View Full Version : Drum Hub Question
Im doing a c5 swap on a 68 Camaro. Could someone get me a dimension on the thickness of the drum brake hub flange please? (The flange the studs mount into). Thanks in advance!
70chevellemalibu
01-06-2016, 07:53 AM
best thing to do is buy your new rotors and bring them to the machine shop. Tell the machine shop to cut down the drum hub until the rotor fits into the hub and add a bit of room for grime build up (couple thousandths)
best thing to do is buy your new rotors and bring them to the machine shop. Tell the machine shop to cut down the drum hub until the rotor fits into the hub and add a bit of room for grime build up (couple thousandths)
I can machine them myself. I am trying to use my old one piece disc hub, machine it to accept the C5 rotors. I have the rotors in hand. The OD is not an issue. I'm thinking the disc hub will be a wider track than the drum hub. I was really trying to get dome random height dimensions from a fellow member to make sure I know what will work. My thoughts are that if it is wider, I can still run Tobins brackets with a custom spacer. Then deal with the offset with my wheel when I order them.
Apogee
01-06-2016, 09:31 AM
Are you looking for the width of the flange (~3/8"), or the flange offset from the inner shoulder of the inner wheel bearing (~2.09")? This would be the same surface as the shoulder on the spindle pin, as that determines your hub flange offset and associated track width. The SET6 inner wheel bearing is .625" thick from cup to cone if you want to calculate the dimension from the bottom of the bearing counterbore to the face of the hub flange.
Tobin
KORE3
Are you looking for the width of the flange (~3/8"), or the flange offset from the inner shoulder of the inner wheel bearing (~2.09")? This would be the same surface as the shoulder on the spindle pin, as that determines your hub flange offset and associated track width. The SET6 inner wheel bearing is .625" thick from cup to cone if you want to calculate the dimension from the bottom of the bearing counterbore to the face of the hub flange.
Tobin
KORE3
Specifically what Im looking for is the dimension from the engine side bearing, outer surface (the surface that rides against the spindle) to the wheel mounting face (the face that the inside surface of the rotor hat lays against. Also, the overall thickness of the stud flange. I may need to trim the rotor mounting face back towards the spindle to achieve the same length (spindle to face) as the drum hub, while keeping the flange thick enough for safety purposes. (I don't want to trim the flange thinner than a drum hub flange thickness).
Mike
Apogee
01-06-2016, 01:41 PM
Specifically what Im looking for is the dimension from the engine side bearing, outer surface (the surface that rides against the spindle) to the wheel mounting face (the face that the inside surface of the rotor hat lays against. Also, the overall thickness of the stud flange. I may need to trim the rotor mounting face back towards the spindle to achieve the same length (spindle to face) as the drum hub, while keeping the flange thick enough for safety purposes. (I don't want to trim the flange thinner than a drum hub flange thickness).
Mike
Be careful. The hub/rotor is ~7/16" wider than the drum hub per side with respect to track width, and the material is not the same, so assuming that equivalent material thicknesses for the cast iron hub/rotor are going to be equally strong or safe as compared to the cast steel (not iron) drum hubs is not a safe assumption IMHO. Most people who choose to use a cut-down OE hub/rotor for the GM short-spindle applications live with the added track width and just run a wheel with more backspacing to make up for it, as this at least retains the same strength and factors of safety as the OEM hub/rotor, so you're not in essence reinventing the wheel...or rather the hub in this case. What you're proposing doing is certainly reducing the strength, rigidity and safety of the hub, potentially up to and beyond the point of concern. While I'm not against a little "comparative engineering" under the right circumstances, I'm not sure that this situation would qualify given the different materials.
That said, the 2.09" dimension I provided above is the distance from the inboard side of the inner wheel bearing to the flange for the GMSS hub and the wheel stud flange is ~.38". Good luck with your project and be safe.
Tobin
KORE3
Be careful. The hub/rotor is ~7/16" wider than the drum hub per side with respect to track width, and the material is not the same, so assuming that equivalent material thicknesses for the cast iron hub/rotor are going to be equally strong or safe as compared to the cast steel (not iron) drum hubs is not a safe assumption IMHO. Most people who choose to use a cut-down OE hub/rotor for the GM short-spindle applications live with the added track width and just run a wheel with more backspacing to make up for it, as this at least retains the same strength and factors of safety as the OEM hub/rotor, so you're not in essence reinventing the wheel...or rather the hub in this case. What you're proposing doing is certainly reducing the strength, rigidity and safety of the hub, potentially up to and beyond the point of concern. While I'm not against a little "comparative engineering" under the right circumstances, I'm not sure that this situation would qualify given the different materials.
That said, the 2.09" dimension I provided above is the distance from the inboard side of the inner wheel bearing to the flange for the GMSS hub and the wheel stud flange is ~.38". Good luck with your project and be safe.
Tobin
KORE3
Very valid points. That's really what I dont want, unsafe hubs. I had no idea they were cast differently. I can live with the extra width. No use reinventing something. Thanks Tobin. Greatly appreciated!
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