Why do 6-speed manuals exist?

[veryHeavy]

In the Honda CRZ the low-end ratio and the top-end ratio are the same as the standard 5-speed in my Civic (and same engine by the way: 1.5 liter).

It's the same overall spread. So where's the benefit of 6-speed, other than making the driver do more shifting?

 

[HerrStig]

They exist because people want them.

 

[Rand]

Originally Posted By: veryHeavy
In the Honda CRZ the low-end ratio and the top-end ratio are the same as the standard 5-speed in my Civic (and same engine by the way: 1.5 liter).

It's the same overall spread. So where's the benefit of 6-speed, other than making the driver do more shifting?



Why have more than a 3 speed right? I mean 3 speeds are enough?

 

[veryHeavy]

Okay. WHY do people want 6 speeds instead of 5? In my driving I saw no advantage to having to shift an extra gear.
Quote:
Why have more than a 3 speed right? I mean 3 speeds are enough?

Clearly you did Not Understand my post. 3-speeds did not have the ultra-high gear ratio as the 5-speed, so there was a real difference upgrading to 5 (fuel savings).

But these new 6-speeds have the same top-end gear ratio, so nothing's changed. No improvement in fuel economy.

 

[topbliss]

The more gears you have, the closer the ratios can be to each other keeping the engine in the powerband after you shift. This will give you more power and better gas mileage

 

[DuckRyder]

Something seems familiar here.

 

[RooflessVW]

Because the more gears you have, the closer to the engines peak power (and efficiency) you can be at any given vehicle speed.

Manuals have 6 (and 7!) gears now for the same reason automatics have 8, 9, and 10.

 

[Rand]

Originally Posted By: veryHeavy
Okay. WHY do people want 6 speeds instead of 5? In my driving I saw no advantage to having to shift an extra gear.
Quote:
Why have more than a 3 speed right? I mean 3 speeds are enough?

Clearly you did Not Understand my post. 3-speeds did not have the ultra-high gear ratio as the 5-speed, so there was a real difference upgrading to 5 (fuel savings).

But these new 6-speeds have the same top-end gear ratio, so nothing's changed. No improvement in fuel economy.



example.

a 1980 fiesta with you have your choice of stringing it out at 5000rpm in second or bogging down in 3rd.

enter a 6speed transmission now with closer gear spacing you have more choices.

It comes down to powerband and fuel economy.

Look at the overall ratios in a sports car such as a miata they will be very close together.

 

[heynow]

Originally Posted By: veryHeavy
Okay. WHY do people want 6 speeds instead of 5? In my driving I saw no advantage to having to shift an extra gear.
Quote:
Why have more than a 3 speed right? I mean 3 speeds are enough?

Clearly you did Not Understand my post. 3-speeds did not have the ultra-high gear ratio as the 5-speed, so there was a real difference upgrading to 5 (fuel savings).

But these new 6-speeds have the same top-end gear ratio, so nothing's changed. No improvement in fuel economy.




Assume that the theoretical three speed DOES have the same gear ratio spread and same top gear ratio as your five speed. Basically your five speed minus second and fourth gears. How do you think it would be to drive?

 

[Bottom_Feeder]

 

[zoli]

Fuel economy. Example:
1. My S60 has 2 liters / 5 cyl turbo engine with automatic 5 speed
2. My wife's Renault 1.2 liters / 4 cyl turbo engine with manual 6 speed

Highway cruising at 80 MPH: both have 3000 rev and same gas consumption.

Our old Daewoo 1.6 liters engine w/o turbo, 5 speed manual: 80 MPH, 4000 rev and worse mileage.

 

[rideahorse]

I don't know why automatics exist. Just for people that don't have the ability to drive.

 

[NateDN10]

Originally Posted By: veryHeavy
In the Honda CRZ the low-end ratio and the top-end ratio are the same as the standard 5-speed in my Civic (and same engine by the way: 1.5 liter).

It's the same overall spread. So where's the benefit of 6-speed, other than making the driver do more shifting?

That might be true for your Honda, but it's not universally true. My new Mazda3 (6 speed) has a higher top gear than my old Cobalt (5 speed).

