6th Gear

[vzshadow]

I was surfing through some thread and noticed the following on charlie b's signature: "I wish the NT had 20 more hp and 6 speeds...". I always felt the same way.

It got me thinking. My Trophy SE has more hp and 6 speeds. However most of my riding is on secondary roads, twisty and curvy state and county roads. Therefore I'm doing less than 60 mph most of the time. Consequently I rarely ever use 6th gear, and most of the time I don't use 5th either. The engine is happy at 4000 ? 500 rpm. If I'm on the Bonneville, I can ride all day and not use fifth. Of course if I'm on an interstate I do used those upper gears.

Funny how things change.

 

[RedLdr1]

I've always found having an "Overdrive" gear, as sixth gear usually is, to be a nice plus for when I'm using the Interstates. Being able to shift into sixth, drop down the RPMs, and turn on the cruise control makes I-time more relaxing. When I was commuting in this God awful traffic mess here I doubt I ever used fifth...

 

[Bear]

I only use 5th gear when I am going over 55 MPH. Most of the roads I ride are secondary with a 55 MPH limit. I usually go 60. and lope along in 5th. In town, I rarely get out of third.

 

[Miairhead]

When I had a BMW CLC with cruise and 6th gear, the only time I was in 6th was on expressway. I really don't miss the extra overdrive gear, and really don't miss cruise ( I seldom ride expressways). Cruise on the roads I ride, would be of little value. I might feel different if I lived in another area.

 

[charlie b]

The 6th gear was desired for cruising at 80. At 65 it was comfortable in 5th, at 80 it had a bit more buzz which annoyed me. And, yes, I did run 75-80 on some of the back roads out here. Interstates 80 was a 'safe' speed, since the limit is 75.

Even with higher hp it would be nicer to cruise at 4000 rpm rather than 5000 and over.

Of course it depends on engine design as well as how the bike is engineered to absorb the vibrations.

 

[Macka]

Here in Oz, except for the Northern Territory, our maximum speed is usually 100kph or 110kph. It is EXTREMELY heavily Policed. 4kph over the limit will result in a ticket. olice1:
100kph (62mph) on mine shows as 4250 rpm. This is comfortable and is right in the middle of the torque band which is great for overtaking.
Therefore, 6th gear is not really needed but I would still like to have it for relaxed touring and slightly improved economy.
Even the new FJR1300 now has a 6th gear. I am very impressed by the detail improvements to it and if the NT came to a sticky end I would replace it with an FJR.

Macka

 

[Warren]

Chris,

I think you are riding your NT in very much the way it was designed to be ridden so its no surprise to me that you would find it totally suitable for your needs the same as I do mine. I can't really think of anything I would change. By the way I would watch your video's. I am addicted to youtube motorcycle videos and subscribe to around 30 motorcycle channels most of them are individual motovloggers.

 

[Bear]

I think that a 6th speed on the NT would, in the long run be a detriment. I am not an engineer but go back many years as a hot rodder. I currently drive a Toyota Matrix XR with 200,000 mi on the clock. The engine is a small 1.8L Four with a 5Sp Manual Transmission. Two weeks ago, I took the engine out of the car and did a valve and ring job, replaced the timing belt, CV Joints and struts. The mains were in good shape. What I did notice was a lot of carbon--in short, the engine was run at too low of an RPM. I cleaned everything up and put it back together. The engine now has lots of pep. I plan to shift at a higher RPM and use 5th as an overdrive when I am on the expressway. I will also use synthetic oil and give the fuel a Techtron treatment twice a year. I think that the NT should be run at higher RPM. I plan to clean the engine out with a Techtron treatment and then run it at higher RPM. Sure, lower RPM gives better economy--but I feel that this also contributes to a shorter engine life.

 

[charlie b]

If running all day at 65 is not bad for the engine, then running 80 at same rpm would not be bad for it either.

I AGREE. If you are going to run mostly at 70 and below you would not need or want a 6th gear. But, those of us who run at higher speeds would benefit from it.

 

[Phil Tarman]

I mildly disagree. The bike runs fine all day at 80-85. A 6th gear would help a little bit with gas mileage, but given the amount of horsepower the NT has, I don't think it would be as responsive as the current 5th gear unless it ended up at the same rpm. Then the only advantage to a 6th gear would be closer ratios, which I don't think the NT needs.

Charlie, I do agree that an extra 20hp would be very nice.

 

[Reniram]

The bike runs fine all day at 80-85 I don't think it would be as responsive as the current 5th gear

Has anyone fitted a larger rear tire? if so, has it been documented as to the difference regarding speed versus rpm..and would it hurt the first gear take off...may have to slip the clutch a bit to counter the higher gearing....I wonder what the difference would be.....if any ?? and what maximum size can be installed....

 

[charlie b]

Of course it would not be as responsive at speed. But, 65 in fifth now is same response (minus increased aero drag) that you would get at 80 in 6th.

Yes, the bike can cruise all day at 80-85 even 90, cause I have done it. It just isn't as comfortable as 65. The engine speed is most of the difference. Which is why I would have liked a 6th gear (and an increase in hp ). Like my sig says, 6 speeds and 20 more hp and I think it would be the perfect bike for me.

I would not want closer ratios, I'd want a taller top gear for higher speed cruising. And, no, you would not want to use it all the time, such as on 55mph roads. And if you used a 6th gear at 65 then you would need to downshift at least once for passing speed (I used to downshift to 4th or even 3rd).

If you fit a larger rear tire you would have reduced (slightly) engine rpm in ALL gears, which is not what I was looking for. 1st gear is tall enough as it is.

Look, this is MY desire for a lightweight touring bike. If you like the NT the way it is then keep it and be happy. It is a great bike the way it is. Just isn't what I want (and is why I don't have one anymore). If I were to buy another bike it would be a larger engine Goose or something like an FJR or RT.

 

[Warren]

Well said Charlie. Even though most of us on this list own have owned an NT it does mean we all have/had the same expectations from them. For some of us they are perfect, for some not so much and they have been sold and the owner moved on to something else. No right or wrong just each persons personal preference or need.

 

[Macka]

Allow me to digress just a little, but on the same subject.
If you take a look at ALL late model cars the final/overall gearing is getting taller.
Many of the new 6-8 speed transmissions have the top two or three ratios as overdrives.
Why is this so? Simple really.
Maufactureres are being pushed by governments to reduce exhaust emissions. The easiest/cheapest way to do this is to reduce fuel consumption.
The best way to reduce fuel consumption is to slow the engine down.
There are other factors such as weight and drag but cars are NOT getting lighter, just the opposite as more features are added.
Many cars now, at 90-100kph have the engine turning over at only 2-2.5 times the idle speed.
The New FJR now has an overdrive 6th gear. It did not need it but Yamaha is being pro-active.
The Newish V-Strom 1000 has an overdrive 6th gear. There are other examples.

Macka

 

[dnktng]

Here is why I find the 6th gear conversation interesting. First, the NT's HP is set, it isn't changing. The graph says the NT (blue line, first graph) has ~54HP to the road. OK, it's good number to start.

Second, assume the drag coefficient isn't changing. The air isn't going to change, the NT (or me) doesn't get slimmer as speed increase...given.

To get a rough estimate of what the air drag of the NT look at the second graph and ask yourself "How fast can the NT go with it's 54 HP and 5 speed transmission?" I'll guess ~110mph, rough estimate. So enter ~54HP on the left, go horizontally to 110mph. It crosses just under the blue line for air drag. So for the rest of this explanation, use the blue line for ease of being able to follow a line.....close enough. So the Blue line is the NT's air drag....always. That's not bad considering the black line is the best, red line the worst.

Now follow the blue down to 80 mph to find the HP needed to push the NT 80mph through the air. I get about 22 HP. Cool, 22 HP is needed to pushed the NT (or any motorcycle with similar air drag) 80 mph. Not bad really. I had a 20 HP CL175 that would almost due 80mph, but surely it had a little less drag.

Now go back to the first graph. Assume the NT is at 6500 rpm at 80 mph with the present 5 speed gearbox (I don't remember the correct rpm). Find the HP, I get 50 HP. So the NT need 22 HP to push it 80 mph, but has 50 HP available at this rpm if I open the throttle fully, which gives me 50HP-22HP= 28 extra HP to accelerate from 80mph. You'll need that much because air drag rises fast as speed increases.

Now assume we drop in a 6 speed gearbox that drops the NT's rpm to 5500 rpm at 80mph. Nice, that should smooth out those vibes at higher rpm. But now how is acceleration? Remember HP and air drag don't change. Now with a lower rpm of 5500 the HP available at a twist of wrist at 80mph is ~41HP. Still need 22 HP to push the NT 80 through the air leaving 41HP-22HP=19HP excess to accelerate. If you think the NT chugs that hill poorly at 80mph now, it would have ~9 less HP less available in a higher gear starting at 80mph.

