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Re: Speedo and Tach

To: trumpet@bellsouth.net
Subject: Re: Speedo and Tach
From: "Robert M. Lang" <lang@ISIS.MIT.EDU>
Date: Sat, 16 Oct 1999 19:48:31 -0400
Cc: triumphs@autox.team.net
Hello,

No doubt you got several responses to your question.

First, 5000 RPMs at 60 MPH is totally wrong. It should be around 3000 RPMs
at 60 MPH in regular (not overdrive). Have you tried a measured mile to see
if the speedo is close???

Given that the tach is correct (or correct-ish, in regard to your "bouncing
needle" comment), I'd venture a guess that you have some "gears" in that
baby. You should spin the rear wheels and count the revs of the input drive
flange for the diff.

I have a guess that you have 4.55 or 4.88 gears in that diff. What that
means is that if you spin both rear wheels, the pinion flange will turn
around 4.55 or 4.88 times per one revolution of the rear wheels. The stock
diff is 3.70, so these represent 121% and 132% more revs at speed
(respectively).

If that is the case - I know of several people (myself included) that would
be interested in getting those gears, and I'll venture to guess that they'd
reward you with $$$ enough to stick in a good used stock diff. maybe with
some $$$ left over.

Note: if the rear-end "clanks" a bit when you go around corners, you might
have a "limited slip" something or other in there. Again, if you don't race
the car, there's not much point in having that part and again, I know some
folks that could probably benefit from whatever is in there.

I'd def. plan on looking further into this situation if I were you.

regards,
rml

=====================================================================
Bob Lang      | TR 6 Guy           | Editor: New England Triumphs
Phone:        | 617-253-7438 (days)| 781-438-2568 (eves)
Occupation:   | ComputerZ          | TR fixer-Upper
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