Can I use a SI transmission on an SuperBravo? Gearing ratio?

[CoolvetteTopic starterBerichten: 107]

Two questions together.

1)
I´m on the progress of getting a pair of 10-spoke wheels from an SI to use on my SuperBravo.
Can I use the SI rear wheel transmission on my machine or is it of no use for me?
If I have no use for it I might as well save the weight and some shipping money.

2)
What is the gearing ratio for the SI transmission compared to the SuperBravo, is it the same?
Wich gearing ratios fitting my SuperBravo is available?
I want to build a short track sprinter and great acceleration is more important than high speed.

[DocsDonateurBerichten: 2680]

1) All Vespa wheel transmissions are the same shape. Ciao,Bravo,SI,Grillo,Citta use the same transmission.

2) Depends on what kind of gear you have. there are 45km/h, 25km/h versions. And there are a set of Vario versions.

[CoolvetteTopic starterBerichten: 107]

I have checked the ratio on my wheel transmission and found it to be in the neighborhood of 14:1.

Do anyone know if that is on on the low or high end of the scale?
I have heard of 10,5:1 and that is better for high speed but how is 14:1?

[MartinoModeratorBerichten: 7384]

This is one of the shortest reduction factors out there. Better find a longer one if you want more top speed.
For variomatic there should be any ratio’s between 1:9 till 1:13,5. For pulley between 1:6,5 and 1:13,5

There are some exceptions on the ratios, but they are very hard to come by.

Link naar Mijn collectie / Projecten.

[CoolvetteTopic starterBerichten: 107]

Martino :
This is one of the shortest reduction factors out there. Better find a longer one if you want more top speed.
For variomatic there should be any ratio’s between 1:9 till 1:13,5. For pulley between 1:6,5 and 1:13,5

There are some exceptions on the ratios, but they are very hard to come by.

Thanks for your replies.
Actually I don´t want the top speed so this might be just fine for my needs.
I´m transforming my SuperBravo to a short track racer to be hard accelerator over just 75 meters so I need the low gearing rather than the high but this might be just too low.

[Gebruiker]

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