Building an FSAE suspension requires careful selection of components that balance weight, strength, stiffness, and cost. Whether you're a first-year team or looking to improve an existing design, this parts list covers the essential hardware and structural pieces you'll need to assemble a functional and competitive suspension. Use this as a checklist to guide your design and procurement.
Key Components of an FSAE Suspension System
A typical Formula SAE suspension consists of several subsystems. Below are the core parts you'll need to source or fabricate.
Uprights and Hubs
Uprights (also called spindles or knuckles) connect the suspension arms to the wheel hub and carry the braking loads. Most teams machine these from 6061-T6 or 7075-T6 aluminum. The hub carries the wheel bearings and attaches to the upright. You will need:
- Uprights (left and right)
- Wheel hubs (often steel or aluminum)
- Wheel bearings (typically double-row angular contact or tapered roller)
- Circlips or retaining nuts for bearings
- Wheel studs and lug nuts
Control Arms and A-Arms
Control arms link the chassis to the upright. They are usually fabricated from 4130 chromoly steel tubing or 6061 aluminum tubing. Each corner requires an upper and lower control arm, often A-shaped. Key parts:
- Tubing (e.g., 0.035" wall or 0.049" wall for steel)
- Tube ends and inserts for rod end attachment
- Welded tabs for pushrod attachment
- Ball joints or rod ends at the upright connection
Pushrods and Pullrods
Pushrods connect the lower control arms to the rockers (bell cranks) when using a pushrod suspension. Pullrods are used similarly but attach to the upper arms. These are typically 7075 aluminum rods or chromoly tubes with rod ends on each end. You'll need:
- Pushrod tubing (e.g., 3/8" or 5/16" diameter)
- Left- and right-hand threaded rod ends
- Jam nuts
Springs and Dampers
Dampers (shock absorbers) control the motion of the suspension. Springs store energy and support the car. In FSAE, you typically use:
- 1.9" diameter coil springs (rates vary from 100 to 500 lb/in)
- Coilover dampers with adjustable rebound and compression damping (e.g., from Penske, Öhlins, Koni, or AFCO)
- Spring perches and adjusters
- Damper mounting brackets or clevises
Anti-Roll Bars (Optional)
Anti-roll bars reduce body roll. They are not mandatory but can improve handling. Parts include:
- Spring steel bar (typically 3/8" to 1/2" diameter)
- End links with spherical bearings
- Bushings or bearing blocks for chassis mounting
Rod Ends and Spherical Bearings
Rod ends provide articulation at control arm and pushrod connections. They must handle tension and compression loads. Common sizes: 1/4", 5/16", 3/8" bore. Materials: steel or aluminum. Use:
- Female rod ends with left- and right-hand threads for adjustability
- Spherical bearings for dampers and rockers
Hardware and Fasteners
High-strength fasteners are critical. Use ARP or Grade 8 bolts in critical locations. Typical hardware:
- 1/4-28 and 5/16-24 bolts for rod ends
- Safety wire or locking pins
- Nylock nuts and washers
- Thread locking compound
Material Selection for FSAE Suspension Parts
Choosing the right material affects weight, durability, and cost. For uprights, 7075-T6 aluminum offers high strength at lower weight than steel. For control arms, 4130 chromoly steel is the most common due to its weldability and high fatigue strength. Some advanced teams use carbon fiber for uprights or arms, but that requires extensive testing. For rod ends, choose stainless steel for corrosion resistance. Always check that materials meet FSAE rules regarding yield strength and dimensions.
Where to Source FSAE Suspension Parts
Most FSAE teams purchase from specialty suppliers like McMaster-Carr, Grainger, or industrial metal distributors. Rod ends and spherical bearings are available from manufacturers like Aurora Bearing or QA1. Racing damper companies like Penske or Koni sell direct to teams. For custom fabrication, partner with local machine shops that have experience with race car parts. Many teams also use online forums and team-to-team sales for used components. Always verify that parts comply with the current FSAE rulebook.
Budgeting for Your Suspension Build
A complete FSAE suspension can cost between $2,000 and $10,000, depending on the level of customization and quality of dampers. Budget breakdown:
- Uprights and hubs: $300-$800 (if machined in-house, lower)
- Control arms: $200-$600 in materials plus welding
- Dampers: $1,000-$4,000 (four high-end dampers)
- Springs: $100-$300
- Rod ends and bearings: $200-$500
- Fasteners and hardware: $100-$200
Plan to order extras of small parts like rod ends and bolts to account for design changes.
Final Recommendation: Build a Custom Parts List
Start with a spreadsheet listing every part needed for one corner, then multiply by four. Use the FSAE rules to confirm minimum thread engagement and fastener strengths. Design your suspension geometry first, then select parts that fit the loads and packaging. For your first build, stick with proven materials like 4130 steel and 6061 aluminum. Upgrade to 7075 or carbon fiber only after you've validated the base design. Test each component for fit and function before final assembly.
A well-prepared parts list save time and reduces mistakes. Use this guide as a starting point, and adapt it to your team's specific rules and resources.