BMW Axles are one of the most expensive things you don't want to break. In this article we will go though current axle options and details. Lets start at the bottom.
If your car model ends in anything with a 2x, like 325 or 328, you have the weakest axles. This is unfortunate, but not something you cant get around if you end up making some real power and driving the car hard. The main difference between these axles, and axles from the next step up (like E46 330 or 135i), is the outer axle stub. On these models BMW was pretty lame and used a smaller spline. When it comes to what transfers the power to the wheel, the spline, smaller is for sure not better.
To make your axles as strong as possible, especially if your car is lowered, we recommend using our axles spacers. If you want to go the next step up, you can swap the trailing arms or knuckles from the model above for the ability to run that same models stronger axles. For example, a E46 32x can swap in 330 trailing arms and axles, and a 128i can swap in 135i axles and knuckles for a stronger setup. Note that you will usually need to run that new models brakes as well.
Axle Spacer Equipped E46
These cars are usually equipped with pretty much the same diff as used in the lower models, but feature stronger axle stubs. The outer axle stub spline is larger, as is the hub that is pressed into the larger wheel bearing. Once you are to this size, it's as big as they go. This is the same size spline as used on M3 and our billet stubs.
They still aren't very strong, so a popular option for 335i and 135i drivers with powerful N54 and N55 engines is to swap in a M3 differential and axle set, and connect it to the transmission using our M3 Diff Swap Driveshaft. This setup gives you the strength in the rear of a M3. The next step up from there is our Ford 8.8 swap, which is the strongest IRS rear available, offers a ton of gear ratios, and a great carbon clutch LSD.
E9x M3 Diff Swapped into Non-M E8x/E9x Subframe
Ford 8.8 Swapped E46
We now also offer upgraded axles for 135i and 335i vehicles, compatible with lower models if you upgrade your knuckles to 135/335/or M3 variants. These axles are sorta overkill when connected to a small diff, but they will not ever fail. Your diff or driveshaft will fail before these axles break. A great investment for those who have invested in a LSD for the stock diff. They feature billet outer stubs, billet diff adapters, huge CV joints by Gforce, a massive solid axle bar, and a lifetime warranty. We have never ever had a failure.
E46 Auto Axle Swap
On a budget friendly note, with the E46, we have found 330i Auto axles to be much stronger than the Manual axles that featured a weird stamped "cap" and un-evenly spaced bolt holes on the inner CV. Not all manuals had these axles, but a lot did.
Auto vs Manual E46 330 Axles
If you have a 330 or 32x E46 that is making some power, and want stay on budget and cant jump to the M3 or Ford diff, we for sure recommend using auto axles, axle spacers, and our HD Diff mount. If swapping from from manual to auto axles you'll need to swap the diff output stubs and add a few washers to space the wheel speed sensor out so they can read and not get touched by the larger tone ring. Different sensors are not required.
SLG HD Diff Mount
You start to get what you pay for with the M models when it comes to drivetrain. These vehicles are the only to come with a LSD (a M-Variable viscous LSD usually, but well take what we can get) from the factory, and feature much stronger axles. Along with the larger spline on the outer stub also featured in the level below, they feature larger CV joints on the diff side.
Standard E36/E46/E8X/E9x non-m axles feature a 6x86mm CV joint. This is strong, but will start to fail when adding big power and aggressive driving like drifting. E36 and E46 M3 models have a larger 6x94mm CV. The E9X M3 axles go one step farther use an odd 5x102mm CV. Any vehicle families past this use an axle that has no bolts, the axles on a F80 for example have stubs that are permanently installed onto the axle bar and slip into the diff.
All of these OEM CV joints are very narrow and have limited plunge, or the ability for it to extend to allow for suspension articulation. This is why we offer axle spacers, and use a much wider custom CV on our upgraded Gforce axles. You can use any alignment setting or ride height and not worry about losing axle strength.
Narrow E36/E46 M3 CV
Speaking of our custom Gforce axles, they are a must have for any big power BMW with a stock diff or Ford 8.8/Winters diff. Our axles have been designed to leave nothing on the table. Heat treated billet stubs, super strong custom CV joints, and massive solid axle bars made of proprietary steel from Gforce. As always, these axles come with a lifetime warranty. Unlike competitors, we reuse nothing from your stock axles. They are built from scratch using all new, much improved, parts made in the USA. They do require some modification to fit, such as adjustable sway bar links on E8x/E9x and shaving some material off arms on E46 and E36.
SLG Spec Axles
If you have a BMW that we don't carry axles for, chances are we can make you custom axles. To help get sorted out, email us and we can price it out. We will ship out stubs, have you measure, and then produce the perfect length axle bar for your application.