Bushings?

Knurled. said:

Driven5 said:

freetors said:

I personally don't like the theory behind OEM rubber bushings having to twist because it ultimately makes your suspension less supple and limits free movement. 

I can't say that I am inclined to agree with this assessment. 

The only real drawback I see with bonded rubber bushings is the geometry change when they deflect under lateral load, which I expect the geometry can be designed to largely take into account. 

Take into account?  There is a whole engineering subfield dedicated to how to vary suspension geometry under various loads with engineered bushing compliance.  Kinematics.

Sorry for the (over) simplification. Having never worked in this bushing deflection geometry subfield myself, I wasn't about to make any assumptions about the what limitations or compromises might or might not generally be involved in compensating for it.

carguy123 said:

Driven5 said:

What make/model/size of sphericals/rod ends are you each using in the various locations?  Have you gone so far as to specifically request only the tighter fit units for the given make/model of sphericals/rod ends?  If even the best teflon and/or injection molded race (nylon based) rod ends have proven to be insufficient, have either of you looked into or considered the off-road originated heavy duty products, like Johnny Joints and the ilk?

 

Well I began with Aurora ends and then went up from there.  I've never looked into off-road stuff because I didn't think it was any different.  Is it?

That's a pretty ambiguous statement.  Aurora makes a wide variety of products, in a wide variety of sizes, across a wide variety of price/strength/durability/quality points.  All of these factors can have considerable effects on the life and functionality of the bearings.  Hence my interest in detailing the make, model, size, and application whenever somebody brings up their rod end suspension experiences...Be their experiences positive or negative.

Have you talked to the manufacturer(s) to see if what you've used was necessarily the best possible option for your application?  While complainants that have not found suitable rod ends for their application are quite common, detailed specifics are scarce.  The proponents I've encountered who have found success in their applications with rod ends also leads me to believe that the typical generalizations offered in most peoples ambiguous rod end anecdotes are not necessarily telling the whole story.

An example of the type of information that I think rod end suspension discussions need would be Jack McCornack, who has specifically spelld out putting over 100k miles on his Locost with a full compliment of Rod End Supply LX series (nylon/teflon injection molded race) slot loader rod ends with apparently no noticeable wear over that period.  Pretty much all the rod end manufacturers have an equivalent.  Of course, the same in a car weighing more than 2x as much, without sufficiently increasing the size, may not have the same positive outcome either.

The off-road joints are like a cross between a balljoint/tierod and a nylon filled rod end.  They've got a sort-of oversize rod end style body with a grease fitting and high misalignment rod end style ball, that then gets sandwiched between two nylon based supports and are all held together by removable (and some adjustable) end caps.  This allows them to not only be rebuilt, but some can also even have the 'tightness' adjusted as necessary to keep them 'just right' through more use and abuse.

Tyler H said:

You should torque all your bushings with the car resting on it's wheels.  If you don't, especially with rubber bushings, you'll introduce binding or preload until the bushing is dead....that won't take very long.

Poor man's solution is an open deck trailer or wheel cribs.  If you want to get fancy, a drive-on lift/alignment rack.

I check what the orientation of the control arm is with the car sitting on the ground, then use a floor jack to get it where it needs to be.  There are bolts that are tough to get to with the car sitting on the ground.

In reply to Toebra :

My method in the shop is to tighten down the bushings in the control arm before attaching the ball joint.  Makes it more of a pain, but it's a good kind of more of a pain.

I wouldn't be so quick to abandon the idea of poly et al in some cars. For instance with MGBs every single replacement rubber suspension bushing you can buy is pure Chinese . Some people have them fall apart in as little as a couple months.

No one who knows those cars has bought the stock style bushes for years - I agree they are all crap. The solution is not to buy solid bushes that instantly start to wear though. It is to buy the A arm bushes used in the MGB GT V8 - an inner metal bush bonded to the rubber outer that last for many years, as they twist instead of moving in the A arm or against the pin..  

I use Delrin on the race car but would never use anything but the V8 Metelastic on a street car.

