Reginald, you should have mentioned a couple of important aspects for newbies that will try to follow your rehauling method. 1. If you like to grease the bearing seat on the axle, MAKE SURE you are not using lithium-based grease. It is better to leave the seat unlubed than to use lithium grease. The water will eventually find its way there. Water is an electrolyte. It takes a little drop to start a galvanic corrosion forming. You will get corrosion in no time. Remember: DT Swiss-style hubs use aluminum axles. Bearing races are made of steel. Different metals + lithium + water = lots of trouble. In extreme cases you wouldn't be able to detach the bearing at all, it will be permanently bonded to the axle. Therefore, use graphite or calcium grease. Or leave the seat unlubed. The problem is exacerbrated by laziness of some grease manufacturers: they like to NOT include the information on contents of the product. All you get is marketing bullshit like "premium super-duper-ultra-durable special wonderful universal magic grease". If a manufacturer does not say which agent was used, avoid such a grease like a plague. Even if it says it's water-resistant. 2. Calcium grease. Not sure which brand of calcium grease you are using, but usually these are very thick and sticky. Case in point: Divinol. It is a rather sticky and thick grease that does slow bearings down. It is advised not to use this grease on something that has to spin fast (cup-and-cone hubs, bottom brackets, etc). Calcium grease is very good at repelling the water, so you can use these in places where water ingress is likely to occur. Just don't lube fast-spinning bearings with it. 3. Spin tests are completely pointless and indicate nothing. Because bearings are not loaded. You can clean out all the grease from bearings and fill them with ultra-thin sewing machine oil. Your hubs will spin like crazy with very little resistance, but such overhaul will last for only 50 kilometers or so and in the end your bearings will be done. 4. Don't buy hubs with hybrid ceramic bearings. It's a waste of money. Hybrid ceramic bearings are bearings where races are made of steel and balls are made of silicon nitride. Ceramics are way harder than steel (steel is like a sponge to them - that's exaggerated for your understanding) and they will cut through races plenty quickly, so bearings will have a significant play/backlash. Hybrid ceramics don't last long due to that. Full ceramics are better in this regard, but don't forget that all ceramics are brittle and strong impact (hitting a pothole at full speed, for instance) may shatter the bearing like the teacup that was dropped from the table.
I agree. Hopefully they read your comment. Note, the spin test is not scientific nor does it show real world performance. But… it does show how freely the wheel spins. 😁👍🏻 PS. I did mention I was using Morgan Blue calcium grease, here is what they say about it: “Firm grease based on Calcium and used for a wide variety of applications. Originally grease used for maintenance in the naval industry. Calcium Grease is used for the general assembly of bike components and the lubrication of moving parts. Ideal for use with bearings, spindles etc.” 😎👌🏻
"4. Don't buy hubs with hybrid ceramic bearings. It's a waste of money. Hybrid ceramic bearings are bearings where races are made of steel and balls are made of silicon nitride. Ceramics are way harder than steel (steel is like a sponge to them - that's exaggerated for your understanding) and they will cut through races plenty quickly, so bearings will have a significant play/backlash. Hybrid ceramics don't last long due to that. Full ceramics are better in this regard, but don't forget that all ceramics are brittle and strong impact (hitting a pothole at full speed, for instance) may shatter the bearing like the teacup that was dropped from the table. " Not hubs but for bottom brackets: What do you make of Enduro XD15 bottom brackets? Only asking because they do offer a lifetime warranty on them and if you google em they do have some pretty glowing reviews which tend to parrot things along the lines of, "the longer they're used the better they get". Of course it's probably hard to spend $300USD on a BB and not have a bit of a positive bias towards it... themtblab.com/2023/04/enduro-bearings-bottom-bracket-test-report.html this article tests a bunch of the bearings used in BBs under perhaps unrealistic circumstances. Not being an engineer myself I don't know how valid a test like this is -- like this "In every instance, one bottom bracket bearing (not two) rotated under 82 kg./180 lbs. radial and 27 kg./60 lbs. thrust loads for a total axial load of 109 kg./240 lbs. This equates to 218 kg./480 lbs. rider pushing a consistent 600 power watts." seems extremely suspect, but then again, maybe testing extremities like that is the only way to actually eke out a difference anyway. (Or, it's the only way that those Enduro bearings can end up on top. Dunno.) Edit: answering my own questions somewhat: re Enduro's lifetime warranty, "Claims from normal wear, product misuse, abuse, product modification, improper product selection, non-compliance with any codes, or misappropriation will void the warranty." this is a choice quote from their page about product warranties. So there's probably very little that the lifetime warranty could possibly cover that a 1 year warranty wouldn't already -- any bearing failure that didn't already occur in that time would probably just be labelled as "normal wear" or "abuse".
