Chadman27
08-02-2012, 04:55 PM
Hi everyone,
I am a long time forum viewer (since 2004) but rarely post. Well, actually my last post was in 2008 for a steering box question, but I have since forgot my username password (lack of posting :hammer:) so I recreated a similarly named account not so long ago. I have found myself in a jam on my project, hence rekindling the posting flame! I could really use some of your guys experience and knowledge, so here goes...
I recently ordered my front brakes for my 81 T/A project, and had DSE/Baer machine the brake rotors for a 1/2-20 wheel stud. The studs are ARP 1/2-20 cadium plated 3 inch. The knurl of the stud sits flush on the rotor and are perfect, but this is not where the problem lies.
About a year ago I received my DSE built Quadralink GM 12 Bolt rear with the 1/2-20 3 inch wheel studs. Because DSE uses Moser rears and components, the studs are black oxide coated studs PN 8010 (verified with Moser over the phone) seen here:
http://www.moserengineering.com/other-parts/studs/1-2-20-x-3-625-knurl-long-ford.html
I have recently ordered my CCW Classics, and was really against cutting studs so I could run a closed stud. I figured I'd rather have the open lug where engagement length could be verified easier for track days. That being said I wanted the rear studs to match the fronts, so I order ARP PN 100-7703 .625 inch knurl studs, seen here:
http://www.jegs.com/i/ARP/070/100-7703/10002/-1
Well I popped a stud out and pulled the new ARP studs through, to find that the knurl sits proud roughly 1/32 ~ 1/16 of an inch. I did not have my calipers available where I work on the car, so I could not take an exact measurement.
Moser stud:
62831
ARP stud:
62832
Side by side comparison:
62833
When placing the Baer Pro+ rear rotor on, the chamfer depth bottoms out on the exposed knurl. Has anyone ran into this issue... how did you resolve it? I feel that the when torquing the lugs when mounting the rims, backing the bearing/shoulder off the backside of the axle flange is obviously unideal, and potentially dangerous in regards to snapping a stud - am I right to think this, or would the limit relief of the stud shoulder not be an issue. My thoughts and options are listed as follow...
1) Because the Pro+ center is aluminum, I could purchas, lets say a .750 inch countersink bit and machine the per-existing chamfers of the rotor to attain clearance... My only reservation is that I know Baer would never approve of such a procedure, being a liability, and I could potentially compromise the bearing strength of the cross section. Has anyone done this successfully? Recommendations? Because the aluminum is soft, I believe I could get away with doing this with even a wood countersink bit... recommendations?
2) Source some type of washer to recess the stud back the required length... realistically this would be very difficult, as I dont beleive any ASTM/ASME spec would ever point to such a washer with such a thin ID to OD width.
3) Keep the wheel studs as are, protrusion and all, but source a thin wheel spacer that I can machine the chamfer (if not large enough on the spacer as delivered). This would eliminate cross section reduction of the rotor which will see load under hard breaking... I just need to make sure I do not rub the wheel wells with the new offset. As it stands, the rims are 18x12 w 5.5 BS on a 9 inch (4.5 inch per side) narrowed rear. Being that the Firebird wheel wells have a little more room than its Camaro counterpart and I have also Eastwood fender lip rolled the wheel lip edge... I may be lucky enough to get away with this. Any advice on wheel spacer with large chamfered ID's... I know there are probably a million companies to choose from.
4) Knock the ARP studs out, quit being a baby, and cut the original Moser studs to necessary length to run closed lugs... Cut the front ARP studs to match. I really don't want to do this, but will leave it as a final (and safe) option.
If you have made it this far, thanks for giving my post a look. I hope you can share any advice or insight. I've been working on my Trans Am for about a year an half now... its been my baby since I was 15! I've been wanting to post a build thread... but never seem to find the time to do so.... the one time I tried my post took about an hour to write... when I posted there was an error and all was lost! :nopity: Maybe I'll get around to it again here soon.
