Billiumss

iTrader: (11)

I'm in the market for a new rear end and while doing some research and over the years I've heard/read that a higher spline axle is better than a lower spline, why is that?

To me it would seem that a 28 spline would be stronger than a 31 spline since there would be more "meat" in between the splines.

Could someone please explain in detail why a higher spline axle (31) is better than a lower spline (28).

Bill

MrDude_1

iTrader: (4)

The force is transferred over a larger area.

mzoomora

iTrader: (36)

There is usually more contact area and in most cases as the spline increases so does the diameter of the axle shaft.

Patrick G

iTrader: (14)

Moved from Advanced Tech section.

FirstYrLS1Z

iTrader: (4)

Splines are like teeth on a sprocket,more teeth=bigger sprocket,more splines=larger diameter shaft.

samdogmx

iTrader: (14)

the larger the number of splines the larger the diameter of the axle shaft, & the more splines there are the less the load is on each spline.

chicane

Well Bill, it is mostly like what has already been stated for replies.

In summation... its overall diameter does lend to greater surface area. The greater the surface area, the greater the area in which to spread the mecahnical load. As for spline count... it really depends on the spline shape and pressure angle, not merely the number of. More splines doesnt necessarily mean 'better' or 'stronger'. And last but not least by any means... the material it is comprised of. You can have a 28 spline 35% stronger than that of a 31 spline just by changing materials. But, material cost becomes the issue from here...

In most cases the larger the better, specifically with like materials. But, better materials in like sizes can do more for you... it just costs more.

LSWaaa?

can someone explain to me what spline means? sorry for

Dex

iTrader: (5)

Its all those little groves on the end of an axle.

Reject

iTrader: (24)

well then for out car's just getting the 31 spline would be a better way to go since it's stronger than the 28 (assuming they are the same material) or is there somthing we should know to stay away from the 31s?

Revelation Z28

iTrader: (10)

its wierd though how 3 more little splines would add strength to something.

MrDude_1

iTrader: (4)

keep in mind, theres a set "standard" for axles.
take the ford 9" for example.

theres the standard 28 spline axle. this is what came in ford cars for years.
theres the standard 31 spline axle. this is what came in ford trucks and HO cars..
and then theres the 35 or whatever spline ones.. this is all aftermarket, low single digit car stuff.

now the spline count is NOT the only diff between them. the physical size of the axle is diffrent. the 31 is larger then the 28.. and the 35 is just massive.
however, its MUCH easier to refer to them by their spline count. afterall, thats how we can tell if they interchange with our diff/spool/locker....
theres an obvious strength diff between a 31 spline late 60s OEM ford axle from a mustang, and a new moser 31 spline axle of the same dimentions... theres length, bolt pattern, bearing size, etc....
but for our website, 90% of us assume we're talking about aftermarket axles for an Fbody... oor we only need to know what centersection spline we need to match.. and because of that, we just refer to the spline count.

mzoomora

iTrader: (36)

That 3 spline is 10% more, plus the increase in diameter and the fact that it is an aftermarket axle Vs. the stock 28 spline axle. Also, you are also talking about a 9" Vs a stock 7.6. Comparing a 28 to 31 spline 9" factory axles the difference isnt nearly as great.

lethal93ta

this isnt the greatest pic but this is 28 vs 35

Billiumss

iTrader: (11)

Great info guys, thanks!!!

Revelation Z28

iTrader: (10)

well i was comparing the same rear ends together. 9" 28splive vs 9" 31 spline 12 bolt vs 12 bolt.

i know from what we have stock compared to any other rear end that we can use its like we have toothpicks in there

MrDude_1

iTrader: (4)

if you go 9", get the 31 spline.

anything larger is overkill.. and theres a TON of cheap 31 spline parts out there....

theres 28 spline stuff, but not as much heavy duty racing stuff, and it costs more (simply because theres not as much of it)

Revelation Z28

iTrader: (10)

im already set on a 12 bolt. im gonna hardly be at the track, i just need something thatll take 3 channel and hold up to a once in awhile track use. i DD the car so a 9" is overkill. once i get an SS itll get the 9"