Drive ratio upgrade HOW TO: Belt Pulleys, Primary sprockets, improve TQ up to 13%
#951
03-13-2017, 10:03 AM
Jim, before playing the smart azz you should first learn to read properly. Obviously you're having serious problems with that....
I wrote that the increase of torque and RPM when going from 32T to 30T is APPROXIMATELY 6.5%!!! NOWHERE did I suggest that it is 10%.
I wrote that the speed displayed by the speedo now is 10% off, showing 10% more than the actual speed verified by several test runs with a GPS unit. So obviously that is the accumulated offset (stock offset + added offset due to the pulley change)
BTW the absolute change when going from 32T to 30T is: 32T - 30T = 2T
Therefore the relative change related to the original value is: (32T-30T)/32T = 2T/32T = 6.25% NOT 6.7%.
Your calculation only gives the gear ratio of two gears (32T and 30T) linked to each other.
I wrote that the increase of torque and RPM when going from 32T to 30T is APPROXIMATELY 6.5%!!! NOWHERE did I suggest that it is 10%.
I wrote that the speed displayed by the speedo now is 10% off, showing 10% more than the actual speed verified by several test runs with a GPS unit. So obviously that is the accumulated offset (stock offset + added offset due to the pulley change)
BTW the absolute change when going from 32T to 30T is: 32T - 30T = 2T
Therefore the relative change related to the original value is: (32T-30T)/32T = 2T/32T = 6.25% NOT 6.7%.
Your calculation only gives the gear ratio of two gears (32T and 30T) linked to each other.
I don't think any one is being a smart azz here- Jim is definitely the opposite of a smart azz and really helpful (me on the otherhand... heh) . Anyway I think you misread his post. Basically all of my numbers are based on Jim's math and verification since he has a lot of years doing this.
For any question on ratios and speedo results check out the links I posted on page 1 to the two different speedometer calculation websites. very good place to estimate and see the changes before ever doing the work on your bike.
Don't forget to optimize your spark advance tables in the roll-on and off-the-line areas- you can now run more advance and get more power without knock due to the more effective overall drive ratio.
That was also a very good thing to point out again on the belt length vs model year (some years have 132 and some 133). But heck if you're going through the 30T upgrade process might as well do the 70t rear or at least a 68t because that end of the upgrade cheap and easy- and really gives you the full upgrade benefit of this mod. Then you can retain the stock 133t belt no worries.
#952
03-13-2017, 10:15 AM
The calculation for exact results is as follows:
For a change from 32Tto 30T: 32/30 = 1.0666 or about a 6.7% change.
For a change from 32/66 to 30/70 = 32/30 x 70/66 = 1.131 or about a 13.1% change.
Note that the 32/66 to 30/70 is a "compound" change (both ends of the driveline being changed), so this is the proper way to calculate the percentage change.
Jim G
For a change from 32Tto 30T: 32/30 = 1.0666 or about a 6.7% change.
For a change from 32/66 to 30/70 = 32/30 x 70/66 = 1.131 or about a 13.1% change.
Note that the 32/66 to 30/70 is a "compound" change (both ends of the driveline being changed), so this is the proper way to calculate the percentage change.
Jim G
---------------
#1 Equals a 3% increase in rear wheel TQ *minor benefit* > 32/68t pulley upgrade, Go to Post #2 below
#2 Equals a 6.07% increase in rear wheel TQ *decent benefit* > 32/70t pulley upgrade, Go to Post #2 below
#3 Equals a 9.7% increase in rear wheel TQ *awesome benefit* > 30t front / 68t rear pulley upgrade, Go to Post #3 below
#4 Equals a 13.1% increase in rear wheel TQ *awesome benefit* > 30t front / 70t rear pulley upgrade, Go to Post #4 below
#5 Equals a 6.06% increase in rear wheel TQ *decent benefit* > 30/66t pulley upgrade, not entirely covered here but post #3 below is very close.
Doing any of these pulley upgrades will require a Powervision or other aftermarket tuner that can modify the speedometer pulse per km so everything reads accurately. I have put the correct speedometer correction setting in each of the specific upgrade posts below.
Generally, to fix your speedometer value all you have to do is look at your stock 'Speedometer Correction' number (VSS), and multiply it by the ratio change to get the new proper valie.
Example: 30/70 is a 13.1% change so you multiply your stock number by 1.131 to get the new number. for the 32/68, multiply your stock number by 1.03, for 32/70 multiply stock number by 1.0607, for 30/68 multiply stock number by 1.097.
If your speedometer reads slightly fast compared to actual speed, lower the number by 10 and re-test.
If your speedometer reads slightly slow compared to actual speed, raise number by 10 and re-test.
----------
#953
03-13-2017, 11:58 AM
Awesome- I'm glad you finally ended up doing the full upgrade. As you noted, your cams and everything else will work a lot better because now you actually have a correct overall drive ratio for the bike instead of the federal / epa / other B.S. mandated too tall drive ratio.
