I resently put a 17 tooth front sprocket on my 2008 GS500F. I have to say I am very pleased with how it works. I didn't loose any take off, I can still make it get down the road if I need to and it rides much smoother than before. The gears are a bit taller and I still have to use all 6 gears on the highway. I did get brave one day and tried to top end it. I ran 105mph in 5th gear at 8500rpm. I didn't go any faster because I ran out of straight away and nerve. I thought something was up with the speedometer because I've read on this forum that they are all off so I asked my wife to clock me at a 45mph pace and my speedo was right on. The one thing I've learnened is that the tires that come stock on a GS are not made for high speed. I get a shutter over 95mph. Is it the tires or something else? Either way I'd have to say the 17 tooth sprocket was the best $30 I've spent on my bike. Thanks for your time.

What are your revs at 65~70mph?

Around 95 mph, it could be any number of things - because at that speed everything needs to be almost perfect. It could be the tires (out of balance, bead slightly off, tread pattern on the road surface, etc), slightly worn / dry bearings somewhere, rear wheel not aligned, so on and so forth. Heck, your body position can catch wind the wrong way and make the bike act up.

"I've read on this forum that they are all off so I asked my wife to clock me at a 45mph pace and my speedo was right on."

Huh?  Scientific?   What did your wife do...run alongside?


How come every other gs500 has 8% to 10 % error, and yours is spot on?

Sounds to me like you managed to turn a 6 speed bike into a 5 speed bike!

Then again...that's just me...just sayin"
Cookie

Quote from: ron freeman on August 30, 2013, 05:51:36 PM
I resently put a 17 tooth front sprocket on my 2008 GS500F. I have to say I am very pleased with how it works. I didn't loose any take off, I can still make it get down the road if I need to and it rides much smoother than before. The gears are a bit taller and I still have to use all 6 gears on the highway. I did get brave one day and tried to top end it. I ran 105mph in 5th gear at 8500rpm. I didn't go any faster because I ran out of straight away and nerve. I thought something was up with the speedometer because I've read on this forum that they are all off so I asked my wife to clock me at a 45mph pace and my speedo was right on. The one thing I've learnened is that the tires that come stock on a GS are not made for high speed. I get a shutter over 95mph. Is it the tires or something else? Either way I'd have to say the 17 tooth sprocket was the best $30 I've spent on my bike. Thanks for your time.

If it was wife in car or other vehicle ... That speedo could be off also ...

It still has 6 gears though ... I don't get that into a 5 speed idea.... 

He only tested to 105 indicated in 5th........why didn't he go to 6th?

I doubt he is ever going to cruise anywhere, anywhere near  at 105....so now 6th gear becomes unnecessary.....

hence a 5 speed gs500........

Part of my work is calibrating aircraft instruments......I have never calibrated any aircraft instruments by having my wife go along.  We have (slightly) more scientific methods!

If somebody is going to tell me that changing one tooth makes such a huge difference...they better come up with some real evidence..

Just sayin"


Cookie

Quote from: Janx101 on August 31, 2013, 02:48:12 AM
If it was wife in car or other vehicle ... That speedo could be off also ...

It still has 6 gears though ... I don't get that into a 5 speed idea.... 

I don't know about a huge difference, but per the all-knowing wiki (I love wiki's - I miss working on that project at work) there should be about a 5.88% drop in RPMs

http://wiki.gstwins.com/index.php?n=Upgrades.Sprocket

Ahh ok ... I missed the 105 in 5th bit ....

But same in my bike at the moment with stock sprockets ... I can get more indicated road speed in 5th with higher rpms ... The engine hasn't got enough grunt to maintain that speed in 6th with my weight etc ... So it could also therefore be called a 5 speed bike? ..

However... For cruising the freeway at sustained speed .. Lower rpms in 6th and changed sprockets still has potential to save fuel .... And in the twisties ... For me anyway .. I don't get up into 5th often.. 6th hardly ever .... So if I changed to a 17/37 say ... And then only used 3rd mostly and 4th sometimes in the twisties ... Would I make it a 4 speed bike? ... No .... Sure the final ratio has changed ... And the speed vs change points a little too ... But at some point all the gears still get used...

You want scientific testing ... But you can claim he changed it effectively to a 5 speed bike? ... Without testing .... That doesn't fly bro?! 

But that drop only matters in 6th gear....where it really doesn't matter.......

Well also in first gear, where it does matter, to the negative..

Cookie

Quote from: 0Bw4n on August 31, 2013, 04:12:40 AM
I don't know about a huge difference, but per the all-knowing wiki (I love wiki's - I miss working on that project at work) there should be about a 5.88% drop in RPMs

http://wiki.gstwins.com/index.php?n=Upgrades.Sprocket

As you say below...you do not often even use 6th gear......it is sort of an overdrive


So ....

Going to a higher 6th gear, make this gear even less useful.....maybe makes 5th questionable...


You also mention that top speed may be faster in 5th than in 6th....I would imagine this is true....
(once you hit the aerodynamic drag "wall"....you can't get enough RPM in 6th to generate full Horsepower.....

