Added 16T info and first tank on 18T to end of first post.

WOW!!!  75 MPH average speed......so you must of been going like 90 MPH at times?

OK.... you need that bigger gear for sure!

But funny thing.........your "stock"  speed/rpm does not match up with mine...I say I'm about 500 rpm less than you .......

The 75 MPH cruising at 5000 RPM might be nice if you go that fast often

I seldom get over 60 mph except for short spurts

So going in the 55 MPH to 60 MPH range (GPS speed not indicated on the stock speedo) puts me in the 5000 rpm to 5500 rpm range...the engine seems happy there.......If I go any much slower I shift down to 5th....

Cookie

Cookie

Quote from: Soloratov on June 01, 2013, 06:49:31 PM




The testing info:

All information is based on US MPG
All speeds were taken from my digital speed & with GPS
All RPM's are based on watching digital tach throughout the riding, so it's close

1990 GS500
K&N Drop in
Stock Exhaust
200lb Rider

16T Sprocket:

Tank 1: 47mpg - Mixed Riding - Avg Speed: 55mph - Avg. RPM: 5500
Tank 2: 49mpg - Mixed Riding - Avg Speed: 55mph - Avg. RPM: 5500
Tank 3: 41mpg - 1/2 Mixed - 1/2 Highway Riding - Avg. Speed: 70mph - Avg. RPM: 6500

18T Sprcket:

Tank 1: 53mpg - 2/3 Highway Riding - Avg Speed: 75mph - Avg. RPM - 5000

I average anywhere from 70-80 mph the entire way to and from work. I live 1/2 mile from the expressway, and work is about 100 yards off the exit, so yeah....it's a long, fast ride.

Keep in mind, your speedo is a percentage off...mine is exact. I also have the digital tach that reads the coil, so that may have an difference as well. When I had the stock gauges, with stock gears, I swore that at 60, in 6th, my bike spun at 6K RPM. As soon as I was reading actual wheel speed and RPM from coil, that changed drastically.

Well, maybe my tach is "off"    but I use  GPS for speed.........I also figured the "error" of the stock speedo at 8% so I account for this too if I don't happen to have the GPS......

80  "true" MPH on a GS 500 on the expressway is sure not my idea of fun...to each his own...

For more "normal riding" ...which I consider to be in the 50 to 65 MPH range...I don't see any advantage in gear ratio  change ....For what you are doing, which I consider to be "sustained high speed"...I can see the advantage of bigger gear ratio...dropping the cruise RPM...and possibly getting better mileage..........

But 80 MPH and good mileage are directly opposed to each other...so you have to consider a "relative improvement"..........

I ride fairly long distance to work on weekends...80 miles each way...but pretty much sustained 50 to 55 mph.....(county roads, no expressway).....In stock 6 th gear.....65 miles per gallon is typical...but occasionally over 70 MPG........I can easily run the mileage down into the 50's by driving faster and accelerating more.....

Remember  drag is the square of the speed...so 80 MPH has 4 times the drag of 40 mph.......

Horsepower required is the cube of the speed...so if you need 5 HP to go 40 mph...you need 40 HP to go 80 MPH.....gas economy goes down as speed goes up.........Gearing can only make the whole deal a bit more efficient at certain speed/rpm combos..

For what  you are doing....gears 1 thru 5 make no difference in mileage at all...it is the 6th gear ratio which matters at those high sustained speeds........

Cookie

Quote from: Soloratov on June 05, 2013, 05:27:23 PM
I average anywhere from 70-80 mph the entire way to and from work. I live 1/2 mile from the expressway, and work is about 100 yards off the exit, so yeah....it's a long, fast ride.

Keep in mind, your speedo is a percentage off...mine is exact. I also have the digital tach that reads the coil, so that may have an difference as well. When I had the stock gauges, with stock gears, I swore that at 60, in 6th, my bike spun at 6K RPM. As soon as I was reading actual wheel speed and RPM from coil, that changed drastically.

But my question is, what model/year are you riding? A newer F model would absolutely get higher mileage.

I have an old E. Wind resistance is...inevitable. As far as riding style, I do a lot of just cruising around to, but I'll ride around in 6th anywhere from 45 mph and up. Ever since I bought the bike, I have never understood how anyone could get over 60 mpg, stock gearing. Even times I granny drive, I couldn't see that happening. Remember, I stated it in my info...sustained higher speeds are only when I'm going to work. Everything else is 55-60, so it's not a speed issue.

I'll dedicate this weekends tank of gas to you.  I'll get 100 miles of leisure in there, see what I can get.

