Description
What ITA Fork Classes Mean
ITA (Industrial Truck Association) classifies fork carriages by the horizontal channel opening that the fork’s upper hook locks into. Each class corresponds to a specific mounting height range and capacity range.
| Fork Class | Mounting Height Range | Typical Forklift Capacity | Cross Section (Standard) |
|---|---|---|---|
| Class 1 | 12-16 inches | 2,000 – 3,500 lb | 1.25 × 4 inch |
| Class 2 | 16-20 inches | 3,500 – 5,000 lb | 1.5 × 4 inch |
| Class 3 | 20-25 inches | 5,000 – 8,000 lb | 1.75 × 4 inch or 2 × 4 inch |
| Class 4 | 25-30 inches | 9,000 – 11,000 lb | 2 × 5 inch or 2.5 × 5 inch |
| Class 5 | 30-35 inches | 12,000+ lb | 2.5 × 6 inch+ |
Class 3 is the most common heavy-duty class — used on standard 5,000-8,000 lb counterbalance forklifts, most rough terrain models, and many container handling forklifts.
Class 4 is the step up — used on larger forklifts that handle heavy steel, concrete, and shipping containers at full capacity.
Class 3 Fork Specifications — Standard Options
| Specification | Standard | Heavy-Duty |
|---|---|---|
| Carriage Class | ITA Class 3 | ITA Class 3 |
| Mounting Height | 20-25 inches (508-635 mm) | 20-25 inches |
| Fork Cross Section (H×W) | 1.75 × 4 inch (45 × 100 mm) | 2 × 4 inch (50 × 100 mm) |
| Capacity Per Pair | 5,500 lb (2,495 kg) | 6,800 lb (3,085 kg) |
| Fork Lengths Available | 36″, 42″, 48″, 60″, 72″, 84″, 96″ | 48″, 60″, 72″, 84″, 96″ |
| Carriage Width | 42 inch (1067 mm) standard | 45 inch (1143 mm) or custom |
| Material | 4142 Alloy Steel — Drop Forged | 4142 Alloy Steel — Drop Forged |
| Heat Treatment | Full-length induction hardened | Full-length induction hardened |
| Surface Hardness | 38-42 HRC | 38-42 HRC |
| Core Hardness | 26-30 HRC | 26-30 HRC |
| Safety Factor | 3:1 (load tested) | 3:1 (load tested) |
| Finish | Orange powder coat | Orange powder coat |
Class 4 Fork Specifications — For Larger Forklifts
| Specification | Standard |
|---|---|
| Carriage Class | ITA Class 4 |
| Mounting Height | 25-30 inches (635-762 mm) |
| Fork Cross Section (H×W) | 2 × 5 inch (50 × 125 mm) |
| Capacity Per Pair | 9,000 lb (4,080 kg) |
| Fork Lengths Available | 48″, 60″, 72″, 84″, 96″ |
| Carriage Width | 45-48 inch |
| Material | 4142 Alloy Steel — Drop Forged |
| Heat Treatment | Full-length induction hardened |
| Safety Factor | 3:1 (load tested) |
| Finish | Orange powder coat |
Note: Class 4 forks require a forklift with a Class 4 carriage. They are not interchangeable with Class 3. Measure your carriage opening before ordering.
Fork Length Guide — Standard vs Custom
| Length | Best For | Recommended For |
|---|---|---|
| 42 inch | Single standard pallet | Class 3 only |
| 48 inch | Single pallet + clearance — the most commonly ordered Class 3 length | Class 3 and Class 4 |
| 60 inch | Double pallet handling, medium-length loads | Class 3 and Class 4 |
| 72 inch | Lumber, pipe, double pallets, oversized crates | Class 3 and Class 4 |
| 84 inch | Long materials, truck trailer deep access | Class 3 and Class 4 |
| 96 inch | 8 ft loads, specialized applications | Class 3 and Class 4 |
Custom lengths are available. Tell us your exact requirement and we’ll manufacture to spec.
Compatibility Check — How to Know if You Need Class 3 or Class 4
Step 1: Measure your carriage mounting height. This is the vertical opening between the top and bottom carriage bars where the fork hooks engage.
