Which is wider Aluminum arms or backing plates?

[flat]

Here we go:

The early 944 (83-85) is the narrowest of the bunch. 24mm offset increase over stock drum (Type 1) brakes per side. The 24mm is not counting the spacer. All early 944's came with stock 20mm wheel spacers. With the spacers, you see that the track is the same as the 86T arms. Without the spacers, it's narrower. The stock studs in these hubs are 66mm long. Punch them out and put in the shorter studs (46mm) from the later (aluminum arm) hubs.

The early 924 5-bolt hubs came without spacer and shorter studs from the factory, but these guys are rare. 1 year only option.

Next up are the 86T alum arms. Roughly these increase about 44mm per side.

Finally, the fat boys are the 87+ alum arms (same for NA or T). These are huge increase, about 76mm per side IFRC. I've never tried it, but it seems that the difference between these and the 86T arms is mainly in the hub, and the hubs should interchange. NOTE: There is no interchangebility between the steel arm and alum arm hubs.


Hope that helps,
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