I was wondering if you can lose much power by going to a larger axle than needed(35 spline)?I have no idea what numbers i'm producing at the wheels so the Moser calculater does me no good? I called Moser and the guy I talked to said it does not affect performance but it says on their site "to acheive maximum performace you should use the smallest axle possible.
What do you guys think.
Thanks,
JE

 

SAE axle splines are cut/rolled with a 24-pitch which means that a 1" diameter axle would have 24 splines.

Going to a higher spline count isn't so much a gain due to the number of splines, as it is going to a larger (thicker) axle that by it's very nature can withstand more loads. Since crossectional area (sheer resistance) is proportional to the SQUARE of the radius, and the torsional loading is proportional to the FOURTH POWER of the radius (similar to a sway bar design)... you can see how small changes in a shaft's thickness can give it substancially larger sheer and torsional capabilities.

In stock 28-spline 10-bolts we usually see the spider gears go first so few people know if the 28 would last had the posi not blown apart. That said, no one makes a spool for our 10-bolts, and mini-spools are used only to satify specific racing class limitiations. Mark Williams has some tech on their site listing 28 spline wholely useless for spools and racing in general. 30 or 31 spile axles are the minimum you want to look at. 33 spline (12-bolt upgrade) or 35 spline (9" upgrade) are excellent choises for drag cars. Beyond that you need to look at Mark William's 40 spline custom floating axles, or a GM 14-bolt with floating 41 spline axles.

35 will be more than enough... and the weight penalty really isn't that much (it's worth the peace of mind IMO).

 

Steve posted some good info, but I differ a little with his conclusion. I can't see 35-spline axles on a small block being aything but overkill unless it's an all out blower or nitrous race setup and using huge tires. Something that I doubt an owner who "has no idea what numbers i'm producing at the wheels" is driving! I assume he is buying a 12-bolt? If that's the case, stick with the 31-spline axles or at most the 33. It's just adding unnecssary rotating weight to use 35-spline.

Rich

 

I don't plan on stopping with my mods and i'm not going with 12 bolt i'm going with the 9".I think that I may go ahead with the 35 spline axles.The guy I talked to at Moser also said I should go with the 35 spline axles.
Thanks for the info,
James

 

Well, suit yourself. My friend who runs a blown alcohol Hemi uses them, so I don't think you will break them! I also don't think you need them but you will certainly never break one.

Rich