rchappelear 28 Report post Posted November 10, 2011 so i have been really twisted on what the big deal between the 28 and 31 spline axles are. recently I read that the 28 spline axle shaft is smaller in diameter that the 31 spline. Is this true? Quote Share this post Link to post Share on other sites
stangs-R-me 120 Report post Posted November 10, 2011 YES, the 31 Spline is a slightly larger shaft and there for can handle more torque. Don't remember what the diameter difference is though. If you've got a small block and are running stock width tires (225 or narrower), 28 Spline axles are just fine. If you are running wider / sticker tires or drag radials and have a built small block or stock (or built) big block then you probably should have the 31 Splines. FYI / interesting factoid ... Ford has been putting 31 Spline axles and 8.8" T-Lok differentials in all 2011-up V6 Mustangs !! Main reasons being the wider & stickier tires from the factory and the car is quite a bit heavier than a classic Mustang ... 305 HP & 280 ft-lbs of torque has a little to do with it too. Weak link now is the 2-pc telescopic stamped-steel drive shaft. Doug Quote Share this post Link to post Share on other sites
sportsroof69 13 Report post Posted November 10, 2011 I'm running low 11s, with continuous 1.5x 60's on stock, 28 spline axles. Quote Share this post Link to post Share on other sites
BuckeyeDemon 211 Report post Posted November 11, 2011 according to Strange Engineering, their 28 spline axles are 38% torsionally weaker than their 31 spline axles. have you ever seen a car launch at a drag strip when an axle breaks? Quote Share this post Link to post Share on other sites
sportsroof69 13 Report post Posted November 11, 2011 Yep. I've done it in other cars. My '71 Camaro did it, and it's a lot worse deal because the axles don't bolt in, so they will actually come out. It can still be bad on the 9", but it's a little better because they do bolt in. It can still tear stuff up though, and if you're down the track, it'll turn the car. And the strange 28 splines are considerably stronger than stock 28 splines. I have a 35 spline spool sitting on the shelf. I just haven't bought the axles yet. Quote Share this post Link to post Share on other sites
Max Power 74 Report post Posted November 12, 2011 I am still running the 28s because my tires are the fusible link. Quote Share this post Link to post Share on other sites
stangs-R-me 120 Report post Posted November 12, 2011 I am still running the 28s because my tires are the fusible link. Mine too ... 225/70-14 BFG Radial T/A's are going to spin before a 28 spline axle will twist !! Doug Quote Share this post Link to post Share on other sites
