[TR] RPM speed calc

[Dave MacKay]

>Date: Sun, 31 May 2020 16:52:23 -0500

>From: bill beecher <notakitcar at yahoo.com>

>Subject: [TR] RPM speed calc

>

>Came across this calculator with all the right input fields.  But, I
wonder how accurate it really is given the following input.

>TR3 with a 3.7 rear, OD at redline of 5,000rpm.  Vredestein 165R/15 tires,
25.4? diameter.   Should be moving along at 124mph!

>

>https://wahiduddin.net/calc/calc_speed_rpm.htm

>

>Anyone get a different answer?

>Bill



Here (attached) is a spreadsheet that I wrote to calculate speed versus rpm
given different parameters. I wrote it to check my speedo after I installed
an HVDA transmission. If the spreadsheet doesn’t make it through the list
as an attachment, just e-mail me directly and I’ll send it to you.



With a standard Triumph gearbox + overdrive, and the parameters you gave, I
calculate speed at 5000 rpm in top gear (with overdrive) as being 124.5
mph. Note that, I think that the tire diameter is 25.25”, slightly less
than you indicated.



I hasten to add that calculating a speed and believing it’s achievable are
two different things!



Regards,



Dave MacKay

1960 TR3A s/n 68639L

near Toronto, Canada
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