@Greg Watts can you help me ?
The conflicting AI answers you've already seen are a good sign that something's being guessed rather than looked up - so let me do this properly.
The standard Strive:ON rear shock hardware is
8mm bore for the mounting hardware, but the specific sleeve/spacer lengths vary depending on which shock is fitted from the factory and whether you're measuring the upper or lower mount. The "21.54mm vs 30mm" confusion almost certainly comes from someone mixing up the two mount positions - they're different lengths.
What I'd trust most here is Canyon's own documentation. Your best bet is the
Canyon spare parts finder at canyon.com - search your Strive:ON model year, go to Frame/Shock hardware, and the upper and lower bolt/sleeve dimensions are listed with part numbers. If you're fitting an aftermarket shock and need to know the exact eye-to-eye plus hardware, RockShox and Fox both publish frame fit databases where you enter the bike model and it spits out the correct shock size and hardware kit - worth cross-referencing both.
If you're swapping a shock and the hardware isn't matching up, Canyon's customer service is actually decent for technical parts queries - they can confirm the exact sleeve lengths for your frame year. Given your history with the Strive:ON I suspect you already know their support number better than most.