@@quasimal I'm dubious. The article you've presented is sponsored by Enduro, therefore it's biased. They may have created the rig that specifically makes XD15 bottom bracket perform better under specific (very narrow, non-real life) conditions, but the truth is there: material hardness for XD15NWTM is 58-59 HRC (Rockwell scale) and Si3N4 hardness is 78 HRC (Rockwell scale), so the point stands. You should be using regular steel bearings, because they will be more durable in the long run. Bicycle bearings are subjected to vibrations and impacts. When you hit the pothole or jump over the kerb, bearing balls hit races in very narrow spots (less than a human hair thickness). The same material hardness helps to even out the kinetic energy of the impact, but once the component of higher hardness (ceramic ball) hits softer material (inner and outer races made of steel), no matter the treatment, races get damaged and in the long run develop play/backlash and/or dead spots that prevent balls from spinning freely around the circumference. You are not riding on roads as smooth as glass, so the perfect conditions simulated on the test rig are too detached from the conditions that you will be subjecting to your bearings in real life: water ingress, grime, gunk, sand particles, hits, vibrations, etc. For the same very reason nobody should ever install fully ceramic bearings in hubs and bottom brackets. Ceramics are hard but brittle. If after serious pothole hit bearings get shattered like a broken teacup, the very next moment you'll get seriously injured. Hubs or bottom bracket get jammed and the bike stops its motion literally on a dime, sending your body into the air. The only application where you can safely use full ceramic bearings is derailleur pulleys. Bottom line: forget about hybrid ceramics as you are just burning money for no benefit and forget about full ceramic bearings as it poses a deadly threat.
@@tweed0929 Thanks for the reply - all makes sense. Naturally, their fancy stainless bearing also outperform the eclectic competition there, which they attribute to the bigger ball bearings it uses, since the BB cup is used directly as the outer race. Seems like a neat idea at least. Wonder how it compares more to NTN, SKF, etc. ones though. The lifetime warranty thing does also seem to be a bit of a ruse, seeing as though "normal wear" is a warranty-voiding condition (which of course is standard for a warranty, but a bit rich to call a "lifetime guarantee")
I think you are supposed to just hammer the bearings in, with quite a bit of force. Make sure to hit it on the edges. When you start to see aluminium chips forming, you know youre doing it right.
Always good to see in depth vids for jobs like this, thanks for your hard work. I don't want to troll but I would say that in my experience the DT Swiss special grease is actually Molykote TP-42. It's an anti-seize paste with solid lubricants, designed for metallic friction applications...exactly why it's used for the DT star ratchet. I'd say something like Shimano freehub grease is much more suitable for ratchet / pawl applications. Also there's a lot of debate on pressing in bearings wet vs. dry. Hope specify greasing the bearing seats, other brands say press in dry. The benefit of dry pressing is if the bearing seizes, it won't rotate in the hub shell and ruin it. What's you take on that?