So making a 6 speed bike...where top gear is not used makes a 5 speed bike in my book.......

But just take a step back and look at the big picture here...

The stock gearing is spot on!

Cookie

Quote from: Janx101 on August 31, 2013, 04:27:41 AM
Ahh ok ... I missed the 105 in 5th bit ....

But same in my bike at the moment with stock sprockets ... I can get more indicated road speed in 5th with higher rpms ... The engine hasn't got enough grunt to maintain that speed in 6th with my weight etc ... So it could also therefore be called a 5 speed bike? ..

However... For cruising the freeway at sustained speed .. Lower rpms in 6th and changed sprockets still has potential to save fuel .... And in the twisties ... For me anyway .. I don't get up into 5th often.. 6th hardly ever .... So if I changed to a 17/37 say ... And then only used 3rd mostly and 4th sometimes in the twisties ... Would I make it a 4 speed bike? ... No .... Sure the final ratio has changed ... And the speed vs change points a little too ... But at some point all the gears still get used...

You want scientific testing ... But you can claim he changed it effectively to a 5 speed bike? ... Without testing .... That doesn't fly bro?! 

Hold the logic....

Who says anyone is going to ride anywhere at 100mph? What ever happened to cruising along at 75 indicated? So at 75 the revs are around 6k stock. Whack on a 17 tooth front and they'll be what, 5,500 instead. How does that make 6th useless? Sure 6th might not have the Punch it used to (if it had any at all), but all that's happening is a Slight lowering of rpm in a given gear for a given speed.

Lambaste the man for his unscientific way of judging his speedo accuracy, but don't tell him 6th no longer is usable when it clearly is still usable.

At 65mph I am taching 5000rpm. I pick-up 10mph for every 500rpm in 6th gear.
I know using my wife's car to calibrate my speedo isn't exactly scientific but she drives a 2012 VW Jetta so I trust the Germans know how to calibrate a speedo.
I didn't change to 6th gear because I ran out of straight away and it's never smart to drive beyond your abilities.
Here in North Carolina,  USA if you can't run 90mph on I-95 you best stay off the highway. And to be honest I like knowing what my bike can do even if it's not how I normally drive.
Thanks guys this forum is pretty cool.

No I didn't say I hardly ever use 6th at all .... In twistie 'fun' roads I don't for sure.. I can't get enough moxy going to attack a twistie road in a suitable rev range in 6th..  waaaaay to quick!.. But out on the flat country I click into top all the time ... Let it just purr along ... On other roads and in general ... I like to use ALL the rev range and ALL the gears as much as possible!

And I have heard the theory that sprocket changes only really affect 1st and 6th ....  ... so is there some kind of warp field in the box that leaves 2-5 untouched by sprocket ratios? ... Sprocket changes HAVE to affect the whole box ... The rpms vs road speed of every gear change ...
You want to affect only 1st and 6th then crack the box open and change THOSE cogs ...

As always each to their own .... People want to mod the bike to wherever .. then as you quoted several posts ago .. 'Have at it' .... An almost OCD-like focus on stock stock stock STOCK!!! is ok too ... So we can assume you have a completely OEM bike which one day could be considered classic or something possibly... Sweet!!! 

A 17T is what I used to get 69.8 Mpg, with Plus Juan jetting, stock pipe & air box. I spent allot of time on the open road and virtually no in town riding with that combination, so it worked well for me.

But in his  test" he only went to 5 th gear....

He gave not one "objective" reason to change the gearing from stock.....


Any test results must contain data from stock gearing...then a test with he new gearing under the exact same conditions.........

Saying that is "feels better" is subjective...but unfortunately not objective....

Really the original post was full of bull and no substance.........


Cookie

Quote from: mister on August 31, 2013, 11:34:39 AM
Hold the logic....

Who says anyone is going to ride anywhere at 100mph? What ever happened to cruising along at 75 indicated? So at 75 the revs are around 6k stock. Whack on a 17 tooth front and they'll be what, 5,500 instead. How does that make 6th useless? Sure 6th might not have the Punch it used to (if it had any at all), but all that's happening is a Slight lowering of rpm in a given gear for a given speed.

Lambaste the man for his unscientific way of judging his speedo accuracy, but don't tell him 6th no longer is usable when it clearly is still usable.

Mmmmm, very interesting, I found Ron's first post to be both interesting and informative.  I also went back and read it again after reading the rest of the posts and searched but couldn't find the bull.     Ron likes his 17T front sprocket and so do Janx and Steve so why shouldn't they express their opinions on them?

Personally I like the standard Suzuki gearing for my 02 GS and only have changed it to a 15T briefly a couple times to correct for larger rear tires bringing my engine speeds back close to standard.  I used a 15T front on my previous 97 GS with the 2 circuit carbs thru the mountain years and most of it's 80k miles and it felt right to me then too.

