My "new" '74 Duster- or why I need a project like a hole in the head
The steering stops being cast into the lower ball joints is kind of a crap shoot. After talking to 72BBSwinger about running a 6.4" backspace on his car, he said he never had any issues with the frame rub, which surprised the heck out of me because even with ~6.1" I had the wheel touch at full lock (when I still had stock LCA's). So I gathered up all the lower ball joints I had from collecting spindles at the local yard and replacing them on all my cars, and found that the height of the steering stops was wildly different between them. Some were barely a bump, others were a 1/2" protrusion. So I stopped putting as much weight on the tire touching the frame at full lock and started looking at steering angle instead.
Now, I run QA1 LCA's so I have no steering stop at all because the lower ball joint doesn't touch anything. But the tires aren't touching the frame yet in this picture...
Older picture, this is with the old set of 275's and before I went to the LED headlights.
Yes, tire specs actually change as much or more by model/manufacturer than by specs sometimes. A 275 should be ~10.8" at the section, but I've seen them go all the way up to 11.2". The Fallen Azeni RT615's on my car now are 10.8" at the section and 9.7" at the tread. The other thing is that the rim makes a big difference too. A 275/35/18 is squeezed on a 9" rim, that's the minimum width. The math would say that I should have .4" hanging over the lip of the rim with 18x9's (they're 10" outside to outside), but really the overhang is closer to a 1/4". So, even with a wider 275 if you're running a 9" rim there's a limit to how wide the section width will really be. The "measuring width" for a 275/35/18 is an 18x9.5". So on a 9" rim you will have a narrower section than the spec, and on a 10" wide rim you might have a wider section than the spec.
It gets even crazier as the tires get taller, the 295/40/18's on my car now are noticeably wider than the 275/35/18's that were on there before. The extra sidewall height allows them to flex out more. I didn't have any rubbing in the quarter with the 295/35/18's, when I went to the 295/40/18's I ended up rubbing a bit on large bumps (which is why I did the reverse tub).
Yes, but it's only about 5mm. It's just the thickness of the rotor at the hub. With the DoctorDiff hub the floating rotor sits on the face of the hub, where with the '73+ disks it's flush. The DoctorDiff hub is basically an aluminum version of a turned down 73+ rotor/hub. DionR has a similar brake set up, he just actually turned his hubs from a set of 73+ rotors.
The steering stops being cast into the lower ball joints is kind of a crap shoot. After talking to 72BBSwinger about running a 6.4" backspace on his car, he said he never had any issues with the frame rub, which surprised the heck out of me because even with ~6.1" I had the wheel touch at full lock (when I still had stock LCA's). So I gathered up all the lower ball joints I had from collecting spindles at the local yard and replacing them on all my cars, and found that the height of the steering stops was wildly different between them. Some were barely a bump, others were a 1/2" protrusion. So I stopped putting as much weight on the tire touching the frame at full lock and started looking at steering angle instead.
Now, I run QA1 LCA's so I have no steering stop at all because the lower ball joint doesn't touch anything. But the tires aren't touching the frame yet in this picture...
Older picture, this is with the old set of 275's and before I went to the LED headlights.
Yes, tire specs actually change as much or more by model/manufacturer than by specs sometimes. A 275 should be ~10.8" at the section, but I've seen them go all the way up to 11.2". The Fallen Azeni RT615's on my car now are 10.8" at the section and 9.7" at the tread. The other thing is that the rim makes a big difference too. A 275/35/18 is squeezed on a 9" rim, that's the minimum width. The math would say that I should have .4" hanging over the lip of the rim with 18x9's (they're 10" outside to outside), but really the overhang is closer to a 1/4". So, even with a wider 275 if you're running a 9" rim there's a limit to how wide the section width will really be. The "measuring width" for a 275/35/18 is an 18x9.5". So on a 9" rim you will have a narrower section than the spec, and on a 10" wide rim you might have a wider section than the spec.
It gets even crazier as the tires get taller, the 295/40/18's on my car now are noticeably wider than the 275/35/18's that were on there before. The extra sidewall height allows them to flex out more. I didn't have any rubbing in the quarter with the 295/35/18's, when I went to the 295/40/18's I ended up rubbing a bit on large bumps (which is why I did the reverse tub).
Yes, but it's only about 5mm. It's just the thickness of the rotor at the hub. With the DoctorDiff hub the floating rotor sits on the face of the hub, where with the '73+ disks it's flush. The DoctorDiff hub is basically an aluminum version of a turned down 73+ rotor/hub. DionR has a similar brake set up, he just actually turned his hubs from a set of 73+ rotors.