The Stovebolt Site Forums The Parking Lot Big Bolts What's it called? Proper terminology.

On the heavier trucks with dish wheels, there is a iron casting between the front brake and the wheel. It spaces the wheel out from the brake so that the center of the tire is in the proper position. I have heard this called a "hub spacer", but am wondering what the proper terminology is for it?

Also, in the later (P30) trucks, there were 8 bolt dual wheels (16") and 10 bolt (19.5") wheels.
Were these cast GM hub spacers interchangeable, since they all bolt on to the brake with 8 bolts? (remove an 8-bolt-to-8-bolt spacer and replace it with an 8-bolt-to-10-bolt spacer)?

Thanks in advance.

Hy journeyman, the proper name for the part is "hub". One ton trucks could have a "hub" designed for single wheels, or one designed for mounting a dual type wheel. The hub adapters you referenced are unfamiliar to me, hope that helps.

A true spacer that is removable is very uncommon, and non existant on the later model P series you're asking about.
Talking about front axles.
The 8 lug P30 hub is the rotor as well, all one piece.
The 10 lug (5 front) P30 has a hub with the 5/10 lug bolt pattern and a removable rotor, two pieces.
You can interchange between the 8 and 10 lug spindles/axles the complete hub and rotor along with respective caliper brackets (the 10 lug rotors are larger).

What are you trying to do?

Grigg

I actually have the 10-7.25" pattern (5 front 10 rear) and am in constant overload on the rear.

I am swapping out the rear axle (10-7.25", hyd. disk) for a larger Eaton with the 10-11.25" wheel.

Of course this means I need to do something with the front. I noticed that it is indeed a 2-piece hub and thought that if I can change the outer hub to 8-6.5, I can easily get an adapter from 8-6.5 to 10-11.25.

This also would give me a complete conversion set up to sell for someone with 8 lug wheels (16") wanting to increase weight capacity up to the 19.5" wheels.

Unless we're talking about different things it's a single piece hub, and the rotor bolts to it. there is no "outer hub" there is only a hub; one piece.

If you want 8 lug hub you need the caliper brackets off of an 8 lug version of that axle and then you can go to NAPA and buy a set of front hub/rotors (all one casting). (Oops, you might not have a NAPA where you are) You can reuse your spindles, caliper and steering linkage.
Basically sounds like you want the 8 lug axle and not the 10, those are the minimum parts you can change to get there.

Is this a good idea though? If you're overloading the rear are you really overloading the rest of the truck too, at what point do you need all bigger components?
Swapping to 8 lug front axle parts is a decrease in capacity, you get smaller disc brakes than you have with the 5/10 version.

This picture is a 5/10 lug and the 8 lug P30 axle side by side.
https://picasaweb.google.com/118082...pgradeForOldGMTrucks#5823745242769935698

Grigg

So the outer part (that the wheel bolts to) is the hub (has the bearing inside) and the "inner part" is just the brake rotor?

Sort of correct, yes "the outer part (that the wheel bolts to) is the hub (has the bearing inside)"

I wouldn't say there is an inner part at all, the hub is the hub, it's one thing/piece. The rotor is a rotor, it bolts to the hub.
For the 5/10 lug.

The 8 lug is even simpler, the hub and rotor are cast as one piece, bearings are fit in it. In other words the hub/rotor is one single thing, nothing bolted together.

Hmmm. This could be difficult.
The ultimate would be to find a rotor/hub for my spindle that would have the 10 on 11.25 lug pattern... But I doubt that is going to happen.

Unfortunately, I do not know of anyone that makes an adapter from 10 on 7.25 to 10 on 11.25.

On another note: Anyone interested in a disk brake rear end (10 lug on 7.25" BC)? I also have 19.5" powder coated wheels

Don't think you'll find a hub for your spindles that takes a 11.25" bolt pattern wheel.

Nor do I know of any adapters made to go from 10 lug on 7.25 up to 11.25, not really enough room to make it happen.

I'm slightly interested in the 10 lug rear and wheels... but where is it located? Russia?

Grigg

Actually, it is located in California (Fresno area).

This is why I was interested in the 8 on 6.5 hubs. Adapters are plentiful.

I have access to a 12,000 Lb GVW P30 chassis with 8 lug hubs, and if the spindles were the same it could be a good swap, EXCEPT if the brakes are smaller (I expect they are, mine is a 16,000 Lb GVW). Obviously, that would be detrimental.

If there was a way to keep the brake rotor and change hubs, it would be magic. It would also allow me a way to sell a complete conversion kit for a 8 lug truck to a 10 lug.

