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Published by Christopher J. Holley | Mopar History & Tech | December 2025

Chrysler did not use two different 5-lug bolt patterns by accident. The 5 on 4.0 in. and 5 on 4.5 in. patterns were a deliberate engineering and cost decision tied to vehicle weight, brake size, and hub durability, and they mirrored what other manufacturers were doing at the time.

The Two Chrysler 5-Lug Patterns

5 on 4.0 inches (5×4″) — “Small Bolt Pattern”

Used on:

• A-body cars (Valiant, Dart, Duster, early Barracuda)
• Lighter Slant-Six and Small-block V8 applications
• Mostly drum-brake cars

Why did it exist?

• Lower vehicle weight
• Smaller wheel bearings
• Smaller brake drums
• Less torque loading on the hub

Engineering logic:
Chrysler designed the A-body to be light, economical, and compact. The 5×4″ pattern was perfectly adequate for:

• ~3,000 lb. vehicles
• Narrower tires
• Modest brake diameters
• Everyday street use

Using a smaller bolt circle:

• Reduced unsprung mass
• Lowered manufacturing cost
• Allowed more compact hub and spindle designs

It was not a “cheap” design—just properly scaled.

5 on 4.5 inches (5×4.5″) — “Large Bolt Pattern”

Used on:

• B-body (Charger, Road Runner, Coronet)
• E-body (Challenger, ’70-up Barracuda)
• C-body (Newport, New Yorker)
• Police, taxi, towing packages
• High-performance and heavy-duty applications

Why Chrysler used it:

• Heavier vehicles
• Larger brake drums and rotors
• Higher torque loads
• Wider tires

Engineering advantages:

• Greater stud spacing reduces shear load per stud
• Allows thicker hubs
• Better heat management with larger brakes
• Improved durability under high lateral and braking loads

This is why every big-block performance car got the 5×4.5″ pattern—even when the engine was optional.

Why Chrysler Did Not Standardize One Pattern

From a modern standpoint, two bolt patterns seem unnecessary. In the 1950s–70s, however:

• Wheels were steel, not aluminum
• Tires were narrow bias-ply
• Manufacturing cost mattered greatly
• “One-size-fits-all” added unnecessary weight

Chrysler engineering philosophy was right sizing, not overbuilding.

Ford and GM did the same thing:

• GM: 5×4.75″ vs 5×5″
• Ford: 5×4.5″ vs 5×5.5″

Why the 5×4″ Pattern Disappeared

By 1976, several things forced Chrysler’s hand:

• Federal front disc brake requirements
• Larger wheel bearings
• Heavier cars
• Radial tires with higher grip
• Parts standardization pressures

The small bolt pattern simply could not:

• Package larger disc brake rotors efficiently
• Support increasing curb weights
• Meet durability standards long-term

As a result:

• Late A-bodies moved to 5×4.5″
• Small bolt pattern was permanently phased out

Summary Table

Feature	5×4″	5×4.5″
Vehicle weight	Light	Medium–Heavy
Brake size	Small drums	Large drums / discs
Performance use	Limited	Yes
Torque capacity	Lower	Higher
Longevity	Obsolete by 1976	Still used today

Bottom Line

Chrysler used two bolt patterns because it was good engineering, not oversight.

• 5×4″ was ideal for light A-bodies
• 5×4.5″ was required for power, weight, and performance

Once cars got heavier, faster, and safer, the smaller pattern had no remaining advantage—and Chrysler retired it.