VFR Discussion Group -> Most Efficient RPM

What is the most fuel efficient RPM for our bikes?

I am trying to save fuel during commuting and so I want to run at that RPM in top gear.

With this information, I can then gear my bike accordingly in order to run at the desired freeway speeds (~75-80mph) and be able to get the best possible fuel economy from my bike at the same time, right?

most fuel efficient RPM's are generally lower. Hence "overdrive" on cages where you are running less than a 1:1 final drive ratio.

However I would caution, not to run too low of an RPM where you don't have enough power to accelerate quickly to avoid an incident or to simply roll off the throttle to engine brake.

The VFR does not have gobs of torque to pull from low RPM's like and ST1300, FZ1 etc.

I'd think you just need to put the bike in 6th gear and keep your speed down around 55-60mph.

The big enemy appears to be wind resistance on the VFR, go 55-60mph and you will get close to 50mpg or maybe even a little better on the VFR.

We already have an extremely tall 6th gear for a sportbike.

I've reached 52MPG once when I went on a long trip with a friend of mine who was riding an old Sportster. He couldn't go over 65MPH without one of his intake vavles sticking, so we did about 60-65 indicated (probably 55-60) for 300 miles. That is the only time I've reached above 50MPG.

Those speeds will not cut it in Atlanta traffic, I MUST run a minimum of 70 in order to not get run over.

you do know, that buy the time you factor in tires you don't really save anything by commuting on the bike vs. a reasonbly fuel effecient car ? I've run the numbers

25 mpg car = .12 per mile (tire cost is .006 per mile) = .126 a mile
32 mpg car = .094 per mile (tire cost is .006 per mile) = .100 per mile
40 mpg bike with ST tires = .075 per mile (tire cost for 8000 mile tire .03) = .105 per mile
40 mpg bike with sport tires = .075 per mile (tire cost for 3000 mile tire .08) = .155 per mile

Assumptions made, oil changes are not a factor since intervals are about the same vs. car. Actual bike cost would probably be higher by the time you factor in much higher maintenance costs such as valve adjust etc.. Modern cars don't need anything but brakes, tires and oil for $100000 miles.

I drive a Honda Accord to work. At best, taking the bike in would cost me 50% more than the car.

Cozye, you are forgetting the fun factor that knocks off .100 per mile making it nearly free to ride you bike everywhere.

I'm not sure what the most efficient RPM is but I just got back from a 1700 mile trip to North Carolina on my VFR. I averaged 47 MPG for the trip and the best I saw was 49 MPG. My bike never got worse than 47 MPG on the freeway and I was going 75-85 MPH the entire time. So that equates to roughly 5000-5500 RPM's in top gear.

Cozye,

I figured that much, I knew tire cost really brought the two down closer together.

Really wish I would not have flipped my civic, that 40mpg and 14" tires were nice for putting high mileage on.

matt_c, May 17 2006, 01:21 PMCozye,

I figured that much, I knew tire cost really brought the two down closer together.

Really wish I would not have flipped my civic, that 40mpg and 14" tires were nice for putting high mileage on.

Yeah, the Civic is the ultimate commuter car. I may end up getting one myself when my accord is toast if Gas prices stay the way they are. I wouldn't mind commuting on a bike either, but with me living 30 miles from work, its not economically practical and all of that interstate riding will flatten out my tires.

matt_c, May 17 2006, 10:07 AMWhat is the most fuel efficient RPM for our bikes? 

I am trying to save fuel during commuting and so I want to run at that RPM in top gear.

With this information, I can then gear my bike accordingly in order to run at the desired freeway speeds (~75-80mph) and be able to get the best possible fuel economy from my bike at the same time, right?

I think it is 11,500 rpm, so I try to stay close to there. Damn 120 mile fill up intervals.

I remember and old formula that said that the most efficient rpm to run would be at 80% of peak torque, whatever than is! tongue.gif

I don't know, I think you should easily be able to get 10,000+ miles out of S-T rubber for commuting use. It's only a question of whether or not you go berzerk from getting a flatspot.

It can easily work out to ride the bike, it is certainly not expensive even if a bottom of the barrel commuter car can beat it on price.

Slower is better usually better because the wind resistance increases with the square of your speed. I don't have a power commander and was wondering if you can you tell how much fuel is being delivered at different revs from the maps?
for example, at 100 km/hour in top gear my bike is around 4000 rpm.
If I shift down to 5th, 5000 rpm.
Same wind resistance, 1000 rpm more am I burning 20% more fuel?

Between Lima and Nazca, I travelled over 460 kms and achieved around 21.9kms/litre whilst keeping my speed between 100 and 110 kms/hr and I also was carrying a fair amount of weight in my rack bag. This equates to over 60 m.p.g. for Australian imperial measurements.

Touring at higher speeds in Australia I could achieve close to 50 m.p.g. or between 17 and 18 kms/litre.

