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Live axle nose angle ?
Jon Ison - 24/6/11 at 08:05 PM

I've always thought the diff flange should be parallel withe gearbox flange ?

I was almost convinced today it should be slightly " tipped" up, what's the general locostbuilders advice ?

blakep82 - 24/6/11 at 08:20 PM

for racing trucks (like mine) the regs say they have to be angled down by a minimum of 1.5 degrees. i thought they had to be parallel too though.
can't really see what difference it makes though
out of interest, why did you think it should be angled up?

Antnicuk - 24/6/11 at 08:35 PM

would it depend on type and length of the arms? would they change the way the angle changes as the axle goes up and down?


[Edited on 24-6-11 by Antnicuk]

D Beddows - 24/6/11 at 08:59 PM

the slight angle is to stop you 'flat spotting' the bearings in your prop UV joints

mark chandler - 24/6/11 at 09:01 PM

slightly tipped

Jon Ison - 24/6/11 at 10:01 PM

quote:
Originally posted by D Beddows
the slight angle is to stop you 'flat spotting' the bearings in your prop UV joints


Hard to get across in words, I am aware of the above, what I am talking/asking about is the flange faces not the angle the prop leaves the gearbox or arrives at the diff.

should the nose/diff flange of a live axle, tip up slightly, be level or dip down slightly ?

nz_climber - 25/6/11 at 07:11 AM

Under acceleration due to torque reaction of the diff the nose of the diff will tend to rise (the amount will depend on how hard your mount bushes are etc) hence why a small dip down is good, as it should pull itself parallel when it is under its most load.

Would worry about flat spotting UJ with a live rear axle as they are moving all the time anyway.

ianclark1275 - 25/6/11 at 08:40 AM

i thought they had to be parallel but not in line?

ie, gearbox higher from ground then diff lower so you bend the ujs but faces are still parallel.

this is why its difficult to measure the prop.


you then need to then leave enough room to slide up the gearbox spline under bumpy road cond.

IC

procomp - 25/6/11 at 09:28 AM

Hi

Yep nose down by small amount assuming you are running the trailing arms parallel to each other. However if the arms are angled to each other to induce squat / Anti squat then map out the axle rotation during it's travel both in normal vertical movement and also in roll and mount to suit.

Cheers Matt

Volvorsport - 25/6/11 at 11:33 AM

if theyre not parallel with each other , then the output at the axle end doesnt equal whats at the gearbox , but thats dependent on the amount of the angle difference .

as im sure your aware the nose angle is always changing anyway even on a normal car .