Longtail Cargo E-Bike Tire Pressure: Tern GSD, Yuba, RadWagon Guide
Longtail Cargo: A Different Beast
Longtail cargo e-bikes (Tern GSD, Yuba Spicy Curry, RadWagon) are built to haul: kids, groceries, gear, passengers. Load capacity ranges from 300-440 lbs total.
This creates unique tire pressure challenges:
- Massive load swings (solo rider vs. +150 lbs kids/cargo)
- Extreme rear bias (most load on rear rack)
- Safety critical (tire failure with kid aboard = unacceptable)
- Wide range of use cases (school run, grocery haul, date night)
Standard PSI charts don't account for this. This guide does.
Understanding Longtail Load Distribution
Solo Rider (Baseline)
Example: Tern GSD with 180 lb rider, no cargo
- Bike weight: 70 lbs (longtails are heavy)
- Total: 250 lbs
- Distribution: 42% front (105 lbs) / 58% rear (145 lbs)
Baseline PSI (20×2.4" tires, typical for Tern GSD):
- Front: 32 PSI
- Rear: 38 PSI
This is your starting point. Everything else builds from here.
One Child on Rear (Common)
Add 60 lb child on rear rack/seat:
- Total: 310 lbs
- Distribution: 38% front (118 lbs) / 62% rear (192 lbs)
PSI adjustment:
- Front: +1 PSI (33)
- Rear: +4 PSI (42)
Why front increases: Bike is longer (longer wheelbase), need front stability.
Two Children on Rear (Heavy Load)
Add 60 lb + 40 lb kids on rear:
- Total: 350 lbs
- Distribution: 35% front (123 lbs) / 65% rear (227 lbs)
PSI adjustment:
- Front: +2 PSI (34)
- Rear: +7 PSI (45)
Approaching limits: Check tire sidewall max. If near max, consider reinforced tires.
Grocery Haul (Variable Load)
Add 50 lbs groceries (rear panniers + top bag):
- Total: 300 lbs
- Distribution: 38% front (114 lbs) / 62% rear (186 lbs)
PSI adjustment:
- Front: +1 PSI (33)
- Rear: +4 PSI (42)
Similar to one-child load.
Maximum Load (Adult Passenger or Heavy Cargo)
Add 150 lbs adult passenger or heavy cargo:
- Total: 400 lbs
- Distribution: 32% front (128 lbs) / 68% rear (272 lbs)
PSI adjustment:
- Front: +3 PSI (35)
- Rear: +10 PSI (48)
Critical: Verify this doesn't exceed:
- Tire sidewall max PSI
- Bike's rated weight capacity (usually 300-440 lbs)
- Your comfort with handling (very rear-heavy)
PSI by Longtail Model
Tern GSD S10/R14 (20×2.4")
Baseline (180 lb rider, solo):
- Front: 32 PSI
- Rear: 38 PSI
Load scenarios:
| Scenario | Front PSI | Rear PSI | Total Weight | Notes |
|---|---|---|---|---|
| Solo commute | 32 | 38 | 250 lbs | Baseline |
| + 20 lb work bag | 32 | 40 | 270 lbs | Minor adjustment |
| + One child (60 lbs) | 33 | 42 | 310 lbs | School run |
| + Two kids (100 lbs) | 34 | 45 | 350 lbs | Heavy family load |
| + Groceries (50 lbs) | 33 | 42 | 300 lbs | Weekly shopping |
| + Adult passenger (150 lbs) | 35 | 48 | 400 lbs | Near max capacity |
Tire specs: Schwalbe Big Ben Plus, typically 35-65 PSI range.
Yuba Spicy Curry (26×2.35")
Baseline (180 lb rider, solo):
- Front: 35 PSI
- Rear: 42 PSI
Load scenarios:
| Scenario | Front PSI | Rear PSI | Total Weight | Notes |
|---|---|---|---|---|
| Solo commute | 35 | 42 | 260 lbs | Baseline |
| + One child (60 lbs) | 36 | 46 | 320 lbs | Standard load |
| + Two kids (100 lbs) | 37 | 50 | 360 lbs | Check tire max |
| + Cargo (50 lbs) | 36 | 46 | 310 lbs | Grocery haul |
| + Heavy cargo (100 lbs) | 38 | 52 | 360 lbs | Near limits |
Tire specs: Kenda Krusade or similar, typically 40-65 PSI range.
RadWagon 4 (22×3.0")
Baseline (180 lb rider, solo):
- Front: 28 PSI
- Rear: 33 PSI
Load scenarios:
| Scenario | Front PSI | Rear PSI | Total Weight | Notes |
|---|---|---|---|---|
| Solo commute | 28 | 33 | 270 lbs | Baseline (heavier bike) |
| + One child (60 lbs) | 29 | 37 | 330 lbs | Comfortable |
| + Two kids (100 lbs) | 30 | 41 | 370 lbs | Heavy load |
| + Groceries (50 lbs) | 29 | 37 | 320 lbs | Weekly shopping |
| + Max load (120 lbs) | 31 | 43 | 390 lbs | Approaching limits |
Tire specs: Kenda Krusade 22×3.0", typically 20-30 PSI max (check sidewall).
