This guide provides insights to help you determine the right Cannondale Synapse size.
The Cannondale Synapse is an endurance road bike with a more relaxed geometry compared to the Cannondale Supersix EVO and System Six.
There are seven frame sizes tailored for riders between 5’3″ to 6’6″ (160 to 198cm).
| Cannondale Synapse size | Rider height (in) | Rider height (cm) |
|---|---|---|
| 44 | 5’0″ to 5’4” | 152 to 162 |
| 48 | 5’2″ to 5’6″ | 157 to 167 |
| 51 | 5’5″ to 5’9″ | 165 to 175 |
| 54 | 5’7″ to 5’11” | 170 to 180 |
| 56 | 5’9″ to 6’1″ | 175 to 185 |
| 58 | 6’0″ to 6’4″ | 182 to 193 |
| 61 | 6’3″ to 6’8″ | 190 to 203 |
Factors to consider beyond your height
From my experience owning multiple bikes, while height is a starting point, achieving the perfect bike fit involves more nuanced considerations.
- Brand-specific sizing. Bike sizes can differ between brands. A size 51 Cannondale Synapse may not align with a size 51 Cervelo Caledonia. Always consult specific brand measurements over generic size labels.
- Stack and Reach are two critical measurements to consider. You can find these measurements in the frame geometry chart below.
- Reach is measured as the horizontal distance from the bottom bracket to the center of the head tube, influencing your riding posture. A longer reach provides an aggressive stance, while a shorter one ensures a relaxed position.
- Stack is the vertical distance from the bottom bracket to the top of the head tube. It determines the handlebars’ height relative height to the saddle. A higher stack ensures a more upright position, ideal for long rides or riders with back flexibility concerns.
- Falling in-between sizes. If you’re between two sizes, it’s generally advisable to opt for the smaller size from my experience and observation. A smaller size would allow for more room to make corrective measures if needed.
- Go for a test ride. Nothing beats a hands-on experience. Visit a local Cannondale dealer, try different sizes, and choose the one that feels just right. Most dealers offer test rides, especially for demo sizes.
Cannondale System Synapse frame geometry (2022-2023)
The geometry chart below applies to all Cannondale Synapse Carbon frames from the following:
- Years: 2022, 2023
- Models: Ltd, 1, 2, 3, 4
- Frame material: Carbon
The frame geometry measurements are explained in this article.
| Frame Size | 48 | 51 | 54 | 56 | 58 | 61 |
|---|---|---|---|---|---|---|
| Rider Height (cm) | 157 to 167 | 165 to 175 | 170 to 180 | 175 to 185 | 182 to 194 | 190 to 203 |
| Rider Height (ft) | 5’2″ to 5’6″ | 5’5″ to 5’9″ | 5’7″ to 5’11” | 5’9″ to 6’1” | 6’0″ to 6’4” | 6’3″ to 6’8” |
| Stack (mm) | 530 | 550 | 570 | 590 | 620 | 640 |
| Reach (mm) | 371 | 376 | 381 | 387 | 393 | 402 |
| Top Tube, Actual (mm) | 510 | 521 | 533 | 547 | 560 | 579 |
| Top Tube, Horizontal (mm) | 533 | 544 | 555 | 567 | 579 | 598 |
| Seat Tube (mm) | 407 | 443 | 480 | 520 | 550 | 590 |
| Seat Tube Angle | 73.0° | 73.0° | 73.0° | 73.0° | 73.0° | 73.0° |
| Head Tube (mm) | 109 | 130 | 143 | 164 | 187 | 218 |
| Head Tube Angle | 71.3° | 71.4° | 73.1° | 73.2° | 73.3° | 73.4° |
| Standover Height (mm) | 712 | 742 | 773 | 787 | 833 | 868 |
| Wheelbase (mm) | 991 | 1002 | 987 | 998 | 1011 | 1028 |
| Front Center (mm) | 588 | 598 | 583 | 594 | 606 | 623 |
| Chainstay (mm) | 415 | 415 | 415 | 415 | 415 | 415 |
| BB Drop (mm) | 75 | 75 | 73 | 74 | 70 | 70 |
| BB Height (mm) | 270 | 270 | 272 | 272 | 275 | 275 |
| Fork Offset (mm) | 55 | 55 | 45 | 45 | 45 | 45 |
| Fork Trail (mm) | 59 | 58 | 58 | 57 | 56 | 56 |
Bernard Lu has 7+ years of experience working in a bicycle shop, overseeing the retail and workshop operations. He’s a qualified bicycle mechanic who understands a cyclist’s needs and speaks the same cycling lingo.
If you meet him at the cafe, he will happily talk to you for hours about all the intricacies of bikes and cycling tech. Just buy him a coffee next time you see him.