Spherical "Bushings"

[turboICE]

Originally posted by ddewhurst@Jan 10 2006, 09:48 AM
***allowing constrained motion***

Now, if we look up the word constrain in a dictionary that will differentiate suspension bushing & spherical bearing.

Will a suspension bushing constrain motion? Answer: YES

Will a spherical bearing constrain motion? Answer: NO

Will a air bearing constrain motion? Answer: NO
ps: We need 10 pages................

[snapback]70548[/snapback]​

I would not say those are accurate conclusions. Depending on what level of compliance you want to use in quantitatively measuring constraint.

Spherical bearings all have constrained motion when installed. They all have a specification of tilt angle defining this constraint. The typical specification is 15 degrees or less in most standard spherical bearings. The specification of the SBs I am familar with for the 240SX are speced at less than 10 degrees depending on the supplier and the link in question. (ID, OD and race width are primary determinants of the resulting tilt angle limit)

I know for a fact that the rubber bushing in the TC rod of the S13 240SX will permit more than 15 degrees of tilt angle.

Does a spherical bearing constrain motion? Absolutely and at its specified tilt angle it does so better than rubber or poly bushings which do not have an absolute contraint until you have metal on metal contact in the bushing which is going to be more than a spherical bearing will allow. It still remains that SBs perform only the functions of the replaced bushing and no others and again does it better and doing it better is not illegal.

Up to tilt angle the "resistance" to motion of a rubber or poly bushing may be higher but as far as "constraining" motion the spherical bearing is significantly more so.

PS and not just to reach page 10.

 

[turboICE]

And BTW I see as nowhere near desirable and not the intent of the definition to constrain rotation in the intended plane and axis of the links - the entire reason for changing materials is to improve rotation in the intended plane and axis. The very purpose of the suspension bushing is to constrain motion of the axis and constrain motion of the link outside the intended plane. Isn't that why everyone is seeking alternate materials to OEM? So as to reduce compliance of the bushing in order to restrict the movement of the axis and outside the intended plane of travel? Is anyone honestly seeking to restrict the rotational movement of their suspension joints?

I guarantee it was not the OEM intent to restrict the rotational movement it is a result of OEM material decisions but was not the intent of the engineers. The engineers selected their material to do the same thing as spherical bearings except they have noise, ride, harshness, vibration concerns resulting in the selection of higher compliance material than spherical bearings or even poly.

 

[Bill Miller]

Originally posted by turboICE@Jan 10 2006, 08:29 AM
And BTW I see as nowhere near desirable and not the intent of the definition to constrain rotation in the intended plane and axis of the links - the entire reason for changing materials is to improve rotation in the intended plane and axis.  The very purpose of the suspension bushing is to constrain motion of the axis and constrain mostion of the link outside the intended plane. Isn't that why everyone is seeking alternate materials to OEM? So as to reduce compliance of the bushing in order to restrict the movement of the axis and outside the intended plane of travel?  Is anyone honestly seeking to restrict the rotational movement of their suspension joints?

[snapback]70556[/snapback]​

Actually Ed, I'd say the primary reason is to minimize (or eliminate) deflection, thereby reducing (or eliminating) dynamic changes in suspension geometry.

 

[turboICE]

Originally posted by Bill Miller@Jan 10 2006, 10:36 AM
Actually Ed, I'd say the primary reason is to minimize (or eliminate) deflection, thereby reducing (or eliminating) dynamic changes in suspension geometry.

[snapback]70557[/snapback]​

The entire design of the suspension joints is that they are going to rotate around their axis. Dampeners are the intended method of controlling that rotation. Dynamic changes are much more the result of the suspension design (angles, link lengths, etc) than bushing compliance. No bushing change is going to eliminate dynamic changes in suspension geometry. Consistency in those dynamic changes is however dependent on bushing compliance regarding minimizing the changes in those angles, link lengths, etc (due to deflection of the bushing).

And the minimization of deflection results in rotation within the intended plane and around the intended axis, they are practically if not completely synonomous in this context.