Excellent comment. Good info. 👌🏻 I feel there are more advantages to a wet press than dray, yes there is a potential problem if the bearings stops moving but normally it’s the axle that suffers in that situation because the tolerance is greater. I have seen plenty of seized bearings but never one that rotates in the bearing seat. (So far!) 😁👍🏻
How does a “professional bike mechanic” not have over axle presses. Also using DT special grease on a pawl and spring setup is not advised by any manufacturer.
Because it’s a small shop and it takes time to justify the cost. Well, DT Swiss use it on ALL their hubs with and without pawls so what do you think the problem is exactly?
Hello, is the axel the same as the d67? Mine has a small amount of movement side to side and I’m having a problem getting the disc to stop running. Could this be that the bearings need to be pressed in more? Thanks
Hi all im wanting to change out my bearings on my Hyper 2003 R33,s. Could anyone please give a list of things i need to do the job properly. I.E a proper bearing press & bearing extractor with the correct over axle press tools. I personally don't want to hammer anything just the way i want to do things. Same bearing size as of this video 8603/8903 . Plus what would you go for non contact or contact bearing covers ? Any help would be great ❤
Depends how much you want to spend on tools? Wheels manufacturing.com will have a kit that will work, but it won’t be cheap. You can find cheaper press kits on Aliexpress.
The dirt grinding when removing/reinstalling the cassette drives me nuts. I swap my cassette between my trainer and my wheel several times a week and I clean off the hub and put a small amount of grease back every time. Maybe you are on to something with not applying grease.
Sounds like you need to pick up some second hand kit from online! Sure you could get yourself a cheap cassette to solve your problem? Or perhaps a cheap Chinese one from Aliexpress/Amazon? 🙂
I have a few cassettes. I'm trying to keep my chain matched to my cassette at all times. I noticed that when I switched from bike to trainer the mismatch of the cassette was causing my chain to wear quicker, and I'm worried that will in turn wear my new cassette and chain unevenly.
The ones I had when making this video do not fit this situation. And using a mallet is fine as long as the drift you use supports the entire surface of the bearing and drives them in straight. 🙂👍🏻
You are full of contradictions! “You can’t have too much grease”, “Always use grease in metal to metal applications” - then you don’t put grease between the cassette and the free-hub body because it attracts dirt! Make your mind up! You use way too much in most areas, and not enough in others.
I hardly think 1 constitutes “full.” 😂That’s why I explained each of my actions and mentioned in the text that their are exceptions. Yes, grease attracts dirt on the outside of the hub but the same rules don’t apply inside the hub! I’m sure you can understand that concept? (Hopefully) 😁 If you do it better then you have no need to follow my advice. 👍🏻🙂
Grease on the freehub body definitely doesn't serve any clear reason. Just torque down the lockring properly, and there will be no movement, and the cassette shouldn't be eating into the freehub body.
That´s a lot of grease, carefull, not that them 8 grams are gonna slow you down.😅 Aluminium dose not rust! Like any metal, aluminum forms a natural oxide layer when it comes into contact with oxygen. In contrast to steel, the corrosive layer comes to a halt after approximately 2.5-4 nm, protecting the underlying metal from corrosive destruction. This layer remains stable in the pH range of 4.5 - 8.5, which means that it is not attacked by corrosive gaseous or liquids, therefore greasing the axels was not necessary and a waste of time and resources.