You can actually squeeze about an extra 1 litre into the tanks - that's 22 litres into the 21 litre tanks - if you take your time.

The debate about cost per mile also needs to include cost per hour.

Here in CA, I can split lanes on the VFR.

In the Civic, I'm just stuck. Granted, Air Conditioning and AM/FM/CD make it less dreadful, but... it still sucks to be in bumper-to-bumper traffic.

Cozye, you're right about the flattened tires; my commute is 45 miles each way on a dead straight flat New Mexico road. For some reason, the dealer installed Metzlers on my '05, and they only lasted about 12k miles with that kind of riding. Jeez, I haven't even taken my bike on any twisty roads yet, and I've got almost 15k on her now. My Metzler's were definately wearing down right down the middle... enough to where I could feel is settling on to the sides when I made the one turn I have on my trip... the exit ramp!

Aardvark892, May 17 2006, 05:16 PMCozye, you're right about the flattened tires; my commute is 45 miles each way on a dead straight flat New Mexico road.  For some reason, the dealer installed Metzlers on my '05, and they only lasted about 12k miles with that kind of riding.  Jeez, I haven't even taken my bike on any twisty roads yet, and I've got almost 15k on her now.  My Metzler's were definately wearing down right down the middle... enough to where I could feel is settling on to the sides when I made the one turn I have on my trip... the exit ramp!

Holy crap, "only 12K miles"!? I think the most I ever got out of rock hard PRoads was 6k. What tire was it, Mez4 or 6?

vleigh, May 17 2006, 04:22 PMThe debate about cost per mile also needs to include cost per hour.

Here in CA, I can split lanes on the VFR. 

In the Civic, I'm just stuck.  Granted, Air Conditioning and AM/FM/CD make it less dreadful, but... it still sucks to be in bumper-to-bumper traffic.

True, here in GA we cant lane split (legally), but we can use the HOV lane and that does save me anywhere from 5 to 20 minutes time. Plus I cant safely cut up traffic in a Civic like I can on my little bike.

I also got to thinking, that per mile estimate doesnt take into account, depreciation of each, initial cost of each, monthly payment, and insurance amounts.

When you factor in all that, I know my bike has to be cheaper to drive in the long run over my 3.5SE Altima. As I rack up the miles on that Altima, I begin to loose thousands of dollars, where as with my 99 Viffer its a lot less.

matt_c, May 17 2006, 09:59 AMThose speeds will not cut it in Atlanta traffic, I MUST run a minimum of 70 in order to not get run over.

You might try a countershaft sprocket with 1 more tooth than stock.

That would be the cheapest way to raise the gearing.

Sprocket Specialists makes an 18 tooth countershaft sprocket.

http://www.sprocketspecialists.com/ProductSearch2.aspx


This will lower your gearing by 6.6%

5080RPM = 70 MPH (more or less) so your new RPM at 70 MPH would be 4797

Of course, you'll have to remember to travel at an indicated 65 MPH Vs 70 because your speedometer will be out.

Or get yourself a Yellow Box, a Speedo Healer, etc. and set it up using a GPS unit for true speed.

I just replaced the OEM tires on my '00 with about 12k miles on them (I only put about 2k on it). Primarily for the same reason, the transition from the "flat" spot to the sides was scary. blink.gif I'd get leaned over a little and then it felt like the back end jumped over as it rode over the edge of the "flat" spot. There was still a good bit of tread left, it just wasn't particularly useful unless you did all highway and never got leaned over very far.

matt_c, May 17 2006, 09:28 PMTrue, here in GA we cant lane split (legally), but we can use the HOV lane and that does save me anywhere from 5 to 20 minutes time.  Plus I cant safely cut up traffic in a Civic like I can on my little bike.

I also got to thinking, that per mile estimate doesnt take into account, depreciation of each, initial cost of each, monthly payment, and insurance amounts.

When you factor in all that, I know my bike has to be cheaper to drive in the long run over my 3.5SE Altima.  As I rack up the miles on that Altima, I begin to loose thousands of dollars, where as with my 99 Viffer its a lot less.

Depreciation of each wasn't taken into account, but neither was a chain and sprockets every 15k, brakes on the vfr every 10-15k, and valve adjustements every 16k. That would certianly add at least another .04 a mile on the bike. Also keep in mind that the depreciation rate for each vehicle percentage wise would be pretty close, that your altima will get 200k miles, and I doubt you will get more than 100k miles out of your vfr. The altima cost 2x as much as the VFR, but you will get 2 to 3x the mileage out of it. Not trying to rain on your commute parade, I'd love to do it and envy those who live in so. Cal where its very practical. Just dont' kid yourself into thinking your saving money.