The spindles are the same enough to swap without any issues at all, only difference I know of is grease fitting location.
The brakes on the 8 lug ARE SMALLER than those on the 10 lug.

No way to keep the large rotor and use 8 lugs that I'm aware of and I've done a lot of research and parts book scouring trying to fit different hubs/rotors on these spindles.

West cost is way to far to go after an axle I don't really need...

Grigg

So Can I attach the larger caliper to the smaller (8 lug) hub and theoretically reinstall the new hub/rotor assy on the larger vehicle using the stock calipers for that brake?

Calipers are the same for both 8 and 10 lug.

How can I say this simply?
From either axle you can remove hub/rotor and caliper bracket all as one package deal and fit it to the spindle of either the 8 lug or the 10 lug front axle.

Feel like were going round and round in circles now not learning anything new. I thought the question has been answered and it's not a good idea to swap your 10 lug stuff out for 8 lug because of the reduced brake size?

In the end if you want to run big tires and have more weight capacity you can/should swap the entire front axle for something larger and suitable. Swapping in parts from a lighter axle doesn't gain you anything that I see.

Grigg

OK, I do see what you are saying. The hub and rotor are inseparable.

I have IFS.
I would love to find a C60 IFS set up, but honestly do not think they exist. I vaguely remember seeing an old (early 60's) C60 school bus that I think had IFS, but I don't think there is anything later or anything that would do me any good. I would love to have the larger brakes, but did not see it as a realistic possibility.

Here's a pic of the rear set up I am planning to adapt in:
http://imagehost.isoftdata.com/phpThumb.php?src=partimages/254076/&productcode=254076&id=60974&w=500

I think that 60-62 a torsion bar front suspension was used.

how do you post a pic (image from internet) on posts?

journeyman - you just need to copy the address of where the picture is and paste that address here

Bill

Oooooh. I just read the policy. Makes sense.


I am a little stuck on the front end issue.
I am getting the Accuride 29644AOP wheels
descr:
ACCURIDE 15° Tubless Aluminum Wheels
Hub-Piloted Dual-Mounting
Two Piece Flange Nut
10-Hole, 285.75mm Bolt Circle, 220mm Bore

But need to figure out a way to bolt them on!

Oh. I just read the posting images policy. Makes sense.

I am stuck on what to do with the front end.
I am getting Accuride 29644AOP wheels:
ACCURIDE 15° Tubless Aluminum Wheels
Hub-Piloted Dual-Mounting
Two Piece Flange Nut
10-Hole, 285.75mm Bolt Circle, 220mm Bore


But need a way to bolt the on!

I have a pic of what I originally had in mind. It is a jpg on my computer (no web link). How can I upload this jpeg to the gallery?

So it looks like I will need to custom machine an adapter to go from 10 on 7.25 to 10 on 11.25" Bummer. This could get tricky. And pricey. Any suggestions?

If you're set on running 10 lug on 11.5" wheels on the front stop looking at small front axles.
Buy/use a front axle that already has the 10 on 11.25" bolt pattern like the front axle that is a match to the rear axle you'll be using (same vehicle).

Grigg

I thought of that (in fact even considered a whole frame swap... Yikes!), but it would involve converting from IFS to beam.


Also I have the cab forward and GM shied away from cab forward in later years, giving the business to Isuzu.
Conventional and Cab forward steering are probably quite different.

For now, the only possibility seems to be machining. If the offsets in the wheels are different enough, I will have enough thickness to make this possible.

All the advice/info I gave about the 8 and 10 lug P30 components was for I-beam front axle, the IFS versions have different spindles and I'm not at all familiar with the IFS versions.
Don't think you mentioned in the beginning you were concerned with IFS.

Good luck with whatever you figure out.

Grigg

Sorry I left that out!

I found one mfg that will make an Aluminum adapter for $700 for the pair:
Motorsport Tech
10 Greg Street, Suite 112
Sparks, Nevada 89431

Although I will be "stuck with" the stock brakes, at least I will be able to bolt things together

Offset question:
If the Accuride 29644AOP has a 6.59" offset and is .935" thick, and the stock steel wheel has a 5.08" offset and is 5/16" thick (my estimate), does the proper wheel geometry require a 1.5" thick adapter? My simple logic tells me it does, but I'm not sure I am thinking about this correctly.

Sign up with photobucket or shutterfly or google-drive something similar, for a free account where you can upload and share files. Then in stovebolt you can include links to your pictures or other files.

To get pictures of your truck into the gallery, you'll need to first upload them to a file-sharing service. Then you write up a gallery submission with links to your pictures, and stove bolt will possibly select it and revise it to put in the gallery...