Getting gravel bike sizing right matters more than it does on a mountain bike, since drop-bar geometry puts you in a more stretched-out riding position and a size that's even slightly off will show up as discomfort on longer rides. Here's how to find your correct gravel bike size using height, reach, and stack, the three numbers that actually matter.
Why Gravel Bike Sizing Is Different From Mountain Bike Sizing
Gravel bikes borrow drop-bar geometry from road bikes, which means a more forward-leaning position and a narrower range of adjustment through stem length and bar height compared to a flat-bar mountain bike. Our gravel bike vs mountain bike guide covers how the two riding positions differ if you're still deciding between them.
Because of that more fixed position, gravel bikes are usually sized off standover height and effective top tube length rather than the more forgiving standover-only approach that works for a full-suspension mountain bike.
Gravel Bike Size Chart by Height
These ranges reflect typical drop-bar gravel geometry across the brands we carry, though exact reach and stack vary by model:
| Rider Height | Frame Size | Approx. Reach | Approx. Stack |
|---|---|---|---|
| 5'0" - 5'3" | XS (47-49cm) | 370-380mm | 540-555mm |
| 5'3" - 5'6" | S (51-52cm) | 380-390mm | 555-570mm |
| 5'6" - 5'9" | M (54-55cm) | 390-400mm | 570-585mm |
| 5'9" - 6'0" | L (56-58cm) | 400-410mm | 585-600mm |
| 6'0" - 6'3" | XL (58-60cm) | 410-420mm | 600-615mm |
| 6'3"+ | XXL (61cm+) | 420mm+ | 615mm+ |
Reach and stack matter more than the frame size label itself. Two brands both selling a "medium" can differ by a full size in actual reach, so treat the size chart as a starting point, not the final word.
Reach and Stack: The Two Numbers That Actually Matter
Reach is the horizontal distance from the bottom bracket to the top of the head tube. It tells you how stretched out you'll be, and it's a far better sizing indicator than seat tube length, since seat height is easily adjusted with the saddle post while reach is fixed by the frame.
Stack is the vertical distance from the bottom bracket to the top of the head tube. A higher stack puts you in a more upright, endurance-friendly position, while a lower stack favors a more aggressive, aerodynamic posture. Riders doing longer BC gravel routes with more time in the saddle often prefer a slightly higher stack than a pure road bike would use.
Standover Height Still Matters for Gravel
Because gravel riding often means unclipping quickly on loose or technical terrain, you want at least 1 to 2 inches of standover clearance over the top tube, more than you'd need on a road bike but less than the clearance typical on a full-suspension mountain bike. If you're between sizes, sizing down slightly and running a longer stem is usually the safer choice for gravel, since it preserves standover clearance without sacrificing much reach.
Tire Clearance and Sizing Go Hand in Hand
Frame size isn't just about rider fit. Tire clearance also changes slightly across sizes on some models, so if you're planning to run wider tires for BC's rougher gravel and forest service roads, check clearance at your specific frame size before buying. Our gravel bike tire width and pressure guide covers how tire width affects ride quality and clearance requirements once you've settled on a size.
When in Doubt, Get a Proper Fit
A size chart gets you in the right range, but a proper bike fit accounts for your specific proportions, flexibility, and riding goals. Our Vancouver and Squamish (Corsa Cycles) shops offer fit consultations on any gravel bike purchase, and it's worth the extra time before committing to a size, especially if you're planning longer rides or bikepacking trips where an ill-fitting bike becomes a real problem over hours in the saddle.
FAQ
Should I size up or down if I'm between gravel bike sizes?
Size down and run a slightly longer stem. This preserves standover clearance for technical terrain while letting you fine-tune reach through stem length, which is easier to adjust than frame size after the fact.
Is gravel bike sizing the same as road bike sizing?
Close, but not identical. Gravel bikes typically run a slightly shorter reach and taller stack than an equivalent road bike, prioritizing comfort and control over pure aerodynamics.
Does tire width affect what frame size I should buy?
Not directly for rider fit, but tire clearance can vary slightly by frame size on some models, so confirm clearance at your intended size if you plan to run wider tires.
Find Your Size at Dunbar Cycles
Ready to find your size? Browse our Gravel Bikes collection or book a fit consultation at our Vancouver or Squamish (Corsa Cycles) location.