And as others have noted, closer-spaced gears help keep the engine in its power (or efficiency) band. With a manual, you get to choose.

Also, you can always skip a gear! That's what I do on 35 mph roads; I shift 1-2-3-4-6.

 

[ls1mike]

Because not everything is a 1.5 liter.

Double overdrive in the Trans Am with 4.10 gears, heads, cam, full exhaust intake and 11 second 1/4 miles, I can still pull down 24-25 mpg on the highway going 70.

When it was bone stock with 3.42 gears. I would run right around 13.20 at 108 mph and going 70mph on the highway it has touched 31mpg average.

 

[Lolvoguy]

Originally Posted By: Bottom_Feeder

 

[Johnny2Bad]

Modern vehicles have what are effectively wide ratio manual transmissions; true close-ratio versions are rare unless you are looking at something exotic. Your Honda does not qualify. Even those described as "close ratio" would be called "wide ratio" had they been sold in the 1960's or 1970's.

The reason, and the reason why the 1st and 6th on your car are the same ratios as the 1st and 5th on an older version, is fuel economy and in particular CAFE regulations. They have to use wide ratio transmissions for fuel economy reasons (keeping the motor out of the higher RPMs, and/or shifting at a lower RPM than the equivalent close-ratio box) so the only way to achieve drivability is to add gears between the top and bottom, which allows a closer ratio while still avoiding higher RPMs at the shift points.

I don't know many people who prefer manual transmissions who dislike picking gears, so I don't see much of a problem. Now, if you hate manual transmissions, that's another story but we both know there is another option that should have been chosen when spec'ing the vehicle.

 

[supton]

My Camry has a six but it's just a gimmick. On the highway it's maybe 100rpm drop going from 5th to 6th. It's really not doing me anything.

The 6AT in my truck doesn't have that, but 6th is something it can only use on flats. Any sort of hill and it wants to kick out. Which isn't that surprising, but it defies years of "if it doesn't have enough power to hold top gear on a hill then it's underpowered." But it's actually a good thing: on flats and downhills the engine is not turning any faster than it needs to be.

I have not driving a 6MT where "good" gear splits exist all the way up. But I don't drive many cars in general. To me, passenger cars with big slow turning gas motors don't "need" more than 5 gears, but I certainly wouldn't argue against it either. Six is nice, assuming it's done right.

 

[Mr Nice]

The best 6 speed I drove was a Porsche 996.

 

[Johnny2Bad]

Originally Posted By: supton
My Camry has a six but it's just a gimmick. On the highway it's maybe 100rpm drop going from 5th to 6th. It's really not doing me anything.

The 6AT in my truck doesn't have that, but 6th is something it can only use on flats. Any sort of hill and it wants to kick out. Which isn't that surprising, but it defies years of "if it doesn't have enough power to hold top gear on a hill then it's underpowered." But it's actually a good thing: on flats and downhills the engine is not turning any faster than it needs to be.

I have not driving a 6MT where "good" gear splits exist all the way up. But I don't drive many cars in general. To me, passenger cars with big slow turning gas motors don't "need" more than 5 gears, but I certainly wouldn't argue against it either. Six is nice, assuming it's done right.


The MT on the Miata (and the ones used in RX7's and RX8's, although different ratios) is reasonably decent. Offered as a 5-speed in the first two versions and a 6-speed in the third and fourth gen cars, the ratios are reasonably close, and the overdrive 5th or 6th is about a .700 ratio, so a true O/D ratio.

Although it's a trivial swap and the transmissions are cheap to buy from the wreckers, many drivers prefer the 5 speed, not because the ratios are "better" (they're not) but because it's a different unit made by Mazda and is possibly the finest shifting transmission ever made. The 6-speed is an Aisin unit, similar to what you can get in any Japanese car, and although the ratios are nicely spaced, the feel is cruder. Note that Honda used the Mazda unit in their S2000 sports car.

 

[supton]

Meh, no interest in driving a Miata. Might wind up wanting one, and that'd be a bad thing: need four doors. But maybe someday... been trying to convince the wife that she wants one for her next car. No luck, so far.