Magnum Cosmo Tire Pressure Guide
PSI by Rider Weight
Use this table as a starting point for your Magnum Cosmo. These values assume pavement riding with no cargo. Adjust for terrain and load (see sections below).
| Rider Weight | Front PSI | Rear PSI | Feel |
|---|---|---|---|
| 120 lbs | 49 PSI | 53 PSI | Balanced |
| 140 lbs | 50 PSI | 54 PSI | Balanced |
| 160 lbs | 51 PSI | 55 PSI | Balanced |
| 180 lbs | 52 PSI | 56 PSI | Balanced |
| 200 lbs | 54 PSI | 58 PSI | Balanced |
| 220 lbs | 55 PSI | 59 PSI | Balanced |
| 240 lbs | 56 PSI | 60 PSI | Firm |
| 260 lbs | 57 PSI | 61 PSI | Firm |
Note: These are baseline recommendations. Use our calculator for precise PSI based on your exact weight, cargo, and terrain.
Factory Tire Specifications
Stock Tire Size
Weight Distribution
PSI by Terrain Type
Adjust your Cosmo's tire pressure based on where you ride. Lower pressure = more traction and comfort. Higher pressure = more efficiency and speed.
🛣️Pavement / Bike Paths
Higher pressure reduces rolling resistance on smooth surfaces. Aim for the upper end of your weight range for maximum speed and battery efficiency.
🌲Gravel / Packed Dirt
Medium pressure balances traction with efficiency. Drop 3-5 PSI from pavement settings for better grip on loose surfaces.
⛰️Trails / Rocky Terrain
Lower pressure lets tires conform to obstacles and provides cushioning over roots and rocks. Stay above 40 PSI to prevent pinch flats.
🏖️Sand / Snow
These 26x1.75 tires are not ideal for sand/snow. If riding these surfaces, stay near minimum PSI.
Cargo & Passenger PSI Adjustments
When carrying cargo or a passenger on your Cosmo, adjust PSI to prevent tire squirm and maintain handling.
Passenger (Child Seat or Rear Rack)
Front: 54 PSI → 54 PSI (same)
Rear: 54 PSI → 58 PSI
Cargo (Panniers, Baskets, Trailers)
Front: 54 PSI → 54 PSI
Rear: 54 PSI → 57 PSI
Safety Warning: Never exceed 65 PSI (tire sidewall max) even with heavy cargo. If you need more support, consider upgrading to reinforced tires or reducing load.
Common Tire Pressure Mistakes
❌ Using the Same PSI as Your Riding Buddy
Optimal PSI depends on total load (rider + bike + cargo). A 150 lb rider and a 220 lb rider on the same bike need different pressure. Always calculate based on YOUR weight.
❌ Ignoring Terrain Differences
Pavement PSI will feel harsh off-road and cause poor traction. Trail PSI on pavement wastes battery and risks pinch flats. Adjust for where you actually ride.
❌ Setting Front and Rear to the Same PSI
The Cosmo has 48% / 52% weight distribution. Rear tire needs more pressure to handle the extra load and prevent squirm.
❌ Only Checking PSI When Tires Look Low
Tires lose 1-2 PSI per month naturally. Check weekly, especially before long rides or when carrying cargo. Use a quality digital gauge for accuracy.
❌ Exceeding Sidewall Max PSI
The 65 PSI limit on 26x1.75 tires is for safety. Going over risks blowouts, especially in hot weather or rough terrain. Always stay within the 40-65 PSI range.
Get Precise PSI for Your Magnum Cosmo
Our calculator uses your exact weight, cargo load, terrain type, and temperature to generate precise front and rear PSI recommendations with real-time safety warnings.
Open PSI Calculator →100% free • No signup • Works on mobile