I felt that this accomplishment deserved it's own post. As you may know I recently switched to an 18 tooth pinion. Well my commute is almost all freeways, and in the span of several days of commuting and some canyon joy riding I amassed 255 miles, hadn't hit reserve yet. So I decide to pull in and fill up. I amazingly only filled up 3.45 gallons. This equates to 74 mpg, my previous milage was about 65. I haven't changed my route, commute, or driving style. In fact my little 20 mile canyon carving session maybe even hurt my average a bit. But this is spectacular gas mileage. I also run taller harder (lower rolling resistance) kings cheapo tires, and inflate them 34 fronts 38 rear alittle bit on the hard side for efficiency. If you are a heavy freeway rider like me I can recommend this gear for the sake of mileage, and reduced buzziness in the handlebars and through the footpegs not to mention drastically reduced rpm. I'm turning only 4500 rpm at 65 mph and only about 5000 at 75. This is great because now I'm in the engines most efficient range when riding freeway speeds.
Now the bad part is you do have to ride the clutch just a tad longer, it's not end of the world burn your clutch-type running. Some of the guys here make it seem like go up a tooth and you'll be riding the clutch like a sixth gear start. Actually off the line you're only riding it maybe another car length, then you hit your powerband and the power is just the same. In fact I like this better because the gears "last longer" as in I'm not always shifting while in stop and go conditions, where as before I'd be in any gear only a couple seconds until I'd be shifting again either up or down. This should be familiar to riders of big bikes, only really needing first or second in the city. The gixxer 1000 especially, since it can do over 100 mph in first gear. So all the big bike riders know all about using that little thing called the friction zone. Highway power is a little bit lower but I can always shift down, the -2 people can't just shift up to escape the buzziness and terrible mileage.
All in all I'm happy with this upgrade as it reflects my riding style more. And I could even go higher on the mpg. The next tank I'll try to see what I can do if I ride more conservatively and cut out the canyons. I bet I could hit 80 mpg. So all those people who say gearing up doesn't increase mpg obviously don't commute like I do. This is as good as my honda rebel since it too got about 75 mpg but it couldn't go any faster than about 75 mph.
are you riding an E or an F ?
if you dropped to 55 mph, i'd bet you'd see another 20-25% increase in milage again.
congrats on another rider finding their niche gearing !
I'm riding a 2006 GS500F I think the wider power band available with the 3 circuit carbs really lets the higher gearing shine. I get no flat spots and I get power at any rpm above 3000.
Hey I got 52MPG the best i could do, Are your Bikes stock?
I'm running K&N Lunch Box 150jets, & just tonight did thr petcock rebuild With JB Weld pluging off vacumm lines,
I was talking about this at the Suzuki shop & a Tech said the most to go is a 17 T ?. He said the same thing about the clutch over worked thing??
[p51.
Quote from: qwertydude on May 09, 2008, 09:14:12 PM
I felt that this accomplishment deserved it's own post. As you may know I recently switched to an 18 tooth pinion. Well my commute is almost all freeways, and in the span of several days of commuting and some canyon joy riding I amassed 255 miles, hadn't hit reserve yet. So I decide to pull in and fill up. I amazingly only filled up 3.45 gallons. This equates to 74 mpg, my previous milage was about 65...
I'm turning only 4500 rpm at 65 mph and only about 5000 at 75.
Well, this is good data to compare against the gearing calculator I made! (the gearing calculator can be downloaded from the wiki:
http://cgi.stanford.edu/~sanjayd/gs500/Main/GearingCalculator (http://cgi.stanford.edu/~sanjayd/gs500/Main/GearingCalculator))
The following was calculated from the spreadsheet for 6th gear:
- 16-tooth sprocket, the theoretical engine speed at 65 mph is 5096 rpm
- 18-tooth sprocket, the theoretical engine speed at 65 mph is 4529 rpm
You reported gas mileage of 65 mpg with the 16-tooth sprocket. This gas mileage can be pro-rated by the engine speed ratio (i.e. 5096 rpm / 4529 rpm) to predict the new mpg:
65 mpg * (5096 rpm / 4529 rpm) = 74 mpg
I'd say the calculation matches your empirical measurements pretty well!
