The MGA With An Attitude
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FRONT SPRING SPECIFICATIONS -- FS-113

MG Model Chassis # Front Spring Part Number Spring Rate, lb.in Coil Dia, in. Wire Dia, in. Free Length, in. Number of Active Coils Static Laden Height, in. Static Laden Load, lb.
MGA 1500 to 15151 139105 348* 3.238 0.498 9.75 7.5 6.6   1095
MGA 1500 from 15152 AHH5546 480* 3.28   0.54   8.88 7.2 6.6   1095
MGA 1600 all AHH5546 480* 3.28   0.54   8.88 7.2 6.6   1095
MGA MK II all AHH5546 480* 3.28   0.54   8.88 7.2 6.6   1095
MGA "Deluxe" all** AHH5546 480* 3.28   0.54   8.88 7.2 6.6   1095
                   
MGA Twin Cam all AHH5789 480   3.28   0.54   9.09 7.2 6.6   1193
                   
MGB Roadster to 293446 AHH6451 348   3.238 0.498 9.9   7.5 7      1030
MGB Roadster*** from 293447  BHH1225 348* 3.238 0.498* 10.2 7.5 7.24 1030
  to 410000                
MGB/GT to 296196 AHH5789 480   3.28   0.54   9.1   7.2 6.6   1193
MGB/GT*** from 296197 BHH1077 480* 3.28   0.54* 9.32 7.2 6.84 1193
  to 361000                
MGB Competition n/a C-AHT21 480       8.63*   6.14 1193
Notes:
* Figure not shown in factory manuals, but calculated from other known factory values.
** Data for "Deluxe" cars show same figures as for Twin Cam in factory manuals. However, the "Deluxe" models carry the lighter pushrod engine, so should have same springs as the 1600 models.
*** Coincides with introduction of radial tires as standard equipment, 1972
coil springs
coil springs
In the middle is the original standard spring from a MKII Deluxe (same for all pushrod engine cars after 15151). On the left is the AHH6451 spring from Moss, which they claim is a suitable replacement for standard MGAs. It is actually an MGB spring with lower spring rate (similar to early spec MGA springs). And on the right is the correct AHH5546 spring from MGOC. Wire diameter of the AHH5546 spring and the original spring is identical, 0.54". The MGB spring is 0.498". While it has same spring rate as the earliest MGA spring, it is slightly longer free length. When installed in the MGA it will have the softer early spring rate, but it will also sit 0.15" higher at the spring, or 0.30" higher ride height. The factory knew the softer front springs were not good for the MGA, which is why they were changed to higher spring rate in early 1500 production after the first 5051 cars.

There is also the MGB competition spring C-AHT21 (if you can find it), which is correct 480-lb/in spring rate for MGA but 0.25" shorter, which will lower the front ride height of the MGA by 0.50".

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