Description
NOS 1953 U.S. Army 155mm M1/M114 Howitzer Carriage Wheel Hub with Bearing Cups – P/N 7122008
Item Overview
This new-old-stock U.S. Army wheel-hub assembly was packed in February 1953 for the M1A1 and M1A2 carriages used with the 155mm Howitzer M1 and M1A1, later represented in the M114 family. The assembly consists of one steel wheel hub with two installed tapered-roller-bearing cups, also called outer bearing races.
Identification and Stock Information
The original Ordnance nomenclature was “Hub with Cups” or “Hub and Cup Assembly.” Later federal supply records identify the same part as a “Hub and Bearings Assembly.” The word “bearings” in the modern name does not mean that the complete bearing cones and rollers are included.
- Original nomenclature: Hub with cups / hub and cup assembly
- Current nomenclature: Hub and Bearings Assembly
- Ordnance part number: 7122008
- 1953 stock marking: C39-7122008
- Later Federal Stock Number: 1025-712-2008
- Current NSN: 1025-00-712-2008
- Primary application: 155mm Howitzer Carriage M1A1 and M1A2
- Quantity used per carriage: Two
- Package date: February 1953
- Listing quantity: One hub with two installed bearing cups
- Status: Inert mechanical component
Included Hub and Bearing Cups
Army parts diagrams identify the assembly as hub P/N 6540656 with two different tapered-roller-bearing cups installed inside it. The cups are the fixed outer races against which the separate bearing cones and rollers operate. Their listed bearing numbers are 3110-100-0323 and 3110-100-0327.
- Hub: P/N 6540656
- Bearing cup: 3110-100-0323
- Bearing cup: 3110-100-0327
Components Not Included
This is not a complete wheel, complete bearing set, or complete hub-and-drum assembly. The bearing cones and rollers, grease seals, hub cap, brake drum, wheel, mounting hardware, and related fasteners were listed as separate Army parts and are not included unless specifically stated.
- Bearing cones and roller assemblies
- Grease seals and retainers
- Hub cap
- Brake drum and brake components
- Wheel and tire
- Studs, nuts, washers, and other fasteners
Original Mechanical Function
The hub formed the center of one carriage wheel and rotated around the axle through its tapered-roller bearings. Each installed cup provided a hardened outer running surface for a separate bearing cone and roller assembly. This arrangement supported the heavy carriage while allowing the wheels to turn during towing. Correct bearing fit, lubrication, seals, and adjustment were important because the complete howitzer weighed several tons and was designed for road and cross-country movement.
155mm Howitzer Carriage Application
Army parts manuals list P/N 7122008 for the M1A1 and M1A2 155mm howitzer carriages and specify two assemblies per carriage. One hub was fitted at each side of the axle. The M1A1 carriage replaced the earlier electric brake system with air brakes. The M1A2 introduced a screw-jack operating system for the central firing support and included a modified traveling lock.
M1 and M114 Howitzer History
The U.S. Army standardized the 155mm Howitzer M1 in 1941 as a modern medium field-artillery weapon. It used a split-trail carriage, pneumatic tires, a central firing support, an interrupted-screw breech, and a hydro-pneumatic recoil system. The design provided a mobile heavy-fire weapon that could be towed by a truck or high-speed tractor. Under the Army’s later naming system, the weapon and carriage configurations became part of the M114 family. The M114 normally used the M1A1 carriage, while the M114A1 used the improved M1A2 carriage.
History of Service
The 155mm Howitzer M1 entered combat during World War II and provided medium-artillery fire for American forces in Europe and the Pacific. The weapon remained important during the Korean War and was widely used during the Vietnam War. Its range, durable carriage, and ability to fire several types of separate-loading ammunition helped give it a long service life. M114-family howitzers were also supplied to allied nations, and foreign armies continued to operate or modernize the design after it left regular U.S. service.
1953 Packing and Supply Markings
The marking “PACKED FEB. 53” records when the component was preserved and packed for military storage. It should not be treated as a confirmed manufacturing date. The “C39” prefix refers to Standard Nomenclature List C-39, which covered the 155mm howitzer and its related carriages. It is a catalog reference and is not part of the later Federal Stock Number or current NSN.
Rock Island Arsenal Drawing Record
Current federal logistics data continues to identify NSN 1025-00-712-2008 as a Hub and Bearings Assembly for the 155mm M1A2 howitzer carriage. Drawing number 7122008 is associated with Rock Island Arsenal under CAGE 19204. This identifies the responsible Army drawing activity and does not, by itself, prove that Rock Island Arsenal manufactured this individual hub.
Related 4.5-Inch Gun Application
The 4.5-inch Gun M1 shared the general carriage and wheel-hub design used by the 155mm Howitzer M1. Army records for that weapon also identify P/N 7122008. However, the markings on this example connect it most directly with SNL C-39 and the M1A1/M1A2 carriage used by the 155mm howitzer.
Condition
This is a new-old-stock military surplus component packed in February 1953. It may retain storage preservative and show oxidation, discoloration, scratches, packing marks, aged protective finish, or other signs of long-term storage. Original packaging may show staining, tears, fading, or handling wear. The bearing cups are installed, but the assembly has not been represented as inspected or tested for operational service. Please check the pictures for the general condition of the item.
Ideal For
This uncommon artillery-carriage component is well suited for historical restoration work, spare-parts reference collections, museums, military vehicle displays, and exhibits explaining the mechanical construction of the M1 and M114 howitzer families.
- M1 and M1A1 155mm howitzer restorations
- M114 and M114A1 howitzer displays
- M1A1 and M1A2 carriage collections
- U.S. Army artillery museums
- Military vehicle parts collections
- World War II, Korean War, and Vietnam War exhibits
- Historic bearing and wheel-hub displays
Approx length 15", Approx width 15", Approx height 10", Approx weight 76lbs.
Pictures are stock images of our inventory. Unless otherwise noted, you will not be receiving the exact item shown in the pictures. The pictures are representative of the item’s general condition. The item you receive might be slightly better, or worse, condition than was shown in the pictures.
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