Re: Looking for high speed gears
Posted by Marty or Marston On 2018/3/14 17:43:09
I'm continuously amazed at the facts, tables and data that Dave (OD) can pull out of his files to share with all of us and his RPM chart is another example of what he has in his goody box. I took the 4.69 data at 90 mph and 4,296 rpm plugged it into an Excel spreadsheet and generated the information found in the table "745 Data' and added to it additional ratios. As you can see the data aligns fairly well with that in Dave's table, which leads me to think the added ratios are OK
Next I went and measured the radius on the 19 inch 6.50 tires (Lucas) that I have on my 901 and found that it shows a radius (center of wheel to the floor) of 15+ 0.25 inches. This calculates to a circumference of 7.85 ft. Sixty miles is 316,000 ft and would require 40,357 tire revolutions to go that distance. To cover that distance in an hour with my tires (assuming I've done everything correctly, the engine would need to be at 3,094 rpm. This differs by about 8% of that found in the table. This would require the height of the rubber for those in the chart to be about an inch less than mine (again assuming I haven't made an error).
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Next I went and measured the radius on the 19 inch 6.50 tires (Lucas) that I have on my 901 and found that it shows a radius (center of wheel to the floor) of 15+ 0.25 inches. This calculates to a circumference of 7.85 ft. Sixty miles is 316,000 ft and would require 40,357 tire revolutions to go that distance. To cover that distance in an hour with my tires (assuming I've done everything correctly, the engine would need to be at 3,094 rpm. This differs by about 8% of that found in the table. This would require the height of the rubber for those in the chart to be about an inch less than mine (again assuming I haven't made an error).
Attach file:
(346.35 KB)
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