Yes I know aluminium doesn’t rust. 🙂 (I meant corrode) I think you might be mistaken about greasing the axle being a waste of time? I presume you saw the damage water had caused to the axle in part 1? Also the steel bearings sit against the axle so it’s definitely wise to grease it, not to mention it’s rotating. 😁 And have you never see holes all the way through an aluminium bar caused by corrosion? Perhaps you are mixing up titanium with aluminium? 😉
@@reginaldscot165 The handlebars break do the sweat and the salt in it, the salt lowers the pH range, Water alone cant damage aluminiun like that. There was no damage on the axle, that was the natural oxidation layer of aluminium. WHAT DO YOU NOT UNDERSTAND WITH THIS SENTANCE? ---> In contrast to steel, the corrosive layer comes to a halt after approximately 2.5-4 nm, protecting the underlying metal from ""corrosive destruction"". This layer remains ""stable"" in the pH range of 4.5 - 8.5, which means that it is not attacked by corrosive gaseous or liquids
@@66mikkim From SAE: "Although aluminum on its own has inherently superior corrosion resistance to steel, galvanic action between the aluminum and steel or galvanized parts can lead to severe corrosion". The mean pH of sweat is 6.3 but still it corrodes aluminum due to the salt content. To prevent aluminum corrosion special galvanic passivations are used and where possible parts are painted too. This is done with great care for aerospace components where corrosion may lead to cracking.
@@PaoloLuraschi and that is basically what I wrote. As long as there is no fluid that benefits galvanic corrosion,there is no need to grease aluminum, not even then when it is in contact with Steel. The oxidated aluminum protects itself, even in aerospace parts, the anodized layer ist just a other, harder oxidated layer.
@@66mikkimSure, without water corrosion will not occur. But if you ride on wet and salty roads it's a different story and a little of grease will help, it's not bulletproof but better than nothing. Did you ever try removing a threaded aluminum bottom bracket installed in a steel frame without any grease ? The anodization used to protect aluminum from corrosion in aerospace is done with specific chemicals, it is not just aluminum let oxidizing with salty water ... parts are also covered with protective paint where possible.
Reginald, you should have mentioned a couple of important aspects for newbies that will try to follow your rehauling method.
1. If you like to grease the bearing seat on the axle, MAKE SURE you are not using lithium-based grease. It is better to leave the seat unlubed than to use lithium grease. The water will eventually find its way there. Water is an electrolyte. It takes a little drop to start a galvanic corrosion forming. You will get corrosion in no time. Remember: DT Swiss-style hubs use aluminum axles. Bearing races are made of steel. Different metals + lithium + water = lots of trouble. In extreme cases you wouldn't be able to detach the bearing at all, it will be permanently bonded to the axle.
Therefore, use graphite or calcium grease. Or leave the seat unlubed. The problem is exacerbrated by laziness of some grease manufacturers: they like to NOT include the information on contents of the product. All you get is marketing bullshit like "premium super-duper-ultra-durable special wonderful universal magic grease". If a manufacturer does not say which agent was used, avoid such a grease like a plague. Even if it says it's water-resistant.
2. Calcium grease. Not sure which brand of calcium grease you are using, but usually these are very thick and sticky. Case in point: Divinol. It is a rather sticky and thick grease that does slow bearings down. It is advised not to use this grease on something that has to spin fast (cup-and-cone hubs, bottom brackets, etc). Calcium grease is very good at repelling the water, so you can use these in places where water ingress is likely to occur. Just don't lube fast-spinning bearings with it.
3. Spin tests are completely pointless and indicate nothing. Because bearings are not loaded. You can clean out all the grease from bearings and fill them with ultra-thin sewing machine oil. Your hubs will spin like crazy with very little resistance, but such overhaul will last for only 50 kilometers or so and in the end your bearings will be done.
4. Don't buy hubs with hybrid ceramic bearings. It's a waste of money. Hybrid ceramic bearings are bearings where races are made of steel and balls are made of silicon nitride. Ceramics are way harder than steel (steel is like a sponge to them - that's exaggerated for your understanding) and they will cut through races plenty quickly, so bearings will have a significant play/backlash. Hybrid ceramics don't last long due to that. Full ceramics are better in this regard, but don't forget that all ceramics are brittle and strong impact (hitting a pothole at full speed, for instance) may shatter the bearing like the teacup that was dropped from the table.
I agree. Hopefully they read your comment.