So Ron wanted to test his top speed with the 17T sprocket but backed off at 105 mph in 5th when he ran out of straight and didn't want to go any faster, his bike was showing some instability at at 95 mph.  I'd of backed off at 95 myself.   I did take my 97 GS up to 110 mph with 235# me and a big Plexi 2 shield on board in the mountains of upstate NY.  Was chasing down a couple of riders who went out ahead of the group to play and found a bit of straight to make up some time but by 110 mph indicated I was braking hard for the next turn.  Had the Z4/Z2 radial tire combo and the 15T sprocket on the GS then and it was smooth and steady all the way. 

Gotta wonder how many have actually hit a hundred on their GSs, a big number but a very small percentage I suspect, if they also have 175,000 GS500 miles under their belts I'll even listen to their opinions of my right to express my opinions about my bike with a smile on my face.     

I might be the odd man out here, or maybe it's just that I'm a bigger rider than most, but taller gearing is the last thing I'd want with my GS. With my 240# self and 140 rear tire, 6th gear is as tall as I'd ever want to go. I don't think the bike would have enough power at highway speeds with taller gearing. I might even switch to a 15T when I buy a new chain and sprockets over the winter.

The fuel economy battle is getting out of hand. The same thing goes for my car as well. The highway MPG war has caused manufactures to put ridiculously low top gear ratios to the point where it's affected the drivability of the car. With all new cars, the top two gears (with most 6 speeds) are strictly economy gears, and you're constantly forced to downshift on the highway or while going up slight grades. I'd personally trade a fraction of a MPG for a couple more hundred RPM's in top gear. My poor little Suzuki SX4 crossover has to run just over 2000rpm in 6th gear at 100kmh. Even with an ECU remap it has no chance of climbing any sort of grade in 6th and I'm constantly having to downshift to 5th or even 4th. All so they can claim an extra 1/8th MPG on the window sticker.

Quote from: twocool on August 31, 2013, 06:43:12 PM


But in his  test" he only went to 5 th gear....

Doesn't make any difference if he went to 5th or 6th or never got out of 4th because all gears will be equally affected by a change in final drive. His bike runs to 105 indicated at 8500 RPM in 5th, significantly lower RPMs than he'd get at that speed with stock gearing. It then follows that 6th should also be geared taller by the same margin as 5th and all other gears, so he got exactly what he wanted - a bike with more relaxed gearing.

Secondly, his method for checking speedo error is not nearly as ridiculous as you make it sound. It falls short in that he doesn't know much error there is in the Jetta's speedo itself. But if you had a car with known accuracy and that car paced you, then you could make that method work quite alright.

Quote from: gsJack on August 31, 2013, 08:42:43 PM
Gotta wonder how many have actually hit a hundred on their GSs, a big number but a very small percentage I suspect, if they also have 175,000 GS500 miles under their belts I'll even listen to their opinions of my right to express my opinions about my bike with a smile on my face.   

Actually hit an indicated 100, or ACTUALLY hit 100? I have never had a motorcycle with more optimistic speedo than my GS-F. It's ridiculous, mine over-reads by over 10%. On the highway I have to hit an indicated 90 to go an actual 80-ish.

I don't think the bike is unstable so much as having a seating position that is less than ideal for those speeds. You are perched upright on the thing acting like a big sail and very prone to helmet buffeting. Tucking under the fairing helps a lot.

Ok....Here's the bull...item by item....

Bull:
"I didn't loose anything on take off"

Fact:...higher starting gear MUST make slower take off.

Bull: I ran 105mph in 5th gear at 8500rpm. I didn't go any faster because I ran out of straight away and nerve.

Fact:  a test of top end with higher gearing should be made it top gear, right?  And test not aborted.

Bull: "my speedo was right on"

Fact:  The gs500 speedo is about 10% optimistic

More bull:

There was no "base line testing" done so we are comparing the new gearing to what?

So based on this test report...who is going to switch to taller gearing?

Cookie

Quote from: ron freeman on August 30, 2013, 05:51:36 PM
I resently put a 17 tooth front sprocket on my 2008 GS500F. I have to say I am very pleased with how it works. I didn't loose any take off, I can still make it get down the road if I need to and it rides much smoother than before. The gears are a bit taller and I still have to use all 6 gears on the highway. I did get brave one day and tried to top end it. I ran 105mph in 5th gear at 8500rpm. I didn't go any faster because I ran out of straight away and nerve. I thought something was up with the speedometer because I've read on this forum that they are all off so I asked my wife to clock me at a 45mph pace and my speedo was right on. The one thing I've learnened is that the tires that come stock on a GS are not made for high speed. I get a shutter over 95mph. Is it the tires or something else? Either way I'd have to say the 17 tooth sprocket was the best $30 I've spent on my bike. Thanks for your time.

Do you somehow get offended by anyone who makes a change to their bike and likes it? I can't find any fault in someone posting about a change they made so that others can have another opinion for reference. Just because you may not like the change, doesn't make their opinion of it invalid. When I posted about my 18T change, I provided a relatively objective riding view, AND hard data numbers based on digital speed tests, and you still tried to tear it down. What exactly are you looking for? A lot of things are subjective, and can't be expressed in some perfect lab experiment way...sometimes, just sometimes, someone changes something and likes it purely because it suits them.