I don't think any one is being a smart azz here- Jim is definitely the opposite of a smart azz and really helpful (me on the otherhand... heh) . Anyway I think you misread his post. Basically all of my numbers are based on Jim's math and verification since he has a lot of years doing this.
For any question on ratios and speedo results check out the links I posted on page 1 to the two different speedometer calculation websites. very good place to estimate and see the changes before ever doing the work on your bike.
Don't forget to optimize your spark advance tables in the roll-on and off-the-line areas- you can now run more advance and get more power without knock due to the more effective overall drive ratio.
That was also a very good thing to point out again on the belt length vs model year (some years have 132 and some 133). But heck if you're going through the 30T upgrade process might as well do the 70t rear or at least a 68t because that end of the upgrade cheap and easy- and really gives you the full upgrade benefit of this mod. Then you can retain the stock 133t belt no worries.
I don't think any one is being a smart azz here- Jim is definitely the opposite of a smart azz and really helpful (me on the otherhand... heh) . Anyway I think you misread his post. Basically all of my numbers are based on Jim's math and verification since he has a lot of years doing this.
For any question on ratios and speedo results check out the links I posted on page 1 to the two different speedometer calculation websites. very good place to estimate and see the changes before ever doing the work on your bike.
Don't forget to optimize your spark advance tables in the roll-on and off-the-line areas- you can now run more advance and get more power without knock due to the more effective overall drive ratio.
That was also a very good thing to point out again on the belt length vs model year (some years have 132 and some 133). But heck if you're going through the 30T upgrade process might as well do the 70t rear or at least a 68t because that end of the upgrade cheap and easy- and really gives you the full upgrade benefit of this mod. Then you can retain the stock 133t belt no worries.
All the valuable information on this thread has helped a lot of people doing this best bang for a buck mod.
The reason why I didn't do the rear pulley swap is because I couldn't find a rear pulley that I really like. Options are very few here in Germany and if you find something in US it's really expensive with all the customs and import tax etc. Plus I wanted to maintain my belt guards. And finally my SEPST does not allow for the speedo recalibration. If I had to do this mod I would end up with an additional 1 grand just in parts, plus labor. As I had my inner primary changed the replacement of the front pulley was just a minor additional task. For me that's the most efficient way to get at least some of the benefit of this mod.
#954
03-13-2017, 10:15 PM
Yeah, maybe I was a bit harsh on Jim. Sorry for that.
All the valuable information on this thread has helped a lot of people doing this best bang for a buck mod.
The reason why I didn't do the rear pulley swap is because I couldn't find a rear pulley that I really like. Options are very few here in Germany and if you find something in US it's really expensive with all the customs and import tax etc. Plus I wanted to maintain my belt guards. And finally my SEPST does not allow for the speedo recalibration. If I had to do this mod I would end up with an additional 1 grand just in parts, plus labor. As I had my inner primary changed the replacement of the front pulley was just a minor additional task. For me that's the most efficient way to get at least some of the benefit of this mod.
All the valuable information on this thread has helped a lot of people doing this best bang for a buck mod.
The reason why I didn't do the rear pulley swap is because I couldn't find a rear pulley that I really like. Options are very few here in Germany and if you find something in US it's really expensive with all the customs and import tax etc. Plus I wanted to maintain my belt guards. And finally my SEPST does not allow for the speedo recalibration. If I had to do this mod I would end up with an additional 1 grand just in parts, plus labor. As I had my inner primary changed the replacement of the front pulley was just a minor additional task. For me that's the most efficient way to get at least some of the benefit of this mod.
#955
03-14-2017, 12:01 AM
Road Warrior
Jim- this is the text from post #1- If you don't mind, can you give it a "once over" and edit as appropriate?
---------------
#1 Equals a 3% increase in rear wheel TQ *minor benefit* > 32/68t pulley upgrade, Go to Post #2 below
#2 Equals a 6.07% increase in rear wheel TQ *decent benefit* > 32/70t pulley upgrade, Go to Post #2 below
#3 Equals a 9.7% increase in rear wheel TQ *awesome benefit* > 30t front / 68t rear pulley upgrade, Go to Post #3 below
#4 Equals a 13.1% increase in rear wheel TQ *awesome benefit* > 30t front / 70t rear pulley upgrade, Go to Post #4 below
#5 Equals a 6.06% increase in rear wheel TQ *decent benefit* > 30/66t pulley upgrade, not entirely covered here but post #3 below is very close.
Doing any of these pulley upgrades will require a Powervision or other aftermarket tuner that can modify the speedometer pulse per km so everything reads accurately. I have put the correct speedometer correction setting in each of the specific upgrade posts below.
Generally, to fix your speedometer value all you have to do is look at your stock 'Speedometer Correction' number (VSS), and multiply it by the ratio change to get the new proper valie.
Example: 30/70 is a 13.1% change so you multiply your stock number by 1.131 to get the new number. for the 32/68, multiply your stock number by 1.03, for 32/70 multiply stock number by 1.0607, for 30/68 multiply stock number by 1.097.