Note, the spin test is not scientific nor does it show real world performance. But… it does show how freely the wheel spins. 😁👍🏻
PS. I did mention I was using Morgan Blue calcium grease, here is what they say about it:
“Firm grease based on Calcium and used for a wide variety of applications. Originally grease used for maintenance in the naval industry. Calcium Grease is used for the general assembly of bike components and the lubrication of moving parts. Ideal for use with bearings, spindles etc.”
😎👌🏻
"4. Don't buy hubs with hybrid ceramic bearings. It's a waste of money. Hybrid ceramic bearings are bearings where races are made of steel and balls are made of silicon nitride. Ceramics are way harder than steel (steel is like a sponge to them - that's exaggerated for your understanding) and they will cut through races plenty quickly, so bearings will have a significant play/backlash. Hybrid ceramics don't last long due to that. Full ceramics are better in this regard, but don't forget that all ceramics are brittle and strong impact (hitting a pothole at full speed, for instance) may shatter the bearing like the teacup that was dropped from the table. "
Not hubs but for bottom brackets:
What do you make of Enduro XD15 bottom brackets? Only asking because they do offer a lifetime warranty on them and if you google em they do have some pretty glowing reviews which tend to parrot things along the lines of, "the longer they're used the better they get". Of course it's probably hard to spend $300USD on a BB and not have a bit of a positive bias towards it...
themtblab.com/2023/04/enduro-bearings-bottom-bracket-test-report.html this article tests a bunch of the bearings used in BBs under perhaps unrealistic circumstances. Not being an engineer myself I don't know how valid a test like this is -- like this "In every instance, one bottom bracket bearing (not two) rotated under 82 kg./180 lbs. radial and 27 kg./60 lbs. thrust loads for a total axial load of 109 kg./240 lbs. This equates to 218 kg./480 lbs. rider pushing a consistent 600 power watts." seems extremely suspect, but then again, maybe testing extremities like that is the only way to actually eke out a difference anyway. (Or, it's the only way that those Enduro bearings can end up on top. Dunno.)
Edit: answering my own questions somewhat: re Enduro's lifetime warranty, "Claims from normal wear, product misuse, abuse, product modification, improper product selection, non-compliance with any codes, or misappropriation will void the warranty." this is a choice quote from their page about product warranties. So there's probably very little that the lifetime warranty could possibly cover that a 1 year warranty wouldn't already -- any bearing failure that didn't already occur in that time would probably just be labelled as "normal wear" or "abuse".
@@quasimal I'm dubious. The article you've presented is sponsored by Enduro, therefore it's biased. They may have created the rig that specifically makes XD15 bottom bracket perform better under specific (very narrow, non-real life) conditions, but the truth is there: material hardness for XD15NWTM is 58-59 HRC (Rockwell scale) and Si3N4 hardness is 78 HRC (Rockwell scale), so the point stands. You should be using regular steel bearings, because they will be more durable in the long run.
Bicycle bearings are subjected to vibrations and impacts. When you hit the pothole or jump over the kerb, bearing balls hit races in very narrow spots (less than a human hair thickness). The same material hardness helps to even out the kinetic energy of the impact, but once the component of higher hardness (ceramic ball) hits softer material (inner and outer races made of steel), no matter the treatment, races get damaged and in the long run develop play/backlash and/or dead spots that prevent balls from spinning freely around the circumference. You are not riding on roads as smooth as glass, so the perfect conditions simulated on the test rig are too detached from the conditions that you will be subjecting to your bearings in real life: water ingress, grime, gunk, sand particles, hits, vibrations, etc.
For the same very reason nobody should ever install fully ceramic bearings in hubs and bottom brackets. Ceramics are hard but brittle. If after serious pothole hit bearings get shattered like a broken teacup, the very next moment you'll get seriously injured. Hubs or bottom bracket get jammed and the bike stops its motion literally on a dime, sending your body into the air. The only application where you can safely use full ceramic bearings is derailleur pulleys.
Bottom line: forget about hybrid ceramics as you are just burning money for no benefit and forget about full ceramic bearings as it poses a deadly threat.
