RE: [ihc] Re: two speed rear axles

["Mac @ TRIAD" <mac@xxxxxxxxxxxx>]

## >> Not quite true...the 2 speed option for the 1510 was RA-184,
## >> not RA-126
## >> like it was for the 1500 in 1970.  I don't know what the
## >> differences are,but
## >> the number changed.
## >>
## >> Mac,  I think your book is too early to list the RA-126, they probably
## >> didn't exist when it was printed.

i think you're right.  i also think that they changed the axle numbering at
some point after the B series, too, probably with the advent of the
Loadstars 1962/1963, with the end of the B and BC series mediums.  RA-184,
that was the other number i was looking for.  i knew there was another one
that came out after the RA-126, but for the life of me i couldn't remember
what it was.

dog GONE it.  i think i missed a line somewhere.  <sigh>

let me back up and trace out what this thing says.

the RA15 and RA20 are both five and a half pint differential housings.
damnit.  i must have jumped lines when i was comparing.  the RA25 is a nine
and a half pint housing, but the listed RA30 is only an eight pint housing.
so.  i guess i am wrong about the RA15 and RA20 being different.  maybe
they're the same after all.  and maybe the FA57 is the matching front axle.
but what about the RA25 to RA30 discrepancy?  how about that?

so allright.  then if i'm reading this right *now*, the RA15 and RA20 *do*
share a housing and differential carrier after all.  which would mean that
what i have...  is what used to be the RA30 before they changed that number.
maybe.  *if* they changed that number later.  the housing is definitely
bigger than the RA15/RA20, but not as big as the RA30 under Allan E's bus.
*AND* it's the same size as the FA50/FA55 as found under Joel/Ken's B140.
the rear axle under that B140 is the same as mine.  but on that truck it's
listed as an RA20, and if the RA20 and RA15 share a housing, then these
axles cannot be the RA20.  they're just too big.  and the *REAL* reason why
i know this is because i know that the original axle under my B122 was an
RA15.  6 on seven and a quarter inch lug pattern, 14" brakes, twelve inch
ring gear, what else could it be?  i had the old differential carrier still
out at the time of the swap, and i compared the two axles and differential
carriers.  the new axle is significantly larger than the old one.  you can
tell at a glance that it's bigger.  so what the heck is it?

and lastly, before i go to bed, if they say you have to have 20" wheels for
those bigger axles, then something isn't right.  the axle under my B122,
whatever the heck it really is, has a set of 16" splitrim duals hammered on
over those huge drums.  hammered.  yes.  those drums are bigger than the 14"
drums that were on the original RA15, so if they're 15" brakes, then you
*can* use smaller wheels than 20".  note, however, that at full inflation in
the tires, that rear axle housing is only a few scant inches off the ground.
way less clearance than the RA15 has.  i wouldn't drive over any really big
rocks with one of these and those smaller wheels.

there was a B122 with an RA15, dual rears, and a flatbed parked in Fresno
for a while.  a local furniture store was using it as a delivery truck.
that one had the same axle as my B122 originally had, and this one had later
model seventeen and a half inch wheels with tubeless tires (no splitrims).
six on seven and a quarter inch lug pattern.  fourteen inch brakes, too.  i
measured the pumpkin, but i don't remember now what the actual measurement
was.  it was a couple inches smaller than the axle currently under my B122,
though.

the original RA15 had 16" splitrim wheels, and 14" drums.  the wheels
cleared the the drums by a decent margin.  this new one...  they don't clear
at all.  but they managed to get on there, so...  it must not be impossible.
seventeen or eighteen inch would have been a whole lot better.  i believe
there's a spacer to push the wheels out from the drums a bit for better
clearance of the drum edge lip, but if so it's not a very big spacer.  and
it's definitely a *tight* fit.  i'm not sure i could get those inner wheels
off the drums without air tools or the jaws of life or something.  still,
16" wheels on a bigger than RA15/RA20 axle.

Greg:  i apologize.  i do believe you're right about the RA15/RA20 sharing a
housing.  somehow in all the hoopla i managed to confuse myself about which
axle matched which other axle.  now about that Traction Equalizer...  did
you get the pictures and see what i was talking about?

--Mac

P.S.:  one question i have is when did the RA20 start carrying 8-lug wheels?
when did *any* of them go with eight lugs?  in the late '50s and early '60s,
the RA20 and whatever those other bigger axles are like the one i have were
either five or six lug Budd pattern, in either the seven and a quarter or
eight and a quarter Budd Six, or the eight inch Budd five.  the even bigger
axles, and i believe sometimes the biggest of the 1500 axles, had ten lugs.
when did they go with eight lugs on the lighter axles?

i'm too tired to think straight.  good night, everbody.  we'll pick this up
again tomorrow, i think.

---------------------------------------------------------------
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Krystof "Mac" MacBryghde
TyrGothi

http://master.triad.ath.cx/