Why is 29 spline better than a 27 spline?

[troys 96 xj]

A 27 spline has less splines,there for each spline would be bigger than the splines on a 29,right?Thicker splines would be stronger than thinner splines I would think.Can anyone explain in easy terms why 29 is better?In my mind bigger splines equal stronger splines.Just putting it out there for discussion.

 

[99SJ_Ex]

More splines = more surface area to distribute the load on the axle shaft...

Same as with gears, the more teeth, the more surface area they have and therefore a stronger connection. This is why people regear with bigger tires, not only does the axle need to sing them more to match the speed, but they also require more power to turn so the greater the surface area, the more evenly distributed the power/load.

 

[old_man]

You are correct to a point. There is a point where increasing the number of splines actually makes it weaker.

 

[5-90]

1) A diametral pitch of 24 is (supposed to be) common to modern axle shafts - so more splines tends to equal a larger shaft. Tom is right about making splines "too fine" in that regard - if you make the splines too fine, there won't be enough material to back them up. This is why they standardised on a diametral pitch of 24 (a 1" diameter shaft would have 24 splines. There is a formula for going back and forth between diametral pitch and shaft diameter, but I'd have to find it - I don't recall it offhand.)

2) Presuming that the splines aren't "too fine," the shaft with the higher spline count (all else being equal) will be somewhat less likely to strip splines, since the load will be spread over a greater area. Again, this really does depend on both shafts having the same diametral pitch (which means the shaft with more splines will be larger, having more material, ...)

 

[WrenchMonkey]

Same as with gears, the more teeth, the more surface area they have and therefore a stronger connection. This is why people regear with bigger tires, not only does the axle need to sing them more to match the speed, but they also require more power to turn so the greater the surface area, the more evenly distributed the power/load.

Um. No.

Robert