Specialized Roubaix SL8 Expert - Shimano Ultegra Di2 vs Specialized Aethos 2 Expert - 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 Roubaix SL8 Expert - Shimano Ultegra Di2 comes out ahead (76% against 74%). That is not a universal verdict — change the terrain or the priority and the order can flip.
What actually separates them
- Price
- The Specialized Roubaix SL8 Expert - Shimano Ultegra Di2 is £250 cheaper — £5,249 against £5,499.
- Weight
- The Specialized Aethos 2 Expert - Shimano Ultegra Di2 is 1.1kg lighter, which you notice on long climbs more than anywhere else.
- Riding position
- The Specialized Roubaix SL8 Expert - Shimano Ultegra Di2 sits you more upright (1.56 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 Specialized Roubaix SL8 Expert - Shimano Ultegra Di2 takes 40mm tyres against 35mm — the single most common thing buyers wish they had more of.
- Climbing gear
- The Specialized Roubaix SL8 Expert - Shimano Ultegra Di2 has the easier bottom gear (27 gear inches against 32), which matters more than weight on anything genuinely steep.
- Mudguards
- Only the Specialized Roubaix SL8 Expert - Shimano Ultegra Di2 takes mudguards, which decides whether it can be your winter bike.
Side by side
| Spec | Roubaix SL8 Expert - Shimano Ultegra Di2 | Aethos 2 Expert - Shimano Ultegra Di2 |
|---|---|---|
| Price | £5,249 | £5,499 |
| Weight | 8.2 kg | 7.1 kg |
| Frame | carbon | carbon |
| Groupset | Shimano Ultegra Di2 R8170 2x12 electronic | Shimano Ultegra Di2 R8170 2x12 electronic |
| Stack / reach | 1.56 | 1.48 |
| Tyre clearance | 40 mm | 35 mm |
| Lowest gear | 27 in | 32 in |
| Mudguard mounts | Yes | No |
| Comfort | 73 | 47 |
| Speed | 53 | 79 |
| Climbing | 71 | 72 |
| 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.
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