Re: alfa-digest V6 #17, 105/115 LSD

[Kevin Charles Trent <trentkc@mindspring.com>]

Paul Irving wrote:

>To the guy wanting to put a limited slip differential in his '71 Spider:
>
>look at the bottom of the casing. The ribs on limited slips form a
>distinctive "V" while the others do not. It's very obvious. The other point
>though is what ratio is it? I believe that those out of Berlinas are
>different.

Both the non-US 1750 and 2000 Berlinas had 4.3 axles (from period road test
articles) but I've never seen the same axle spec listed in US road tests
where it is always listed as 4.56.  Here is what Road  & Track said in
their Sept. '71 issue about the introduction of the US 2000 models:
"...now LSD on Spider and GTV...extra on Berlina...final gearing remains
the same at 4.30:1 for the Berlina, 4.1:1 for the two sports models; thus
it will probably remain at 4.56:1 for all US versions as it is now."
Motor Trend reported a 4.56 in Oct. '74 as did Road & Track in '75 for the
Berlina.

I agree that the US 2000 Berlinas have a different rear axle ratio - I
believe it is 4.3:1.  I have two '73 Berlinas (2000w/LSD) , a 73 spider
(2000w/LSD), a '71 1750 Berlina,  and a 69 GTV.   The 2000 Berlinas
definitely turn less rpm than the other cars, and they all use 195/65-14
tires.  The transmission speedometer gears from the 2000 Berlinas are 8x18,
but the gears from the 1750 cars and the 73 spider are 9x21. 

Other notes about the rear axle:  I thought all US 115 2000 models came
with LSD standard; on the non-LSD axles, the gear ratio (pinion/ring teeth)
is stamped on the ring gear and visible when the filler plug is removed,
however I have not been able to find this stamping on the LSD axles.  

Can anyone verify the Berlina axle ratio and ring gear stamping?

KCT 
Knoxville TN