Is this normal wear on a crank?

I use a wheels manufacturing thread together “press fit”. It utilizes Enduro Bearings and I replace them every 6 months (2500-3000 miles).


I am currently using this grease. It was recommended to me by a machinist (who rides bicycles). Couldnt find any info on what its made with (seems to be a common theme in grease and lubrication products).

I wish there was a best of trainer road forum, I would nominate this!

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Broc, the grease you show here is not too bad but you could do better. I pulled up the product information sheet here: https://pim.liqui-moly.de/pdf/en_US/liqui/4/P003500
This is German so it doesn’t have the ASTM data that I am used to. However there are some issues. Adding molybdenum sulfide to grease is kind of “gimmicky”. MOS2 is used to protect bearings that are exposed to shock loads such as might be found on earth-moving equipment. MOS2 is what is referred to as a solid lubricant in that it embeds itself into the asperities of the metal and help with boundary lubrication which is what happens when the fluid film boundary of the lubricant is compromised and metals momentarily touch. MOS2 or “Moly” sounds good and probably doesn’t hurt, but I would rather see the manufacturer spend money on a better thickener or extreme pressure additives.

This grease uses a lithium thickener which is poor against water washout, one of my most important criteria. Also, the four-ball weld test result is mediocre and the four-ball scar diameter is twice what I would consider acceptable. Oil separation is terrible on this grease, as well. For instance, the grease that I sell has a four-ball weld test result double of this grease. The Lubri-plate I mentioned is a better grease in my opinion. If you are interested in what I use, this is it: Chesterton 630 SXCF 220 #1 . It is not available on a retail basis. I could probably sell it to folks if there was a way to arrange to do that. Is it okay to give out email addresses? Not sure.

I apologize that this information sounds like gobbledy-gook but testing data is the only way to compare greases. Marketing departments write all kinds of vague, glowing information but one has to be familiar with the testing data to actually compare greases. Also, this grease issue would definitely fall under the marginal gains criteria because the low-tech nature of the application, namely bike bearings, does not really require an exceptional grease. Changing/cleaning/greasing bearings with almost any grease will give 99% of the results needed, so I don’t want to come across as a grease snob. I get my grease for free and happen to have an excellent grease but if I didn’t, it would not matter that much.

So my advice would be to keep using the grease you are using, but tear down your bike once a year, at least, and try to purge the old grease as best you can and put in new grease. By doing that you are removing wear metals and dirt from the bearings and extending bearing and component life which is much more important than the specific grease used.

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The plastic “seal” can be pried open, allowing you to add grease and even to flush before adding. I’ve tried it a couple times on different bearings, but wasn’t too confident with what I’d done because the tool I used to open up the seal gouged the plastic seal… so I replaced it after not too long. But it seemed like it did the job, certainly for the short term.

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Paul,

When you “retire” I think its time for you to start a bicycle grease/lube company or at-least sell your knowledge and product to a company in our space and help them capture your best lubrication in more cyclist friendly package.

Just my $.02

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I used every kind of bearing possible on my Trek BB90 gravel bike. I replace them OFTEN. :slight_smile:
I also have a Rotor crankset, so I can just replace the axle as needed. (This might also be the cause of the bearing failure. I’m trying ceramic angular contact bearings now as I suspect the issue is that there’s no way to get bearing alignment/spacing/preload correct)

In any case - changing BB is no big deal. Unfortunately, you don’t know it’s going to fail until it’s failed enough to score your crank. The old one will work just as good as a new one until it doesn’t in most cases, so more preventative maintenance is pointless as there’s a bigger risk you new one will have an install issue than old-reliable failing.

FSA and Rotor make interference for spindles for 24mm (Shimano), Shimano and most BB use a plastic spacer between the bearing and spindle, and the mechanical “cost” of that sounds being scored is pretty low- so it’s better now to worry about it.

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I wouldn’t call it a seal, more like a dust cover. You can use a fine pick to pop the cover off to service the bearings and re-pack with grease. It’s also convenient for inspection purposes.

In all fairness, its a gravel bike. I race hard, through a myriad of conditions which are detrimental to anything that isn’t sealed. I wash my bike 2-3 times a week and deep clean about every 6-8 weeks. The gravel bike takes 10x more wear and tear than my road bike, but that is because I only use the road bike when bib-shorts and short-sleeves are required :grinning:

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I also come from an industrial background (shop owner with two dozen CNC machines). It’s easy for people like us to look at the bike industry and think, “what a bunch of hacks,” as so many common practices in cycling do not conform to standards followed in general industry.

However, I’ve learned over the years that there’s method to the madness. While I still don’t agree with a lot of it (check out Hambini’s roasts and rants), I’ve come to accept a lot of the practices as well.

The main thing to keep in mind is that when talking about anything drivetrain related, accuracy always takes a backseat to efficiency. A bottom bracket (which btw, is a stupid name… should’ve been called a “Crank Spindle Assembly”), can have 0.020" of runout and it wouldn’t matter as long as the drag is low. This is about 100-200X greater than the allowed runout on a pretty basic electric motor shaft.

There are two ways to keep drag low in a crank/BB assembly. Either the whole thing is dead nuts accurate, or the whole thing is sloppy. There can’t really be an in-between. If your crank and BB are super tight, but the BB shell in your carbon frame is out of alignment, it will bind up and you’ll lose a bunch of watts. Not good. When everything is sloppy, they spin freely.

Back when Contador was racing, rumor has it that his mechanic would remove the rubber seals on his bearings, flush the grease, and relube with oil. The bearings might only last one ride, but it was worth the handful of watts saved.

As for the bike industry-wide practice of greasing the living crap out of everything, some of it has to do with the sloppy tolerances, but a lot of it also has to do with corrosion. Bikes need to withstand rain, road grit, mud, and a poorly aimed pressure washer. Easiest solution is to unload the grease.

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What I’m finding with this specific BB and crank, is the driveside bearing will spin freely but …“chunky?” After some months of use. Non-drive side will be perfect. However, upon chasing a noise in the past I have unthreaded the BB, cleaned, re-greased, and re-installed the same BB and the drive-side is buttery smoothe again without performing maintenance on the bearing itself. My instincts tell me the shell on my drive side is either oval and/or too tight. This same problem has been replicated with 2 seperate BB’s of the same model/bearings.

If I had to guess, I would say it’s undoubtedly the frame that’s giving you issues. The BB conforms to the misaligned frame, and that’s causing the binding.

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Makes since. The science of roundness. Simple in theory, difficult to execute.

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Well said.

I cannot speak as to this particular grease, but Liqui Moly is a well-known German brand selling oils, lubricants and the like for the automotive sector.

The area just around the spindle may be touching the bearing seal or outer race. Try putting an o-ring between the outer seal and the crank.