Note: Wider tires (3.0") allow lower PSI for same support vs. Tern/Yuba.
Urban Arrow Family (20×2.6")
Baseline (180 lb rider, solo):
- Front: 40 PSI (front box weight)
- Rear: 44 PSI
Load scenarios (front cargo box bikes):
| Scenario | Front PSI | Rear PSI | Total Weight | Notes |
|---|---|---|---|---|
| Solo | 40 | 44 | 280 lbs | Empty box |
| + Two kids in box (100 lbs) | 45 | 46 | 380 lbs | Box fully loaded |
| + Box load + rear (120 lbs) | 47 | 48 | 400 lbs | Maximum capacity |
Different dynamics: Front cargo box changes everything. Front PSI critical.
Multi-Child Safety Considerations
Stability with Kids Aboard
Why PSI matters more with passengers:
- Kids shift weight (lean, squirm)
- You brake harder (protecting precious cargo)
- Handling must be predictable (no surprises)
PSI strategy:
- Use upper end of weight-adjusted range
- Rear +5-7 PSI vs. solo (even if heavy)
- Front +2 PSI for steering stability
Example:
- Calculator says: 33F/42R
- With kids aboard: 35F/44R (extra margin)
Braking Forces
Longtails with kids require aggressive braking (stopping 350+ lbs quickly).
Under-inflated tires during hard braking:
- Tire squirms, reduces braking power
- Longer stopping distance
- Risk of tire rolling off rim
Solution: Never go below minimum PSI for your weight + cargo, especially with kids.
Cornering Stability
Kids on rear shifts center of gravity back and up. Cornering requires more care.
PSI impact:
- Too low rear PSI = wallowy, unpredictable corners
- Proper rear PSI = stable, confidence-inspiring
Rule: If you feel hesitant cornering with kids, add 2-3 PSI rear.
Terrain Adjustments for Loaded Longtails
Smooth Pavement (Baseline)
Use load-adjusted PSI from tables above. This is your standard.
Rough Pavement (Potholes, Cracks)
Adjustment: +2-3 PSI rear if carrying kids/heavy cargo
Why: Pinch flat with passengers aboard is unacceptable. Extra PSI = safety margin.
Example:
- Smooth pavement with two kids: 34F/45R
- Rough pavement with two kids: 34F/48R
Light Trails (Packed Dirt, Rail Trails)
Adjustment: -3 to -5 PSI from pavement (if no passengers)
With passengers: Only -2 PSI max (safety priority)
Example:
- Pavement solo: 32F/38R
- Trail solo: 29F/34R
- Trail with kids: 31F/40R (can't drop as much)
Never on Technical Terrain
Reality check: Longtail cargo bikes aren't for technical trails, especially loaded.
Reasons:
- Long wheelbase (poor maneuverability)
- Heavy weight (hard to control)
- Cargo/passengers (safety risk)
Stick to: Pavement, bike paths, smooth gravel maximum.
Cargo Weight Distribution Strategies
Rear-Heavy (Most Common)
Typical: Kids/cargo on rear rack, some in panniers.
PSI priority: Maximize rear support.
Example:
- 80 lbs rear (two kids)
- 20 lbs mid-frame (frame bag)
- Front: +1 PSI, Rear: +6 PSI
Balanced Load (Bikepacking)
Setup: Front rack + panniers, rear panniers, frame bags.
PSI priority: Balance front and rear increases.
Example:
- 40 lbs front (panniers/rack)
- 50 lbs rear (panniers/rack)
- Front: +3 PSI, Rear: +4 PSI
Less common: Most longtail use is rear-biased.
Uneven Load (One Rear Pannier)
Problem: Weight on one side (e.g., 30 lbs left pannier, nothing right).
PSI impact: Doesn't change overall PSI, but bike handles poorly.
Solution: Balance load side-to-side. If impossible, add 1-2 PSI rear for stability.
School Run Optimization
Morning Routine (Two Kids + Lunch Boxes + Bags)
Load:
- Kid 1: 60 lbs
- Kid 2: 40 lbs
- Bags/gear: 15 lbs
- Total cargo: 115 lbs
PSI setup (Tern GSD example):
- Front: 34 PSI
- Rear: 46 PSI
Check: Before every school run. Kids' safety depends on it.
Return Trip (Solo, No Cargo)
Option 1 (Lazy): Leave PSI high (34F/46R).
- Pro: No adjustment needed
- Con: Harsh ride, less efficient
Option 2 (Optimal): Drop to solo baseline (32F/38R).
- Pro: Comfortable, efficient
- Con: Requires pump/gauge at school
Recommendation: Keep portable pump in bag, adjust if you have time. If rushed, riding slightly high is fine.
