You go into a turn and at speed and the wheel fails to keep proper contact, it pushes. Equal length may be easier by a little, but are not superior at all. Egual works fine on the street as the wheel has very little travel. But the more that wheel moves, the more the issue becomes a issue.

Most off roaders would agree that a-arm in the rear are best for track and fast trails. While most would say trailings are best for the desert or hard riding. There better because there easier to make, and take alot of abuse as they flow with the terrain. Just like a vw or pilot front. Most would also agree that both those machine absolutly suck susepnsion wise. You can get big travel numbers from them, they just weight a ton. I'm partial to a semi trailing/ linked rear my self. Trailing arm tough, a-arm adjustment. Another huge diff between trailing verse arms is plunge. You see broke axles, it's cause they likely needed more plunge in the axle for their set up or less travel to stop the plunge. This is why I will be doing a trailing/linked rear with a 930 axle set up. More travel with the massive amounts of plunge in the same width design

Xbird said it over steers or pushes in a turn.Thats what ive been saying,the swing aarm acts as anti role in back witch makes the front bite and it still over steers.Thanks Chuck!

Ok aarm building 101,square tube is the easy way.
No need for a jig your only building 2 each.
#1.draw the arm on a table or floor the right size for the mounting points on frame and how long it should be.
#2.Cut tube to the line and put it on top of the line.
#3.When you have all the tubes cut and put on all the lines tack.
#4.Cut more tub same as in step #1 put this on top of the 1st aarm to use for a jig and repeat.
Every keeps saying tools I only had a welder and grinder I cut every tube and saddled every tube with a grinder.Then skill like ive said before I had never done this before and it dident over steer by the way.So I looked at bmi karts and it looks like it would cost $280 for 4 aarms ans 2 spindles.
Now 1'' .095 wall tube is $1.38 a foot bmi said the yd arms are about 15'' so 10' of tube is under $13.80.for the spindle get 2 foot square and 2 foot of flat bar,that should be under $10 also.It looks like for you can build it for half price.
http://www.stockcarsteel.com/hot-rol...led-round-tube

I can build and tack 4 aarm in under 1 hour it not hard as yall are trying to make it.For a new guy looking at this he may think this is hard,but its not.A 16 year old kid just built the hole buggy and yall are talking about an aarm being to hard!

By the way racing aspirations calc does it all for you but the fab work,and if you cant do I know of a 16 year old that may do it for you.HEHEHE
http://www.racingaspirations.com/?p=286

AHAHAHAHAHAHAHA. If you do want to make a jig as I will be(mainly cause I'm looking to make better Joyner arms folks can buy) any old bed frame has all the steel you need. As long as the frame mounts are the same, one jig will make a shoorter arm. Just take a bolt that fits the heim, weld it to a 3in piece of bed frame or what ever your using. Drill two holes in the bottom. Then drill two holes in the jig. So aster you make the long one, you remove it, add this incert, and there ya go, dual jig.