Hi all, looking for some advice. I picked up a second hand Canyon Aeroad on eBay for £1,200. The seller seemed genuine and had raced at a high level a couple of years ago before switching to disc brakes.
The main issue is the chain keeps slipping when I put power through the pedals. I'm trying to work out whether this is a Di2 configuration problem (I'm new to Di2) or an issue with the crankset itself. The bike itself is in good condition and doesn't look like it's been crashed which would cause the crankset to warp. Wondering if it was a storage issue.
The crankset situation
The previous owner fitted a SRAM Quarq DZero crankset with a Praxis 53/39 chainring. The power meter doesn't work, which I knew when buying. The small ring looked warped, so I took it off and it wasn't flush when placed on the ground. I'm assuming this means the chainring needs replacing at minimum, possibly the whole crankset. From what I can tell, the correct replacement would be an R8100 crankset. The slipping is worse in certain gears and gets more pronounced as power and cadence increase.
Di2 configuration findings
When I downloaded the E-Tube Cyclist app and worked through the settings, I found the following:
- All firmware updated, no error codes
- Battery (BT-DN300) showing healthy charge
- Front shifting unit adjustment value was at -19 (the scale runs roughly -20 to +20, so this was nearly at its limit, suggesting the derailleur was physically mispositioned and the software had been maxed out to compensate)
- Rear shifting unit adjustment value was at -11
- The 53/39 chainring isn't listed in E-Tube, which caused an error when trying to run the Synchronized Shift setup wizard
- Synchro shift was active (S1: Semi-Synchronized, S2: Synchronized) and can't be fully disabled as the app requires at least one profile to be assigned
- After some physical repositioning of the derailleur I got the front adjustment value down from -19 to -8, but it's still negative
Questions
- Is a SRAM Quarq DZero crankset with a 53/39 Praxis chainring compatible with Shimano R8150 Di2, or is this a fundamental mismatch?
- Is a warped chainring likely to be causing the slipping under load, separate from the Di2 setup issues?
- Can the front adjustment value be brought closer to 0 with further physical adjustment, or does the non-standard chainring make this impossible to dial in properly?
Any help appreciated. Happy to share more screenshots from E-Tube if useful.