Mountain Bike Reviews Forum banner
Cancel
Create thread New Forums

How do you service rear hubs.

Jump to Latest
1 - 17 of 17 Posts

S!lver

· Registered
Joined
·
12 Posts
Discussion starter · #1 ·
Hey guys. First if this is the wrong category please move. I’m wondering how you guys service your rear hubs.

so it’s time to service the rear Hub. You take the wheel off. You take the free hub off and you want to clean everything (paws, springs and teeth) and regrease. What do you guys use. Do you just wipe away all the old dirty grease? Do you pull out a can of wd40 and spray away then wipe down? Do you use something else.

this questions goes for any type of rear hub that can be serviced and has sealed bearings.

I ask bc the searches on YouTube show a lot of people pulling out a can of wd40. Spraying it and wiping it all down. The issue with this is the potential of getting wd40 in the bearings and messing them up. But just wiping down doesn’t get all the dirty grease out very easily.

second questions. What grease do you guys use for reassembly?
 
#2 ·
Yikes, depends on the hub!

I would keep WD-40 well away from bearings, as it will get in there and mess them up.

I generally pull the axle, wipe the crud out of the pawls, drip some good quality lube on them, and check the bearings for smoothness. They don't have to sping fast, just smooth. If they feel gritty, replace.
 
#4 ·
I also avoid a degreaser in the hubs and bearings as you don't want that staying in there with the new grease. I'm not too concerned with used grease in terms of getting it all out, but if it's contaminated/gritty then I'll make a better effort of cleaning it all out.

I do feel my bearings and if they're not smooth I'll pop off the seal, wipe what I can out and grease about 1/3 to 1/2 of the bearing. I just use any standard grease, though you could probably get something more specific (I have Park Tools polylube 1000 and muc off bio grease in my toolbox at the moment).

The hub drive is going to be a bit more particular to brand and type of drive. Ratchets for example only need a fine film of low viscosity lube/grease, pawls probably have a bit more leeway with what you use. On my pawl hubs I've been trying a bit of slickoleum mixed with gear oil as I've wanted to silence them a bit.
 
Save
Reply Quote Like Like
#6 ·
As far as cleaning: if you aren't punching out the bearings (if applicable for your hub--not all are cartridge bearings), you would generally wipe away old grease, and use solvent only locally if necessary to remove heavy buildup (which a drive ring shouldn't have unless it has sat neglected unused for several years). A hub being completely rebuilt can be cleaned using degreaser in most cases.

Q-tips (cotton buds) are an excellent tool for the above work on your average pawl type hub. They can be trimmed/sharpened to the shape required using a utility knife.
 
#7 · (Edited)
WD40 is over 50% solvent, and maybe 30% mineral oil. The solvent thins out the oil so that it can penetrate. When the solvent evaporates, what's left is a thin film of mineral oil, which can be barely considered a light machine oil.

I recall Chris King saying that WD40 can be used to flush actual bearings of old grease, to be replaced with actual grease. I figure that it's better than straight up solvent, since the metals aren't ever 100% stripped of protective lubricant like it would be with degreasers and other harsh cleaners.

The metal has a chance to "cold weld" when stripped of lube, especially stainless steel that has minimal air between touching surfaces.

There's something called hydrogen embrittlement that happens when stripped and submerged in water too, especially with soapy with detergents which contain sulfides--many brands of dish soap have sulfides and even salts, check the msds (e.g. Dawn has sulfuric acid and sodium hydroxide). I recall Simple Green being blamed for hydrogen embrittlement on military aircraft, even leading to the loss of aircraft (e.g. helicopter bodies that showed cracking, but they were maybe made of a secret high grade of alum). People using it to clean chains were confused as to why their chains were cracking in multiple places over time, despite "meticulous maintenance".

In comparison, WD40 is a much more metal-friendly cleaner, when it comes to avoiding issues caused by stripping metal bare, at least on surfaces that need to be lubricated for real afterwards. The concentrations of harmful chemicals might be quite low in the other cleaners for the makers to think it's generally safe, but the miniscule damage adds up over time. There are oils that you don't want to strip out of the bike, like oils in rubber and exterior finishes that keep them from drying out.
 
#8 ·
I guess the thread you were referring to was about cleaning Chris king hubs which have bearings with accessible balls and which can be completely accessed, cleaned and then relubed.

Id keep solvents and wd40 away from cartridge bearings and non disassemblable free hubs, any lubed space That wd40 is allowed to seep into must be relubricated because the solvent thins and cleans away the grease.
 
Save
Reply Quote Like Like
Discussion starter · #9 ·
Thank you for all the good reply's

The hubs I have are Reynold hubs. I have had CK hubs in the past and you can tear them completely down so using wd40 can work as long as you are planning on regressing everything.

From what most people say I would stay away from wd40 in for cleaning unless you are replacing bearings. q-tips are a good idea. Sounds like just a thorough wipe down is the best we can do for intermittent cleaning.
 
#12 · (Edited)
Some hubs don't come with manuals that state regular maintenance. They have a design that mostly uses non-serviceable components, like cartridge bearings, that you replace, rather than clean and grease, etc.

