Asked earlier but was wondering since our bikes die around 10k with a 16 t is it safe to say a 15 t would keep the bike in the powerband and maybe increase top end?
Ride around in one gear lower than you have been and never go any higher than 5th gear ~ if you think this gives you 'more top end' go ahead and change over to a 15t front sprocket
Gearing is a pretty simple idea if you just look at the sprockets. The closer the 2 are in size, the less reduction you have. If they were the same, your tires spin at the same speed as the motor....imagine that wheel dingin around at 8-9k rpm! The more they differ in size, the faster you can get up to speed (faster acceleration) but you will top out at a much lower speed.
Short answer = No.
Long answer: Determine speed at 10k in 6th. Now determine speed at 10k in 5th. The speed in 5th at 10k will be slower right? Well, if you drop down a front tooth you are basically make your current 6th gear act as if it was 5th gear. You mistakenly Think you are making 6th more usable, but you are just changing the speeds at which the gears work at - making your 6th gear work like a stock 5th gear. There is No Hain
As I said elsewhere, the ONLY advantage is when you first start moving. After that, there is no advantage to a 15 tooth front sprocket. If you want to experience what it is like for a 15 tooth front, ride everywhere one gear lower and Never go into 6th.
We Proved this with a comparison chart.
Michael
Ok wasn't sure. Have you compared top speeds with both?
Trying to figure out what the underlying point is to the question.....
I have a 16T, and I can ride along at 75mph pushing roughly 6K rpm assuming I don't hit a bump, if I shift to 5th which is almost dead on 1:1, it's 7K for the same speed.
According to the GSwiki calculator it is as follows for theoretical top speeds:
15T - ~131mph
16T - ~140mph
Without engine modifications and/or big aerodynamic changes, the Gs500 won't reach redline in 6th (or 5th) because there is too much drag and not enough power.
No, a 15t sprocket won't increase top speed. It won't decrease it either.
So if it neither decreases or increases top speed, and I'm assuming gives you more torque off the line a fast 0-60 and 1/4 mile can be achieved?
In a 1/4 mile situation, absolutely. Dropping a tooth will certainly get you that 1/4 mile speed better than a 16T.
It never gives you more torque or more top end, it just makes the engine turn at a higher rpm in every gear. For most bikes this means an rpm range where it is making more torque and hp, henceforth the idea that it magically makes the bike 'more powerful', although it doesn't really.
So putting higher gears in a car is pointless? I would think a smaller sprocket would help get you through the rev range faster, thus being faster. I know it made a significant change in my mustang...and with a theoretical top speed of 131( which I doubt ill ever do anyways.) I'm ok with losing a little up top to gain faster 1/4 mile since most races don't last much longer..lol call me selfish but I still wanna get around five flat on the 0-60. Any suggestions on rear sprockets to accompany? Bike bandit only has 39 tooth
Quote from: SAFE-T on May 11, 2012, 08:34:22 AM
It never gives you more torque or more top end, it just makes the engine turn at a higher rpm in every gear. For most bikes this means an rpm range where it is making more torque and hp, henceforth the idea that it magically makes the bike 'more powerful', although it doesn't really.
True. I guess that's the better way to look at it. Doesn't make the bike stronger, just puts it at a stronger torque point in the RPM range.
Quote from: mahemmjr on May 11, 2012, 09:01:13 AM
So putting higher gears in a car is pointless? I would think a smaller sprocket would help get you through the rev range faster, thus being faster. I know it made a significant change in my mustang...and with a theoretical top speed of 131( which I doubt ill ever do anyways.) I'm ok with losing a little up top to gain faster 1/4 mile since most races don't last much longer..lol call me selfish but I still wanna get around five flat on the 0-60. Any suggestions on rear sprockets to accompany? Bike bandit only has 39 tooth
I wouldn't say pointless. I think what Safe-T was trying to say is that the overall torque numbers won't change, just the RPM from the engine will alter at the same road velocity as stock. So if you go 20MPH in first gear at 4000 RPM, it will be 5000 RPM at 20MPH in first gear after the sprocket swap (hypothetically speaking for illustration purposes).