Using the spreadsheet calculator, similar analysis could be done with different sprocket combinations, or different tire sizes.
Thanks for the data! :icon_mrgreen:
Quote from: p51mustang on May 09, 2008, 10:44:33 PM
Hey I got 52MPG the best i could do, Are your Bikes stock?
I'm running K&N Lunch Box 150jets, & just tonight did thr petcock rebuild With JB Weld pluging off vacumm lines,
I was talking about this at the Suzuki shop & a Tech said the most to go is a 17 T ?. He said the same thing about the clutch over worked thing??
[p51.
I think his stock mileage is higher than "normal" because he does long commutes at high speed. This gives the bike time to fully warm up and ensures long periods of time with efficient fuel consumption.
I get about 50 mpg riding mostly in the city.
I do have a lot of extended riding, but during my down time I've gone almost entirely city miles where my tank lasted a whole week. And I've never seen worse than 58 which is what the bike is rated for. I also think the enhanced precision of the 3 circuit carb lets me take advantage of low revs better. As for p51, I think the k&n lunchbox is definitely messing with the carburetion. Lets face it the suzuki engineers did a damn fine job designing the intake system.
Sure you can extract more power but you'll lose efficiency, I've always been a proponent of airboxes. In fact a lot of guys riding gixxer 1000's who've gone to individual k&n's have lost power as measured by a dyno. Do the filters flow more air? Yes. theoretically, but intakes are a system and the airbox volume and velocity stack effect of intake runners and headers are a tuned system that can be thrown out of whack by imbalancing the volume and diameter of either.
In a carbureted system it's even more important, we can't just plug in a computer and remap our injection to match the flow rates and velocities at any given combination of throttle, load, rpm and ambient conditions. I've learned, from tuning scooters for max power, that the airbox does create some restriction, you can get slightly more power by eliminating it but you'll then get an engine that only likes to run at a certain altitude and temperature, head out of there and it doesn't perform at it's peak, to compensate you can always run rich. You'll get a wider operable band since you don't go lean and start to bog. But guess what the downside is? That's right poor efficiency and on top of that running rich reduces your power output so you're back to square one but at the greater disadvantage of running inefficiently. On top of that jetting can only take you so far, then if you want to fine tune it and you've already done the black art of shimming and rejetting a lot, you then have to get into the blacker art of retapering the needle, hard enough with 1 needle on a 50cc now you've got to make two identical needle tapers. This is what the engineers have to struggle with for months just to make this work, and the aftermarket just wants to say "slap these on, you'll make more power trust me I've engineered this baby" yet they come out almost at the introduction of the bike when I know almost for a fact they weren't designed in conjunction with the entire actual engine. Oh yeah and every one of my friends that have k&n's I like to remove their filters and run my hand inside their intake runner, I show them my dirty greasy fingers and ask them if the price of a few horsepower is worth destroying their engines. It ALWAYS comes out dirty.
I know a lot of you may be thinking if I'm so pro factory stock why am I changing gears? But this is one area where I don't mind sacrificing performance for effeciency and I'm not messing with any state of tune of the engine. Plus this bike was designed for more congested japanese and european roads. Shorter trips, nothing like our vast interstates and long commutes. Plus if it was so bad for the clutch I don't see why, the sv650 which has similar final gearing ratios as my 18 tooth has, and a more powerful engine, yet our clutches are basically interchangeable right?
http://www.suzukicycles.org/SV-series/SV650_specs.shtml
I got gas yesterday on my completely stock 02 GS500 after going to reserve at 230 miles. Stopped for gas at 238 miles and put in 3.7 gal. My usual suburban and nearby country twistie road riding on that tankful. About 64 miles per US gal.
