Spherical Bearings and Rod Ends

[ckiesz]

What sort of load ratings should I be looking for when choosing bearings for my suspension?
I am building an unequal dual a-arm suspension for the front and rear and plan to use spherical bearings at the outer ends and rod ends on the inners. Coilover dampeners will be attached to the lowers.

The car should be less than 2600lbs with decent aero, 315/35/18 and 345/35/18 race compound tires and roughly 500 whp. Similar to an ALMS GT1/GT2 car.

I am especially interested in the axial or "push-out" load for the lower outer pivot. Most bearings are only rated at 6000-7000 pound area, which seems low to me. Radial load doesn't seem to be a problem(35,000lbs+)
Any info would be much appriciated,
Christian

[Nero]

Why use rod ends and not spherical bearings all round?

[bdwoody]

Originally Posted by ckiesz

What sort of load ratings should I be looking for when choosing bearings for my suspension?
I am building an unequal dual a-arm suspension for the front and rear and plan to use spherical bearings at the outer ends and rod ends on the inners. Coilover dampeners will be attached to the lowers.

The car should be less than 2600lbs with decent aero, 315/35/18 and 345/35/18 race compound tires and roughly 500 whp. Similar to an ALMS GT1/GT2 car.

I am especially interested in the axial or "push-out" load for the lower outer pivot. Most bearings are only rated at 6000-7000 pound area, which seems low to me. Radial load doesn't seem to be a problem(35,000lbs+)
Any info would be much appriciated,
Christian

this is an interesting question we have a vw golf 20v turbo that bent its lower tca which was made of chrome moly tubing upon strengthing it the spherical bearing rose joint snapped off at the base of the thread.i am looking at different suppliers for a stronger unit in possibly ph17/4 but i will know on tues when we all get back to work..i will let you know the outcome.

[ckiesz]

The rod ends will, for the most part, be used only in a push-pull fashion. But, yes, sphericals could be used at all points.
I was mainly questioning the strength of the spherical bearings in the outer pivot position, replacing a ball joint. The bearing will be supporting the weight of the car in it's "weak" direction.
Is this normal, and what ratings should I be looking for in this direction? Or is there a better joint/method for doing this?
Thanks,
Christian

[bdwoody]

there appears to be quite a few "rose" joints there is a cheap type from SKF which is ok for general use but not for high loading ie motorsport applications
aurora do a very comprehensive range and they are good to talk to.the ph 17/4 range is an anti corrosive joint which is pretty strong that is used in the marine industry .the propper motor sport jobbie comes at nearly twice the price of the standard unit no supprises there then!!

[Nero]

I have seen a number of rose joints used in such a manner and have also seen the failures of the joints and the resultant damage. I would respectfully suggest that you be conservative. If the car will run the kerbs on the track then accout of a 4G bump, so multiply the cars corner weight by 4 and add in what safety margin you feel is reasonable and this might assist with the loading required.