Cargo E-Bike PSI: How Passenger and Rear Loads Change Pressure
Why Cargo E-Bikes Are Different
Cargo e-bikes have:
- Higher weight capacity (300-440 lbs typical)
- Longer wheelbase (more stable but weight shifts matter)
- Reinforced tires (often 2-4 PSI higher max than standard)
- Rear-biased loading (most cargo/passengers on rear)
Standard e-bike PSI recommendations don't account for 100+ lb load swings. This guide shows how to adjust pressure for safe, comfortable hauling.
Load Distribution Basics
Solo Rider (No Cargo)
Baseline PSI depends on rider weight and tire specs. Example for 180 lb rider on Tern GSD:
- Front: 28 PSI
- Rear: 32 PSI
Rear already 3-4 PSI higher due to motor/battery weight.
Rear Passenger (Child or Adult)
Passengers on rear rack/seat put 100% weight on rear wheel.
80 lb child:
- Front: +0 PSI (28)
- Rear: +3 PSI (35)
120 lb adult:
- Front: +1 PSI (29, for stability)
- Rear: +4 PSI (36)
Critical: Know your tire's sidewall max. If passenger PSI exceeds it, you need higher-rated tires.
Rear Cargo (Rack/Panniers)
Distribute weight evenly in panniers when possible. PSI adjustment depends on total load:
| Cargo Weight | Front Adj. | Rear Adj. |
|---|---|---|
| 20 lbs | +0 | +1 |
| 40 lbs | +0 | +2 |
| 60 lbs | +1 | +3 |
| 80 lbs | +1 | +4 |
| 100 lbs | +2 | +5 |
Example: 180 lb rider + 70 lbs groceries = 29F/35R.
Front Cargo (Basket/Rack)
Less common but requires front PSI increase:
20 lbs front basket: +2 PSI front (steering impact)
40 lbs front cargo: +3 PSI front, +1 PSI rear (balance)
Front cargo affects handling more than rear, so overcompensate slightly.
Multi-Load Scenarios
Parent + Child + Groceries
Setup: 180 lb adult, 60 lb child (rear seat), 30 lbs groceries (rear rack)
Calculation:
- Baseline: 28F/32R
- Child: +0F/+3R
- Groceries: +0F/+1R
- Total: 28F/36R
Dual Passengers (Tandem/Longtail)
Setup: 180 lb rider, 80 lb child (rear), 120 lb adult (rear bench)
Calculation:
- Baseline: 28F/32R
- First passenger: +0F/+3R
- Second passenger: +1F/+4R
- Total: 29F/39R
⚠️ Warning: Verify tire sidewall max (often 40-50 PSI on cargo bikes). This example is near max.
Heavy Cargo Hauling
Setup: 200 lb rider, 100 lbs cargo (rear panniers + top rack)
Calculation:
- Baseline: 29F/33R
- 100 lbs cargo: +2F/+5R
- Total: 31F/38R
Terrain Adjustments with Load
Standard terrain modifiers (pavement, mixed, dirt, sand) apply AFTER load adjustments.
Example: Cargo on Mixed Terrain
Baseline (solo, pavement): 28F/32R
Add 40 lbs cargo: 28F/34R
Mixed terrain (-10%): 25F/31R
Always apply load adjustments first, then terrain reductions.
Example: Passenger on Dirt Trails
Baseline (solo, pavement): 28F/32R
Add 80 lb child: 28F/35R
Dirt trails (-12%): 25F/31R
Safety note: Riding cargo bikes with passengers on rough terrain requires extra caution. Consider front suspension or staying on paved paths.
Dynamic vs. Static Weight
Static (Parked)
Use full calculated PSI when checking pressure at home.
Dynamic (Riding)
Pedaling/braking shifts weight fore/aft. Higher PSI accounts for momentary load spikes.
Example: Hard braking with 100 lbs rear cargo temporarily puts 80% weight on front wheel. Extra 1-2 PSI front prevents rim strikes.
Tire Pressure Monitoring
Check Frequency
- Solo riding: Weekly
- Regular cargo/passenger: Before every loaded trip
- Heavy loads (80+ lbs): Before AND after trip
Visual Inspection
With heavy loads, inspect for:
- Sidewall bulging (PSI too low)
- Tread squirm in corners (PSI too low)
- Harsh ride/vibration (PSI too high)
Adjust Mid-Trip
Carry a portable pump for long cargo trips. If handling feels off, add 2 PSI and retest.
Common Mistakes
1. Forgetting Passenger Weight
Wrong: Solo PSI with 120 lb passenger
Result: Sluggish rear, pinch flat risk, poor braking
Right: +4 PSI rear minimum for adult passenger
2. Overinflating Front
Wrong: Matching front to rear with rear cargo
Result: Harsh steering, reduced traction
Right: Front increases 0-2 PSI, rear increases 3-5 PSI
3. Ignoring Tire Max
Wrong: Calculating 42 PSI rear on 40 PSI max tire
Result: Blowout risk, unsafe
Right: Never exceed sidewall max. Reduce load or upgrade tires.
4. Using Cold Pressure After Ride
Wrong: Checking PSI hot (after 10 mile ride)
Result: Reads 2-3 PSI high, underinflate next time
Right: Always check pressure "cold" (before riding or 3+ hours after).
Cargo-Specific Tire Upgrades
If you frequently exceed tire max with cargo:
Option 1: Higher PSI Tires
- Standard: 40 PSI max
- Reinforced: 50 PSI max
- Cargo-rated: 60-65 PSI max
Example: Schwalbe Super Moto-X (62 PSI max) vs. standard Big Apple (55 PSI).
Option 2: Wider Tires
More volume = lower PSI for same load capacity. Example:
- 27.5×2.0" at 45 PSI = similar load capacity as
- 27.5×2.4" at 38 PSI (more comfortable)
Option 3: Tubeless
Run 2-3 PSI lower than tubed for same rim protection. Reduces pinch flat risk with heavy cargo.
Safety Guidelines
- Never exceed tire sidewall max (PSI rating printed on tire)
- Reduce speed on rough terrain with heavy loads (pinch flat risk)
- Distribute cargo evenly (left/right balance)
- Secure loads properly (shifting cargo affects handling)
- Check spokes monthly (heavy loads stress wheels)
Cargo Bike Calculator
Get precise PSI for your cargo bike, rider weight, passenger weight, and cargo distribution:
Select your cargo bike model (Tern GSD, Riese & Müller Load, Yuba Spicy Curry, etc.) and input exact weights for front/rear cargo. Calculator shows safe PSI ranges with warnings if you exceed tire limits.
Last updated: November 10, 2025