John,
The axle ratios were LAT options, and stock Ford. None were 3.10:1. They
were LAT-51 through 54, of 3.07:1, 3.31:1, 3.54:1, and 3.73:1. With
only the stock close ratio gears, performance off-the-line wasn't very
exciting with the 2:88, due to the selection of the transmission gear
ratios. I am sure there are some courses in which rear axle gear
selection would aid in course timing, but the real problem was that the
wide ratio 4 speed wasn't stock until the Mk II. At that point, low
gear performance was what it should have been all along, and the rest
were spread fairly equally. A 2.88:1 was still used, and performance was
fine, even discounting the 289.
A word of caution. The DANA Salisbury standard rear axle (as well as
the Jaguar Mk II DANA Limited Slip Differential) use larger bolt
diameters to clamp the supplied ring gear. The rear axle gear plate has
a matching hole the bolt fits through. A US axle has smaller threaded
holes in the ring gear, so a stepped bolt would be required.
Many have changed transmissions to 5 spd to get rid of the very high
rpm's at cruise. With the wide ratio 1, 2, and 3 gears in the standard
box, a rear end change (and subsequent transmission change) would be
unnecessary except for exceptionally unusual race courses.
Of course there are differences of opinion here (typical Tiger List
freedom of thought), so many have elected these ratios for quick starts,
but were annoyed with the high rpm cruise. A major driver in changing
transmissions to a T-5. But the use of Hokanson's Excel Gear ratio
calculator, free download from TigersUnited.com, would allow you to
compare resultant speed/rpm for transmission gear and rear end gear
ratios and tire size for both 4 and 5 speed transmissions very easily.
That way, the numbers will allow you to make the right decision for your
own application.
Steve
Carmods@aol.com wrote:
>I have the following questions.
>
>Tiger
>What is the genesis of the 3.10 axle ratio? Was it a factory option or a
>certified dealer option? Was it a LAT option?
>
>Alpine
>Was a 4.22 axle ratio available from the factory or a certified dealer
>option? Was an automatic transmission a factory option for Alpines?
>
>
> John Logan
>
>
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Steve Laifman
Editor
http://www.TigersUnited.com
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