# 6 Speed Vs 5 Speed



## bmw325 (Dec 19, 2001)

grayghost said:


> Perhaps we're in the minority, but I cannot imagine why anyone would prefer to cruise down the road at 500-700 RPM more than is at all necessary. Higher RPMs increase fuel consumption and increase wear. Shifting in or out if 6th is a nit... True, I'll normally go into 6th only when I'm on the interstate (and expect to be cruising at 60 or more) but whether it's one mile or 100 really isn't significant. Use the gear that's approporiate for the current conditions.... Honestly, I was a bit shocked when I found out that the 5 speed trans did not have an 'overdrive' gear... Close ratio gears are nice, but as engine power goes up, close gear spacing becomes less important. I'll take an easy, low-rpm cruise any time....


Agree. I think BMW did the right thing by making 6th an over-drive gear. Most other manufacturers 5 speeds are OD in 5th-- whereas BMW has been 1:1 in 5th for about the last 10 years. This is great (makes for a closer ratio box), but it is nice to have an OD for easy cruising on the highway. I also think that the 6 speed would be more appropriate on the 325-- it has a higher final drive, which means that it revs higher at a given speed, which would make an OD 6th even better. It is funny that people equate 6 speeds with better performance-- I thikn there's very few, if any, 6 speeds out there that actually stack the gear ratios closer for better performance-- most of them just seem to tack on OD 6th gears.


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## Artslinger (Sep 2, 2002)

For the busy dumbass driver infested highways in the Midwest I like the gearing of my 5th gear. I'm not sure how much I'd use a 6th gear because the roads are so congested. Maybe if I lived near an autobahn, or in the great expanse of the American west it would be of some use.


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## mtbscott (Jul 16, 2003)

I'm with you Grayghost. I use 6th gear anytime I'm on the freeway at 55 or better. Quieter, better fuel economy, less wear and tear. If I need to pass someone in a hurry, I downshift to 5th or 4th. I just took my first weekend trip in my 2 month old 330I with ZHP, averaged over 27 mpg at around 75 mph on the way to my destination. On the way back, traffic was a bit heavier and I only got 24 mpg. This compares with the 22 or so I've been getting around town. Call it marketing genius, but 6 speeds aren't going away, if anything they are trickling down to lower priced vehicles all the time. Motorcycles have had 6 speeds for decades, it seems to be a good number for performance/economy. While shopping for my car, I also considered a 330CI, the dealer had a 2003 5-speed available at invoice, a 2004 for around a $1000 off. If I had chosen the coupe, I would have taken the 2004 and the 6-speed would have been a major consideration. It's a significant upgrade that a consumer is unlikely to add after the fact. No need to rationalize 5 speeds though, they were adequate and state of the art for their time, but technology marches on for better or worse.


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## Tanning machine (Feb 21, 2002)

mbr129 said:


> On my 330i (ZHP) I only shift into sixth if I am doing over 75mph AND if I expect to do so for an extended stretch. On my trip from Montreal, I did 80+mph the whole way and it made the ride very comfortable and got me excellent fuel economy (almost 500 miles of range). But I don't remember shiftig to 6th in a long time. As it is, I barely shift into 5th.


Based on a week and half, in Europe, that's how I feel too. I now have two cruising/overdrive gears instead of one. On the autostrada, I found myself shifting between 5th and 6th, simply to make sure there was enough power to do anything. I wo;uld have been perfectly content leaving it in fifth the whole time. I suppose if there were no traffic and I were going long distances, 6th might have been helpful. And this was at 90-100mph. But, really, in the US, unless you live in the midwest/plains/rockies/desert SW, where you have long driving distances without tons of traffic, the 6th gear seems more something to talk about having than to use.


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## kdshapiro (May 1, 2003)

Isn't what this is all about is local use conditions? That is the reason I have an automatic and not a manual. My 20 mile trip to work sometimes takes me over an hour never exceeding 20 mph. Why would I even want a manual, much less a manual with 6 speeds.  But BMW has to produce cars to the lower common denominator, not only keeping up with the market, but making the market. However, for those rare moments I can actually drive more than 3 seconds at 75+mph, a six-speed would be the ticket. :thumbup:


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## grayghost (Jan 10, 2003)

rumatt said:


> Do you have any evidence for the second two in your list?
> 
> Lower is not always better; there is a sweet spot somewhere. Otherwise we'd all be cruising on the highway in 12th gear at 100RPM.


Well, seems to me it would be obvious (at normal highway speeds anyway), but think of it this way. Let's say that 70 mph in 6th is 2300 rpm and 5th would be 2800 (not exact, but reasonably close). OK, put your car in neutral and carefully run the rpm up to 2300. Now, to get it up to 2800 do you have to give it more gas or less?? If your car is like most, you have to feed it more fuel to increase the rpms. (If you find an exception, I'd sure like to hear about it!! :yikes: ) Of course lower rpms save fuel and wear and tear (the higher the rpms, the further the pistons and other components travel, and the more severe the stop/start stresses at the ends of the piston travel for example.) 
And of course, there are 'reasonable' limits... Don't floor it and try to accelerate from 1000 RPM in 6th... It will take a long time and that is not good on the engine. But, we're talking about constant speeds or very mild acceleration at highway speeds. Within these normal conditions, the lower the rpm, the higher the mpg and lower the wear.
By the way, I'm a private pilot and one aspect of many small aircraft is that we can adjust the prop pitch and mainfold pressure so that we can get the same HP at different RPMs. Within the approved ranges of operation, the lower the RPM for a given HP, the less the fuel comsumption. Althought the engines are much different, the physics and results are the same.


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## SergioK (Aug 14, 2002)

The HACK said:


> [sarcasm]
> 
> Granted his fuel economy (averaging 15mpg) is worse than mine (averaging ~27mpg). There goes the theory that a 6 speed is more economical than a 5 speed.


Can u imagine what kind of mpg #s we'd get if our cars had a 6th gear... 30+ probably at the elusive 90-100mph range.


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## Patrick330i (Sep 30, 2002)

Memphis10 said:


> I recently bought a 5 speed 325i. I waited long enough to make the decision because I was hoping that they would have the 6-speed on the 2004 model. I don't uderstand why they still have the 5 speed manual on the 325i but are offering the SMG. All other manufacturers have switched to 6 speed (MB, Acura, Audi, Lexus, Infinity to name a few). What really pissed me off is that even the Mini Cooper has the Getrag 6 speed manual transmission. I did consider buying the C230 for the 6 speed but the ride and handling was not even close to the BMW.


I probably should read the whole thread, but I don't want to, so I'll just come out and ask you, why is it so important to have a 6-spd v. a 5-spd? I barely even use 5th as it is. I have to be "stuck" on a freeway cruising at about 75 or more with no chance of really passing and making maneuvers before I put it into 5th.



> Can u imagine what kind of mpg #s we'd get if our cars had a 6th gear... 30+ probably at the elusive 90-100mph range.


Watch your mpg meter and you might be surprised that the difference between two gears is not always that great. Get on the freeway and go about 70 in 4th, then put into 5th and you'll see what I mean.


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