Run too narrow or too firm a setup and BC's gravel and fire roads will beat you up. Run too wide or too soft and you lose speed on the paved sections connecting them. Here's how to land on the right width and pressure for how you actually ride.
Why Width and Pressure Matter More on Gravel
A road tire only has to manage smooth pavement. A gravel tire has to manage everything from hardpack fire road to loose rock and washboard, often in the same ride. Width and pressure are the two variables that do the most work absorbing that terrain before it reaches your hands and your back, and they interact with each other: go wider and you can run lower pressure for the same amount of support, which is what actually makes a gravel setup comfortable and fast over rough ground.
Get either one wrong and the bike either wallows on pavement or bottoms out on the rough stuff. Neither is a huge deal to fix, but most riders never revisit their factory setup, so if you're on stock tires and pressure, chances are you're leaving comfort and grip on the table.
Choosing the Right Tire Width for BC Terrain
Most gravel bikes accept a range of widths, typically 35mm to 50mm, and the right one depends on where you actually ride:
- 35–38mm: Best if your riding leans toward paved and hardpack routes, like the Sea to Sky corridor's smoother forest service roads. Faster on pavement, less cushion on rough sections.
- 40–45mm: The sweet spot for most BC gravel riding, mixed terrain that includes loose rock, washboard, and the odd root or rut. This is where most riders on the North Shore and around Squamish end up.
- 45–50mm: Worth it if you're riding genuinely rough forest service roads or dipping into singletrack on a drop-bar bike. At this width you're trading some pavement speed for real cushion and grip.
Frame clearance is the limiting factor, not preference alone. Check your frame's max tire clearance before sizing up, and remember that mud clearance in wet BC winters eats into that number fast.
How to Dial In Your Tire Pressure by Weight and Width
Tire pressure should be set by rider weight (you plus gear) and tire width, not by a single number you set once and forget. Use this as a starting point, then adjust from feel:
| Rider weight (with gear) | 38mm tire | 42mm tire | 45mm tire |
|---|---|---|---|
| Under 65kg | 30–33 PSI | 26–29 PSI | 24–27 PSI |
| 65–80kg | 33–37 PSI | 29–33 PSI | 27–30 PSI |
| 80–95kg | 37–41 PSI | 33–37 PSI | 30–34 PSI |
| Over 95kg | 41–45 PSI | 37–41 PSI | 34–38 PSI |
Run tubeless if your setup allows it. Tubeless lets you run 3–5 PSI lower than you would with tubes before flat and pinch risk becomes a real concern, which matters on BC's rockier fire roads where a pinch flat on tubes is a common way to end a ride early.
Common Mistakes Riders Make
Running mountain bike pressure. If you came from mountain biking, your instinct might be to run gravel tires much softer than they need. Gravel tires are narrower and rounder in profile than MTB tires, so they need more pressure for the same support, not less.
Running road bike pressure. The opposite mistake: riders coming from road bikes often overinflate gravel tires out of habit. Above a certain point, extra pressure buys you almost nothing in rolling resistance on rough surfaces and costs you grip and comfort. More pressure only pays off on smooth pavement.
Never adjusting for the route. If your ride is mostly pavement with a short gravel section, running slightly higher pressure than your gravel baseline makes sense. If you're headed onto rougher terrain than usual, drop 2–3 PSI before you start rather than fixing it mid-ride.
Which Setup Fits Your Riding
Choose narrower and firmer if you: mostly connect paved sections with occasional smooth gravel, prioritize speed over cushion, or are commuting on a gravel bike around Vancouver.
Choose wider and softer if you: spend most of your time on rougher Sea to Sky forest service roads, want more comfort on longer days, or are running your gravel bike on mixed terrain that dips into light singletrack.
If you're still deciding between a gravel bike and a mountain bike in the first place, our gravel bike vs mountain bike guide breaks down which one actually fits your riding.
FAQ
What PSI should I run on gravel bike tires?
Most riders land between 25 and 40 PSI depending on tire width and body weight, wider tires and lighter riders toward the lower end. Use the chart above as a starting point and adjust from there based on feel.
Is 28mm wide enough for gravel?
Not for genuine gravel riding. A 28mm tire is really a road tire that can tolerate light gravel in a pinch. For BC fire roads and mixed terrain, 35mm is a more realistic minimum.
Is 40mm enough for gravel?
Yes, for most mixed BC terrain, 40mm is a solid, versatile choice. It only becomes limiting on genuinely rough forest service roads or if you're riding loaded for bikepacking.
Why aren't wider gravel tires always better?
Width beyond what your terrain needs adds rolling resistance on pavement and weight without a comfort benefit, since you're already getting adequate cushion at a narrower width. Match the tire to the terrain, not the other way around.
Get Your Gravel Setup Dialled at Dunbar Cycles
Not sure what width your frame can fit or where to start with pressure? Bring your bike into Dunbar Cycles in Vancouver or Corsa Cycles in Squamish and we'll set you up properly. Browse our full gravel bike lineup to see what we carry, or come in and we'll help you get the width and pressure right for how you actually ride.
