A while back I reverse-engineered the SRAM 8-bolt spline for their current generation cranks.
The 3D printed test piece I made has a way better fit than SRAM’s own chainrings.
Regardless, before I go ahead with ordering a custom 8-bolt 104 BCD spider for someone to use a Gates belt sprocket with SRAM’s T-type cranks, I figured I’d share it here and also invite others to upload their reverse-engineered interfaces for a sanity check.
Here’s mine.
SRAM 8-Bolt Interface.STEP (163.5 KB)
I’ll take a look when I get a minute. I’ll admit I didn’t spend much time and went pretty quick with my “reverse-engineered” interface.
SRAM 8 Bolt Chainring Interface.step (79.3 KB)
I decided I didn’t know how to express the differences. But this is the one I have. All I did was 3D print a test, so I don’t know if yours or mine is better.
Did either of you end up getting a spider machined out of these designs and how do they fit?
Found my 3D printed test-piece and the fit wasn’t as good as I remembered it to be (I got it mixed up with another project). Still as good as SRAM, but I’d prefer a tighter fit.
So I ended up going back to the beginning. Purchased some radius gauges and reverse-engineered the interface from scratch again.
I’ve got some spiders on order and should have them within a few weeks.
I’ll report back with a report on how well they fit (or don’t fit). 