SOS! FMJ Swap issues

slickchick said
NOTE: PLEASE DO NOT USE ANY OTHER BODY STYLE CALIPERS: ROTORS: PROPORATING VALVE: OR BEARINGS, OTHER THAN A-BODY FACTORY PARTS
***** MUST READ !!!!!!!! DO NOT USE VALORE' OR ASPEN DISC BRAKE PARTS, THIS WILL CAUSE YOUR CAR TO HAVE WHAT IS CALLED "BUMP STEER" :glasses7:

Complete BS. :wack:

66Dvert said
????? seriously? do you still believe in that outdated article? just asking is all I'm not trying to start a war here, but I think that's one article that has been busted.

Yes exactly, and it actually HAS been busted. Everything is right here in black and white...

http://www.moparmusclemagazine.com/techarticles/suspension/mopp_0503_swapping_a_and_b_disc_brake_spindles/

Mopar Muscle did an actual analysis of the geometry changes (vs. the BS from the original article). Did you notice the author? Bill Reilly. Yes, that one. Turns out that the geometry changes from using FMJ spindles are minimal at best. And, if anything, are actually beneficial. Especially on cars with wider, more modern tires/compounds, where the ridiculously small increase in toe change will be minimized even further, while the larger improvement in camber gain will be accentuated. Running big torsion bars? You guessed it, even less of an effect. Bigger torsion bars = less dive/travel = less toe change.

So, please, all the FMJ deniers, take the time to read the Mopar Muscle article posted above. Maybe take a look at a chassis/suspension design book.

Or even look at the ACTUAL numbers (from the MM article).

'73-'76 A-body Spindle
Static alignment - 0 camber, 1.18 caster, 0.059 toe-in

Dive Caster Camber Roll Ctr. Toe-In
2.25 4.892 -1.226 5.608 0.041
2.00 4.502 -1.020 5.756 0.042
1.75 4.108 -0.830 5.901 0.042
1.50 3.707 -0.657 6.043 0.043
1.25 3.302 -0.500 6.180 0.045
1.00 2.890 -0.361 6.312 0.047
0.75 2.473 -0.241 6.435 0.049
0.50 2.048 -0.140 6.549 0.052
0.25 1.617 -0.059 6.650 0.055
0.00 1.177 0.000 6.735 0.059
-0.25 0.730 0.036 6.800 0.064
-0.50 0.273 0.046 6.840 0.069
-0.75 -0.194 0.028 6.849 0.075
-1.00 -0.672 -0.020 6.816 0.081
-1.25 -1.163 -0.103 6.730 0.089
-1.50 -1.669 -0.225 6.574 0.096
-1.75 -2.191 -0.392 6.323 0.105
-2.00 -2.734 -0.612 5.94 0.113
-2.25 -3.300 -0.895 5.366 0.122
'73-and-up B-Body Spindle
Static alignment - 0 camber, 1.32 caster, 0.059 toe-in

Dive Caster Camber Roll Ctr. Toe-In
2.25 4.77 -1.697 6.678 -0.013
2.00 4.407 -1.448 6.848 -0.007
1.75 4.039 -1.213 7.017 0.000
1.50 3.666 -0.993 7.187 0.007
1.25 3.289 -0.787 7.355 0.014
1.00 2.906 -0.597 7.521 0.022
0.75 2.518 -0.422 7.684 0.031
0.50 2.125 -0.264 7.843 0.039
0.25 1.725 -0.123 7.995 0.049
0.00 1.319 0.000 8.141 0.059
-0.25 0.906 0.104 8.276 0.070
-0.50 0.486 0.188 8.399 0.081
-0.75 0.057 0.250 8.505 0.094
-1.00 -0.380 0.288 8.591 0.107
-1.25 -0.827 0.300 8.651 0.121
-1.50 -1.284 0.284 8.677 0.136
-1.75 -1.754 0.236 8.658 0.151
-2.00 -2.237 0.151 8.580 0.168
-2.25 -2.737 0.025 8.421 0.186

Read more: http://www.moparmusclemagazine.com/...isc_brake_spindles/viewall.html#ixzz2XOjHXMRj