Skip to content
WhichBike

Specialized Roubaix SL8 Comp - Shimano 105 Di2 vs Cannondale Synapse Carbon 4

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 Comp - Shimano 105 Di2 comes out ahead (77% against 73%). That is not a universal verdict — change the terrain or the priority and the order can flip.

Specialized

Roubaix SL8 Comp - Shimano 105 Di2

77% for a typical rider

£3,599 at Brand website
✓ Checked

Cannondale

Synapse Carbon 4

73% for a typical rider

£3,795 at Brand website
✓ Checked *

What actually separates them

Price
The Specialized Roubaix SL8 Comp - Shimano 105 Di2 is £196 cheaper — £3,599 against £3,795.
Weight
The Specialized Roubaix SL8 Comp - Shimano 105 Di2 is 0.4kg lighter, which you notice on long climbs more than anywhere else.
Riding position
The Specialized Roubaix SL8 Comp - Shimano 105 Di2 sits you more upright (1.56 stack-to-reach against 1.52). The Cannondale Synapse Carbon 4 is the more aggressive of the two — quicker if you can hold it, harder work if you cannot.
Tyre clearance
The Cannondale Synapse Carbon 4 takes 42mm tyres against 40mm — the single most common thing buyers wish they had more of.

Side by side

Spec Roubaix SL8 Comp - Shimano 105 Di2 Synapse Carbon 4
Price £3,599 £3,795
Weight 8.8 kg 9.2 kg
Frame carbon carbon
Groupset Shimano 105 Di2 R7170 2x12 electronic Shimano 105 Di2 R7100
Stack / reach 1.56 1.52
Tyre clearance 40 mm 42 mm
Lowest gear 26 in 27 in
Mudguard mounts Yes Yes
Comfort 73 68
Speed 46 44
Climbing 66 57
Value 18 12

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 bike

Related comparisons