Driven5 said:

carguy123 said:

Driven5 said:

What make/model/size of sphericals/rod ends are you each using in the various locations?  Have you gone so far as to specifically request only the tighter fit units for the given make/model of sphericals/rod ends?  If even the best teflon and/or injection molded race (nylon based) rod ends have proven to be insufficient, have either of you looked into or considered the off-road originated heavy duty products, like Johnny Joints and the ilk?

 

Well I began with Aurora ends and then went up from there.  I've never looked into off-road stuff because I didn't think it was any different.  Is it?

That's a pretty ambiguous statement.  Aurora makes a wide variety of products, in a wide variety of sizes, across a wide variety of price/strength/durability/quality points.  All of these factors can have considerable effects on the life and functionality of the bearings.  Hence my interest in detailing the make, model, size, and application whenever somebody brings up their rod end suspension experiences...Be their experiences positive or negative.

Have you talked to the manufacturer(s) to see if what you've used was necessarily the best possible option for your application?  While complainants that have not found suitable rod ends for their application are quite common, detailed specifics are scarce.  The proponents I've encountered who have found success in their applications with rod ends also leads me to believe that the typical generalizations offered in most peoples ambiguous rod end anecdotes are not necessarily telling the whole story.

An example of the type of information that I think rod end suspension discussions need would be Jack McCornack, who has specifically spelld out putting over 100k miles on his Locost with a full compliment of Rod End Supply LX series (nylon/teflon injection molded race) slot loader rod ends with apparently no noticeable wear over that period.  Pretty much all the rod end manufacturers have an equivalent.  Of course, the same in a car weighing more than 2x as much, without sufficiently increasing the size, may not have the same positive outcome either.

The off-road joints are like a cross between a balljoint/tierod and a nylon filled rod end.  They've got a sort-of oversize rod end style body with a grease fitting and high misalignment rod end style ball, that then gets sandwiched between two nylon based supports and are all held together by removable (and some adjustable) end caps.  This allows them to not only be rebuilt, but some can also even have the 'tightness' adjusted as necessary to keep them 'just right' through more use and abuse.

Actually it wasn't all that much of an ambiguous statement, I was trying not to go into a long winded discussion over all the things I'd done to try to find a rod end that would last.  I thought that by using the brand name people would realize I hadn't used Chinese junk.

I discussed it at length to see what was the best rod end for my situation.  Every time they went out I discussed it again, and again.  I followed "professional" advice and spent lots of money doing it.  Now, the off road rod ends sound interesting so I'll have to go research them and I might try some, mostly because it would save me from remaking the suspension attachment points.

And Jack drives his cars rather leisurely, he doesn't track or autocross them so they don't get as much abuse as most of us give ours.

In reply to carguy123 :

The point is, using Aurora (or any other name brand) has absolutely nothing to do with not using junk, regardless of where it comes from.  And the idea of "Chinese junk" is a bit of a misconception, as there are plenty of high quality rod ends that come from China, and plenty of junk rod ends that come from America. 

Even the best rod ends from the best manufacturer from the 'best' country of origin will become 'lose' considerably sooner starting out with tolerances resulting in a lower break away torque, than the same exact ones with tolerances resulting in a higher break away torque. This is why some brands, like FK allow you to specify the 'fit' of a given rod end being purchased.

What is typically used for racing may also not always be the 'best' for the application, as real racecars are apt to to replace them much more often than we would be looking for.  So I'm genuinely curious if any of your attempts included the nylon based injection molded slot loader style rod ends, or just variations of the teflon lined? Because they do appear to have a lot of potential for such applications, but don't seems to be as widely known... Well, at least outside of off-roaders.

By no means am I trying to invalidate your experience. Quite the contrary. Negative data points can be just as valuable as positive ones. I'm simply trying to be able to better quantify your experience, to be able to better learn from it.

And while Jack may not use his on the track, as far as I'm aware that is a virtually unheard of numbers of suspension cycles on the rod ends for a Locost or race cars in general, and it has done so through all manner of road conditions including rain and even snow.  So while maybe not the same type of abuse as track use, in regards to general wear and environmental conditions,  his has also probably seen more of those types of abuse than any other rod end equipped car I've known. Which combined with his sharing the specifics of what he's found such success using, quite simply makes it one of the best data points I've been able to find.