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5 reasons why you have a creaking BB30 bottom bracket and the best solutions on how to fix them

In this article I’m going to discuss everything you need to know to fix your creaking bb30 bottom bracket. And it’ll also include a couple of things you’ll also need to look out for when dealing with this type of bottom bracket.

Let’s get started.

What are the benefits of a BB30 bottom bracket?

A creaking BB30 bottom bracket is extremely common. I would even go so far as to say that the creaking symptom is inevitable. My MTB mechanic even stated he thought it the worst bottom bracket ever and the one who came up with it is an idiot.

A sign that the benefits outweigh the possible downsides is usage, and the BB30 is still being installed on high-end bikes today. So that’s a sure sign it does something right. So before you decide to throw your BB30 out the window, let’s discuss the benefits being perfectly explained in a video from bearing expert Hambini.

He basically states:

  • Consisting of just 2 bearings and 2 snap rings, which are pressfit not threaded into the bottom bracket shell, the system is lighter.
  • A standard Shimano axle is 24 mm whereas the BB30 bottom bracket holds a 30 mm axle, hence the 30 in the name. The bigger number means the axle is inherently stiffer resulting in a better power transfer between a rider and his or her bike.
  • Because of the smaller diameter between bearings (a standard 68 mm shell width) there’s the opportunity to create a better ankle clearance.

Why is your BB30 bottom bracket creaking?

Any creaking sound your bicycle makes, including a creaking bb30 bottom bracket, is caused by friction between moving parts. So if your bottom bracket is creaking, it means some part of your bottom bracket is moving against another part. It really is that simple.

bb30 bottom bracket mtb
BB30 as held by the bottom bracket shell. Courtesy of SRAM

1. Bearing misalignment

The fact that the system is dependent on the frame as the primary holder of the bearings, and there’s no sleeve or container that connects the two, the chance of misalignment is totally dependent on the quality of the frame.

And it’s much more complex to make a frame with a precisely machined bottom bracket shell within the manufacturer’s tolerances specific for the BB30 bottom bracket. Especially when we’re talking about carbon frames.

Misaligned bearings mean the bearing load is spread less even, which speeds up wear and ultimately results in bearing failure. And bearings don’t go down silently.

encased BB30 bearings
Image courtesy of BBInfinite

solution: Since you can’t re-machine your frame, the only solution would be to use a third-party sleeved bottom bracket. An expensive solution.

2. Bearing movement

If a frame’s bottom bracket is not manufactured within bearing tolerances, but is either too wide or too narrow, it’s detrimental for the bearings. And this happens a lot with frames with creaking and dying bearings as a result.

Too tight and too much stress is applied to the bearings. Too wide and the bearings can move around when pedaling pressure is applied through the axle onto the bearing. I don’t have to tell you what happens in either situation.

solution: By cleaning the bottom bracket shell and the bearings, you can then seal them into place using Loctite 641 for alloy frames, or Loctite 641 in combination with Loctite 7471 for carbon frames.

Loctite 641 is especially made to bond cylindrical parts in their container, and you’ll need a Loctite 7471 activator since 641 itself doesn’t do its job with carbon.

3. Bearing exposure

bb30 bottom bracket exploded
Image courtesy of Wheels Manufacturing

The bearings naturally sit right outside the shell. And apart from the bearing shield from the cartridge itself a separate outer seal is installed on top of it.

This is the least protection against the elements of any bearing system out there. The chances of stuff getting into your bearings and doing all kinds of nasty things to your bearings is extremely high, especially in wet and muddy conditions. Bearing failure and the accompanying creaking is the result.

solution: Obviously there are many ways to minimize bearing contamination, with not riding in bad conditions being the most obvious one. The other obvious one is simply cleaning and drying your bottom bracket.

If your bearings are already damaged, there’s nothing left but to replace them.

4. Axle wear

worn bb30 axle surface
dark worn areas on a BB30 axle. Courtesy of weighweenies

An axle rotating in misaligned bearings will have the same amount of force applied to a smaller area of the axle. This in conjunction with a bearing that spins less and less smoothly, means the axle can start to move independently of the bearing.

As the axle surface slides across the inner area of the inner race it starts to wear out. A worn area causes minute movement of the axle onto the bearing and the accompanying creaking noises.

solution: To create a tighter fit between the axle and the bearings, BBInfinite tells you to put the spindle in the freezer. The cold shrinks the diameter ever so slightly. As the axle is reinstalled and fits snugly when still cold, it will fit even tighter with normal temperatures.

And if your bearings are shot, you’ll need to replace them obviously. With replaced bearings it’s usually not necessary to replace the axle.

5. Axle end wear

bb30 spindle wear

One of the biggest advantages of the traditional square taper bottom bracket is that basically play between crank and spindle is virtually impossible.

Not so with many other bottom brackets, including the BB30 bottom bracket. Because the crank doesn’t slide onto an ever expanding area, like with a square taper, it needs to fit perfectly to not show play. And while with a new crank this might be the case, not torquing down the nut according to specs, may cause wear and subsequent wear to the axle.

solution: re-torque the crank according to specifications, and maybe even a bit more.

Concluding remarks on creaking BB30 bottom bracket

I own many bikes and it’s a sign of the time that my most expensive bike, a Cannondale Scalpel Team Replica, had a bottom bracket with multiple of the aforementioned issues.

Personally I couldn’t care less about the weight safe of a couple grams. And I wouldn’t care so much if not for the fact that the bottom bracket setup and crank is so incredibly expensive and hard to find. But I guess that those two, rarity and cost, go hand in hand.

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