pinion angle help
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From: milton florida
pinion angle help tried to set my pinion angle via BMR's web site. when my pinion angle reads -5 my D/S reads +5 which equals 0 so if i keep cranking the D/S angle seems to stay the same as the pinion angle..IE if the rear is -7 the D/S reads +7 and pretty much the best i could do was a -1.5 maybe..but she is vibrating like shitty under 40mph..help me out im confused..thanks, Tom
Yeah, it can be a little confusing.
+5 + -5 = 10 degrees total (BAD). If you simply count the degree marks between the 2 measurements, you'll find your total.
Think of it this way .. 0 would represent a straight line between the pinion and the driveshaft. You want the sum between the 2 angles to read what you're looking for (A4 somewhere between 1.5 and 2.5) Since your transmission is obviously higher than your rear, it should read +. So your pinion going to read -. EX. +1 + -1 = 2 total degrees of pinion angle.
+5 + -5 = 10 degrees total (BAD). If you simply count the degree marks between the 2 measurements, you'll find your total.
Think of it this way .. 0 would represent a straight line between the pinion and the driveshaft. You want the sum between the 2 angles to read what you're looking for (A4 somewhere between 1.5 and 2.5) Since your transmission is obviously higher than your rear, it should read +. So your pinion going to read -. EX. +1 + -1 = 2 total degrees of pinion angle.
Directly from BMR Adjustable TA instruction:
9. Set pinion angle using the following method:
• Make sure the rear end is loaded by either setting the car on the ground or letting the car rest on jack stands positioned under the rear axle.
• Place angle finder on the driveshaft and record the angle. Now place the angle finder on the rear end torque arm mounting plate and record the angle.
• Subtracting the two results in your pinion angle.(Ex: -6 rear end angle subtracted from +4 driveshaft angle = -2 degrees)
• Turn adjuster to achieve the desired angle.
• As a starting point, most F-Bodies seem to like the following initial settings: Automatics: 1-2 degrees negative Manuals: 2-3 degrees negative
10. Once pinion angle has been set, tighten all jam nuts and rear bracket cross bolts.
9. Set pinion angle using the following method:
• Make sure the rear end is loaded by either setting the car on the ground or letting the car rest on jack stands positioned under the rear axle.
• Place angle finder on the driveshaft and record the angle. Now place the angle finder on the rear end torque arm mounting plate and record the angle.
• Subtracting the two results in your pinion angle.(Ex: -6 rear end angle subtracted from +4 driveshaft angle = -2 degrees)
• Turn adjuster to achieve the desired angle.
• As a starting point, most F-Bodies seem to like the following initial settings: Automatics: 1-2 degrees negative Manuals: 2-3 degrees negative
10. Once pinion angle has been set, tighten all jam nuts and rear bracket cross bolts.
Yeah, it can be a little confusing.
+5 + -5 = 10 degrees total (BAD). If you simply count the degree marks between the 2 measurements, you'll find your total.
Think of it this way .. 0 would represent a straight line between the pinion and the driveshaft. You want the sum between the 2 angles to read what you're looking for (A4 somewhere between 1.5 and 2.5) Since your transmission is obviously higher than your rear, it should read +. So your pinion going to read -. EX. +1 + -1 = 2 total degrees of pinion angle.
+5 + -5 = 10 degrees total (BAD). If you simply count the degree marks between the 2 measurements, you'll find your total.
Think of it this way .. 0 would represent a straight line between the pinion and the driveshaft. You want the sum between the 2 angles to read what you're looking for (A4 somewhere between 1.5 and 2.5) Since your transmission is obviously higher than your rear, it should read +. So your pinion going to read -. EX. +1 + -1 = 2 total degrees of pinion angle.
Here is where I'm confused.. you said " +5 + -5 = 10 degrees total (BAD)." Which indicates you add the two numbers together, but BMR says to subtract those numbers.
• Subtracting the two results in your pinion angle.(Ex: -6 rear end angle subtracted from +4 driveshaft angle = -2 degrees)
Shouldn't it be +5 - -5 = 0 according to your example?
• Subtracting the two results in your pinion angle.(Ex: -6 rear end angle subtracted from +4 driveshaft angle = -2 degrees)
Shouldn't it be +5 - -5 = 0 according to your example?
Here is where I'm confused.. you said " +5 + -5 = 10 degrees total (BAD)." Which indicates you add the two numbers together, but BMR says to subtract those numbers.
• Subtracting the two results in your pinion angle.(Ex: -6 rear end angle subtracted from +4 driveshaft angle = -2 degrees)
Shouldn't it be +5 - -5 = 0 according to your example?
• Subtracting the two results in your pinion angle.(Ex: -6 rear end angle subtracted from +4 driveshaft angle = -2 degrees)
Shouldn't it be +5 - -5 = 0 according to your example?
Doh see what you're questioning: The BMR dirrections seem to imply that a condition of -5 rear end angle and +3 driveshaft angle would be in the sweet spot for an A4 rather than being a difference of 8 in the range.
Last edited by Brewski; Mar 20, 2008 at 02:12 PM. Reason: Looked back through BMR dirrections and see his point
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it's easier to look at it like this:
subtract rear end angle from driveshaft angle
so, (Driveshaft angle (-) Angle of pinion = working pinion angle)
to make the numbers easier convert them all to 90degree numbers so there's no -3 and +3 etc.
if the driveshaft is pointing to 87 degrees note it as that. If the rear is going positive past 90 degrees say to 1 or 2 degrees, then note that as 91 or 92 degrees.
so if you have an angle of 87 degrees driveshaft minus 91 degrees pinion then that = -4 degrees of negative pinion angle (pinion turned downward)
hope this helps
subtract rear end angle from driveshaft angle
so, (Driveshaft angle (-) Angle of pinion = working pinion angle)
to make the numbers easier convert them all to 90degree numbers so there's no -3 and +3 etc.
if the driveshaft is pointing to 87 degrees note it as that. If the rear is going positive past 90 degrees say to 1 or 2 degrees, then note that as 91 or 92 degrees.
so if you have an angle of 87 degrees driveshaft minus 91 degrees pinion then that = -4 degrees of negative pinion angle (pinion turned downward)
hope this helps
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also it wouldnt matter if the car was on a drive on lift or the back wheels were on rhino ramps. the front wheels end up being the piviot point and the angles will change accordingly.