Subject: [Fot] Salisbury rear axle questions

From: Duncan Charlton <[email-masked]>
Date: Sat, 16 Jul 2016 12:46:27 -0500

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I hope there is someone on this forum who might be able to answer the =
following three questions:

A) Would I be likely to miss having a limited slip diff when racing a =
1450-lb car (not on slicks) with engine power of around 120 hp and final =
drive ratio of 4.56:1?

B) Does anyone know whether Salisbury axles would have used the same =
taper at the outer ends?  I have a set of Morgan rear hubs from a =
Salisbury axle and am wondering if I can fit them to a TR3 axle that=E2=80=
=99s mounted in my Morgan 4/4.

A bit of background: My Morgan Series V 4/4 has a Detroit Locker (a.k.a. =
"Detroit Unlocker") limited slip, which is great for drag racing but not =
ideal for road racing because it unlocks the outer wheel when cornering, =
allowing all of the torque to go to the inside wheel. It would seem to =
offer no advantage over an open diff except when going in a straight =
line should there be enough power available to cause one wheel to spin. =
I'm aware of other drawbacks to my current setup as well -- front and =
rear wheel stud patterns are different, and it is not unheard of for =
these axles to break under racing conditions (when mounted in a 2000+ =
lb. Triumph, at any rate), causing loss of a rear wheel.

I have before me several options -- 1) find a stock Morgan 4/4 rear axle =
with a 4.56:1 final drive and either a) use it without limited slip or =
b) purchase a Salisbury or Quaife limited slip for it. 2) Use the =
Triumph TR3 axle currently in the car but adapt Morgan 4-lug hubs to =
gain interchangeability of wheels fore and aft and either a) remove the =
limited slip apparatus entirely or b) replace the lsd with a Quaife lsd, =
3) use a 7Ha Salisbury with lsd from another Morgan but in need of =
different ring and pinion, or 4) use an MGA "banjo" type axle with a =
Quaife lsd unit.

Choice #1a sounds straightforward -- but I only have one (albeit highly =
experienced) racer's opinion that lsd is not necessary on a 4/4 race =
car. Option #1b would add at least $900 to the cost of the conversion. =
This does not address the question of potential axle breakage.

Choice #2 might be possible but #2b requires replacing the lsd with a =
different type and the question of likelihood of axle breakage remains.

Choice #3 likely would not be the least expensive way to go once I've =
purchased a new ring and pinion set and perhaps new axle half-shafts but =
if the axle tubes are of the proper length (this axle came out of a Plus =
8 so the axle may be wider) there would be few modifications needed. =
This option doesn't address the question of likelihood of axle breakage.

Choice #4 offers full-floating axles, removing the risk of losing a =
wheel when an axle snaps, and one of the available final drive ratios is =
probably close enough to 4.56:1. Quaife makes an lsd for this unit and =
the larger rear brakes (10" diameter, I understand) reportedly will not =
present a problem but altering the outer axle flange to fit the Morgan =
wheel stud pattern doesn't look likely (from photos it appears that the =
flange is not large enough), so adaptor plates would be required, =
introducing one more potential failure point. This option would also =
require redoing the spring mounting bracketry. Besides answering any =
concerns about losing a wheel, should an axle break, unsprung weight =
would be reduced since these axles weigh less than the Salisbury units.

