shimano hollowtech ii bottom bracket cup

Bottom bracket creaking: reasons, fixes, don’ts


I saw a lot of people complaining about bottom bracket creaking. However, bottom bracket creaks are rarely related with bottom brackets. There are lots of areas on a bike that can create those annoying creaks. Spotting the exact problem can be easy, or almost impossible, depending on the problem. Seatpost creaks, pedal creaks, chainring bolt creaks, even frame creaks are mistaken for bottom bracket creak. Most of the time, bottom bracket creaking fix is easy.

Creaks are super annoying, and I saw a lot of people complaining about bottom bracket creaking. However, bottom bracket creaks are rarely related with bottom brackets. There are lots of areas on a bike that can create those annoying creaks. Spotting the exact problem can be easy, or almost impossible, depending on the problem.

To cure a problem, we have to ask the right questions first: why people automatically think it is the bottom bracket that creaks? Bacause people tend to think cranksets are not good enough for them. I’ ve seen a lot of people, who cannot sustain 100 watts for a few minutes, complaining about flexy frames or cranksets. Well, I don’t meant to harm your feelings, but you’ re not that strong to flex a frame or bend a fine crankset. That’s where pros or avid riders can complain. These ridiculous claims are popularised by bike media and silly forums.

On my prime, I can sense I’m going past my cars’ chassis limits, via a seismic device located on my sitting organ. That took like a year or so of competitive driving, almost all day. I lost the skill now, because I’m not practicing anymore. That’s fine. People change. Things change. Our bodies change. And you know what? On biking, I’m only good enough for 200-ish watts for an hour, at best. I’m 47, work as a software developer, and living a quite unhealthy life, despite improving the condition in the last years.

Is it really bottom bracket creaking?

Human ears is not marvel when it comes to locating the source of the sound. Especially, except very high pitched (treble) sounds. That’s why subwoofer location in sound systems does not matter much, though tweeter location is mega-critical. High pitched sounds in a mechanical failure is generally a very high force, dry metal to metal contact under high speed, like a bearing failure under hew thousands of rpm’s. That’s not happening in a bike; so what we hear in bikes is generally hard to spot.

Before taking apart your crankset and bottom bracket and reaming the bottom bracket shell, it is a good idea to isolate the problem. When you push a pedal, lots of things happen: your pedals crush in stress, your seatpost, even the handlebars deflect because you’re rocking back and forth and right to left. Your chain gets under tension, so do chainrings, sprockets, rear hub, even rear triangle.

So, let’s inspect what could that creak can be, from the most obvious to less likely:

ultegra crankset split
Divorce rate amongst some Ultegra and Dura Ace Hollowtech II cranks is fairly high. As you know, 2 parts of the crank glued together. Looks like corrosion and maybe glue itself is the reason behind this. Creaks can be the manifestation of quarrels amongst two sides. A problem superglue won’t fix.

Seatpost and saddle creaks

Bottom bracket creaking when standing? You can eliminate seatpost and saddle creak, if this is the case.

Seatpost creaks are quite often but mostly overlooked. Saddle creaks is a thing too, but it is rarer.

Your seatpost can creak, because it’s not dead-tight, and there is debris between seatpost and seat tube. Most riders and mechanics do not bother cleaning seat tubes, so lots of dirt trapped between the seatpost and seat tube, creating the noise.

Luckily, it’s very easy to pinpoint the problem: stand and pedal. If the creak is gone, you now know what it is.

To remedy it, remove your seatpost, clean it. Then, you have to clean inside the seat tubes. I’ve made a simple tool for cleaning suspension fork legs, which will work perfect for the case.

If it’s the saddle that creaks, that’s probably the rail to seatpost interface, which is either loose, or not a good fit for the saddle. Either fix it or replace it.

Once the seat tube is cleaned, I advise using copper grease. It reduces corrosion, eliminate water and dirt ingress and improve tightness as it includes copper particles. In fact, it is mostly called “copper montage paste” instead of copper grease. Your seatpost clamp should be fairly tight, though.

For carbon fiber seatpost, obviously you wouldn’t use copper paste but use special carbon fiber paste. It’s similar to copper paste but includes an epoxy-safe carrier and plastic particles instead of copper. It promotes retention. In fact, you should never use carbon fiber parts without carbon paste.

Chain ring bolts

Chainrings take a lot of abuse. Even if a single chainring bolt is loose, it will creak.

Finding a chainring creak is relatively easy. While standing next to your bike, apply brakes hard, and try to stand on drive-side pedal while shifting your weight up and down steadily.

Curing the problem may be harder than that. These bolts generally don’t loosen without an underlying reason. If the threads are stripped, you have to have the holes repaired, preferably with a helicoil. Unfortunately, if they are loose, they can also cause crankset holes to enlarge, due to friction or shock. They have to fit snugly, otherwise they creak and ruin chainring holes in the long run.

For many newer cranks, big rings attach to spider with two-part, thru-hole bolts: Bigger one goes through the chainring hole, and the smaller one fits the other. These are pretty safe, but inner ring has only one part bolt that goes through aluminium spider. This is where to look first. As I said, they can be repaired with heli-coil or similar product.

cheap pedals
For the cost-conscious riders, these pedals will creak in the earliest opportunity if they don’t separate from spindles before that. You can either buy decent ones, or buy these in bulk.

Pedal spindles

Pedal spindles creak due to worn bushings, or bearings if there is any. They can be easily mistaken for bottom bracket creaking, due to their location.