Quote from: Soloratov on June 05, 2013, 05:27:23 PM
I average anywhere from 70-80 mph the entire way to and from work. I live 1/2 mile from the expressway, and work is about 100 yards off the exit, so yeah....it's a long, fast ride.

I am constantly going 75-80 mph at like 6k rpm on I5, would you recommend the 18T sprocket? And have you checked to see what your top speed is now? How much does it even improve?

Top speed...actual? Theoretically it improves, but there is really no way this little 500 could ever reach it's "top speed". I have never taken it much over 90, so I couldn't answer that. As far as the swap, for the higher highway speeds, the main improvement has just been the buzzy vibration. It's a lot smoother at the higher speeds, so more comfort for the longer rides, less hand irritation as well.

OK more good points...

My bike is an 2009 F.......two things here...one, Maybe the fairing offers slightly less aerodynamic drag......I doubt it though...some  say the fairing acts like an air scoop and actually increases drag...hmmm.

Second..........the later models have a three stage carburetor...earlier are two stage......I have also heard that the later bikes come from the factory set up to run on the very lean side.......

Actually though, my spark plugs are nice color, so I am not running excessive lean....

Tires make a difference too....I still did good mileage on the stock battleax tires..but now I run on Avon... fairly hard tire.......and I keep the pressure up to spec...

Yet another possibility for better mileage...I have clubman bars..so I sit a bit lower and flatter on the bike.

To achieve better gas mileage, IMHO, requires many, many little factors which all add up and contribute.....not that one change will suddenly give you great mileage.

When you come right down to it, mileage is pretty much elementary....Just one big...equation....

Weight of the bike....drag....speed..acceleration, wind, hills...etc...It takes a certain amount of power to do this..no more, no less....The power comes from the fuel....So you  are gonna use the same fuel to do the same work....

All you can hope for with gearing to to avoid waste...in effect getting the optimum efficiency...Since with gears 2 thru 5, you can up shift or down shift, these ratios don't matter....you can choose the optimum shift points for maximum efficiency....Gear one really doesn't matter much since you use it only to get started from a dead stop...actually a lower gear one might improve mileage...but this is insignificant........So it is only gear six that matters....IF you travel at high speeds.....

In a much earlier discussion we came up with dyno charts of the power curve at various shift points....basically this curve follows the theoretical curve you would get with a theoretical perfect CVT...continuously variable transmission.......(or you could say infinite number of gears)...

But the actual curve is so close to the theoretical that it again shows that only gear one ..and gear 6 actually change anything....and again gear one is used only to get started ...so it is gear 6 that matters.......

So, long winded to say.....you want to optimize gear six to fit your cruise speed.......

I would estimate that stock gear six is optimized for maybe 60 to 70 MPH........If you're gonna cruise at 80 to 85 a higher gear would be more optimized for fuel mileage........(speed and or acceleration however, is a different story....this is where some opt for LOWER gearing!!)

Cookie

Quote from: Soloratov on June 05, 2013, 07:32:52 PM
But my question is, what model/year are you riding? A newer F model would absolutely get higher mileage.

I have an old E. Wind resistance is...inevitable. As far as riding style, I do a lot of just cruising around to, but I'll ride around in 6th anywhere from 45 mph and up. Ever since I bought the bike, I have never understood how anyone could get over 60 mpg, stock gearing. Even times I granny drive, I couldn't see that happening. Remember, I stated it in my info...sustained higher speeds are only when I'm going to work. Everything else is 55-60, so it's not a speed issue.

I'll dedicate this weekends tank of gas to you.  I'll get 100 miles of leisure in there, see what I can get.

Getting the max top speed, vs getting best fuel mileage at high speed are going to require different thought process..........

For best mileage at a given cruise speed....we want the engine to be operating at its most efficient RPM...this will be a relatively low RPM........We should choose the gearing as appropriate...This would be relatively high gear ratio...and the engine will be producing relatively low HP...

For the fastest possible top speed, flat out.....we need the engine to produce the max possible Horsepower....This comes near or at redline..........If we go with too high of gearing.....the engine will be bogged down, and never reach redline......the top speed will be too slow........If we go with too low of gearing the engine will hit redline, before the top sped of the bike is reached......there is a perfect middle ground here where the  bike hits its max possible top speed jsut as the RPM its the max HP point.....

At this configuration, the fuel economy would be about the worst it could possibly be......Wide open throttle, almost redline RPM...high speed...maximum drag....

Cookie

Quote from: Soloratov on June 05, 2013, 08:53:46 PM
Top speed...actual? Theoretically it improves, but there is really no way this little 500 could ever reach it's "top speed". I have never taken it much over 90, so I couldn't answer that. As far as the swap, for the higher highway speeds, the main improvement has just been the buzzy vibration. It's a lot smoother at the higher speeds, so more comfort for the longer rides, less hand irritation as well.

