Cars and Automotive Design

In the normal transmission system, reduction happens at three places from engine output speed to tire rotation/speed.

1) First reduction take place inside the transmission, that is generally happen at 4th stage (Based on required speed at 4th gear). This is default reduction applied.

2) Second reduction taken place for individual gear pairs in the transmission system

3) Third reduction take place at crown-pinion pair near differential

So first you have to calculate what is required speed of wheel (kmph) for each gear stage and then you can decide ratios accordingly.

Regards,

Viral Tilva

Hi there,

Thank you for your quick reply. I understand what you are talking about and it make alot of sense why you would chose the speed to then choose the ratios.

However my question is that what is the general trend for the speeds.

1. What speeds are we looking at
2. What place do you require to have a ratio
3. Is there a table of data this comes from

The reason I as is that I would like to know the reason and not just pluck the answers out of thin air.

Regards

Yohann

Hi Viral,

what do you mean with the 4th stage? The choice of the ratios hasn't anything to do with the 4th gear... The important speeds are the 1st speed and the last one in classic gearbox development.

The distribution of the ratios is defined by the factor of progression and not by the speeds.

Regards,

Alex