Cheaper pedals have bushings, or tiny, useless cartridge bearings. Unfortunately, these pedals are not repairable. Some such pedals are repairable by changing cartridge bearings. But such tiny bearings won’t last long. They’ re either very cheap, because made like crap. Decent ones are much more expensive then the pedal itself, because making such bearings good enough is not easy.

Get some good pedals, preferably cup and cone like Shimano’s, or with heftier cartridge bearings. Stay away from any product with small cartridge bearings. They either don’t last or crazy expensive.

Also, loose end nuts can cause creaks. If you have issues like bottom bracket creaking when pedaling, this is probably it.

broken crank bolt hole
Carefully look at the eyelet on the left side: there is a tiny, hairline crack. This probably happened due to loose chainring bolt. Can look trivial, but it creaks like mad, very easily mistaken for bottom bracket. This is a SRAM GXP crankset, so it’s easily mistaken for GXP bottom bracket.

Crank spindle

On bottom brackets with outboard bearings, like Hollowtech II, either one or both sides (some Campagnolo cranksets) of the crankset have spindles pushed into the crank. The fit may not be tight enough; so when you push the pedal, spindle moves very slightly in the crankset, causing a creak. This is more common on Sram cranksets, which are not liked by many, and sometimes poorly judged as worst at bottom bracket creaking, but they have their own problems.

Another reason of crank spindle creak is, bearing can get stuck, and spindle moves inside the race. This is not common, and manifests itself with jerky movement and lots of drag in the crank.

Both problems are almost impossible to fix without the crank replacement. The latter is a bottom bracket issue, and can be solved with replacing the bottom bracket. But if your crank spindle is worn, it is unsafe, and must be replaced. Since the spindles are not replaceable, at least with superior machining skills and equipment, the whole crank must be replaced.

Suspension and frame pivots

This is quite common as far as I can see, but unfortunately, I have zero experience with this, because I never had a softtail. (I had a crappy one which I rode less than 100 km’s, and ditched right away)

However, they seem to be easy to spot, at least, my logical thinking makes me believe so: if your seatpost is not creaking, and the bike creaks under load while not pedaling, you know what it is…

Phantom reasons for creaks

If you’ re still stuck, and know it for sure it’s not the bottom bracket itself, then strip your bike accessories and visually check your frame.

A minor crack in frame can cause excess flex which can cause creaking. Sometimes these are surprisingly hard to spot. Clean your bike, then start inspecting it, especially around top and bottom tube weld areas and rear triangle.

Sometimes, it’s the accessories that creak, especially pannier racks. You do not need to completely remove them; most of the time, rocking them hardly will manifest the problem.

shimano hollowtech ii bottom bracket cup
I’m not too keen to obey manufacturers’ orders. I disassembled these cups millions of times. These Hollowtech II bottom brackets accepts modified (1mm narrower) 6805 bearings, which I happen to have many. Sadly, I ran out of them, thanks to ingenious design and cheap Chinese manufacturing. Now I’ll modify these to accept standard 6805’s, which is cheaper and more abundant.

Yes: my bottom bracket is creaking!

If all these checks fail, it’s %90 of the time, the bottom bracket creaking. Contrary to popular belief, packing half a kilo of grease into the bottom bracket will never solve the issue.

Unfortunately, solving the bottom bracket creaking problem can be a very expensive and hard fix, depending on the problem. The reason can be the bottom bracket shell itself. More on that later…

Do you have a cartridge, square taper bottom bracket? It shouldn’t creak – if it creaks, check the bottom bracket spindle to crankset mating. Remove the crankset, preferably applying copper grease or any grease, tighten and try. If it still creaks, you should have worn-out bearings. Either replace the bearings, which in most cases not possible or too expensive, or the bottom bracket itself. Cartridge-type square taper bottom brackets don’t creak, but make a grinding noise if the bearings are shot.

Why outboard bottom brackets creak ?

Bearings should fit perfectly to bottom bracket. Cartridge bearings do not mean to carry radial loads. If the bottom bracket is not perpendicular to frame, even by a minuscule amount, the spindle forces the bearings at a weird angle, causing race or ball-bearing failure. Most people attribute bottom bracket shell problems to bottom brackets, because it is almost impossible to spot the problem, even for a bike shop.

Outboard bottom brackets like Hollowtech II or GXP have no proper “bridge” to keep both cups aligned: so, you can insert your crank spindle, almost the bottom bracket shell is crooked way beyond the allowed deviance. That doesn’t mean it will run perfectly fine. It will cause drag and premature bearing failure, even scored spindle, and obviously, bottom bracket creaking.

Pressfit bottom brackets shells and creaking

Most people think pressfit bottom brackets is a recipe for bottom bracket creaking, for a good reason: they are mainly found on carbon fiber bikes, and most of the frames, even the very high-end ones are lousy! Carbon fiber frames are hand-made, most of them are made by unskilled workers, quality control is almost non-existent. Either the two sides of the shell is not round enough (I didn’t say perfect circle; there is no such thing as a perfect circle!) or it’s misaligned.

Pressfit bottom brackets is not inheritedly bad – they are bad, because they are used in frames made lousily. They creak, because 2 bearings on the spindle are off-axis. They cannot be corrected by user intervention, or a bike shop: they either need to be machined to specs, or used by custom-made bottom brackets as Hambini does, which is a sure way of bottom bracket creaking fix.

Poor bearings

Unfortunately, most outboard bottom brackets are badly designed, which is the primary reason of bottom bracket creaking. They have tiny, non-standard bearings. Sealing on them is not immune to dust or water contamination. Some are better then others, but inherently, most of them are not great designs. So, we need to embrace the fact that bearings can fail prematurely.

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