Exactly. Main reason I never have gotten over 90, not that I want to, is more for the fact of at 90, on an E Model, it's like riding down the road with a parachute attached to my back. Remember, this is all relative to the rider. All I can provide is the difference I get with my riding style and my bike. Everyone gets something different.

I would agree to some degree on the only 1st and 6th mattering, but at the same time, effectively adding another gear (compared soley to a 16t) it basically lowers the operating RPM in ALL gears by roughly 1500. Now consider how much fuel is used at idle over the course of, say an hour and half...roughly how long it would take to go 100 miles. That's the amount of fuel I am saving over the course of a tank, because at any given speed I am now one gear lower, at a lower RPM. This is just me though, thats my riding style. I have always owned cruisers, so I have always shifted to the next gear early at a lower RPM. Instead of shifting around 6-7K I have always shifted around 4-5.

You made the perfect point, it's all dependent on the person and how they ride. Lets face it, Johnny Rocket next door that wants to do 100, will never get good mileage. All i am trying to do is provide objective numbers based on my previous numbers. Let others decide. When I look around Fuelly, everyone will an early E model gets roughly the same mid-high 40's, occasional low 50's. These are the people who can benefit from my research. 

This is a common fallacy.....

Changing the ratios on gears 2,3,4,5 does not change the operating RPM of those gears...........

YOU choose the operating RPM.....

For example I could use my stock gearing and shift up at 4000 RPM....or I could shift up at 5500 or I could sift up at 7500...the rider chooses the shift point, not the gear.........

You have to think of the six gears as one continuous curve...it is not a perfect curve, but really close ....

The power curve which would give you the max speed and acceleration would be having the shift points at or close to redline.

The power curve which would give the best fuel economy would have the shift points at a much lower RPM...........

But in either case above.....No matter what the actual gear ratios are, (within reason) the body of the respective power cure will look exactly the same!  The speeds at the shift points will be different, but the curve will look exactly the same...except for a tiny part at the beginning of the curve, and the tiny part at the end of the curve.....

Cookie

Quote from: Soloratov on June 06, 2013, 05:55:21 AM


I would agree to some degree on the only 1st and 6th mattering, but at the same time, effectively adding another gear (compared soley to a 16t) it basically lowers the operating RPM in ALL gears by roughly 1500.

 

Yeah, that's true...I can see your point there. Well...fine. Then...I'm still sticking with longer gears, and lower 6th gear RPM. Going to be miserable and rainy here for a few days, but should get some more numbers up this weekend. I want to see if I can hit the magic 60 just cruising around, exploring the back roads.

Quote from: twocool on June 06, 2013, 04:57:13 AM
For the fastest possible top speed, flat out.....we need the engine to produce the max possible Horsepower....This comes near or at redline.........

Theoretical top speed at redline of a stock GS500 in 6th gear is 140 mph, actual top speed is in the 100-110 mph range.  Max HP is produced at 8500 rpm which would be at about 108 mph in 6th close to published road test top speed results but not too close to the GS500's 11,000 rpm redline.

http://www.gs500.net/gallery/data/500/GS500tests.jpg

Quote from: Soloratov on June 06, 2013, 05:55:21 AM
Exactly. Main reason I never have gotten over 90, not that I want to, is more for the fact of at 90, on an E Model, it's like riding down the road with a parachute attached to my back.

LOL, the only time I ever got to top speed or close to it was on my 97 GS in the mountains of upstate NY 10 years ago with a barn door size Plexi 2 shield on it.  I hit 110 mph indicated which might have been an honest 100 mph and I've used a smaller Spitfire shield for summers ever since.

After approx 175,000 miles on my 97 and 02 GSs I'm convinced the stock 16/39T gearing is best for me, your needs may vary.  I've got a consistant 60-65 mpg overall including dropping to 50-55 mpg winters and for 70-80 mph indicated Interstate days and when running at 7-9k rpm for hours in the mountains.

Somewhere on the site it was suggested you could use an 18tooth 520 conversion front sprocket for a GSXR1000.

The 18t front sprocket we put on the '07 GS500F we had was made by Afam.

I don't think the effect on gas mileage is going to be significant for everyone. What I liked most about changing the gearing was that the bike no longer felt like it was working harder than it needed to at 60+ mph

I'm expecting an average of about 5-7 mpg increase. On a bike, it may not be significant enough to get excited, but think of it in term of a car. An extra 5 would be awesome! I'm just enjoying the very noticeable difference in the feel of the bike.