I got my 95 VFR used last fall, mint, >8K miles for $3250. Original chain and sprokets, new D205 on the back, put an AVON on the front this spring. My mileage has gone from 33 to 38 mpg sofar this year, getting better for some reason, driving the same.
If your initial cost of the bike is low, thats gotta help.
$10000 upfront thats a whole new ballgame.
my 2 cents

fing02.gif beer.gif

steve_mn, May 18 2006, 08:15 AMI got my 95 VFR used last fall, mint, >8K miles for $3250. Original chain and sprokets, new D205 on the back, put an AVON on the front this spring. My mileage has gone from 33 to 38 mpg sofar this year, getting better for some reason, driving the same.
If your initial cost of the bike is low, thats gotta help.
$10000 upfront thats a whole new ballgame.
my 2 cents

This is my point exactly, and is unique to my senario. The altima has 83k on it, and I still owe 14k. The bike has 18k on it and I owe 4k on it. The bike was purchased for 5k and it is still worth 5k around here, the altima was 17k and is only worth about 11.5k right now.

An altima with 200k on it is gonna be worth about 4500 bucks max.
An VFR with 100k on it is gonna be worth 1000 bucks max.

17000-4500 = 12500 (total depreciation)
5200-1000 = 4200 (total depreciation)

If I did it twice with the VFR in order to hit 200k, I would only loose 8400, versus the 12,500 for the altima, thats 4.1 thousand dollars difference, which would equate to another VFR or a crap load of chains sprockets and brake pads.

As far as chain and brakes go, your estimates are a little low I would say. I have 18k on my original chain, sprockets and brakes and none of them are anywhere near needing to be replaced yet. Commuting down the interstate is not hard on any of these, its the stop and go stuff that is, and hard acceleration and deceleration of sport riding. Personally I can see getting 25-30k out of my stock stuff.


I may sit down and actually estimate all concerns of both vehicles for all services and see which is cheaper. It may be closer than I think it is, but I would bet my beans on VFR being cheaper in the long run. You just cant cover the depreciation factor fast enough with a vehicle that also gets lower gas mileage and higher up front cost.


Either way it doesnt really matter, my whole point is to save mileage on my Altima, so I dont loose my arse when I go to buy me a truck in a couple of years, and to save time and parking fees at work ($90 a month to park the car, $0 for the bike, thanks to being able to share a space with a coworker), When I must drive the car, I pay $5 a day to park).

The VFR I plan to keep FOREVER.

There are all sorts of scenarios you could come up with to save with either way really. I was just comparing the prices of new vehicles. Obviously if you buy used on one or the other, or both, depending on the deal you could have a vastly different calculation depending on who at the most depreciation up front. Basically you bought a VFR for half of new, but not an Altima for Half of new. If you would have paid 8 or 9k for a 6 year old Altima with 100k miles on it, it would probably even out the equation again. It all depends on what your goals are really I reckon. If your trying to save the most amount of money, I'm sure a used bike in good condition, hard rubber tires that you mount yourself, and doing all of your own maintenance can make commuting on a bike a lot cheaper. It just seems that a lot of people overlook all of the hidden cost and say "my bike gets 45mpg, I'll save a ton driving it to work". I used to think that riding was cheap, until I started looking at the cost of tires really.

Yeah, its all relative. And your right, tires and gas alone is not going to be a big difference from a bike to a cage.

400 miles a week

$3 a gallon, for easy math

23 miles per gallon Altima = 17.39 gallons = $52 a week

35 miles per gallon VFR = 11.42 gallons = $34 a week


where I really start to save is the parking fees of working downtown.

$208 a month fuel +90 a month parking = $298

$136 fuel + 0 a month parking = $136

Thats a saving of over HALF the cost of driving the cager.

A big bonus is I get to park the bike right next to the elevator in the parking deck.

Yeah, if you can park for free, thats a huge difference. I pay $22 a week regardless. 90 a month in parking is enough to pay for tires alone. I'm surprised however that your altima only gets 23 mpg. I get about 32-33 mpg out of my accord.

I like living out away from the city, but I do miss living in the city as well. Getting to work in 15 minutes, only driving 10k miles a year (instead of 30k). If i lived in the city, riding the bike would make more sense too, as it wouldn't cost as much and it would be more fun that 28 miles of interstate. We might move back in town once the kids get out of school.

Its a 210hp V6. I can stretch it out to about 27 if I stay out of it. I hate that car, it was a hand me down from my wife, because shes spoiled rottten and gets what ever she wants. She just got a Murano, loaded to the gills, of course I bought it 2 years old and saved about 14k off the MSRP of a new one. smile.gif

Yeah I know what you mean. My wife just got an 06 Pilot for xmas...

Those Pilots are very nice, a buddy of mine has one. Of course, I like just about anything Honda makes. Before I flipped my civic, I had all Hondas.

A CR125, VFR800, Civic, and a Riding Lawnmower. I may get another civic if I keep working in Atlanta, it was such a GREAT car. I drove it for 3 years, and put 65k on it, and when I flipped it, it was still worth 10,500, and I only paid 12,995 for it brand new.