Re: impossibly low gearing

[bearbvd@domain.elided (Greg Hermann)]

>Well, with the kind of gearing usually available on these axles, plus the
>ground clearance issue being significant (obviously, the Eaton diffs are
>BIGGER) 35" tires would probably be the Smallest you could use
>effectly...(just guessing, there)
>HOWEVER, the gearing in the two speed usually had a spread like 4.88 high,
>5.86 low, stuff like that.
>
>As for Lockers, I'm not sure of the availability.  The light line handbook
>does show the detroit "no-spin" being used, but perhaps it didn't work with
>the big two-speeds.

They do. You can get a No-Spin for virtually ANY big truck differential.

 Perhaps howard Pletcher or someone could find out...
>
>Mind you, you Could get away with two separate emergency brake controls,
>one for each rear wheel...if something slips, simply pull the brake lever
>(mount them between the front seats) of the wheel that is spinning....sort
>of the same action seen on auto-traction control...most of the old 2wd farm
>tractors have separate left and right brakes for the rears...
>
>...not to stir the pot, or anything :-)....
>
>: Issues - every two speed rear end I've seen has had a low 4.X or 5.X as
>: the HIGH range.. with 7s or something for the lows.  I guess with 35s or
>: larger tires a 5.X series "high" rear end would be OK.. but for 33s, you
>: can forget highway mileage.

I am not sure about the current two speeds--but for the Eaton 19050, which
is used in mid '80's Chevie medium duty trucks, with the single speed
pumpkin you can get a wide variety of r& p ratios from 3.36 up to 7.17. Not
so sure for the two speeds, but I suspect an almost as wide range is
available. (you can also get a planetary double reduction pumpkin to fit
these housings.)

IHC was not so nice with ratio selection for the bigger stuff--For an RA 15
/20 --4.30, 4.88, & 6.17 are it. for the RA 25 / 30, there is more
selection, but it starts at about 4.88.
>:
Greg