GSJack - It's one reason I like living where I do, a lot of nice places to ride, and the Adirondacks are only a few hours away. Not sure I could ever allow myself to put a windscreen on a bike, but the advantages are great!

Quote from: SAFE-T on June 06, 2013, 08:08:12 AM
I don't think the effect on gas mileage is going to be significant for everyone. What I liked most about changing the gearing was that the bike no longer felt like it was working harder than it needed to at 60+ mph

^  What that guy said.  I'm currently running the stock 16/39 setup but am in the process of ordering a new chain and sprockets.  I wasn't sure I really wanted to change the front sprocket up a tooth because I felt like I could possibly be losing a lot of low end power.  I  have decided to try a Sunstar 33317 17-tooth front sprocket to see if it will make my highway riding more bearable.  I am hoping that the 17-tooth will be a good compromise because I feel that the bike struggles between 70-80mph and I typically ride interstates at those speeds.

I personally couldn't find an 18-tooth made for anything past 1993 but I'm not sure if I really dug that deep in the sprocket world.

18T sprocket for '94 and up at bottom of the page

http://www.jcwhitney.com/1990-2002-suzuki-motorcycle-gs500/motorcycle-sprocket/p3067786d58770y1990-2002j1.jcwx

By theoretical top speed I am guessing you mean redline RPM in sixth gear.........This would be disregarding the aerodynamic drag (and other drag)

If the bike hits 108 mph flat out in sixth gear...  but can't get past 8500 rpm.....then the gear ratio is too high for max possible top speed......A (slightly) lower gear would allow the engine to spin up to redline, thus producing more horsepower and (slightly)more speed.........)

Max HP comes just a little before redline, I believe.......for max acceleration you should SHIFT at redline though..

The problem lies in the fact that drag is the square of the speed.........and horsepower required is the cube of the speed.........so you basically "hit the wall" no matter what you do........

But all of the above has to do with performance, as in speed...not economy.....

So running higher gear (6th) can improve economy at typical high speed cruise.........

But again I stress that the stock gearing is pretty darn good over a wide range of driving conditions...........To me the only advantage of higher gear is if you consistently cruise in the 85 MPH range for long periods of time.........Engine is turning slower, economy is slightly better....bike might be slightly more comfortable with less vibration.....etc.

What is the actual fuel economy gain?  I bet not really significant!  When you figure the cost savings of like one or two MPG over the life of the bike it is really too small to matter much....

An if you really want or need fuel economy there are other ways.......aerodynamics would be big...as would be driving style..... limiting WOT...lowering weight  etc....

in the big picture my GS gets roughly twice the mileage of my car...and my car gets pretty good mileage..........so I am happy and don't see the need for modification for my driving...


Cookie







But this whole range is not really important in normal driving

Quote from: gsJack on June 06, 2013, 08:00:12 AM


Theoretical top speed at redline of a stock GS500 in 6th gear is 140 mph, actual top speed is in the 100-110 mph range.  Max HP is produced at 8500 rpm which would be at about 108 mph in 6th close to published road test top speed results but not too close to the GS500's 11,000 rpm redline.

Quote from: twocool on June 06, 2013, 04:57:13 AMFor the fastest possible top speed, flat out.....we need the engine to produce the max possible Horsepower....This comes near or at redline..........

Quote from: twocool on June 06, 2013, 12:05:03 PMBy theoretical top speed I am guessing you mean redline RPM in sixth gear.........This would be disregarding the aerodynamic drag (and other drag)

If the bike hits 108 mph flat out in sixth gear...  but can't get past 8500 rpm.....then the gear ratio is too high for max possible top speed......A (slightly) lower gear would allow the engine to spin up to redline, thus producing more horsepower and (slightly)more speed.........)

Max HP comes just a little before redline, I believe.......for max acceleration you should SHIFT at redline though..

I'm talking about a stock GS500 which does hit the approx 108 mph top speed at the max HP which is the point I was making, Suzuki got it right, and it is as you said:  For the fastest possible top speed, flat out.....we need the engine to produce the max possible Horsepower.  But this happens at 8500 rpm on a stock GS500 long before the 11.000 rpm redline and so max acceleration can be had shifting at 9-9.5k rpm.  Doing so drops the rpm about 2k rpm to the top of the torque curve at approx. 7000 rpm.  That's why I refer to running at 7-9k rpm for max performance on stock GS shifting up and down to keep it there.  Typical dyno curve for a stock GS looks like this:



Do a good job of modifying intake, exhaust, and jetting and you can extend the power peak close to the redline like John did on Annie's GS: