What all this hopping around?
Bullitt Member
Joined: April 3, 2010
Posts: 309
Likes: 0
From: Geismar, LA
I'll tell you from experience... If you get solid lowers with poly bushings you should get the upper with poly bushings- especially if you have a manual car. That clunk you hear if you don't shift just right is very exaggerated since the poly bushings don't absorb as much force and it gets transferred to the rubber bushing in the upper. Save yourself the hassle and do lowers and uppers at the same time.
Joined: November 25, 2009
Posts: 1,519
Likes: 0
From: Metro Detroit
First and foremost the axle does not Hop. It is actually "walking".
Please see the video below of me using a pen at my desk to illustrate in a VERY exaggerated manner what the rear axle is actually doing.
http://www.youtube.com/watch?v=UJDMaNzb1Ls
Proper LCA's will by themselves eliminate tramp 95%+ of the time. You basically have to a do a burnout over a rail road track to upset them.
UCA with LCA will equal a complete elimination of the tramp under all conditions. HOWEVER the NVH concern of the UCA's is staggering.
Gear Noise and other drive train and road noise will be transmitted directly into the body of the car and where the UCA attaches is the highest noise path in the car and terminates basically right behind your right ear.
UCA's don’t really do anything for handling either (our Grand-Am and NASA race cars all have stock UCA's).
However taking the vast compliance out of the LCA's is critical both for planting the axle for straight line and serious cornering.
NONE of our race cars have ever required the relocation brackets (please note NONE of our cars drag race, so I can not speak to that application) and our cars are as "planted" as the come.
We recommend the FR-500-C LCA's ($189.95) and these are made in the USA.
In the other thread there is a post about LCA's with a three piece bushing, (two cups and a poly ball inside) this is the LCA's design we run on my car. I do NOT recommend this bushing style for a street car. The NVH concerns out weigh ANY benefit provided by this design. My car has them as my car is a track rat. I am aiming for a national championship in my class and need that extra 10% they provide and am willing to sacrifice the major NVH increase.
Please see the video below of me using a pen at my desk to illustrate in a VERY exaggerated manner what the rear axle is actually doing.
http://www.youtube.com/watch?v=UJDMaNzb1Ls
Proper LCA's will by themselves eliminate tramp 95%+ of the time. You basically have to a do a burnout over a rail road track to upset them.
UCA with LCA will equal a complete elimination of the tramp under all conditions. HOWEVER the NVH concern of the UCA's is staggering.
Gear Noise and other drive train and road noise will be transmitted directly into the body of the car and where the UCA attaches is the highest noise path in the car and terminates basically right behind your right ear.
UCA's don’t really do anything for handling either (our Grand-Am and NASA race cars all have stock UCA's).
However taking the vast compliance out of the LCA's is critical both for planting the axle for straight line and serious cornering.
NONE of our race cars have ever required the relocation brackets (please note NONE of our cars drag race, so I can not speak to that application) and our cars are as "planted" as the come.
We recommend the FR-500-C LCA's ($189.95) and these are made in the USA.
In the other thread there is a post about LCA's with a three piece bushing, (two cups and a poly ball inside) this is the LCA's design we run on my car. I do NOT recommend this bushing style for a street car. The NVH concerns out weigh ANY benefit provided by this design. My car has them as my car is a track rat. I am aiming for a national championship in my class and need that extra 10% they provide and am willing to sacrifice the major NVH increase.
Bullitt Member
Joined: March 31, 2010
Posts: 291
Likes: 0
First and foremost the axle does not Hop. It is actually "walking".
Please see the video below of me using a pen at my desk to illustrate in a VERY exaggerated manner what the rear axle is actually doing.
http://www.youtube.com/watch?v=UJDMaNzb1Ls
Proper LCA's will by themselves eliminate tramp 95%+ of the time. You basically have to a do a burnout over a rail road track to upset them.
UCA with LCA will equal a complete elimination of the tramp under all conditions. HOWEVER the NVH concern of the UCA's is staggering.
Gear Noise and other drive train and road noise will be transmitted directly into the body of the car and where the UCA attaches is the highest noise path in the car and terminates basically right behind your right ear.
UCA's don’t really do anything for handling either (our Grand-Am and NASA race cars all have stock UCA's).
However taking the vast compliance out of the LCA's is critical both for planting the axle for straight line and serious cornering.
NONE of our race cars have ever required the relocation brackets (please note NONE of our cars drag race, so I can not speak to that application) and our cars are as "planted" as the come.
We recommend the FR-500-C LCA's ($189.95) and these are made in the USA.
In the other thread there is a post about LCA's with a three piece bushing, (two cups and a poly ball inside) this is the LCA's design we run on my car. I do NOT recommend this bushing style for a street car. The NVH concerns out weigh ANY benefit provided by this design. My car has them as my car is a track rat. I am aiming for a national championship in my class and need that extra 10% they provide and am willing to sacrifice the major NVH increase.
Please see the video below of me using a pen at my desk to illustrate in a VERY exaggerated manner what the rear axle is actually doing.
http://www.youtube.com/watch?v=UJDMaNzb1Ls
Proper LCA's will by themselves eliminate tramp 95%+ of the time. You basically have to a do a burnout over a rail road track to upset them.
UCA with LCA will equal a complete elimination of the tramp under all conditions. HOWEVER the NVH concern of the UCA's is staggering.
Gear Noise and other drive train and road noise will be transmitted directly into the body of the car and where the UCA attaches is the highest noise path in the car and terminates basically right behind your right ear.
UCA's don’t really do anything for handling either (our Grand-Am and NASA race cars all have stock UCA's).
However taking the vast compliance out of the LCA's is critical both for planting the axle for straight line and serious cornering.
NONE of our race cars have ever required the relocation brackets (please note NONE of our cars drag race, so I can not speak to that application) and our cars are as "planted" as the come.
We recommend the FR-500-C LCA's ($189.95) and these are made in the USA.
In the other thread there is a post about LCA's with a three piece bushing, (two cups and a poly ball inside) this is the LCA's design we run on my car. I do NOT recommend this bushing style for a street car. The NVH concerns out weigh ANY benefit provided by this design. My car has them as my car is a track rat. I am aiming for a national championship in my class and need that extra 10% they provide and am willing to sacrifice the major NVH increase.
What are your thoughts on the people saying that just lowering it solves the hop? That seems unlikely to me.
Bullitt Member
Joined: March 17, 2010
Posts: 383
Likes: 0
From: Farmington Hills, MI
As far as installing these yourself in the driveway, it can be done in under an hour on jackstands. It is a real easy swap.
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