@@tweed0929 Thanks for the reply - all makes sense. Naturally, their fancy stainless bearing also outperform the eclectic competition there, which they attribute to the bigger ball bearings it uses, since the BB cup is used directly as the outer race. Seems like a neat idea at least. Wonder how it compares more to NTN, SKF, etc. ones though. The lifetime warranty thing does also seem to be a bit of a ruse, seeing as though "normal wear" is a warranty-voiding condition (which of course is standard for a warranty, but a bit rich to call a "lifetime guarantee")
I think you are supposed to just hammer the bearings in, with quite a bit of force. Make sure to hit it on the edges. When you start to see aluminium chips forming, you know youre doing it right.
Darn! 🤦🏻♂️
Always good to see in depth vids for jobs like this, thanks for your hard work.
I don't want to troll but I would say that in my experience the DT Swiss special grease is actually Molykote TP-42. It's an anti-seize paste with solid lubricants, designed for metallic friction applications...exactly why it's used for the DT star ratchet. I'd say something like Shimano freehub grease is much more suitable for ratchet / pawl applications.
Also there's a lot of debate on pressing in bearings wet vs. dry. Hope specify greasing the bearing seats, other brands say press in dry. The benefit of dry pressing is if the bearing seizes, it won't rotate in the hub shell and ruin it. What's you take on that?
Excellent comment. Good info. 👌🏻
I feel there are more advantages to a wet press than dray, yes there is a potential problem if the bearings stops moving but normally it’s the axle that suffers in that situation because the tolerance is greater. I have seen plenty of seized bearings but never one that rotates in the bearing seat. (So far!) 😁👍🏻
How does a “professional bike mechanic” not have over axle presses. Also using DT special grease on a pawl and spring setup is not advised by any manufacturer.
Because it’s a small shop and it takes time to justify the cost.
Well, DT Swiss use it on ALL their hubs with and without pawls so what do you think the problem is exactly?
If you don't need that internal reduction in the drift cup, a drill press will make the internal diameter the same all the way through. No problem...
I think I follow. 👍🏻
Hello, is the axel the same as the d67? Mine has a small amount of movement side to side and I’m having a problem getting the disc to stop running. Could this be that the bearings need to be pressed in more?
Thanks
The disc and rim have slightly different axes. It might be, but it could also be a manufacturing defect or the same issue
Are u sure dt swiss special grease (for ratchet) is good for pawls?
Yes, you will find the same grease on their pawl hubs.
@@reginaldscot165 on the pawls they use universal grease
Hi all im wanting to change out my bearings on my Hyper 2003 R33,s. Could anyone please give a list of things i need to do the job properly.
I.E a proper bearing press & bearing extractor with the correct over axle press tools. I personally don't want to hammer anything just the way i want to do things.
Same bearing size as of this video 8603/8903 .
Plus what would you go for non contact or contact bearing covers ?
Any help would be great ❤
Depends how much you want to spend on tools? Wheels manufacturing.com will have a kit that will work, but it won’t be cheap. You can find cheaper press kits on Aliexpress.
The cheaper the better as I'm only a home user. I just don't know what to look for
The dirt grinding when removing/reinstalling the cassette drives me nuts. I swap my cassette between my trainer and my wheel several times a week and I clean off the hub and put a small amount of grease back every time. Maybe you are on to something with not applying grease.
The cassette should be seated on dry.
Sounds like you need to pick up some second hand kit from online! Sure you could get yourself a cheap cassette to solve your problem? Or perhaps a cheap Chinese one from Aliexpress/Amazon? 🙂
I have a few cassettes. I'm trying to keep my chain matched to my cassette at all times. I noticed that when I switched from bike to trainer the mismatch of the cassette was causing my chain to wear quicker, and I'm worried that will in turn wear my new cassette and chain unevenly.
Wasnt hammering bearings a bad thing? You even have several videos about different bearing presses. What happend to using them?
