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Re: Replacing the Speedometer Posted by Justin VanAbrahams [Email] (#32) [Profile/Gallery] (more from Justin VanAbrahams) on Tue, 29 Mar 2016 11:03:25 In Reply to: Re: Replacing the Speedometer, Justin VanAbrahams [Profile/Gallery] , Tue, 29 Mar 2016 09:43:42 Members do not see ads below this line. - Help Keep This Site Online - Signup |
When did I become so bad at math?
VSS = 2458 pulses per kilometer
2458 pulses per kilometer = 3965 pulses per mile
(For what it's worth, 4000ppm is a common configuration, so maybe this is that.)
At 60mph, one mile per minute, I should see 3965 pulses per minute or 66 pulses per second.
At 60mph, a 195/60-15 tire has a 24.21" height and a 76.0194" circumference. A 195/60-15 tire is at 833.47rpm (63360"/76.0194"), or 13.9 rotations per second. The tire rotation is tied to the ring gear.
So... how do I tie 13.9 tire rotations per second to 66 pulses per second? If it's a 4 pulse per rotation, I would have a ratio of 1.19:1 (speedo:ring).
Buuuuuuut... that does not agree with the drill speed test. 760rpm = 12.67 rotations per second = 189Hz. I should be seeing 60Hz, not 189.4Hz.
I've gone horribly wrong somewhere, or Hz does not translate to pulse, or my drill speed indicator is way off.
posted by 12.195.130...
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