4th gear A/T, 5th gear M/T, why not 6th gear?

**altec** · April 11th, 2004 03:31 PM

Kung mga IH trucks have 9th gear or even 11 or 12th gear, bakit hanggang 4th gear lang ang auto tyranny at 5th gear sa manual? Why not 6th, or even 7th gear, especially with the auto tyranny?

**OTEP** · April 11th, 2004 03:45 PM

First, there is the expense involved.

Then there is the packaging constraints that need to be addressed. Even 5 speed automatics are pretty hard to package in today's mid=-size vehicles (let alone the compacts). The more gears you put in, the bigger the transmission housing has to be.

Most SUV's with dual range transmissions have ten forward gears. But you rarely use the other five because the five gears of 2H are already good enough to propel the vehicle from rest to top speed.

**Walter** · April 11th, 2004 05:02 PM

Trucks need all those gears since they would be carrying varying loads. With vehicles that we use daily, one can compute the maximum and minimum load we would carry. It's harder for trucks. Plus the high gears were designed for long distance travel.

We rarely use the 5th gears of manual transmissions considering the traffic we have.
Mercedes and higher end brands have 5th gear automatic transmissions and 6th gear manual transmissions. The new Accord has 5th gear automatic transmission. Like OTEP said, it's a matter of cost also.

**OTEP** · April 12th, 2004 01:33 AM

And CVT transmissions are also gaining popularity nowadays. These transmissions are not limited to 5 or 6 gears. They have an INFINITE number of ratios...

**empy** · April 12th, 2004 04:15 AM

it's also a matter of optimal gearing. if a car can reach its top speed in 5th without straining the engine, what's the point of spending a lot of money to put a 6th gear in?

6th gear is primarily an 'overdrive' type of gear designed for high-speed cruising at low engine speeds (for fuel economy). low-hp, low-torque engines in economy cars can't pull strongly from 6th gear, either, so they are rarely used.

now, high-performance machines with really broad powerbands like the BMW M3 or Chevy Corvette have a 6th gear because their engines can pull even in the 'tall' gears and are good for ultra-high speed acceleration (like 200+ kph)

**boybi** · April 12th, 2004 08:36 AM

bakit ka pa magpapakahirap mag shift ng 6 times kung ok na sa 5 times di ba? ;)

**mikaelrules** · April 12th, 2004 11:02 AM

Mercedes now has a 7-Speed Automatic and BMW has a 7-Speed SMG in the upcoming M5 as well.

**ian_rex** · April 12th, 2004 01:20 PM

a very interesting one. honestly, 4th gears in A/T are very common. in fact, these 4 speed A?T don't have 4th gears at all. these 4th gear we are referring to is the "overdrive" gear or the 5th gear in a M/T. while the 5 speed A/T is becoming a trend in automobiles today, this is due to the fuel efficiency issues concerning the A/T equipped cars. as for the case of the Honda City which uses CVT 7 speed and the Mitsubishi's 6 speed A/T which we can consider a "novelty" treat for the car enthusiasts. on the other hand, 6th speeds in M/T are fast becoming trend among the luxury and sport cars, this is more of a performance tweak only that it was OEM. of course this was added to boost performance as well as efficiency. if you're wondering why 5 speed M/T are being offered, this is simply because the manufacturers are reducing the production cost of their cars. so it will be affordable to the masses.