Thanks,
-Chad
I am a long time forum viewer (since 2004) but rarely post. Well, actually my last post was in 2008 for a steering box question, but I have since forgot my username password (lack of posting :hammer:) so I recreated a similarly named account not so long ago. I have found myself in a jam on my project, hence rekindling the posting flame! I could really use some of your guys experience and knowledge, so here goes...
I recently ordered my front brakes for my 81 T/A project, and had DSE/Baer machine the brake rotors for a 1/2-20 wheel stud. The studs are ARP 1/2-20 cadium plated 3 inch. The knurl of the stud sits flush on the rotor and are perfect, but this is not where the problem lies.
About a year ago I received my DSE built Quadralink GM 12 Bolt rear with the 1/2-20 3 inch wheel studs. Because DSE uses Moser rears and components, the studs are black oxide coated studs PN 8010 (verified with Moser over the phone) seen here:
http://www.moserengineering.com/other-parts/studs/1-2-20-x-3-625-knurl-long-ford.html
I have recently ordered my CCW Classics, and was really against cutting studs so I could run a closed stud. I figured I'd rather have the open lug where engagement length could be verified easier for track days. That being said I wanted the rear studs to match the fronts, so I order ARP PN 100-7703 .625 inch knurl studs, seen here:
http://www.jegs.com/i/ARP/070/100-7703/10002/-1
Well I popped a stud out and pulled the new ARP studs through, to find that the knurl sits proud roughly 1/32 ~ 1/16 of an inch. I did not have my calipers available where I work on the car, so I could not take an exact measurement.
Moser stud:
62831
ARP stud:
62832
Side by side comparison:
62833
When placing the Baer Pro+ rear rotor on, the chamfer depth bottoms out on the exposed knurl. Has anyone ran into this issue... how did you resolve it? I feel that the when torquing the lugs when mounting the rims, backing the bearing/shoulder off the backside of the axle flange is obviously unideal, and potentially dangerous in regards to snapping a stud - am I right to think this, or would the limit relief of the stud shoulder not be an issue. My thoughts and options are listed as follow...
1) Because the Pro+ center is aluminum, I could purchas, lets say a .750 inch countersink bit and machine the per-existing chamfers of the rotor to attain clearance... My only reservation is that I know Baer would never approve of such a procedure, being a liability, and I could potentially compromise the bearing strength of the cross section. Has anyone done this successfully? Recommendations? Because the aluminum is soft, I believe I could get away with doing this with even a wood countersink bit... recommendations?
2) Source some type of washer to recess the stud back the required length... realistically this would be very difficult, as I dont beleive any ASTM/ASME spec would ever point to such a washer with such a thin ID to OD width.
3) Keep the wheel studs as are, protrusion and all, but source a thin wheel spacer that I can machine the chamfer (if not large enough on the spacer as delivered). This would eliminate cross section reduction of the rotor which will see load under hard breaking... I just need to make sure I do not rub the wheel wells with the new offset. As it stands, the rims are 18x12 w 5.5 BS on a 9 inch (4.5 inch per side) narrowed rear. Being that the Firebird wheel wells have a little more room than its Camaro counterpart and I have also Eastwood fender lip rolled the wheel lip edge... I may be lucky enough to get away with this. Any advice on wheel spacer with large chamfered ID's... I know there are probably a million companies to choose from.
4) Knock the ARP studs out, quit being a baby, and cut the original Moser studs to necessary length to run closed lugs... Cut the front ARP studs to match. I really don't want to do this, but will leave it as a final (and safe) option.
If you have made it this far, thanks for giving my post a look. I hope you can share any advice or insight. I've been working on my Trans Am for about a year an half now... its been my baby since I was 15! I've been wanting to post a build thread... but never seem to find the time to do so.... the one time I tried my post took about an hour to write... when I posted there was an error and all was lost! :nopity: Maybe I'll get around to it again here soon.
Thanks,
-Chad