- 20-25 inches = Class 3
- 25-30 inches = Class 4
Step 2: Check your forklift’s rated capacity.
| Forklift Rated Capacity | Likely Class | Recommended Fork Class |
|---|---|---|
| 3,000 – 4,500 lb | Class 2 | Class 2 (different page) |
| 5,000 – 8,000 lb | Class 3 | Class 3 |
| 9,000 – 11,000 lb | Class 4 | Class 4 |
| 12,000+ lb | Class 5 | Custom spec |
Step 3: Measure your existing fork shank thickness.
- 1.75 inch thick = Class 3 standard
- 2.0 inch thick = Class 3 heavy-duty or Class 4
- 2.5 inch thick = Class 4 or Class 5
Construction: Class 3 Fork Quality Benchmarks
Not all Class 3 forks are the same. The spec sheet may say “Class 3 forks 48 inch 5,500 lb” but the manufacturing quality varies significantly between suppliers.
Drop forged, not flame cut. Drop forging compresses the steel grain structure to follow the fork’s shape — especially through the heel curve where forks experience the most stress. Flame-cut forks (cut directly from steel plate) cut across the grain at the heel, creating a crack initiation point.
A drop-forged Class 3 fork at 5,500 lb capacity has a genuine 3:1 safety factor. A flame-cut fork with the same 5,500 lb marking may fail at under 12,000 lb — well below the rated 16,500 lb minimum for a 3:1 margin.
Full-length heat treatment, not just the heel. Some manufacturers only induction harden the first 6-8 inches from the heel. This leaves the fork tip soft. Under heavy point loads, a soft tip bends permanently. Our Class 3 forks are hardened the full length of the blade, from heel to tip.
| Manufacturing Method | Heel Strength | Tip Strength | Typical Life in Daily Use |
|---|---|---|---|
| Drop forged + full-length hardened | Excellent (3:1 safety factor verified) | Excellent | 8-12 years |
| Drop forged + heel-only hardened | Excellent | Poor — tip bends under load | 3-5 years |
| Flame cut + heel-only hardened | Poor — grain interrupted at heel | Poor | 1-3 years |
4142 alloy steel, not 1045. 4142 has chromium content for deeper, more uniform hardening. 1045 is cheaper but has lower fatigue resistance and shallower hardening depth. In daily use at 5,000+ lb loads, 1045 Class 3 forks develop micro-cracks at the heel 2-3x faster than 4142.
Class 3 Forks vs Class 2 — When to Upgrade
| Factor | Class 2 Fork | Class 3 Fork |
|---|---|---|
| Forklift capacity required | Up to 5,000 lb | 5,000 – 8,000 lb |
| Mounting height | 16-20 inches | 20-25 inches |
| Shank thickness | 1.5 inch | 1.75 – 2.0 inch |
| Best for | Warehouse, light duty | Yard, construction, heavy duty |
If your forklift has a Class 3 carriage, do not install Class 2 forks. The fork hooks are smaller and can disengage from the carriage under load under certain conditions. Always match the fork class to the carriage class.
Inspection Threshold: When to Replace Class 3 Forks
Per OSHA and ANSI/ITSDF B56.1 standards, forklift forks must be replaced when:
- Wear exceeds 10% of original thickness at the heel (the most common reason for replacement)
- Heel crack of any length — immediate replacement
- Blade deflection (bend) — more than 0.5% of fork length
- Tip wear that reduces fork length by more than 10%
- Visible heat damage — discoloration from contact with hot materials
For a standard Class 3 fork with 1.75 inch shank thickness: replace when heel thickness measured at the wear point drops below 1.575 inches (10% wear threshold).
We carry replacement Class 3 forks in all standard lengths for quick delivery.
Why Buy Class 3 Forklift Forks from Hebei Maoxiang?
Manufactured in-house. We forge, heat treat, and finish our forks in the same facility as our forklifts. No outsourcing, no distributor markup.
Full-length hardened. Every fork — Class 3 or Class 4 — is induction hardened the full blade length, not just the heel.
Drop forged 4142 steel. No flame-cut forks. No mild steel substitutes.
Load tested. Every pair is tested to 3:1 safety factor before shipment. Test certificate available on request.
CE certified. Complies with EN 1757-3 and ISO 2328 fork carriage standards.
Custom options available. Need a non-standard length, cross section, or coating? Tell us the spec.
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