And another side thought is that the power (HP) needed at a given speed (80mph above) is the same regardless of the gear your in. Above it needed 22HP...4th gear...5th gear...6th gear.....doesn't matter. To make 22HP at the road the engine will use so close to same amount of gas that your MPG won't change much. The biggest difference between 4th gear and 5th gear (or the non-existant 6th gear) is caused by losses in the engine at slightly higher rpm. Losses..yes, but I dont think the losses between 5500 rpm and 6500 rpm are that great. A better way to get better mpg at higher speed is to lower the air drag. So duck down and lower your wind screen.

A 6th gear would be nice, but it didn't come with 10 more HP there would be a lot of downshifting to pass or go up hills.

 

[charlie b]

Totally correct. You would need to shift into 5th or even 4th to accelerate more briskly. That is not the purpose of me wanting a 6th gear. The sole reason was to be in the 'sweet spot' of engine vibration on my NT. 80mph on mine, IIRC was right around 5500rpm.

Remember that I want(ed) a 6th gear AND an extra 20hp. The extra power for grins and the extra gear for that vibration issue. I consider the existing combination of power and gearing to be sluggish at 80mph.

FWIW, the term overdrive is used only when a transmission output is at a lower RPM than engine RPM. Typically the top gear in a transmission is at 1:1. In use this distinction has no meaning as the total ratio from engine to wheel is what is important and it doesn't matter if the transmission has an overdrive ratio or not. Originally, an overdrive was a separate gear box and the additional gearing could be used with more than one selection in the transmission.

 

[Macka]

All valuable input and information but remember the purpose of an "overdrive" gear.
It is not to increase top speed. Of course it will decrease top speed as it reduces the torque at the wheel(s) and drag will triumph.
It is there to "relax" the engine under normal "cruising" conditions.
It is not meant to be used when maximum speed or overtaking accelleration is needed.
On any older vehicle you would achieve maximum speed in "top" gear. On most modern vehicles you will almost certainly achieve a higher top speed using a lower gear.
On the subject of fuel consumption, of course , if the engine is labouring into a head wind or uphill, fuel consumption will be worse in an "overdrive" situation.
Again, that is not when you should use an overdrive gear. Also, please remember that overdrive is not necessarily a physical ratio.
It is a gearing situation in which maximum speed is achieved in a lower gear than the highest one.
Any overall ratio that reduces maximum speed is "effectively" an overdrive if not a physical one.

Macka

 

[EODEAN]

When I had my 1800 Gold Wing I would like to have had a 6th gear. It had the horse power and torque to pull the bike just fine. My 01 Buick could run at 70 mph at 1800 rpm. Where the Wing would pushing 3,000 rpm for it at that speed.
My daughter has a VT 700 Shadow and it has a 6 speed on it. I have ridden it but not all that far to check out how it would pull at say 75 mph.

 

[DirtFlier]

There are a fair number of modestly-powered cars that will actually go faster (top speed) in 4th gear versus 5th gear.

 

[RedLdr1]

A large part of the "sixth gear" and power is directly related to where the bike was originally designed to be marketed. And when it was originally designed. Since the NT was an old design, heavily based on a even older design, based on an even older yet design, the concept of a sixth gear, on a Euro spec bike, probably wasn't even considered when the NT700 family was designed. Had the NT been designed for the North American market, with its higher average speeds and more open spaces, the idea of an overdrive sixth gear, and a bit more power, would have made more sense.

All valuable input and information but remember the purpose of an "overdrive" gear.
It is not to increase top speed. Of course it will decrease top speed as it reduces the torque at the wheel(s) and drag will triumph.
It is there to "relax" the engine under normal "cruising" conditions.
It is not meant to be used when maximum speed or overtaking [/I] is needed.
On any older vehicle you would achieve maximum speed in "top" gear. On most modern vehicles you will almost certainly achieve a higher top speed using a lower gear.

+1... I commonly downshift from 6th to 4th to pass another vehicle in my car so it would not be a problem, for me anyway, to do so on a motorcycle... My ancient FJ1200 dates back to same time frame as the NT family for its design and it only has a five speed transmission...and it really needs a sixth "overdrive" gear.:rolleyes1: Thankfully Yamaha fixed that oversight in the new FJR.