 

[stevel]

Originally posted by GregAmy@Jan 8 2006, 03:06 AM

If your suspension bushings differ from stock in any way other than the substance of which they were originally made, they are illegal.

Greg

then that makes every poly bushing i've seen illegal, because hardly ever are they exact copies of the OEM bushings.

Which, in my mind, the intent of the rule was to allow poly bushings (or other alternate "material" such as delrin, etc). Under Greg's interpretation you'd have a hard time finding a poly bushing out in the market that meets that rule.

steve

 

[Greg Amy]

Originally posted by stevel@Jan 10 2006, 09:48 AM
...in my mind, the intent of the rule was to allow poly bushings (or other alternate "material" such as delrin, etc).  Under Greg's interpretation you'd have a hard time finding a poly bushing out in the market that meets that rule.

[snapback]70560[/snapback]​

I agree with you on both counts, Steve. However, just because a part that meets the rule is not available does not allow us to break that rule. - GA

 

[Bill Miller]

Originally posted by GregAmy@Jan 10 2006, 09:24 AM
I agree with you on both counts, Steve. However, just because a part that meets the rule is not available does not allow us to break that rule. - GA

[snapback]70569[/snapback]​

Greg,

Did I read that right? Are you saying that most (all?) of the aftermarket bushings out there are illegal?

 

[Greg Amy]

Originally posted by Bill Miller@Jan 10 2006, 10:40 AM
Are you saying that most (all?) of the aftermarket bushings out there are illegal?

[snapback]70570[/snapback]​

I cannot make such a blanket statement, given my limited knowledge of the available parts, however it's certainly a possibility. The rules allow nothing more than material change; if a specific set of bushings does not meet that standard, what other conclusion can one make?

If you're trying to draw me into an argument of degrees ("significant" dimensional change is/is not allowed) then you're out of luck: they either meet the rules or they don't... - GA

 

[Doc Bro]

Originally posted by stevel@Jan 10 2006, 02:48 PM
then that makes every poly bushing i've seen illegal, because hardly ever are they exact copies of the OEM bushings.

Which, in my mind, the intent of the rule was to allow poly bushings (or other alternate "material" such as delrin, etc).  Under Greg's interpretation you'd have a hard time finding a poly bushing out in the market that meets that rule. 

steve

[snapback]70560[/snapback]​

So.....nothing prevents you from making them. That is what I've been told countless times by members of this BB. (it feels good to say it too!!!) Why not talk to a company and show/tell them what you want. Delrin isn't that hard to obtain or work with.

That's what I HAVE to do if I want underdrive pulleys because they aren't offered for my car. Fabricate a set to the rules at what cost...who knows?...but it is do-able.

As I was so (un)kindly told by a member of this BB...if you don't have the stomach for it don't do it. You don't HAVE to run an aftermarket suspension bushing, just as you don't have to run a header it's really up to you to decide what level of preparation you want to achieve.

my .02 ....I'm sorry if this sounds abrasive it isn't meant to be abrasive only meant to illustrate the market vs. the need.

R

 

[Bill Miller]

Originally posted by GregAmy@Jan 10 2006, 09:53 AM
I cannot make such a blanket statement, given my limited knowledge of the available parts, however it's certainly a possibility. The rules allow nothing more than material change; if a specific set of bushings does not meet that standard, what other conclusion can one make?

If you're trying to draw me into an argument of degrees ("significant" dimensional change is/is not allowed) then you're out of luck: they either meet the rules or they don't... - GA

[snapback]70574[/snapback]​

Not trying to draw you into any kind of arguement Greg, just trying to understand what you meant by your comment.

 

[JohnRW]

Originally posted by GregAmy@Jan 10 2006, 11:53 AM
The rules allow nothing more than material change; if a specific set of bushings does not meet that standard, what other conclusion can one make?

If you're trying to draw me into an argument of degrees ("significant" dimensional change is/is not allowed) then you're out of luck: they either meet the rules or they don't... - GA

[snapback]70574[/snapback]​

Ten pages of debate that can be summed up quickly as 'Strict Constructionists' vs. 'Originalists' vs. 'Activists' (you can search around legal sites a bit and learn what that is all about).