I frequently rode with a big cruiser friend back when I got my first GS and followed him at his pace getting close to 70 mpg some days. I decided to go for 300 miles one day on the 4.5 gal tank and made it and then pulled in and added a little over 4 gal of gas.
Both of my GS's have been completely stock except fot a 15T sprocket I added on the 97 after 37k miles on 16T sprockets. No sprocket change needed on the 02 with the 3 circuit carbs, can't improve on perfection. :laugh:
How slow did you have to go to get 70 mpg on a 15 tooth?
How do you guys ride? Im a new rider and been only getting about 45 mpg around town and a stock 2006!
If you wanna get the mileage figures we get you have to ease up on the throttle and shift early. I usually shift at around 3500 rpm if I don't need the speed. Also opening the throttle more at lower rpm's to get the power needed to accelerate is more effiecient than letting the engine rev at partial throttle. There are more throttling and intertial losses at higher rpms. The engine creates more vacuum at that higher throttle which means more fighting for the engine to breathe, and imagine that piston changing directions so fast. Which would get your arms tired faster lifting 5 pounds 10 times in 10 seconds or 2 pounds 25 times in 10 seconds. Try it and you'll quickly see how intertia plays a role in engines. Both mean you're doing the same amount of work but doing things at lower loads and higher rpms is simply more inefficient. To train yourself to go at the proper speeds and learn how to coast gently to a stop try to ride while using the minimum amount of brake necessary. I myself, to keep aware, purposely use only my rear brake to stop unless I need to stop quickly. I also do a lot of coasting, like when I know I'll need to stop ahead of time I pull the clutch in and coast for a distance. All this effort is called hypermiling. Do it enough and you'll soon be aware of how inefficiently people drive, especially on the freeway. A good article to read is this one called anti-traffic, gives good insight into driving psychology. And that agressive driving bug that resides in us all, maybe even more so in motorcyclists.
http://www.eskimo.com/~billb/amateur/traffic/trafexp.html
people aren't usually aware of what they're doing, generally, and even motorcyclists with their enhanced awareness of the surroundings typically don't pay attention to what they themselves are doing. It's a big reason why the accident rate is so high with us. Yes generally two vehicle collisions with bikes are generally the cars driver's fault but many single vehicle accidents could be prevented. How many people here can claim 190,000 accident free miles on their bikes? I can raise my hand to that, not so much as a lay down. The worst thing that ever happened to me was the time where I parked my gs in the post office parking lot, went in to mail a package, when I got out the gs was on it's right side mirror broken off, what rally ticks me off is there was lay down damage on it's left side too. Looks like somebody knocked my bike on it's left side tried to pick it up and in the process kncoked it on it's right side then just left :mad: I'm especially mad because this was just 3 days after getting it. So learn the little quirks of your bike, how it handles, it's limits and your limits and you can ride both efficiently and more importantly safely and like me lead the fast pack on the canyon rides in your motorcycle club.
Where did you get the sprocket? I have not found a source for even 17 tooth sprockets yet.
Thanks in advance.
I'm curious too, can someone suggest a place to order a 18 tooth front sprocket, I would perfer to order through a vender in North America.Thanks ! :thumb:
bikebandit.com
http://www.bikebandit.com/brand-nav/afam
My order was delayed a about 4 days before they could ship it because it was out of stock but maybe they're in stock now. I can see my gas mileage has attracted lots of attention. By the way I've taken it easy now and my last fill up has moved to a now astonishing 78 mpg. It could be even higher since I did do some 2 up riding for about 15 miles in the city but with such a long range now it's in the 270 mile range it's doubtful I'll ever get to ride a perfect tank.
This was shipped from a wherehouse in the us. Made in france though.
Bike Bandit told me they did not carry an 18-tooth sprocket for the GS500 :confused:
Maybe you can point out the part # or something :dunno_black: