Rear upper adjustable control arms

[350Regal]

Hey guys I'm looking for some input I've been hunting this vibration issue for a while I'm thinking my pinion angle is out of alignment it looks like it from my understanding the drive shaft is at 6° and the rear axle I think is at 4-5 degrees. I have different rims and tires and a transmission so far as well in the hunt to find this issue. I'm looking to get BMR adjustable uppers they look like a decent set without breaking the bank anybody else have thoughts. Thanks Josh

 

[565bbchevy]

I have the UMI rears in my Regal they are adjustable and have a "roto joint" that articulates better than a poly bushing.

UMI Performance 3037-B UMI Performance Rear Adjustable Upper Control Arms | Summit Racing

Free Shipping - UMI Performance Rear Adjustable Upper Control Arms with qualifying orders of $99. Shop Control Arms at Summit Racing.

www.summitracing.com

 

[scoti]

Hey guys I'm looking for some input I've been hunting this vibration issue for a while I'm thinking my pinion angle is out of alignment it looks like it from my understanding the drive shaft is at 6° and the rear axle I think is at 4-5 degrees. I have different rims and tires and a transmission so far as well in the hunt to find this issue. I'm looking to get BMR adjustable uppers they look like a decent set without breaking the bank anybody else have thoughts. Thanks Josh

Transmission output shaft & pinion are the two dimensions you need to compare. The driveshaft angle is just along for the ride. This is something you can't guess. You need to measure the drivetrain angle as well as the pinion output stub angle to do the math. Less than 3° is not horrible but the target should be <1° difference. People will measure the drivetrain angle off of the crank pulley, the starter pad, or off of the trans output.The measurement off the differential can be pulled off the pinion stub 'flats'.

 

[350Regal]

If this post in the sequence I picked them the first picture is off I believe the 1st picture is off the axle itself and the next one is off the flat(I think.. also the place for the u-joint) and the last one is off the drive shaft

 

[350Regal]

The first one is a picture of front pulley with a piece of flat stock to keep it straight and the other picture as you see it is just a general picture of the rear. looking for input for leading me in the right direction thanks Josh

 

[64nailhead]

Don't measure the driveshaft. You need to have the two u-joints on the same angle +/- 1.5 degrees. The driveshaft is not important until it starts getting at radical angles like what is seen is a lifted truck.

 

[350Regal]

Well I ordered the bmrs I don't drive the car more than a thousand miles a Summer and I know this fall I'm going to pull the transmission out and dump some money into it because it's slipping going in the second and I'm just going to take it easy through summer...I can hear the wife already

 

[GroceryGetter83]

I used TRZ rear adjustable control arms:

Rear Upper Control Arms (G-Body) - TRZ Motorsports

Adjust Pinion Angle Without Removing Control Arms 1/4″ Thick Formed Steel Clevis Double Gussetted for Strength Premium Chrome-Moly Rod Ends – Oversized with Teflon Liner Right Hand / Left Hand Double Adjustable Threads 4130 Chrome-Moly Double Adjusters 6061 Aluminum Bushings with 1/2″ ID’s

www.trzmotorsports.com

You want the rear end pointing down (negative angle), the amount depends on the type of activities you are doing

 

[SS_Malibu]

Sometimes you have to break it to justify a new one. Especially when explaining it to the wife.
"Look Honey, this one is broke. We will definitely need to replace this with something stronger."

 

[scoti]

I used TRZ rear adjustable control arms:

Rear Upper Control Arms (G-Body) - TRZ Motorsports

Adjust Pinion Angle Without Removing Control Arms 1/4″ Thick Formed Steel Clevis Double Gussetted for Strength Premium Chrome-Moly Rod Ends – Oversized with Teflon Liner Right Hand / Left Hand Double Adjustable Threads 4130 Chrome-Moly Double Adjusters 6061 Aluminum Bushings with 1/2″ ID’s

www.trzmotorsports.com

You want the rear end pointing down (negative angle), the amount depends on the type of activities you are doing

This is only true under certain situations. Leafs utilized the slight downward pinion angles because spring wrap allowed them to pivot-up under the duress of a built drivetrain vs a weak OE motor/set-up. OE link set-ups can flex as well from the chunky rubber bushings & stamped steel construction. It also depends on the height of each angle relative to the ground & each other.

Link suspensions that are upgraded don't get that flex so they should be dialed in according to the angles.

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