Double A-Arms with u joints?

[The_Machine]

Dissasembled my big buggy and have loads of parts and am currently collecting more parts and ideas for a f1/indy/formula ford inspired road kart with 4~ inches of road clearance. I already have some heavy duty universal joints for 1 inch keyed axle and was wondering if someone can clue me into how I would make it so the hub would stay 90 degrees relative to the bearing plate where the arms connect.

With a single A arm, it's much simpler. Just put the U-joint in line with the a arm pivot, throw a bearing on the outer plate and run the axle through. Problem there is you get camber throughout travel, which I don't want. the front spindles solve this problem already.

For example,

So, my question is, are there bearings I can mount on the bearing plate that do not pivot like pillow blocks and flange bearings? If not, do I have to mount 2 flange bearings against each other to lock the axle and hub to 90 degrees?

 

[KieranM]

i just thought you might want to take a look at this video.

http://www.youtube.com/watch?v=BEXrEbfbzLw&playnext_from=TL&videos=1Osq4Cx6RKQ

interesting points.

 

[Kaptain Krunch]

In the setup you pictured, your a arm mounts look very weak... VERY weak.

Anyways, What is your power source? if at all possible i would look for a small set of CVs.

 

[The_Machine]

What I am asking is there a bolt on mountable bearing that doesn't pivot?

Those rear single a arms were for a 2 seater buggy i built and jumped, flipped, shredded the hell out of. When finished it had double rear shocks and was braced. Never had any problems with it.

As for the video. Scrub radius, ackermann, etc are irrelevant. I've already designed the front end. And this kart in the video has no rear suspension.

 

[The_Machine]

Well, it has a swingarm, which is garbage.

 

[The_Machine]

I like Dave's videos but one thing he is wrong about in this video is the "about 15 degree angle" of the steering arms on the spindles. As most of us already know, the steering arms should be at an angle where it is in the imaginary line from the kingpin to center of rear axle. The angle then, depends on the wheelbase and the wheel track distances.

 

[Raywelder]

Those look like the u-joints I had and sold!

 

[Kaptain Krunch]

Tapered needle bearings?

 

[The_Machine]

They are mcmaster heavy duty. 185 foot pounds of torque rated universal joints. Braking will be through the jackshaft, so the engine size is less relevant as braking will torque more than any engine.

 

[The_Machine]

a mountable product?

 

[The_Machine]

maybe bolting flange bearings to either side of the a arm plate is the best bet. cheap and simple.

 

[Kenny_McCormic]

I'm thinking you need 2 joints per wheel if you want static camber.

 

[Kaptain Krunch]

kenny's got a point.

 

[modelengineer]

Well, it has a swingarm, which is garbage

Front and rear swingarms

If you want less camber gain then you'll need to go to double a-arm AFAIK
FWIW I think single swingarms are fine for off-road. The camber gain is not as big of an issue as you think.

 

[Kenny_McCormic]

Single arms are fine wherever you go, doesn't the Porshe 911 rides on struts?

 

[Doc Sprocket]

Well, it has a swingarm, which is garbage.

As far as single rear swingarms go, that's not the worst design I've ever seen. At least the engine is suspended. I wouldn't call it garbage. It's not ideal, but a fairly good compromise between function, weight, cost, and complexity.

 

[The_Machine]

Static camber? that's why I said 2 flanges per outer plate. Bolted on opposite sides of 3/16" plate.

You think I should go double a arm? Read the thread title.

As far as swing arms and single a arms go, they WORK but they don't satisfy me with performance or challenge my engineering. Also, I bent 1 1/4 axles jumping my buggy and landing crooked with a swingarm. As soon as I got home after the second one I unbolted it and started on single a arms. And this was with the pillow blocks 1 inch away from the hubs. Single a arms work OK on the dirt, but are boring. If you want to raise serious hell and not even wonder if your machine can hold up, heims and independant suspension, double or not, is the only way to go.

Here's my old buggy in early stage of development I tore apart because I was unsatisfied with a great deal of how it performed.

This time around I'm making something that does more than does what it has to do, but does it to the maximum potential. All heim joints, pushrod suspension, very low center of gravity, completely adjustable, and as light as possible.

 

[Blazkowiez]

Dude! Machine. I loved seeing that build, what was that 3 years ago? Its so awesome when you have to scrounge up parts because of cost or lack of availability.

For off-road use this kart you're building or have built will be fine, I'm not sure about bracing but camber and alignment will not come in to play as severely as you might think. The off-road buggy experience is about deep mud and drifting, everyone has a separate idea of what they enjoy, if you need to go over 50 then you might want to start worrying about these things, if 30 and torque is all you care about then lighten up and concern yourself with re-enforcement.

 

[The_Machine]

Thing is, as stated in the first sentence, it will be for high performance on-road use.

Nobody here reads! seems half my posts are to correct people's lack thereof Maybe it's a weekend thing

I love off road shredding. Not bored of it, just want to do something new. Something that challenges my brain and my skills where build tolerance, weight, and engineering are of greatest importance.

 

[Blazkowiez]

Alright, I read the part about ford inspired road kart... all I can say for now is bracing. I'll see if I can't figure out something to help you with the front end if this is indeed the problem. My bad!