The ones I had when making this video do not fit this situation. And using a mallet is fine as long as the drift you use supports the entire surface of the bearing and drives them in straight. 🙂👍🏻
It's better to call it copper grease because anti seize isn't specific. It could be anything.
Bingo. Then use anything. Or specifically use copper grease
@@TobiMcTobeface I use lithium grease because I have a big tube of it.
True 😁👍🏻
Where did buy your ntn bearings from?
See part (1) 😁
You are full of contradictions! “You can’t have too much grease”, “Always use grease in metal to metal applications” - then you don’t put grease between the cassette and the free-hub body because it attracts dirt! Make your mind up! You use way too much in most areas, and not enough in others.
I hardly think 1 constitutes “full.” 😂That’s why I explained each of my actions and mentioned in the text that their are exceptions. Yes, grease attracts dirt on the outside of the hub but the same rules don’t apply inside the hub! I’m sure you can understand that concept? (Hopefully) 😁 If you do it better then you have no need to follow my advice. 👍🏻🙂
@@reginaldscot165 So you could say that contradiction is not the only thing you’re full off!
Grease on the freehub body definitely doesn't serve any clear reason. Just torque down the lockring properly, and there will be no movement, and the cassette shouldn't be eating into the freehub body.
That´s a lot of grease, carefull, not that them 8 grams are gonna slow you down.😅 Aluminium dose not rust! Like any metal, aluminum forms a natural oxide layer when it comes into contact with oxygen. In contrast to steel, the corrosive layer comes to a halt after approximately 2.5-4 nm, protecting the underlying metal from corrosive destruction. This layer remains stable in the pH range of 4.5 - 8.5, which means that it is not attacked by corrosive gaseous or liquids, therefore greasing the axels was not necessary and a waste of time and resources.
Yes I know aluminium doesn’t rust. 🙂 (I meant corrode)
I think you might be mistaken about greasing the axle being a waste of time? I presume you saw the damage water had caused to the axle in part 1? Also the steel bearings sit against the axle so it’s definitely wise to grease it, not to mention it’s rotating. 😁 And have you never see holes all the way through an aluminium bar caused by corrosion? Perhaps you are mixing up titanium with aluminium? 😉
@@reginaldscot165 The handlebars break do the sweat and the salt in it, the salt lowers the pH range, Water alone cant damage aluminiun like that. There was no damage on the axle, that was the natural oxidation layer of aluminium. WHAT DO YOU NOT UNDERSTAND WITH THIS SENTANCE? ---> In contrast to steel, the corrosive layer comes to a halt after approximately 2.5-4 nm, protecting the underlying metal from ""corrosive destruction"". This layer remains ""stable"" in the pH range of 4.5 - 8.5, which means that it is not attacked by corrosive gaseous or liquids
@@66mikkim From SAE: "Although aluminum on its own has inherently superior corrosion resistance to steel, galvanic action between the aluminum and steel or galvanized parts can lead to severe corrosion". The mean pH of sweat is 6.3 but still it corrodes aluminum due to the salt content. To prevent aluminum corrosion special galvanic passivations are used and where possible parts are painted too. This is done with great care for aerospace components where corrosion may lead to cracking.
@@PaoloLuraschi and that is basically what I wrote.
As long as there is no fluid that benefits galvanic corrosion,there is no need to grease aluminum, not even then when it is in contact with Steel. The oxidated aluminum protects itself, even in aerospace parts, the anodized layer ist just a other, harder oxidated layer.
@@66mikkimSure, without water corrosion will not occur. But if you ride on wet and salty roads it's a different story and a little of grease will help, it's not bulletproof but better than nothing. Did you ever try removing a threaded aluminum bottom bracket installed in a steel frame without any grease ?
The anodization used to protect aluminum from corrosion in aerospace is done with specific chemicals, it is not just aluminum let oxidizing with salty water ... parts are also covered with protective paint where possible.