Which clutch springs to choose for your Lambretta? Technical guide to choosing

If you are restoring or tuning a Lambretta and you are faced with the doubt of which clutch springs to adopt, you are in the right place. Choosing the correct spring is essential to guarantee perfect clutch operation and to avoid slipping problems, especially on boosted engines.

What makes a spring “right”?

The hardness of a clutch spring is determined by several technical factors:

• Spring wire thickness: the larger the diameter, the greater the compression force.

• Number of coils: affects the progressiveness of the spring.

• Production material: special or heat-treated steels offer greater strength and durability.

• Overall length: Affects clutch travel and responsiveness.

These technical characteristics must be carefully evaluated based on the type of engine installed on your vehicle.

Scooterthefero proposals for your Lambretta

To effectively respond to the different needs of Lambretta riders, Scooterthefero offers two clutch spring kits compatible with the LI, LIS, SX, DL, GP, LUI and J models:

1. STF – Kit Molle Frizione Standard

• Carico di compressione: pari alle molle frizione originali Innocenti

• Applicazione: ideali per motori originali o leggermente potenziati, fino a 14-16 CV

• Vantaggi: mantengono una modulabilità della frizione simile all’originale, adatta all’uso quotidiano e a chi cerca un comportamento prevedibile

Questa è la scelta ideale per chi ha un motore Lambretta tradizionale o con elaborazione medio-leggera e desidera mantenere comfort e durata nel tempo.

2. STF – Kit Molle Frizione Rinforzate

• Carico di compressione aumentato del 30%

• Applicazione: studiate per supportare motori con potenze fino a 30 CV

• Vantaggi: migliorano il grip della frizione sotto carichi elevati, evitando slittamenti durante accelerazioni brusche o regimi elevati

Una soluzione tecnica efficace per motori elaborati ad alte prestazioni, utilizzati sia su strada che in ambito sportivo o raduni speciali.

When to choose reinforced clutch springs?

If your Lambretta engine has been modified with:

• Oversized cylinder

• Early tree or full shoulders

• Large section carburetor

• Racing muffler

• Extended ratios

…then the standard springs may not be enough. In this case, reinforced clutch springs are the only choice to avoid slipping and ensure a consistently effective power transfer.

Contacts and Technical Assistance

Still have doubts about which kit to assemble or do you want personalized advice? Contact us without obligation:

📧 info@scooterthefero.com

Our technical team is always available to help you find the ideal configuration for your Lambretta clutch, ensuring reliability, performance and safety.

Conclusions

Choosing the right clutch springs is an aspect that is often overlooked, but which directly affects the performance and reliability of the transmission. With STF kits, you have specific solutions for every level of tuning, designed to perfectly fit historic Lambretta models.

Trust those who know the needs of Lambretta riders inside out. Choose the right clutch springs. Choose Scooterthefero.