People sometimes change sprockets to increase the off-the-line acceleration, and for stunts like wheelies, etc. This is due to reaching the powerband in the GS sooner than a stock configuration.
Your results may vary of course.
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I had a 520 conversion kit on my VFR800 a few years ago with different gearing that essentially moved 6th gear to 5th. In the city it was good ~ the bike had better pick up in every gear because of the different ratios. But if I actually wanted to go a longer distance on the open road the sustained 7500 rpm required to keep with traffic got annoying.
On the GS500, 1st gear is already so low that I wouldn't have wanted to make it lower. Even stock I felt like I could barely get across an intersection from a stop without having to shift. We put an 18-tooth front sprocket on it (same gearing as the SV650) which brought down the rpm on the highway (much less buzzier, BTW) and also gave us a little better fuel mileage. My wife had to keep up with me on the VFR, and she never complained that the bike was 'less powerful' with this change.
Quote from: mahemmjr on May 11, 2012, 09:01:13 AM
So putting higher gears in a car is pointless? I would think a smaller sprocket would help get you through the rev range faster, thus being faster. I know it made a significant change in my mustang...and with a theoretical top speed of 131( which I doubt ill ever do anyways.) I'm ok with losing a little up top to gain faster 1/4 mile since most races don't last much longer..lol call me selfish but I still wanna get around five flat on the 0-60. Any suggestions on rear sprockets to accompany? Bike bandit only has 39 tooth
For the last time.... it will Only make you start moving quicker. After that, stock or one less, the bike will be in whatever rev range you put it in and for a given speed the 15 will be revving higher. That's for a given speed.
So.... 4th will give you 140kph at 9000 stock. With a 15 that same gear at the same speed will be possibly 10k, ok?
But the gears and rev ranges overlap. Eg. 140kph can be ridden in 4th at 9000, 5th at 8500 and 6th at 8000 - not sure on the exact rpm just giving example.
So while dropping to 15 will make the bike rev higher in 4th at That speed and 5th also, it doesn't mean the bike will be faster because you choose the speed at which to change gears.
First might get your 0-20 in stock. Dropping to a 15 might mean 0-15 instead. At which point you change into 2nd. That other bike will still be in 1st but will shortly change into 2nd. His 2nd will be able to achieve higher speed before needing to change. BUT, once you are out of first, whether it be stock or 15, you only change gears when you feel the revs are right to change gears. As the 15 will be revving higher for any given speed/gear than the stock, you'll be changing sooner with the 15 for any given speed than the stock that is all.
If a stock and 15 were dragging, what would happen is, the stock would pull away Initially (maybe a yard or two), then the bikes would level peg until the 15 ran out of legs, at which point the 16 would gain, get level then pull away.
Instead of asking questions Around your intention, you'd just be better off asking "I want to do faster 1/4 miles on my GS, what do I need to do to achieve that?"
Michael
A smaller front or bigger rear sprocket will give you faster acceleration over a short distance. Just not 'more top end'.
I disagree that the 15tooth will have a slower terminal speed. With stock gearing, the GS won't pull redline anyway. Someone needs to run their bike to redline in 5th gear and see what speed it will pull to :)
Then do the same thing but in 6th gear
The Charts that were posted here Prove the smaller front only benefits from first movement.
Did find Another chart however which also Proves the smaller front only benefits first movement - and this was even reference by you Safe-T in your post here (http://gstwins.com/gsboard/index.php?topic=58608.msg665992). Read about how it only benefits first here http://www.fz6r-forum.com/forum/f89/effects-changing-sprockets-23986/
And found a couple GS500 charts which show dyno comparison between smaller front (1st image) and stock (2nd image)...
(http://i261.photobucket.com/albums/ii63/ctbarbour/gs500-shift-chart-12.jpg)
(http://i261.photobucket.com/albums/ii63/ctbarbour/gs500-shift-chart-stock-1.jpg)
Don't know if these were the ones I was lokoing for cause I found them out of context. But they still show the point - smaller front only benefits first movement and loses top.
Michael
Has anyone compared trap Times with both?