I've seen hubs that had a lot of contamination inside due to being ridden on the East coast (USA), whereas hubs used in the SW USA look clean inside. If I were to buy used parts, I'd be checking the location that it was ridden...

I've heard of people removing the rubber seals on cartridge bearings, carefully prying the seal's lip out of the groove, and trying to clean and regrease it. I'm sure they'll say that it helps more than it hurts, and that knowing the condition of the bearings is better than not knowing, but...
 
#13 ·
The vast majority of my cleaning involves simply wiping things off. I only pull out stronger cleaners or solvents for very occasional (maybe annual) thorough cleanings.

Right about now tends to be when conditions change over from being more persistently damp to the more summer-like pattern of alternating between wet and dry. It's a good time for a thorough cleaning. So I'll be tackling a bunch of jobs piecemeal over the next week or so. Cleaned and greased my headset and some cable guides today to eliminate a creak when steering (successful job - it was coming from the cable guides). I only wiped out the old grease in the headset. No need for anything else. I used some isopropyl alcohol to get some help with the cable guides.

One of the next ones will be my hubs (I9 Hydra). It's mostly going to involve wiping off the old stuff, but I might get some solvents out to clean off the pawls and springs. Q-tips will be used on the nooks and crannies in the freehub body, maybe with a little solvent to help loosen persistent grime. Dumonde Tech freehub grease to re-lubricate, and done.
 
#14 ·
I recall Chris King saying that WD40 can be used to flush actual bearings of old grease, to be replaced with actual grease. I figure that it's better than straight up solvent, since the metals aren't ever 100% stripped of protective lubricant like it would be with degreasers and other harsh cleaners.
Click to expand...
I did some experimenting with this once on a hub bearing and the results weren't all that great. I removed the exposed seal, flushed the bearing with WD40, and injected new grease. Then I extracted the bearing, removed the hidden seal, and took a look at the result. The hidden side still had most of the old grease and it seemed compromised by the WD 40.

If you have a crunchy bearing, I guess it can't hurt to give this a try. But otherwise, I'm not so sure it's a good idea.

Also keep in mind, that removing a bearing seal always damages it a little, no matter how careful you are.
 
#15 ·
bayposter said:
I did some experimenting with this once on a hub bearing and the results weren't all that great. I removed the exposed seal, flushed the bearing with WD40, and injected new grease. Then I extracted the bearing, removed the hidden seal, and took a look at the result. The hidden side still had most of the old grease and it seemed compromised by the WD 40.

If you have a crunchy bearing, I guess it can't hurt to give this a try. But otherwise, I'm not so sure it's a good idea.

Also keep in mind, that removing a bearing seal always damages it a little, no matter how careful you are.
Click to expand...
I also noticed at first that I couldn't get the bearings clean, which is why I really soak them now. I'm pretty sure there's no grease or dirt left but it takes two minutes of work, not a casual squirt. I keep spinning and spraying until nothing comes out onto my white towel.

I spray thoroughly with wd40, then once I believe its clean I hose it all out with isopropyl, then let it air dry. I don't use pressurized air because my compressor doesn't have a drier and what comes out is pretty wet.

I am always amazed how frighteningly creaky and grotty the bearings feel once they're really clean. Then just a small amount of grease and they turn back into butter.

Edit: Oh didn't realize you were talking about regular cartridge bearings... I've also never had success cleaning them out but probably because by the time I do they're all crunchy nuggets and no longer round. It definitely works to clean out ck bearings.
 
Save
Reply Quote Like Like
Discussion starter · #16 ·
I haven’t serviced cartridge bearings in a hub before but I’ve done a lot of pivot bearings. They are sealed and the dust covers pop out pretty easily. Once the bearings are exposed I do the same as you. Wipe clean isopropyl then regrease. The dust covers are a bit of a trick to not damage but a small wooden pick does the trick and doesn’t damage anything.

I’m pretty sure to service hub bearings you have to pop them out first. At that point it’s probably easiest to just replace.
 
#17 ·
S!lver said:
I haven’t serviced cartridge bearings in a hub before but I’ve done a lot of pivot bearings. They are sealed and the dust covers pop out pretty easily. Once the bearings are exposed I do the same as you. Wipe clean isopropyl then regrease. The dust covers are a bit of a trick to not damage but a small wooden pick does the trick and doesn’t damage anything.

I’m pretty sure to service hub bearings you have to pop them out first. At that point it’s probably easiest to just replace.
Click to expand...
Pressing/pulling bearings isn't hard with the proper tools. Neither is popping off the seal. Trashing a perfectly good bearing is silly, but people do it all the time.
 
1 - 17 of 17 Posts
About this Discussion
16 Replies
11 Participants
Last post:
noapathy
Mountain Bike Reviews Forum
posts
16M
members
534K
Since
1990
A forum community dedicated to Mountain Bike owners and enthusiasts. Come join the discussion about bike parts, components, deals, performance, modifications, classifieds, trails, troubleshooting, maintenance, and more!
Full Forum Listing
Explore Our Forums
General Discussion Downhill - Freeride California - Norcal Shocks and Suspension Passion