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Discussion Starter #1
I must be doing something wrong.. Going to the Scout spec page, I look at rear tire size, I calculate an 80 inch circumference. Multiplying gear ratios, I get about 9 1/2 engine revs per wheel rev in sixth. Dividing that into a mile I come up with 7530 revs per mile. I cannot fathom turning 7500 rpm at 60 mph. I must be doing something wrong. I musta hit a dumb spot here this morning.

Anyone here who can check my math on this?
 

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Web, I read an early review stating that the bike was running 70 mph @ 3700rpms in 6th

Also read, the bike will do 55 in first, 88-90 in second and 110 in third(though rpms were not given)
The bike may be able to exceed 130 though I haven't tried to calculate it.

Might post the ratios and people can chime in and work out a detailed on-paper figures, together.
 

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Discussion Starter #6
I knew I went wrong somewhere. Now it's bugging me. I gotta find out where I goofed up.
 

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Gearing Commander: Motorcycle Speed, RPM, Chain & Sprockets Calculator



1st10.782 : 1
2nd7.328 : 1
3rd5.841 : 1
4th4.957 : 1
5th4.380 : 1
6th4.034 : 1
Final Drive 2.357 : 1


Tires/Front130/90-16 72H
Tires/Rear150/80-16 71H
WheelsCast 16" x 3.5" Front and 16" x 5" Rear

Source - 2015 Indian Scout Thunder Black Smoke Motorcycle : Specs



I didn't have the primary drive ratio but using a reported 60 mph top speed in 1st I got the following estimate which is
subject to revision.



View attachment 2158



"Powering the Scout is a 69 cu. in. (1133cc) 60-degree liquid-cooled V-twin, a DOHC engine with four valves per cylinder that prefers high-test. Fed by EFI with a 60mm throttle body, the new Indian mill, which has a redline of 9,000 rpm, puts out a claimed 100 horsepower at 8,100 rpm and 72.2 pound-feet of torque at 5,900. It has a six-speed tranny and a left-side belt drive. The Scout is geared high and it comfortably rolls along at 70 mph in sixth gear at 3,750 rpm."
Source: 2015 Indian Scout- Cruiser Motorcycle First Ride Review- Photos- Pricing






"On the straights, I learned the Scout’s engine can be revved higher than most cruiser V-Twins. First gear didn’t tap out until 55 mph, about 10 mph higher than the standard cruiser, and we wound second out to approximately 88 mph before hitting red line. On most cruisers you’re lucky to hit freeway speed in second gear. Acceleration is snappy and it’s quick off the line. A healthy midrange kicks in around 5000 rpm and it continues to give generously up top as I squeezed the powerband for everything it’s got, and even at redline it still tries to rev out instead of sign off. "
Source: 2015 Indian Scout First Ride - Motorcycle USA



"110 mph in 3rd" - Watch


On the clip's youtube page, I asked TimC, the man who made the above demo clip if the 110 mph in 3rd was a typo. (just to confirm)

Here's his reply:
"That's no typo, 110 in 3rd. 1st gear topped out around 55, 2nd around 90mph! Not sure what the top speed would be. It does feel really light, and seemed to have quite a bit of lean angle, though I was restricted by the demo riders. I would have loved to get it out on the twisties for a proper run through. I guess I'll have to wait until December when mine arrives!"

Below is a revised chart based on Tim C's demo ride account of 110 in 3rd.

Indian Scout Drivtrain Chart 1.2.JPG

Above chart from:
Motorcycle gear/rpm/speed calculator
 

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I am having conflicting results
I had re-entered all the data as provided by the Scout's Owner's Manual (see link below) and what I came up with
is a bike's engine and drivetrain gear ratio configuration that can do 225mph at redline! (on paper) - I think I may have entered that wrong
however it reconfirms it's numbers. Either the above is correct or my current calculation is incorrect or the calculator is wrong.
Not sure just yet, but I know the bike with rider cannot do 225mph! No way, Jose!

(Will post the graphic )

Anyone wishing to help investigate this sure would be welcomed to do so.

http://polaris.hs.llnwd.net/o40/archive/ind/2015/manuals/9925953r02_IND_Scout_OM_Lo-Res.pdf

Here is the calculator's link, for your convenience. - Motorcycle gear/rpm/speed calculator
 

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PS,

If you look at my last graphic above, you'll see "10.782" in the First Gear Ratio box. Those numbers were "overall drive numbers"

Here is what should be the Ratio Boxes

Transmission Gear Ratios:
1st 2.769:1
2nd 1.882:1
3rd 1.500:1
4th 1.273:1
5th 1.125:1
6th 1.036:1

Indian Scout Drivtrain Chart 1.3.jpg

Golly!
That's a fast potential.

All the Scout really needs at the moment is maximizing it's torque and horsepower output potential to push that bike that fast.
 

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Using 2X3.14Xradius, I get 2X3.14X 1.06 X12 in = 79.88 in. So 80 seems right next 5280 feet/mile = 5280X12 in = 63360in/mile so 63360/80 = 792 revs/mile (of the back tire.). At 60mi/hr you have 1 mile per min therefore
you have with a final drive ratio of about 4.08:1 or 4.08*792 = 3231 rev/min at 60 miles per hour.
I am probably off by a bit on rear tire circumference.
 
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