I'll try tonight. Have yet to top her out yet I've been curious anyways. I must say coming from an 08 ninja 250 its a nice jump
The numbers are neat, and they certainly seem to show that altering gearing has less of an effect than one might expect. I was intrigued by the charts comparing 'relative driving force' between bikes of different gearing, though ~ the bike with the smaller front sprocket shows higher numbers in every gear ~ wouldn't it also be accelerating faster in every gear as well ?
Also, if we add in the effect of aerodynamic drag, isn't it possible that the bike in the 2nd chart with the stock gearing wouldn't actually be able to get to the same top speed it did on the dyno ?
Look closely at the two charts again, at 80mph. Driving force is the same, but the next higher gear is engaged.
Nonetheless, we are drag limited to about 110 mph. Only two things you can do: more power or less drag.
I'll finally have an opinion next week. When putting Junior back together, we found a new 15t sprocket. We put on Junior to make him different. I'll see if I notice anything in my around town driving.
I remembered something today. I had an older gs450 once. Replaced rear with +3 teeth than stock. It did take off faster off the line, and revved higher on highway. I do agree with the others. It was like I was down a gear on the interstate. I did it mainly to accelerate quicker, but noticed on the top end it didn't help as much as I thought. Later realized that the sprocket change took me out of the powerband at higher speeds. Sold it soon after that.
Now that Junior has a 15t front, I have an opinion.
Better for slower city riding and twisties. More responsive at lower speeds. Can keep engine above 3k RPM at slow speeds.
For highway, I'd say no. RPM needs to get too high for sustained highway speeds.
For city and twisties: I think I like it better than a 16t.
I have a 15t and I would agree. You have to be up around 6-6.5k to maintain good speed on the interstate with the 15t. I would rather be able to be lower in the RPMs. It's worth it for me though seeing as most of my riding is in town or on country blacktop.
It gives the engine a better mechanical "leverage" advantage, but also decreases fuel economy as you will be at higher RPM for the same speed.
It also can throw your speedo off on some bikes.
For instance, on the blackbird, the increased leverage shows improved HP on a dyno chart even though the top speed is reduced.
I've seen it make a pretty substantial difference on some bikes -- others not so much.
Most twins are geared for torque as opposed to HP anyway, since two cylinders (whether in-line or V) really isn't the best configuration
for HP
TJ
Speedo is fine. It is mechanically connected to the front wheel and generally reads 10% fast.
Quote from: speedfreek on May 29, 2012, 09:29:18 AM
It gives the engine a better mechanical "leverage" advantage, but also decreases fuel economy as you will be at higher RPM for the same speed.
It also can throw your speedo off on some bikes.
For instance, on the blackbird, the increased leverage shows improved HP on a dyno chart even though the top speed is reduced.
I've seen it make a pretty substantial difference on some bikes -- others not so much.
Most twins are geared for torque as opposed to HP anyway, since two cylinders (whether in-line or V) really isn't the best configuration
for HP
TJ
I've yet to see a dyno chart show a measurable (outside the margin of error) HP improvement with back to back runs where the only change was a sprocket. Can you point me to one?
Not online. One of my blackbird friends went from 140 to 144 on a third gear run. I was there at the time (the 144) and saw it. (Dynojet dyno)
TJ
Quote from: dougdoberman on May 29, 2012, 06:04:17 PM
Quote from: speedfreek on May 29, 2012, 09:29:18 AM
It gives the engine a better mechanical "leverage" advantage, but also decreases fuel economy as you will be at higher RPM for the same speed.
It also can throw your speedo off on some bikes.
For instance, on the blackbird, the increased leverage shows improved HP on a dyno chart even though the top speed is reduced.
I've seen it make a pretty substantial difference on some bikes -- others not so much.
Most twins are geared for torque as opposed to HP anyway, since two cylinders (whether in-line or V) really isn't the best configuration
for HP
TJ
I've yet to see a dyno chart show a measurable (outside the margin of error) HP improvement with back to back runs where the only change was a sprocket. Can you point me to one?
Quote from: speedfreek on May 29, 2012, 07:16:54 PM
Not online. One of my blackbird friends went from 140 to 144 on a third gear run. I was there at the time (the 144) and saw it. (Dynojet dyno)
Since that doesn't correlate to the way that engines & gearing actually works, I'm gonna remain skeptical.