Aprilia v4 swingarm extension
Case Study — Reverse Engineering & Mechanism Design
Aprilia V4 Swingarm Extension
Custom CNC swingarm extension plates and axle sliders for an Aprilia Tuono V4 — designed from laser scan data with no OEM drawings, validated through printed prototypes, and machined in aluminum.
The Problem
No OEM Extension. No Drawings. An Asymmetric Swingarm.
The Aprilia Tuono V4 uses a cast aluminum swingarm that is asymmetric — the passenger side is narrower than the drive side where the axle hardware mounts. No aftermarket swingarm extension existed for this platform. No drawings, no dimensional data, no reference geometry.
The client needed a 6-inch extension to the chain adjustment slot range, custom axle sliders to match the extended position, and hardware that worked with the existing caliper bracket without interference — all while maintaining the visual language of the OEM casting.
The asymmetry of the Aprilia swingarm was the central engineering challenge. Most swingarm extensions assume symmetric mounting geometry. This one didn't have it — and that assumption had to be caught and corrected in prototype before machining.
Our Approach
Scan First. Model Second. Print to Validate. Then Machine.
With no OEM drawings available, the geometry had to come from the part itself. Schimmel Engineering scanned the Aprilia swingarm with a Creaform HandyScan Black Elite, capturing the axle slot geometry, hat mounting faces, caliper bracket position, and casting profile at ±0.025mm accuracy. That point cloud became the foundation for a fully parametric SolidWorks assembly.
The extension was designed as a set of interlocking plates that bolt to the existing swingarm structure — extending the chain adjustment slot by 6 inches and providing two adjustment positions: the original location and a new position 1.25 inches further back, for a total adjustment range of 2.25 inches.
Rather than sending drawings directly to a machine shop, a full-scale FDM prototype was printed and shipped to the client for fitment validation. This caught the asymmetry issue before any metal was cut — saving the cost of a machined revision.
| Scanner | Creaform HandyScan Black Elite — ±0.025mm NIST-traceable |
| CAD software | SolidWorks 2026 Professional |
| Extension offset | 6 inches (new slot) — 1.25 in additional adjustment |
| Total adj. range | 2.25 inches (stock + new position) |
| Material specified | 7075 aluminum (extensions) · 17-4PH stainless (axle sliders) |
| Axle slider fit | 25.05mm nominal — confirmed against 25.03mm aftermarket adjuster |
| Hat flange | Reduced to 4mm to clear caliper bracket — confirmed in 3D assembly |
| Engraving | "V4" — min inside corner radius 0.5mm for 1mm end mill tool path |
| Prototype method | FDM — Bambu printer — dispatched same day as print completion |
| Machined by | One Ten Machining |
Deliverables Package
Complete deliverables package — SolidWorks native files, STEP/IGES exports, and GD&T manufacturing drawings
Engineering Detail
The Asymmetry Problem — Caught in Prototype
The Aprilia Tuono V4 swingarm casting is narrower on the passenger side than the drive side — a difference of 4mm — at the face where the extension hat mounts. This is not documented anywhere. It was only discovered when Sam W. fitted the first prototype and found interference on the passenger side.
After receiving photos of the modified prototype and measuring the asymmetry, the extension plate thickness was corrected by 4mm on the right side, making the gap spacing symmetric at the installed position. A corrected prototype was printed and dispatched before the final production drawings were released.
The caliper bracket was also modeled in SolidWorks and confirmed to clear the hat flange at 4mm thickness — the original 5mm design created a collision. 3D modeling the full assembly, including the caliper, is what caught this before machining.
Laser Scan Session
Aprilia swingarm scanned with HandyScan Black Elite. Axle geometry, hat mounting faces, caliper bracket, and casting profile captured at ±0.025mm.
Initial Design Presented
Parametric SolidWorks assembly shared with Brandon and Sam. Geometry approved. "V4" (not RSV4 — Tuono variant) confirmed for engraving. Prototypes approved immediately.
First Prototypes Off Printer
FDM prototypes completed and dispatched same day. Shipped to Sam for fitment check.
Design Review — Iterations
Review call with Brandon and Sam. Axle slider diameter adjusted to 25.05mm. Brake stub corrected. Hat flange reduced from 5mm to 4mm to clear caliper. New prototypes printed overnight.
Asymmetry Discovered & Resolved
Sam reports passenger-side interference. Photos confirm 4mm asymmetry in swingarm casting. Extension geometry corrected. V3 prototype dispatched.
Final Drawings Released
Production drawings completed and reviewed. Final design confirmed. Payment processed. Files sent to One Ten Machining for CNC production.
Parts Installed
Machined aluminum extensions and axle sliders installed on the Tuono V4. Client feedback: "It all turned out amazing."
Ryan it all turned out amazing! Thanks again.
Brandon C. — Client
GD&T manufacturing drawing — dimensioned for CNC machining at One Ten Machining
What This Project Demonstrates
Scan-to-CNC With No Starting Point
This project had none of the usual inputs — no drawings, no CAD files, no dimensional data from the manufacturer. The only reference was the physical swingarm. Laser scanning converted that casting into actionable geometry in a single session, and SolidWorks parametric modeling built a production-ready assembly around it.
The prototype-first workflow is why this project succeeded. The asymmetry in the Aprilia casting would not have been caught from scan data alone — it required a physical prototype in the client's hands, on the actual motorcycle. Three prototype iterations over two weeks validated every critical dimension before a single piece of aluminum was cut.
The final parts were machined by One Ten Machining in Nashville. Schimmel Engineering supplied the SolidWorks files and GD&T drawings — and the parts fit on the first attempt.
If you have a vintage, custom, or one-off motorcycle component with no drawings — we can scan it, model it, and get it into production. Mail-in scanning starts at $130. Mechanism design and drawings are quoted per project.
Have a Part With No Drawing?
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