Dimensions of rear hubs.

J

jnunez1955

Member
Hello, i was wondering if anyone out there can help me get these dimensions.
Im trying to figure out which one i should use, since i know they all have different offsets and dimensions.


I need to know the dimensions of the rear hubs from the following 3
1930 Model A rear hubs
1940 rear hubs (that mount outside the drum)
1946 rear hubs (that mount inside the drum)


heres a picture of what things i need from it

Untitled.jpg
 
Might be an idea to redo the diagram with the ?'s replaced bu A, B, C, etc so people can just say a=such and such B= so and so etc..

Mart.
 
From your description, I have a 40 hub, the drum sits inside of the hub.
A= 6.2mm, 0.244"
B= 193mm, 7.6"
C= 146.4mm*, 5.764"
D= 67mm, 2.63"
E= 73.2mm, 2.88"

* not measured directly, C=A+D+E

Mart.

EDIT: I believe this style of hub is the later style, not 40 as stated.
 
Last edited:
One of the dimensions that you might want to be considering is exactly where the hubs sit on the tapered axle and how that fits into how the hubs are in relation to the backing plates, say if you're installing later (hydraulic) brakes on an earlier rear. I might be putting hydraulics on an A rear, and the warning is that the drums (used with say '40 hubs) will hit the backing plates. I intended to see if using '48 hubs would cure that, but, I haven't gotten around to that yet.
 
PeteVS said:
One of the dimensions that you might want to be considering is exactly where the hubs sit on the tapered axle and how that fits into how the hubs are in relation to the backing plates, say if you're installing later (hydraulic) brakes on an earlier rear. I might be putting hydraulics on an A rear, and the warning is that the drums (used with say '40 hubs) will hit the backing plates. I intended to see if using '48 hubs would cure that, but, I haven't gotten around to that yet.
Click to expand...

yeah, im trying to figure out which hub had a 1/4" higher offset.
i know 1/8" has to be grinded down from both the drum and backing plate.
and i original thought that the model a hub had a different offset because their brakes didnt have clearance issues. but i guess i was wrong.
 
If you're willing to wait until spring, I'll drag out the Model A rear from the shed and see how it fits with hydraulic backing plates and '48 hubs with '40 drums mounted on the OUTSIDE. If you get there before I do, post with how it works out. You might not be wrong!
 
I wasn't sure when I initially replied, but have checked now, But the callup for inside/outside drum fitment is the wrong way round in the initial question.
The hub I measured is the type with the hub exposed and the drum behind, making it a later type not "40" type as stated in the initial question and my reply.
Mart.
 
You must log in or register to reply here.
Back
Top