Spherical Bearing or Regular ball bearing

[Mapes]

On the shock/pull arm relay triangle for our suspension. Is it better to use a pin/roller type bearing or spherical bearing to allow for suspension movement?

[Mapes]

On the shock/pull arm relay triangle for our suspension. Is it better to use a pin/roller type bearing or spherical bearing to allow for suspension movement?

[Psychosis]

simple answer i believe to be correct:

spherical bearings unless you've managed to get everything exactly in plane

[Cement Legs]

Or pivot your bracket on a 3 axis gyroscope...

[kozak]

why would you use a spherical to pivit your bell crank. it would just get pushed into some cockeyed position by the suspension.

[D-Train]

I think by 'pull arm relay' he meant the pullrod attatchment to the bellcrank. Had me confused at first too. http://fsae.com/groupee_common/emoticons/icon_rolleyes.gif

[kozak]

ok yeah that makes more sense. i think 1/4 - 20 rod end would be fine. the link should only see compression tension. unless i am mistaken.

[Z]

Mapes,

I am guessing that you want to know what sort of bearing to fit between the chassis and the "bellcrank" or "rocker" (what you call the "relay triangle")?

Since friction is the enemy of suspensions I suggest you use some type of "rolling element" bearings such as "needle-roller", "deep-groove-ball", or "angular-contact-ball" bearings. You might have to use two of these, on a common shaft, to stop the bellcrank/rocker tilting out of its plane (depends on details).

Use "Find" for previous threads on this subject.

Z

BTW, a "spherical plain bearing" is what you get in "rod-ends", and a "spherical roller bearing" is a self-aligning, low friction, high load type of rolling-element bearing (it has barrel shaped rollers running on the inside of a spherically ground outer race).

[Omer]

hey guys

what is the distance of your rod end inside the A-arms?

last year team bought 40 rod ends which i beleive has too short thread.

and can please someone explain to me the difference between sphricals and rod ends?
and what makes the difference between rod end in bending to the right way of placing it?

pictures would be very appreciated

[Denny Trimble]

http://www.aurorabearing.com/img0.jpg
The one with threads is a "Rod End". The one without is a "Spherical Bearing".

The weak link with rod ends is the threaded shank. It is easy to install, but if you put the threaded shank in bending by applying large transverse loads, you risk failure. Rod ends are generally suitable for the toe links (tie rods), pushrods / pullrods, and inner locations on a-arms / wishbones / control arms. The outer balljoints on the upright should not use rod ends because the brake torque and vertical loads are transverse to any rod end shank orientation you can come up with.

[Omer]

thnkes Denny
your explanation was clear to me.
ok so lets say i'm using rodends on the in board a-arms,we have a 10 mm (i think 3/8") thread,how long shuld the thread be inside the a-arms,do you think this diameter would be sufficent for the outboard?

[Denny Trimble]

1/4" diameter on the inboard locations and 3/8" on the outboard should be sufficient, but the aurora catalog has load ratings, and you really should do the calculations.

Off the top of my head, you should have at least 1.5 * the bolt diameter in thread engagement length.