Differences between drum brake hubs?

[Map67Dart]

As the title suggests, what exactly is the difference between 10" and 11" drum brake hubs? To me it seems like there wouldn't be any practical difference as the bearings would be the same (they go on the same spindle at least) and the bolt patterns would be the same.

Mostly asking because I'm looking at doing a junkyard disc brake upgrade on my Dart. I currently have vintage disc brakes of some variety (I think they might be E body brakes based on the brake lines at least) that work fine, but I'm interested in going to a more modern separate rotor and hub design. I'm working on putting a front wheel speed sensor on for traction control with my computer upgrade and it would be way easier to mess with if I only have a hub to work around instead of a full hub/disc assembly. I found InvincibleExtreme's caliper mounting kit that lets you run late model Mustang rotors and calipers on the stock drum brake hubs, but I need to come up with hubs first before I can do anything. I've seen people advertise 10" and 11" hubs separately, but wasn't sure what was different about them and if I should favor one over the other. The only thing I can imagine being different would be the offset on them, but even then I'm not sure that even makes sense.

Along the lines of difference, any reason I can't put drum brake hubs on disc brake spindles? From everything I can find online it seems like the actual spindles are the same and the knuckle is just different to carry the caliper mounting. The seals and bearings are different because of different ODs to fit in the hub or rotor, but the IDs seem to match up, which would indicate a common spindle at least, unless one is longer than the other or something.

 

[Cranky]

I know there are differences but don't know exactly what they are. Another member posted awhile back what they were and maybe he will chime in soon....

 

[Jeffj]

The inner bearing inner diameter is smaller on the drum spindle and some disc conversion kits for that combo add a machined spacer in order to use, for example, an 11.75 Cordoba rotor/hub on a drum brake spindle. I have one of those setups from Scare Bird, they have a different kit now than the one I got years ago. The spacer wall thickness is only about .060 or so. You could search the relevant bearing specs and see exactly what the diameter differences are. The outer bearings are the same.
Jeff J

 

[66chargerpat]

The 11" are spaced out about .250" farther from the brake backing plate

 

[Cranky]

The inner bearing inner diameter is smaller on the drum spindle and some disc conversion kits for that combo add a machined spacer in order to use, for example, an 11.75 Cordoba rotor/hub on a drum brake spindle. I have one of those setups from Scare Bird, they have a different kit now than the one I got years ago. The spacer wall thickness is only about .060 or so. You could search the relevant bearing specs and see exactly what the diameter differences are. The outer bearings are the same.
Jeff J

I'm wondering if there's a cone that will fit the original spindle size and a race to fit the hub and cone.....? There are a lot of variations with tapered roller bearings within the same range of size.

 

[Map67Dart]

The inner bearing inner diameter is smaller on the drum spindle and some disc conversion kits for that combo add a machined spacer in order to use, for example, an 11.75 Cordoba rotor/hub on a drum brake spindle. I have one of those setups from Scare Bird, they have a different kit now than the one I got years ago. The spacer wall thickness is only about .060 or so. You could search the relevant bearing specs and see exactly what the diameter differences are. The outer bearings are the same.
Jeff J

Yeah, I think I was looking at the wrong bearings when I was comparing things on RockAuto. I tried to see if an "adapter" bearing existed by looking through the Timken catalog, but looks like that package doesn't exist. I wonder if you could bore out the inside of the drum hub to fit the larger bearing, but it's probably just as easy to swap spindles at that point. Could also maybe just trade someone straight across for what I have as well.

The 11" are spaced out about .250" farther from the brake backing plate

Sweet, that's exactly the kind of info I was looking for. I was thinking maybe the larger ones were also wider, so maybe they changed the offset to keep things centered or something. Would be interested to see how the drum hubs measure up compared to the disc hubs as well now that I think about it. I guess I always just assumed that my disc hubs stuck out further since the rotors stack behind them, but maybe it's not as far off as I thought. I'm already running some spacers on my front wheels to deal with the offset I have on my rims, so I could maybe just go down to smaller spacers if I stack a rotor on the outside instead of the inside, assuming the caliper brackets will still center up okay.

 

[66chargerpat]

Wilwood also make two hubs for the drum spindles
part# 270-10812 and 270-12281
the offset are listed from the flange to the back of the inner bearing race.
I have no idea how that is for the 11" or 10" drum hubs.
the Wilwood may also be stronger.
The flange on the drum hubs are slim.

 

[Map67Dart]

Hmm, interesting. Thanks for the info! At least gives me some kind of number to start with. Kind of a hard number to easily measure, but thinking I can probably get close if I take off what I've got and do some comparisons.

 

[R/T Boy 67]

Dr. Diff has these.

 

[Map67Dart]

Yeah, I had seen those as well, but that's way more than I feel like paying if I can get away with something else.

I did just take everyone off one corner and found some interesting measurements though. Looks like I have 71 E body disc brakes on my car based on caliper casting numbers, but even more interesting (and potentially useful) is that the spindles are still the smaller drum size ones, so I could actually swap drum hubs onto the car pretty easily if I wanted to go with the InvincibleExtreme kit. I measured the offset for the hubs I have on the car now as well and they could probably be made to work, but they look like they are around 3/8" further outboard than the Wilwood aftermarket ones at least. That would actually probably be fine with my wheels because I basically have FWD wheels on my car and have a big spacer to make up the offset, but it would likely mean a caliper spacers as well, which I'm not quite as fond of. It's one thing to stack a washer or two to center a rotor, but a 3/8" spacer starts making me a little more worried about how it's loading up mounting bolts under heavy braking. A little more bending load in the bolts along with the shear.

 

[1967coronet]

I'm wondering if there's a cone that will fit the original spindle size and a race to fit the hub and cone.....? There are a lot of variations with tapered roller bearings within the same range of size.

Cranky I am kinda sorta dealing with a similar problem.
Bought a scarebird bracket set to do a front disc conversion on my 67 coronet.
I'm using the one that retains your original hub.
Putting it together my rotor will just touch the caliper bracket.
I contacted scarebird and we measured hub to flange ect .
Turns out sometime in the past my b body ended up with a set of c body hubs.
Mark at scarebird was great to work with and is shipping me the correct brackets.
He told me mopar used 4 different hubs.
I didn't know you could toss them on the same spindle ?

 

[OKDart]

Here’s a pic of a 10” (left) and 11” (right) hub.