If you're a 'Strict Constructionist', then you read the rule as 'only the material can be changed'. So...alternate designs, alternate colors, alternate metal sleeve thicknesses...all would be 'illegal'. There is no middle ground here. To take it to extremes, although the material may be different, if the compliance of that material is different then, technically...according to the 'strict constructionists', it's illegal. You don't get any diddle-room here. Read the words, don't interpret anything. If it doesn't say the 'flavor' can be different, then if I taste it and it's different, you're illegal.

'Originalists' ? Nobody here was listening when the rule was first written, and the memories of those who did the writing then are fuzzy. Or they're dead. See below.

'Activists' ? They're the ones arguing about just where the 'line in the sand' should be - pink poly bushings vs. cartridge bearings etc.. Some of them think that spherical bearings are OK, even if they have to mod or weld on the control arm to do it (that's the point where I draw my own 'line in the sand' and cry 'illegal').

It sounds like Greg may be leaning toward 'strict constructionist', but that may just be because he can't discuss the rule with the 'Originals nee Originalists' who actually wrote the rules, because they are happily playing shuffleboard or would need a 6+ft. periscope and/or reincarnation to join in this discussion.

The rule is poorly written. Some here are tying themselves into knots to justify their positions. Waste of time, as the rule is poorly written and the energy expended in trying to interpret would be better spent trying to fix it.

Just have the damn rule rewritten so it makes sense in today's environment.

I've got 3 race cars torn apart right now...I'll just be stopping by once daily to watch the fun...

Anybody have a 1.6 Miata motor CHEEP ? Leakdown on the #2 hole was blowing oil out the dipstick tube (really...). Back to work....

(edited...so it might actually make sense....)

 

[Andy Bettencourt]

Originally posted by JohnRW@Jan 10 2006, 12:13 PM
Ten pages of debate that can be summed up quickly as 'Strict Constructionists' vs. 'Originalists' vs. 'Activists' (you can search around legal sites a bit and learn what that is all about).

If you're a 'Strict Constructionist', then you read the rule as 'only the material can be changed'.  So...alternate designs, alternate colors, alternate metal sleeve thicknesses...all would be 'illegal'.  There is no middle ground here.  To take it to extremes, although the material may be different, if the compliance of that material is different then, technically...according to the 'strict constructionists', it's illegal.  You don't get any diddle-room here.  Read the words, don't interpret anything.  If it doesn't say the 'flavor' can be different, then if I taste it and it's different, you're illegal.

'Originalists' ?  Nobody here was listening when the rule was first written, and the memories of those who did the writing then are fuzzy.  Or they're dead.  See below.

'Activists' ?  They're the ones arguing about just where the 'line in the sand' should be - pink poly bushings vs. cartridge bearings etc..  Some of them think that spherical bearings are OK, even if they have to mod or weld on the control arm to do it (that's the point where I draw my own 'line in the sand' and cry 'illegal').

It sounds like Greg may be leaning toward 'strict constructionist', but that may just be because he can't discuss the rule with the 'Originals nee Originalists' who actually wrote the rules, because they are happily playing shuffleboard or would need a 6+ft. periscope and/or reincarnation to join in this discussion.

The rule is poorly written.  Some here are tying themselves into knots to justify their positions.  Waste of time, as the rule is poorly written and the energy expended in trying to interpret would be better spent trying to fix it.

Just have the damn rule rewritten so it makes sense in today's environment.

I've got 3 race cars torn apart right now...I'll just be stopping by once daily to watch the fun...

Anybody have a 1.6 Miata motor CHEEP ?  Leakdown on the #2 hole was blowing oil out the dipstick tube (really...).  Back to work....

(edited...so it might actually make sense....)

[snapback]70591[/snapback]​

What a great post. Maybe the issue fpr me is that I fall inbetween the 'Strict Constructionalist' and the 'Originalist' - and that is why I can't see some of the interpretations as legal.

