Specialized Aethos 2 Expert - Shimano Ultegra Di2 vs Cannondale Synapse Carbon 2
Both are endurance bikes at a similar price. Here is what actually separates them.
The short answer
These two score within 1 point of each other for a typical all-round rider, so there is no single winner — the right one depends entirely on which of the differences below you care about.
What actually separates them
- Price
- The Specialized Aethos 2 Expert - Shimano Ultegra Di2 is £496 cheaper — £5,499 against £5,995.
- Weight
- The Specialized Aethos 2 Expert - Shimano Ultegra Di2 is 1.3kg lighter, which you notice on long climbs more than anywhere else.
- Riding position
- The Cannondale Synapse Carbon 2 sits you more upright (1.52 stack-to-reach against 1.48). The Specialized Aethos 2 Expert - 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 takes 42mm tyres against 35mm — the single most common thing buyers wish they had more of.
- Climbing gear
- The Cannondale Synapse Carbon 2 has the easier bottom gear (27 gear inches against 32), which matters more than weight on anything genuinely steep.
- Mudguards
- Only the Cannondale Synapse Carbon 2 takes mudguards, which decides whether it can be your winter bike.
Side by side
| Spec | Aethos 2 Expert - Shimano Ultegra Di2 | Synapse Carbon 2 |
|---|---|---|
| Price | £5,499 | £5,995 |
| Weight | 7.1 kg | 8.4 kg |
| Frame | carbon | carbon |
| Groupset | Shimano Ultegra Di2 R8170 2x12 electronic | Shimano Ultegra Di2 R8100 |
| Stack / reach | 1.48 | 1.52 |
| Tyre clearance | 35 mm | 42 mm |
| Lowest gear | 32 in | 27 in |
| Mudguard mounts | No | Yes |
| Comfort | 47 | 68 |
| Speed | 79 | 53 |
| Climbing | 72 | 68 |
| 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
- Cannondale Synapse Carbon 2 vs BMC Roadmachine 01 THREE
- Cannondale Synapse Carbon 2 vs Canyon Endurace CF SLX 9 Di2
- Cannondale Synapse Carbon 2 vs Trek Domane SLR 7 Gen 5
- Cannondale Synapse Carbon 3 SmartSense vs Specialized Aethos 2 Expert - Shimano Ultegra Di2
- Giant Defy Advanced Pro 0 vs Cannondale Synapse Carbon 2
- Giant Defy Advanced Pro 0 vs Specialized Aethos 2 Expert - Shimano Ultegra Di2