Toyota / Peugeot / Citroën C550–C551 Close-Ratio Gear Set

5 Speed Close-Ratio Synchromesh Gear Set – Toyota / Peugeot / Citroën (C550 / C551 Gearboxes)

This close-ratio synchromesh gear kit was originally developed for Kobe Motor (Spain) and their Aygo Cup cars used in gravel rally and circuit racing.

The Toyota C550 / C551 gearboxes are found mainly in the Toyota Aygo and Yaris, but also in several Peugeot and Citroën small-car models, as well as other Japanese compact vehicles.

⚙️ Gearbox Applications

C550
• Type: 5-speed manual, FWD
• Engine compatibility: 1.0 L 1SZ-FE / 1KR-FE
• Typical vehicles: Toyota Yaris / Vitz (XP10); Toyota Aygo (AB10); Peugeot 107 / Citroën C1 (shared platform); Toyota Passo (KGC10); Daihatsu Sirion / Boon (M300)
• Years of use: ≈ 1999 – 2006
• Notes: Early small-car gearbox used in Toyota/Daihatsu A-segment cars. Typical final drive 3.944. Compact case, cable-shift.

C551
• Type: 5-speed manual, FWD (updated C550)
• Engine compatibility: 1.0 L 1KR-FE
• Typical vehicles: Toyota Aygo (AB10 facelift / AB20); Toyota Yaris (XP90); Toyota iQ (KGJ10); Peugeot 108 / Citroën C1 (2nd gen); Subaru Justy (rebadged Daihatsu/Toyota); Daihatsu Sirion / Cuore (M600)
• Years of use: ≈ 2006 – 2021
• Notes: Successor to C550 with revised 4th/5th gears and optional 4.294 FD. Widely used in Toyota-PSA 1.0 VTi applications.

⚙️ Gear Ratios
1st — 2.78 (39/14)
2nd — 1.94 (33/17)
3rd — 1.47 (28/19)
4th — 1.20 (29/24)
5th — 1.06 (31/29)

🧱 Technical Specifications

• Material: Billet & forged Ni-Cr-Mo steel
• Hardness: HRC 56 – 60
• Surface treatments: Sandblasting, shot peening, and WPC (under request)
• Heat treatments: Carburizing and cryogenic

🏁 Key Features

• Optimized close ratios for improved acceleration and flexibility
• High durability and fatigue resistance for rally and circuit racing
• Proven in competition with over 25 cars in the Kobe Motor Aygo Cups (gravel and circuit racing) — zero failures after multiple seasons.
• Compatible with both Toyota and PSA 1.0 L 3-cylinder platforms