Here is where I fall:

- A bearing can act as a bushing
- The rules state that only a material change is allowed
- A bearing is not 'simply' a material change, it CAN BE a change in overall design
- The rules do not say that bushings are 'free', like I submit they would if that was the original intent (and I do think that Greg has a point that in other parts of the GCR, they are called out as free for other classes - leading me to believe they are not for IT)

Some people are looking at this from the persepctive of the suspensions they know. The VW example is one of them. The SB replacements searve no other purpose than to provide reduced friction (if I am getting that right). If you allow them, SB's can be used to provide 'out-of-stock' range of motion (look simply at a sway-bar end-link).

Bottom line? I wish I was at the Sebring National in SM instead of chipping ice off the front entrace of our shop...

Good debate.

AB

 

[stevel]

Originally posted by GregAmy@Jan 10 2006, 03:24 PM
However, just because a part that meets the rule is not available does not allow us to break that rule. - GA

[snapback]70569[/snapback]​

I agree. But for a rule that has an intent of allowing a poly bushing and poly bushings that are widely available on the market for tons of different cars (and while they do differ from exact stock replacements they don't have any other advantage) they are, as you read illegal.

Just curious Greg. Will you be replacing any suspension bushings on your car? What are you going to go with? Nismo I would assume, as they do fit the rule.

steve

 

[mustanghammer]

Originally posted by ddewhurst@Jan 7 2006, 04:15 PM
IMPROVED TOURING car rule 17.1.4.D.5.d.6.

Bushing MATERIAL, including that used to mount a suspension subframe to the chassis, is unrestricted.

PRODUCTION car UNRESTRICTED SUSPENSION rule 17.1.1.D.5.d.4.

Suspension bushings are UNRESTRICTED. Adjustable SPHERICAL BEARINGS or rod ends are permitted on all suspension components.

PRODUCTION car RESTRICTED SUSPENSION (limited preparation) rule  17.1.1.D.6.d.5.

Bushing MATERIAL, including that used to mount a suspension subframe to the chassis, is unrestricted.

[snapback]70351[/snapback]​

It is interesting that the LP Production rules use the same Bushing rule that is found in IT. That said, this LP rule trumps any comparison between the LP Production and IT:

17.1.1.D.6.c.1.

Contol arms may be reinforced or alternate control arms may be fitted.

However, since many have used other definitions in the GCR to dredge the meaning of the IT rule 17.1.4.D.5.d.6. it would interesting to know how the same rule is Viewed in LP Production. Has the use of S/B's to substittue bushings been tested in Limited Prep Production?

 

[Geo]

Originally posted by ddewhurst@Jan 10 2006, 06:48 AM

Will a spherical bearing constrain motion? Answer: NO

[snapback]70548[/snapback]​

Nicht so.

A spherical bearing allows rotation around the center of the x, y, and z axis. It will NOT allow movement along the x/y plane.

 

[Geo]

Originally posted by stevel@Jan 10 2006, 11:11 AM


Just curious Greg.  Will you be replacing any suspension bushings on your car?  What are you going to go with?  Nismo I would assume, as they do fit the rule.

[snapback]70597[/snapback]​

Nismo do NOT fit the rule under Greg's very strict interpretation. The trailing front lower control arm bushings are solid rubber (last I saw) for the Nismo item, yet the OEM is hollowed out (for lack of a better term off the top of my head) some to further isolate NVH.

 

[Andy Bettencourt]

Originally posted by Geo@Jan 10 2006, 02:32 PM
Nicht so.

A spherical bearing allows rotation around the center of the x, y, and z axis.  It will NOT allow movement along the x/y plane.

[snapback]70606[/snapback]​

Why not? What of you had an oval shaped hole and a slot in said hole? You could pivot INSIDE the SB and the SB could move along the slot. Just like in a upper strut mount...

This is part of my problem. If you open it up to SB's, you leave yourself open to initended consiquenses because we don't know the potential design allowances for every car in the GCR. Hardly a material-only change IMHO.

AB

 

[Greg Amy]

Very well done, John.

