Number of gears

  • Thread starter Dan
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Dan

Dan

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Hey everyone. I'm always confused with the numbers of gears in transmissions. Some cars have 3 gears (Chaparrals), 4 gears (older muscle cars), 5 gears (sports cars), 6 gears (Modern muscle cars, sports cars, Supercars), 7 gears (Hypercar territory), and 8 gears (Lexus IS F). I understand that some of these cars were built with automatic transmissions (Chaparrals and the 8 speed ISF), but I want to know why did the manufacturer choose the numbers of gears?

Also, why do we (sometimes) have the option of choosing a 5 or 6 speed close ratio gearbox for a few cars?
 
I can answer the Lexus and the 2j

The Lexus is a very easy answer. They wanted to have a economy gear to raise the MPG. The 8th gear in realality you would never reach its top speed in real life. But when you were driving down the road and were going say 70MPH down the highway the RPMs would be so low you would save a lot of gas in a result.

The 2j race car however I am pretty sure they only did a 3 speed transmission to have really long gears to maximize grip while taking off the line and in corners and being to better in the power band.
 
A stock Suzuki Cervo has 7 gears, and it's not exactly a hypercar.

The short answer is that they have that many gears as that's what they came with IRL, and the manufacturer chose that many gears to suit the car at the time.

If the car came with a 4 speed as standard, then the close ratio box will have 5. If it came with 5 as standard, then the close ratio box will have 6.
 
It generally depends on the cars factory final drive ratio, and the power.

you need to understand that if a car had the single gear, like a bmx, either you would take off quickly, and top out quickly, or struggle to get moving, and reach a decent speed eventually.

Now, we add another gear, say at a drive of 2.000 and we can take off quicker, and still reach a decent speed in second gear. Add a3rd gear, and its even better. However, if you have too many gears, and not a low enough Final Drive Ratio, you will be changing gears every three seconds, which is obviously debeneficial, as you lose time and speed in the neutral between shifts.

Now, you may opt for a low final drive to accomplish this, but do you have the horsepower and torque to still be accelerating whilst in your highest gear?

Thats off the top of my head and not even scratching the surface.
 
daan
A stock Suzuki Cervo has 7 gears, and it's not exactly a hypercar.

The short answer is that they have that many gears as that's what they came with IRL, and the manufacturer chose that many gears to suit the car at the time.

If the car came with a 4 speed as standard, then the close ratio box will have 5. If it came with 5 as standard, then the close ratio box will have 6.
Click to expand...

Sorry. I don't drive Suzukis very often, and the only ones that I do drive are the Escudo and Cappuccino RM. I'm so original.

But anyway, thanks for the help everyone.
 
Does the '54 vette come with its proper 2 speed powerglide? I cant say i've ever taken mine out of the garage.
 

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