Ball joints

[Black_Moons]

Hi, Where would I find lots of cheap ball joints in canada? Suitable for a homemade front multilink suspension on a light vehicle (about 300~400lbs with rider, max speed 60kph on flat pavement, 15kph or so light offroad)

Thing is I am not exactly sure how much stress these joints actually will endure. The shock absorbers will be supporting most of the weight, so its only turning forces and impacts.. Still, Definitely do not want anything coming apart at speed, I am amazed ball joints are trusted at all for suspension...

[browne92]

You mean rod ends?

http://www.surpluscenter.com/sort.as...s&keyword=PRMF

They're pretty strong. AFAIK, every race suspension, including the baja guys, use them.

Of course, as with all things, there are many grades and materials.

[Willy]

Automotive ball joints will be too big, heavy, and usually not cheap.

I know you shop Lordco Auto so you might want to see what they have as far as smaller rod ends and ball joints.

Personally I would check with a local MC/ATV dismantler. With the large number of cheap, small, kid's ATVs out there, there's bound to be a large selection of smaller suspension pieces there for not too much money.

Here's what I'm talking about.
Although this example is new, it does give you 4 small ball joints. If you can source these used the cost should be much lower.
Small ball joints can be expensive but taking the used mini-atv direction should point one toward several options.

[darryl]

I think what you are looking for is called a Heme joint. Every one that I've had occasion to deal with has had a hardened ball in it, and the bolt part has been a good steel.

[Robin R]

VXB are worth a look, though check their shipping, as I believe that can be significant. http://www.vxb.com/page/bearings/CTGY/HR

[lugnut]

Have you looked at the quadracycles. if not you might want to take a peek here, http://www.quadracycleinc.com/. There a a lot of them here on the Oregon coast that are rented out to tourists to cruse around beach towns.
I have been thinking about building one.

[Black_Moons]

VXB are worth a look, though check their shipping, as I believe that can be significant. http://www.vxb.com/page/bearings/CTGY/HR

Wow, the 10mm (Ball joint hole size and thread size?) ones are rated '1000KGF', I assume thats kilogram force, so really amazing. I was expecting small ones like that to be rated maybe 250Kg.

Then again, I guess the whole point of a ball joint is its compliant in all directions except compression and tension, and in those directions its fully supported and basically a solid chunk of metal.

How/why do ball joints fail?

[ikdor]

Note that such rod ends are rated in the direction of the connecting rod. They usually don't have specs for the tangential load and if they do they are an order of magnitude smaller.

Igor

[ogre]

Balljoints biggest reason for failure is lack of being greased regularly,which some do not come w zerks to grease them,get one that does,and once the rubber boot is cracked or torn,water and dirt will enter and make short use of the ball and socket.

[Clevelander]

Race ya ... Just kidding my basement is too big a handicap

But we are pretty much on the same program. Early on I came to the same conclusion about ball joints, just too everything. Rod ends (AKA...heime joints, spherical rod ends, etc, etc. are the way to go. The biggest issue is to keep the contamination out of them. I suggest two types the female rod ends and the rod end inserts. The reason I suggest the female type is because of their superior strenght where the threaded portion meets with the body of the rod end. The other thing you need to be aware of is the number of degrees of deflection the rod end will allow. Some are very limited in their angles. The other thing you want to take into account is the direction of the stress on the joint no bending stresses. Where possible tension is best compression is OK. For applications where you'll be using the rod ends make sure they are of adequate size and watch them for wear in use. They do this job on race cars all the time but they are changed (relatively) frequently as they wear far more quickly than a ball joint will both as a result of contamination and the comparatively small wear surface on the inside of the rod end. For tension and compression loads a medium quality rod end should be sufficient (I would only use cheap ones to do mock ups) but for the "ball joints" I'd get a superior grade both for wear and safety.

I still have to get my shop together and my autocad back on line before I'll be able to work out my suspension. I'd be very interested to hear more from you as you progress as this project has been on my back burner for years and I just bought my lathe to get it back on the active side by allowing me to rework my wheels to change them to make the scrub radius better and to allow for the addition of hydraulic disc brakes that I got from micro bikes.

Because I've been down this road so far already I may have a lot of answers for you rather than making you do the whole trip over again. So if you email me a list of questions I can let you know what I've learned.

Man I need to get set up with a camera to start sharing some of this stuff.