Opinions?
Duncan Charlton
Elgin, Texas USA

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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dutf-8"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space;" =
class=3D""><span style=3D"color: rgb(51, 51, 51); font-family: Arial, =
Helvetica, sans-serif; font-size: 15px; background-color: rgb(255, 255, =
255);" class=3D"">I hope there is someone on this forum who might be =
able to answer the following three questions:</span><br style=3D"color: =
rgb(51, 51, 51); font-family: Arial, Helvetica, sans-serif; font-size: =
15px;" class=3D""><br style=3D"color: rgb(51, 51, 51); font-family: =
Arial, Helvetica, sans-serif; font-size: 15px;" class=3D""><span =
style=3D"color: rgb(51, 51, 51); font-family: Arial, Helvetica, =
sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);" =
class=3D"">A) Would I be likely to miss having a limited slip diff when =
racing a 1450-lb car (not on slicks) with engine power of around 120 hp =
and final drive ratio of 4.56:1?</span><br style=3D"color: rgb(51, 51, =
51); font-family: Arial, Helvetica, sans-serif; font-size: 15px;" =
class=3D""><br style=3D"color: rgb(51, 51, 51); font-family: Arial, =
Helvetica, sans-serif; font-size: 15px;" class=3D""><span style=3D"color: =
rgb(51, 51, 51); font-family: Arial, Helvetica, sans-serif; font-size: =
15px; background-color: rgb(255, 255, 255);" class=3D"">B) </span><span =
style=3D"background-color: rgb(255, 255, 255);" class=3D""><font =
color=3D"#333333" face=3D"Arial, Helvetica, sans-serif" class=3D""><span =
style=3D"font-size: 15px;" class=3D"">Does anyone know whether Salisbury =
axles would have used the same taper at the outer ends? &nbsp;I have a =
set of Morgan rear hubs from a Salisbury axle and am wondering if I can =
fit them to a TR3 axle that=E2=80=99s mounted in my Morgan =
4/4.</span></font></span><br style=3D"color: rgb(51, 51, 51); =
font-family: Arial, Helvetica, sans-serif; font-size: 15px;" =
class=3D""><br style=3D"color: rgb(51, 51, 51); font-family: Arial, =
Helvetica, sans-serif; font-size: 15px;" class=3D""><span style=3D"color: =
rgb(51, 51, 51); font-family: Arial, Helvetica, sans-serif; font-size: =
15px; background-color: rgb(255, 255, 255);" class=3D"">A bit of =
background: My Morgan Series V 4/4 has a Detroit Locker (a.k.a. "Detroit =
Unlocker") limited slip, which is great for drag racing but not ideal =
for road racing because it unlocks the outer wheel when cornering, =
allowing all of the torque to go to the inside wheel. It would seem to =
offer no advantage over an open diff except when going in a straight =
line should there be enough power available to cause one wheel to spin. =
I'm aware of other drawbacks to my current setup as well -- front and =
rear wheel stud patterns are different, and it is not unheard of for =
these axles to break under racing conditions (when mounted in a 2000+ =
lb. Triumph, at any rate), causing loss of a rear wheel.</span><br =
style=3D"color: rgb(51, 51, 51); font-family: Arial, Helvetica, =
sans-serif; font-size: 15px;" class=3D""><br style=3D"color: rgb(51, 51, =
51); font-family: Arial, Helvetica, sans-serif; font-size: 15px;" =
class=3D""><span style=3D"color: rgb(51, 51, 51); font-family: Arial, =
Helvetica, sans-serif; font-size: 15px; background-color: rgb(255, 255, =
255);" class=3D"">I have before me several options -- 1) find a stock =
Morgan 4/4 rear axle with a 4.56:1 final drive and either a) use it =
without limited slip or b) purchase a Salisbury or Quaife limited slip =
for it. 2) Use the Triumph TR3 axle currently in the car but adapt =
Morgan 4-lug hubs to gain interchangeability of wheels fore and aft and =
either a) remove the limited slip apparatus entirely or b) replace the =
lsd with a Quaife lsd, 3) use a 7Ha Salisbury with lsd from another =
Morgan but in need of different ring and pinion, or 4) use an MGA =
"banjo" type axle with a Quaife lsd unit.</span><br style=3D"color: =
rgb(51, 51, 51); font-family: Arial, Helvetica, sans-serif; font-size: =
15px;" class=3D""><br style=3D"color: rgb(51, 51, 51); font-family: =
Arial, Helvetica, sans-serif; font-size: 15px;" class=3D""><span =
style=3D"color: rgb(51, 51, 51); font-family: Arial, Helvetica, =
sans-serif; font-size: 15px; background-color: rgb(255, 255, 255);" =
class=3D"">Choice #1a sounds straightforward -- but I only have one =
(albeit highly experienced) racer's opinion that lsd is not necessary on =
a 4/4 race car. Option #1b would add at least $900 to the cost of the =
conversion. This does not address the question of potential axle =
breakage.</span><br style=3D"color: rgb(51, 51, 51); font-family: Arial, =
Helvetica, sans-serif; font-size: 15px;" class=3D""><br style=3D"color: =
rgb(51, 51, 51); font-family: Arial, Helvetica, sans-serif; font-size: =
15px;" class=3D""><span style=3D"color: rgb(51, 51, 51); font-family: =
Arial, Helvetica, sans-serif; font-size: 15px; background-color: =
rgb(255, 255, 255);" class=3D"">Choice #2 might be possible but #2b =
requires replacing the lsd with a different type and the question of =
likelihood of axle breakage remains.</span><br style=3D"color: rgb(51, =
51, 51); font-family: Arial, Helvetica, sans-serif; font-size: 15px;" =
class=3D""><br style=3D"color: rgb(51, 51, 51); font-family: Arial, =
Helvetica, sans-serif; font-size: 15px;" class=3D""><span style=3D"color: =
rgb(51, 51, 51); font-family: Arial, Helvetica, sans-serif; font-size: =
15px; background-color: rgb(255, 255, 255);" class=3D"">Choice #3 likely =
would not be the least expensive way to go once I've purchased a new =
ring and pinion set and perhaps new axle half-shafts but if the axle =
tubes are of the proper length (this axle came out of a Plus 8 so the =
axle may be wider) there would be few modifications needed. This option =
doesn't address the question of likelihood of axle breakage.</span><br =
style=3D"color: rgb(51, 51, 51); font-family: Arial, Helvetica, =
sans-serif; font-size: 15px;" class=3D""><br style=3D"color: rgb(51, 51, =
51); font-family: Arial, Helvetica, sans-serif; font-size: 15px;" =
class=3D""><span style=3D"color: rgb(51, 51, 51); font-family: Arial, =
Helvetica, sans-serif; font-size: 15px; background-color: rgb(255, 255, =
255);" class=3D"">Choice #4 offers full-floating axles, removing the =
risk of losing a wheel when an axle snaps, and one of the available =
final drive ratios is probably close enough to 4.56:1. Quaife makes an =
lsd for this unit and the larger rear brakes (10" diameter, I =
understand) reportedly will not present a problem but altering the outer =
axle flange to fit the Morgan wheel stud pattern doesn't look likely =
(from photos it appears that the flange is not large enough), so adaptor =
plates would be required, introducing one more potential failure point. =
This option would also require redoing the spring mounting bracketry. =
Besides answering any concerns about losing a wheel, should an axle =
break, unsprung weight would be reduced since these axles weigh less =
than the Salisbury units.</span><br style=3D"color: rgb(51, 51, 51); =
font-family: Arial, Helvetica, sans-serif; font-size: 15px;" =
class=3D""><br style=3D"color: rgb(51, 51, 51); font-family: Arial, =
Helvetica, sans-serif; font-size: 15px;" class=3D""><span style=3D"color: =
rgb(51, 51, 51); font-family: Arial, Helvetica, sans-serif; font-size: =
15px; background-color: rgb(255, 255, 255);" =
class=3D"">Opinions?</span><br class=3D""><div class=3D"">
<div class=3D"">Duncan Charlton</div><div class=3D"">Elgin, Texas =
USA</div><div class=3D""><br class=3D""></div><br =
class=3D"Apple-interchange-newline">

</div>
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