Cannondale Synapse Carbon 2 SmartSense vs Specialized Aethos 2 Pro - Shimano Ultegra Di2
Both are endurance bikes at a similar price. Here is what actually separates them.
The short answer
For a typical all-round rider the Specialized Aethos 2 Pro - Shimano Ultegra Di2 comes out ahead (76% against 72%). That is not a universal verdict — change the terrain or the priority and the order can flip.
What actually separates them
- Price
- The Cannondale Synapse Carbon 2 SmartSense is £254 cheaper — £6,995 against £7,249.
- Weight
- The Specialized Aethos 2 Pro - Shimano Ultegra Di2 is 2.4kg lighter, which you notice on long climbs more than anywhere else.
- Riding position
- The Cannondale Synapse Carbon 2 SmartSense sits you more upright (1.52 stack-to-reach against 1.48). The Specialized Aethos 2 Pro - Shimano Ultegra Di2 is the more aggressive of the two — quicker if you can hold it, harder work if you cannot.
- Tyre clearance
- The Cannondale Synapse Carbon 2 SmartSense takes 42mm tyres against 35mm — the single most common thing buyers wish they had more of.
- Climbing gear
- The Cannondale Synapse Carbon 2 SmartSense has the easier bottom gear (25 gear inches against 32), which matters more than weight on anything genuinely steep.
- Mudguards
- Only the Cannondale Synapse Carbon 2 SmartSense takes mudguards, which decides whether it can be your winter bike.
Side by side
| Spec | Synapse Carbon 2 SmartSense | Aethos 2 Pro - Shimano Ultegra Di2 |
|---|---|---|
| Price | £6,995 | £7,249 |
| Weight | 9.1 kg | 6.7 kg |
| Frame | carbon | carbon |
| Groupset | SRAM Force AXS | Shimano Ultegra Di2 R8100 2x12 electronic |
| Stack / reach | 1.52 | 1.48 |
| Tyre clearance | 42 mm | 35 mm |
| Lowest gear | 25 in | 32 in |
| Mudguard mounts | Yes | No |
| Comfort | 68 | 47 |
| Speed | 45 | 83 |
| Climbing | 64 | 77 |
| Value | 0 | 0 |
Neither might be the right answer
This page assumes an average rider. Tell us how you actually ride and we will rank these two against everything else at the price.
Find my bikeRelated comparisons
- BMC Roadmachine 01 THREE vs Cannondale Synapse Carbon 2 SmartSense
- Cannondale Synapse Carbon 2 SmartSense vs Cervélo Caledonia-5 Force AXS
- Cannondale Synapse Carbon 2 SmartSense vs Cervélo Caledonia-5 Ultegra Di2
- Cannondale Synapse Carbon 2 SmartSense vs Giant Defy Advanced SL 1
- Cannondale Synapse Carbon 2 SmartSense vs Specialized Aethos 2 Pro - SRAM Force AXS
- Cannondale Synapse Carbon 2 SmartSense vs Specialized Roubaix SL8 Pro - SRAM Force AXS