Grocery Hauling
Weekly Shop (50-70 lbs)
Load placement:
- Rear panniers: 40 lbs
- Rear top bag: 20 lbs
- Frame bag: 10 lbs
PSI adjustment:
- Front: +1-2 PSI (33-34)
- Rear: +4-5 PSI (42-43)
Pro tip: Deflate slightly if pavement is rough. Full panniers add suspension.
Costco Run (80-100 lbs)
Heavy load:
- Multiple pannier bags
- Top rack fully loaded
- Possibly front basket too
PSI adjustment:
- Front: +2-3 PSI (34-35)
- Rear: +7-8 PSI (45-46)
Check tire max: Ensure you're not exceeding limits.
Liquid Cargo (Heavy and Unstable)
Challenge: Gallon jugs, beverages = heavy, shifts in panniers.
Strategy:
- Add extra 2 PSI rear (vs. same weight dry cargo)
- Secure liquid cargo tightly (bungees)
- Ride conservatively (no aggressive corners)
Tubeless on Cargo Bikes
Benefits for Loaded Longtails
1. Lower PSI possible (more comfort under load)
- Can run 2-3 PSI lower for same rim protection
- Improves ride quality with kids aboard
2. Pinch flat elimination (critical with passengers)
- No tube to pinch = one less failure mode
- Peace of mind with kids
3. Self-sealing punctures
- Thorn/glass flats rare
- Reduced roadside stops (important with kids)
Tubeless PSI Adjustments
Example (Tern GSD, 180 lb rider, two kids):
- Tubed: 34F/45R
- Tubeless: 32F/42R (same rim protection, more comfort)
See our tubeless guide and burping prevention guide for setup.
Tire Selection for Longtails
What to Look For
1. High Weight Rating (E-Bike Specific)
Look for "ECE-R75" or "E-50" markings. These tires are tested for e-bike loads.
2. Cargo-Rated Construction
Some tires are explicitly cargo-rated:
- Schwalbe Big Ben Plus
- Schwalbe Super Moto-X
- Schwalbe Pick-Up
3. High PSI Maximum (50-70 PSI)
Gives you headroom for heavy loads without exceeding max.
4. Puncture Protection
Longtails are utility vehicles. Flats waste time. Choose:
- Schwalbe Marathon Plus (best puncture protection)
- Continental Contact Plus (excellent urban tire)
- Tannus Armour inserts (adds protection to any tire)
Tire Upgrade Timing
Replace tires when:
- Tread below 1.5mm (safety critical with passengers)
- 2,000 miles (cargo bikes wear tires fast)
- 2 years old (age limit for safety)
Don't cheap out: With kids aboard, tire quality matters. Buy the best.
Common Longtail PSI Mistakes
Mistake 1: Using Solo PSI with Kids
Problem: Running 32F/38R with two kids (should be 34F/45R).
Result:
- Rear tire feels soft
- Pinch flat risk
- Poor handling (wallowy)
Fix: Always adjust for load. Check pressure before every kid-hauling trip.
Mistake 2: Exceeding Tire Maximum
Problem: 180 lb rider + 120 lbs kids/cargo = need 48-50 PSI rear, but tire max is 50 PSI.
Result:
- Zero safety margin
- Heat from riding can push over max
- Blowout risk
Fix: Upgrade to reinforced tires with 60-70 PSI max.
Mistake 3: Forgetting Front Adjustment
Problem: Adjusting rear but leaving front at solo PSI.
Result:
- Front feels too soft relative to rear
- Steering vague
- Less stable
Fix: Always adjust both tires, even if front adjustment is small (+1-2 PSI).
Mistake 4: Never Checking Pressure
Problem: "Tires look fine" (visual check only).
Result:
- Gradual pressure loss (1-2 PSI/week)
- After 4 weeks: 8-10 PSI low
- Dangerous with kids aboard
Fix: Digital gauge check weekly minimum, before every kid trip.
Emergency Procedures
Flat with Kids Aboard
Step 1: Safely stop, get kids off bike immediately.
Step 2: Assess flat.
- Slow leak? Pump up, ride slowly to safe location.
- Fast leak? Call pickup or walk bike.
Step 3: Repair or replace.
Prevention: Carry portable pump + spare tube always when hauling kids.
Tire Pressure Too Low Mid-Trip
Signs:
- Rear feels soft/wallowy
- Heard loud "thunk" hitting pothole (rim strike)
Action:
- Stop safely
- Check pressure with gauge (if you have one)
- Inflate with portable pump
- If no pump: Ride very slowly to safe location, avoid impacts
Prevention: Check before trip. Carry mini pump or CO2 cartridges.
Calculate Your Longtail PSI
Our calculator includes cargo bike presets with passenger/cargo weight inputs.
Select your longtail model (Tern GSD, Yuba, RadWagon), input exact cargo/passenger weight, and get safe PSI for your specific load.
Safety first: Longtail cargo bikes carry precious cargo. Proper tire pressure isn't optional—it's a safety requirement. Check pressure weekly, adjust for load every time, and never cut corners on tire quality or maintenance.
Last updated: November 14, 2025