Re: Lower control arm bushings.... Urethane or rubber?
[Re: Plumcrazyracing]
#748663
07/15/10 07:03 AM
07/15/10 07:03 AM
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Joined: Jun 2010
Posts: 798
Houston TX
GregCon
super stock
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super stock
Joined: Jun 2010
Posts: 798
Houston TX
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For weight transfer I'd think loose old rubber would be the best. Or. urethane bushing that are left loose enough that they slip along the bolts rather than flex.
I usually have an argument with the suspension guys every time I order a front end kit. They are amazed anyone would want rubber over urethane.
It goes like this:
Them: Rubber is cheap, that's why OEM's use it!
Me: Actually,vulcanizing rubber and bonding it to steel is much more expensive - that's why you aftermarket guys use urethane.
Them: Rubber is cheap, that's why the OEM's use it!
Me: So an $85,000 Lexus, a $110,000 Mercedes, and a $135,000 Porsche all use rubber to save a few cents when they are simultaneously adopting electronic active suspensions, sound deadened laminated steel,and a million other tricks in an effort to get the most of the car? I think they'd be smart enough to spend $5 on urethane and drop the $3,200 active suspension if that were the case.
And what does a Viper use?
Them: Urethane out performs rubber!
Me: Well, it does on a track car, maybe, but it hurts ride quality and durability.
Them: Urethane outlasts rubber!
Me: It does as a compound sitting on a shelf but not when installed in a suspension. We've all seen rubber bushing last decades - where is your decades of proof on urethane? We've all seen urethane squeeze and cut itself right out of a bushing sleeve.
Them: Urethane improves the suspension!
Me: Actually, it just changes the suspension arbitrarily. Rubber is bonded to the
steel sleeves for 'flex'. Urethane is not - it just acts as a big hinge. During a medium-to-big move in suspension position it you have created two friction surfaces; can't be so great for that to happen.
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Re: Lower control arm bushings.... Urethane or rubber?
[Re: GregCon]
#748664
07/15/10 07:36 AM
07/15/10 07:36 AM
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Joined: Aug 2003
Posts: 11,179
Atco NJ
DJVCuda
I Live Here
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I Live Here
Joined: Aug 2003
Posts: 11,179
Atco NJ
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the rubber in the bushings are not bonded to the shells...  also the rubber does not rotate in the lower pivot - it flex's - thats why you have to have weight on it and tighten it down or you rip it. Since the rubber only flexes so much it will bind and be more friction during excessive suspension travel ( at the launch ) A poly setup will rotate, not bind when you have excessive weight transfer. Without the t-bar hooked up there is a night and day difference from rubber to poly in terms of suspension travel. Want even more friction free travel? Get a set of jointed strut rods, that is the next place you can get alot of travel, they also keep your alignment in more consistent locations during excessive suspension travel.
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Re: Lower control arm bushings.... Urethane or rubber?
[Re: DJVCuda]
#748666
07/15/10 09:09 AM
07/15/10 09:09 AM
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Joined: Jun 2003
Posts: 52,972
Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
the rubber in the bushings are not bonded to the shells...
also the rubber does not rotate in the lower pivot - it flex's - thats why you have to have weight on it and tighten it down or you rip it. Since the rubber only flexes so much it will bind and be more friction during excessive suspension travel ( at the launch )
A poly setup will rotate, not bind when you have excessive weight transfer.
Without the t-bar hooked up there is a night and day difference from rubber to poly in terms of suspension travel.
Want even more friction free travel? Get a set of jointed strut rods, that is the next place you can get alot of travel, they also keep your alignment in more consistent locations during excessive suspension travel.
This is where a few of us have had different poly
bushings... I see that a few are using a poly insert
where the ones I tried had the poly bonded to the
shells both inner and outer SO if its a bonded style
it was a VERY STIFF bushing... much stiffer than a
oem style rubber.... BUT I can see them IF its a
insert where it can pivot.... so for drag racing the
insert style could be beneficial.... but I havent
tested any myself.... YET
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Re: Lower control arm bushings.... Urethane or rubber?
[Re: GregCon]
#748668
07/15/10 09:31 PM
07/15/10 09:31 PM
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Joined: Mar 2005
Posts: 2,489
Pacifica, CA
Devilbrad
top fuel
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top fuel
Joined: Mar 2005
Posts: 2,489
Pacifica, CA
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Quote:
The rubber in many cases is indeed bonded to the shell. On my Lexus SC and GS's they are bonded, for example.
In cases where it isn't, such as Mopar control arms, the fit is so tight it acts as would a bonded fit. I've never seen a urethane bushing in nearly as tight a fit. The flexing is a key part of the suspension action.
In addition to all the benefits of rubber I mentioned, there is also the fact that rubber can be produced in different durometers to allow tuning. Urethane can't/isn't.
Vipers, Corvettes, 911's, Camaros, Challengers, etc. all use rubber. That's gotta tell you something.
Until they get serious at the track and convert to poly, delrin, del-alum or steel monoballs. Rubber is great for keeping warranty costs down on new cars when the uppity millionaire types complain about squeeks and rattles.
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Re: Lower control arm bushings.... Urethane or rubber?
[Re: GregCon]
#748669
07/15/10 09:41 PM
07/15/10 09:41 PM
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Joined: Aug 2003
Posts: 11,179
Atco NJ
DJVCuda
I Live Here
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I Live Here
Joined: Aug 2003
Posts: 11,179
Atco NJ
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Quote:
The flexing is a key part of the suspension action.
you had me till there - FLEX is NOT a key part of any suspension system no way , shape , or form....
suspension TRAVEL yes... flex? no way!
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Re: Lower control arm bushings.... Urethane or rubber?
[Re: GregCon]
#748672
07/16/10 12:28 AM
07/16/10 12:28 AM
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Joined: Jan 2003
Posts: 19,382
Las Vegas
Al_Alguire
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 19,382
Las Vegas
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For a drag race application rubber is best. Not debating just stating what i have seen on many occasions with customer cars in the past.
"I am not ashamed to confess I am ignorant of what I do not know."
"It's never wrong to do the right thing"
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Re: Lower control arm bushings.... Urethane or rubber?
[Re: Big Squeeze]
#748675
07/17/10 02:14 AM
07/17/10 02:14 AM
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Joined: Dec 2008
Posts: 184
Central Coast
Plumcrazyracing
OP
member
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OP
member
Joined: Dec 2008
Posts: 184
Central Coast
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Wow, lots of feedback and a topic for discussion. I just pulled out the lower RUBBER control arm bushings and they were tore. Both sides. I would think that they were not working properly and affecting my weight transfer. Maybe even causing more of a bind  Put the URETHANE in and as mentioned, with the pivot pin tightened up, i could move the control arm pretty freely. We'll see how it works at the track. Steve
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this was on 1973 and later A body parts for the bigger brakes and bigger ball joints and so on 