If your speedometer reads slightly fast compared to actual speed, lower the number by 10 and re-test.
If your speedometer reads slightly slow compared to actual speed, raise number by 10 and re-test.
----------
---------------
#1 Equals a 3% increase in rear wheel TQ *minor benefit* > 32/68t pulley upgrade, Go to Post #2 below
#2 Equals a 6.07% increase in rear wheel TQ *decent benefit* > 32/70t pulley upgrade, Go to Post #2 below
#3 Equals a 9.7% increase in rear wheel TQ *awesome benefit* > 30t front / 68t rear pulley upgrade, Go to Post #3 below
#4 Equals a 13.1% increase in rear wheel TQ *awesome benefit* > 30t front / 70t rear pulley upgrade, Go to Post #4 below
#5 Equals a 6.06% increase in rear wheel TQ *decent benefit* > 30/66t pulley upgrade, not entirely covered here but post #3 below is very close.
Doing any of these pulley upgrades will require a Powervision or other aftermarket tuner that can modify the speedometer pulse per km so everything reads accurately. I have put the correct speedometer correction setting in each of the specific upgrade posts below.
Generally, to fix your speedometer value all you have to do is look at your stock 'Speedometer Correction' number (VSS), and multiply it by the ratio change to get the new proper valie.
Example: 30/70 is a 13.1% change so you multiply your stock number by 1.131 to get the new number. for the 32/68, multiply your stock number by 1.03, for 32/70 multiply stock number by 1.0607, for 30/68 multiply stock number by 1.097.
If your speedometer reads slightly fast compared to actual speed, lower the number by 10 and re-test.
If your speedometer reads slightly slow compared to actual speed, raise number by 10 and re-test.
----------
#1 Equals a 3% increase in rear wheel TQ *minor benefit* > 32/68t pulley upgrade, Go to Post #2 below
#2 Equals a 6.07% increase in rear wheel TQ *decent benefit* > 32/70t pulley upgrade, Go to Post #2 below
#3 Equals a 9.9% increase in rear wheel TQ *awesome benefit* > 30t front / 68t rear pulley upgrade, Go to Post #3 below
#4 Equals a 13.1% increase in rear wheel TQ *awesome benefit* > 30t front / 70t rear pulley upgrade, Go to Post #4 below
#5 Equals a 6.67% increase in rear wheel TQ *decent benefit* > 30/66t pulley upgrade, not entirely covered here but post #3 below is very close.
Jim G
#956
03-14-2017, 12:03 AM
Road Warrior
Yeah, maybe I was a bit harsh on Jim. Sorry for that.
All the valuable information on this thread has helped a lot of people doing this best bang for a buck mod.
The reason why I didn't do the rear pulley swap is because I couldn't find a rear pulley that I really like. Options are very few here in Germany and if you find something in US it's really expensive with all the customs and import tax etc. Plus I wanted to maintain my belt guards. And finally my SEPST does not allow for the speedo recalibration. If I had to do this mod I would end up with an additional 1 grand just in parts, plus labor. As I had my inner primary changed the replacement of the front pulley was just a minor additional task. For me that's the most efficient way to get at least some of the benefit of this mod.
All the valuable information on this thread has helped a lot of people doing this best bang for a buck mod.
The reason why I didn't do the rear pulley swap is because I couldn't find a rear pulley that I really like. Options are very few here in Germany and if you find something in US it's really expensive with all the customs and import tax etc. Plus I wanted to maintain my belt guards. And finally my SEPST does not allow for the speedo recalibration. If I had to do this mod I would end up with an additional 1 grand just in parts, plus labor. As I had my inner primary changed the replacement of the front pulley was just a minor additional task. For me that's the most efficient way to get at least some of the benefit of this mod.
Jim G
#958
03-15-2017, 06:04 PM
So I recalibrated my Rocker speedo today. If you are doing a sprocket/pulley upgrade and use an FP3 tuner, the process couldn't be easier. You just start the "Speedometer Calibration" feature on your phone app ( I mount the phone on the bars) and it will start showing your actual speed, then you hit "Calibrate" it will show both actual speed and your current speedometer reading, once you hit 60mph it will say "Calculating" for about 10-15 seconds. It then shows "Calculation complete" and the difference of %, in my case 11.9%. You can then hit "Cancel" or "Apply". If you hit "Apply" it saves the info and you can "Flash" the change when you shut the bike off. I have a Dakota Digital speedo and could have recalibrated it directly, but it's much simpler and should be more accurate using the FP3s/GPS....
Last edited by Rocker B; 03-15-2017 at 06:06 PM.
#959
03-20-2017, 03:14 PM
#960
03-20-2017, 03:36 PM
Open your tune from the PV in WinPV software and go to Speedometer Correction. Look at your current value in there. take that value and multiple it by 1.0607. that will equal your new value. save file, re-upload to the PV, flash to bike. use a gps to fine tune it as the existing number is in the 4%-5% error ballpark.