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I HAVE 16 T FRONT SPROCKET.. RACING MY FRIEND ON HIS 929 ACCELERATION WAS VERY QUICK ON THE 10R .. AT ONE POINT SAW 189 ON THE SPEEDOMETER... I KNOW THAT THIS WASNT THE TRUE SPEED... BEING AS THOUGH I HAD THE 16T.. CAN ANYONE TELL ME WHAT THE ESTIMATED SPEED REALLY WAS.. ID APPRECIATE IT
 

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with new D218 on the rear, and a 16T on the front, 12,800 rpm in 6th should be 188mph actual, not indicated. 189 indicated-12.4%(correction)=is only 166 mph. 166MPH actual with a 16T should be about 11,300rpm.
Not sure what you were turning for revs though.
 

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gladding24 said:
with new D218 on the rear, and a 16T on the front, 12,800 rpm in 6th should be 188mph actual, not indicated. 189 indicated-12.4%(correction)=is only 166 mph. 166MPH actual with a 16T should be about 11,300rpm.
Not sure what you were turning for revs though.
Actually, with a 190/50 tire (77.25" circumfrence) 16/39 geraring at 12800rpm would be 182.676mph under ideal conditions without areo drag and tire slip.

At 12800 engine rpm in 6th gear, the front sprocket is turning 6093 rpm.

12800 / 1.611(primary reduction ratio) / 1.304(6th gear ratio) = 6093.0794(front sprocket rpm)

6093.0794 / 2.44 (final drive ratio of 16/39) = 2497.1636(rear wheel rpm)

2497.1636 * 77.25"(tire circumfrence) = 192905.8881(inches)

192905.8881" / 12(1 foot)= 16075.490675(feet per minute)

16075.490675' * 60(minutes) = 964529.4405'(feet per hour)

964529.4405' / 5280(feet per mile ) = 182.676 mph

I have measured my rear tire with a stagger tape to get the size of 77.25"
I have tried different gearing and have radar'd my zx10r each time, and 1 tooth in the rear equals about 1.5 mph difference. Going down 1 tooth in front is like going up 2 7/16ths in the rear. The best speed I could get out of mine in 3/4 mile was 178mph with the stock gearing(17/39). The best I could get out of it with a 16/39 was 174mph. I have 17/41 on it now and get 176mph. It seems the error from theoretical speed and real speed is about 6%. The same 6% as the speedo error with the stock gearing. my speedo healer seting with 17/41 is -13%, and its within 1 mph at top speed.

I have come to believe that the tach may also have error.

Sorry for getting technical, but I had to back up my answer with the figures so i don't get flamed or told to STFU. [smilie=B:
 

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black10r_n_nc said:
I HAVE 16 T FRONT SPROCKET.. RACING MY FRIEND ON HIS 929 ACCELERATION WAS VERY QUICK ON THE 10R .. AT ONE POINT SAW 189 ON THE SPEEDOMETER... I KNOW THAT THIS WASNT THE TRUE SPEED... BEING AS THOUGH I HAD THE 16T.. CAN ANYONE TELL ME WHAT THE ESTIMATED SPEED REALLY WAS.. ID APPRECIATE IT
About 167. My speedohealer required -13.2% correction when I went to the 16T in front. -13.2% correction from 189 is 167.
 

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Actually, with a 190/50 tire (77.25" circumfrence) 16/39 geraring at 12800rpm would be 182.676mph under ideal conditions without areo drag and tire slip.

At 12800 engine rpm in 6th gear, the front sprocket is turning 6093 rpm.

12800 / 1.611(primary reduction ratio) / 1.304(6th gear ratio) = 6093.0794(front sprocket rpm)

6093.0794 / 2.44 (final drive ratio of 16/39) = 2497.1636(rear wheel rpm)

2497.1636 * 77.25"(tire circumfrence) = 192905.8881(inches)

192905.8881" / 12(1 foot)= 16075.490675(feet per minute)

16075.490675' * 60(minutes) = 964529.4405'(feet per hour)

964529.4405' / 5280(feet per mile ) = 182.676 mph

I have measured my rear tire with a stagger tape to get the size of 77.25"
I have tried different gearing and have radar'd my zx10r each time, and 1 tooth in the rear equals about 1.5 mph difference. Going down 1 tooth in front is like going up 2 7/16ths in the rear. The best speed I could get out of mine in 3/4 mile was 178mph with the stock gearing(17/39). The best I could get out of it with a 16/39 was 174mph. I have 17/41 on it now and get 176mph. It seems the error from theoretical speed and real speed is about 6%. The same 6% as the speedo error with the stock gearing. my speedo healer seting with 17/41 is -13%, and its within 1 mph at top speed.

I have come to believe that the tach may also have error.

Sorry for getting technical, but I had to back up my answer with the figures so i don't get flamed or told to STFU.

ummmmm WOW i believe you :D
 

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scottymizt said:
Actually, with a 190/50 tire (77.25" circumfrence) 16/39 geraring at 12800rpm would be 182.676mph under ideal conditions without areo drag and tire slip.

At 12800 engine rpm in 6th gear, the front sprocket is turning 6093 rpm.

12800 / 1.611(primary reduction ratio) / 1.304(6th gear ratio) = 6093.0794(front sprocket rpm)

6093.0794 / 2.44 (final drive ratio of 16/39) = 2497.1636(rear wheel rpm)

2497.1636 * 77.25"(tire circumfrence) = 192905.8881(inches)

192905.8881" / 12(1 foot)= 16075.490675(feet per minute)

16075.490675' * 60(minutes) = 964529.4405'(feet per hour)

964529.4405' / 5280(feet per mile ) = 182.676 mph

I have measured my rear tire with a stagger tape to get the size of 77.25"
I have tried different gearing and have radar'd my zx10r each time, and 1 tooth in the rear equals about 1.5 mph difference. Going down 1 tooth in front is like going up 2 7/16ths in the rear. The best speed I could get out of mine in 3/4 mile was 178mph with the stock gearing(17/39). The best I could get out of it with a 16/39 was 174mph. I have 17/41 on it now and get 176mph. It seems the error from theoretical speed and real speed is about 6%. The same 6% as the speedo error with the stock gearing. my speedo healer seting with 17/41 is -13%, and its within 1 mph at top speed.

I have come to believe that the tach may also have error.

Sorry for getting technical, but I had to back up my answer with the figures so i don't get flamed or told to STFU.

ummmmm WOW i believe you :D
Damn look at the big brain on Tom, I beleive you :D
 

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Thanks for the math Tom, I've been using someone else's gearing spreadsheet, and wasn't sure if it was 100% accurate, but I knew it was pretty close. I think our differences come from tire circumfrence. My calcs use 641.5MM diameter*3.14159=2015.33mm Circ.
2015.33mm / 10= 201.35CM
201.35cm /2.54= 79.27in. circ. of the tire.
This is where we differ, by about 2".
 

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176 indicated was 164 on GPS on mine for an approximae (and quite average) correction factor around 7%.

With that in mind, it would seem that you were around the 175ish actual speed.
 

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Watched Men and Motors the other day and they had a stock 10 on a two mile straight reach an indicated 194MPH on the clock. It actually broke the timing beam at a true 189MPH.

~Not bad for a stockie
 

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what about tire growth?
 
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