To all,

Let's get something straight here: I'm a very reasonable person (as Dick alluded to). I am open-minded and I fully hear and understand (although don't necessarily agree with) everyone's viewpoints. However, this group (and the racer community as a whole) is infamous for picking away at rules using incrementalism to arrive at idiotic conclusions. Give an inch, then another inch, then another inch, and suddenly you're twenty miles from where you started. There comes a point where one must argue from the extremes in order to avoid this destructive incrementalism.

The "spherical bearings" issue is a perfect case in point. The rule is very clear, and I've said it repeatedly: the only change allowed is 'the substance of which the parts are made'. John, Steve, and Bill (among others) have accurately illustrated the idiotic extremes of that fact. The alternative, though, to such an extreme position is to admit there's some "wiggle room" or "gray area" in the literal reading of this. However, if one were to admit to this gray area it will immediately be picked away and picked away (definition of bushings/bearings, axis of movement, degree of deflection, friction/non-friction, rotational inertia, location of Venus relative to Mars when the period was typed in the original rule) until someone, somewhere has somehow decided that alternate bushing material means we are allowed to install cassette bearings and spherical bushings.

Sorry, no buena. That's just a patently ridiculous conclusion. I can't even see you waving when you're twenty miles away.

So, in order to remove that opportunity to increment yourselves to that ridiculous position, I am forced to dig my heels in the stand, be rigid, and stick to what the rules state and what I believe is right. I go through these mental gymnastics each and every time there's a disagreement on what a rule means (as if the rules REALLY need to be interpreted, trying to fit the square "I wanna do this" peg into the "you are allowed to do that" hole, versus using common sense). The result of these gymnastics is a question of "which extreme position is best for Improved Touring?"

And, given a choice between the rigid "material only" position and one that accepts and allows spherical bushings (and its implied conclusions) into Improved Touring, the choice is very clear for me: these things do not belong in IT, regardless of how it may or may not affect me or others.

John is wrong on one point: I was there back when the class was first subscribed. My mind isn't even that fuzzy, as I was a 19-ish-yr-old college student scratching to be able to keep racing on the odd weekend I didn't have to study for a Mechanical Engineering exam. I have a pretty good idea of what the original intent and mindset of the organization was when this class started (see the "IT/Prod" discussion). I like IT enough that I eventually came back after my foray into so-called "National" racing because it's fun. And, I will fight to maintain that environment as long as possible. So, called me a pseudo-Originalist, if you must label me.

To all you pro-SB folks: this is a perfect case of where the old tired saying of "if you don't like it here, get out" applies. SBs do not belong in Improved Touring; the siren song of Production racing beckons you...

Greg...

P.S. Earl and I are finalizing our 13.9 submission; Earl pro-SB, I opposing. We are significantly short of the $250 required for the request. If you want to put your 2 cents (or more) into the idea, best speak up soon.

 

[Geo]

Originally posted by Andy Bettencourt@Jan 10 2006, 12:42 PM
Why not?  What of you had an oval shaped hole and a slot in said hole?  You could pivot INSIDE the SB and the SB could move along the slot.  Just like in a upper strut mount...

This is part of my problem.  If you open it up to SB's, you leave yourself open to initended consiquenses because we don't know the potential design allowances for every car in the GCR.  Hardly a material-only change IMHO.

AB

[snapback]70608[/snapback]​

Andy, the SB itself does NOT allow x/y movement. What you are discussing when discussing x/y movement is the HOUSING for the SB. That's a whole other debate.

I disagree with your second point about unintended consequences because the working interpretation out there is they ARE legal. They are certainly in wide use so what additional consequences can there be that don't exist today?

 

[Bill Miller]

Give an inch, then another inch, then another inch, and suddenly you're twenty miles from where you started.

For a very current example of this, read some of the discussions on the Prod board, about limited-prep cars. They're now requesting dry-sumps, full-prep suspensions, modified rods, fully ported heads, etc. etc. Warning, it's not for the faint of heart!

Greg,

Before you guys spend money on a 13.9, how about a simple letter to the CRB? Could save some folks some money, and may get us to the point we need to be (a yes/no answer).