HerrKaLeun

I have a fatbike with cartridge bearings. I believe it has 4 or even 5 bearings in the rear. I want to remove them, inspect, possibly re-grease. So the removal must not destroy it.

It is my understanding pulling on the inner race ruins the bearing. I realize they are not designed to be serviced and upon removal one usually installs new ones. But i still want to do it without destruction. For one to see how it all is made, what condition grease is in etc.

there are V-Pullers, there are blind pullers and there are the methods of jsut hammering them out.

The V-puller and blind puller seem to pull on the inner race. Or am I missing something? How would they not ruin the bearing? And chiseling them out from the other end would also have the risk of accidentally hammering on the inner race. With 4 bearings I'm also not sure how i would push the outer ones out while navigating through the inner ones (I'm not 100% positive on having 4 cartridges, just read somewhere, is a novatec hub)

What options do i have to remove the bearings without ruining them and what exact tools would I need?

wesmamyke

I don't think you'll have much luck, press fit bearings damage very easily upon removal. You would need access to the outer race, and that's impossible in most hubs.

The only time you can pull bearings just to inspect is when they are not press fit, like most cartridge headsets for example. I have one cartridge bottom bracket that pops apart without tools, but that's not common.

Why not just pull the seal off the outer most bearing? You can check things out, if for some reason it looks bad you can dive in and pull the rest of it apart.

Edit: Some press fit bearings can be pulled and repressed, BMX bottom brackets with huge bearings will tolerate that to some degree. They also have a very loose press fit, loose enough that they come out when you didn't intend them to.

sweeks

Have you tried checking the hub manufacturer's web site for service instructions?
If there are no signs of problems with the bearings, and the axles spin smoothly with the wheels off the bike, I'd be tempted to leave things alone. Cartridge bearings aren't meant to be serviced other than replacement. Of course, you can add grease, but just adding grease to a failing bearing without thorough cleaning simply postpones the inevitable.
Steve

FBinNY 

It's a myth that pulling on the inner race harms the bearing.

This isn't an invitation to pound on it with a steel hammer, but pullers used properly aren't a problem.

HerrKaLeun

I didn't find a manual (and couldn't find the specific manufacturer link again) but recall they didn't have documents. But I found a catalog page that indicates it has 5 bearings. I think i will start by just opening it up and seeing what I can see without any removal.

i got this idea while reading "zinn and the art of MTB maintenance" and he shows them to be tapped out with an allen key or similar.

FBinNY: interesting point, even when that is contrary to most sources. but that is how myths work :-) I guess I will see if i feel brave or not.

xenologer

assuming 2 in the freehub
and 2 for the hub shell
where's #5?

also, I've tapped a cartridge bearing out with a hammer and punch against the inner race.
It felt grindy after doing that.
Thankfully, they were angular contact (yours probably aren't) and that grindy sensation wore away eventually.

cyccommute 

Honestly, don't. There is simply no need for servicing cartridge bearings. Ride them until they wear out and replace. You can pry off the seal and add grease but even that may compromise the seal. Just ride them.

Not in my experience. Although I usually don't take bearings out unless they need replacement, they can be reused in a pinch. Press fit cartridge bearings don't need a lot of force to remove and as long as you don't go Barney Rubble (i.e. tap them out) on them, you should be fine.

Or, again, just leave them be.

sweeks

FB is right. The thing that kills bearings when they are hammered on is the high loads that are applied; these are essentially "shock" loads which can result in dimpling of races and flattening of ball surfaces. A bearing puller applies the necessary force more gradually and uniformly, so bearing damage may be avoided.

Another example of this is something I was taught years ago about removing cotters from cranks in the absence of a special tool. The crank is supported by a piece of steel pipe while rapping on the threaded end of the cotter; this allows the shock loads to be absorbed by the pipe and not the bottom bracket bearings.
Steve

cny-bikeman

Given even the potential for damage to the bearing or the seating surface, the time and trouble involved, and the questionable benefit, I don't see any good reason for removal. As suggested just pry off the seal and grease if you want to. Inspection of the bearing will yield little info, and if you want to know "how it is made" the Internet will show you cross sections, exploded diagrams, videos of the manufacturing process, etc.

IrishBrewer

When I overhaul a bike's bearings, I always remove, clean/replace and regrease loose and caged bearings. However, with cartridge bearings, if they feel buttery smooth, I just clean up around them as much as possible and leave them alone.

Kontact 

I don't understand doing this. Cartridge bearings are not designed to be inspected and serviced, they are designed to be used until they need replacement. You're just going to make the hub worse by goofing with them.

maddog34

how do you know that the bearing needs replaced if you never inspect it?

most bicycle ball bearing assemblies have "rubber" seals that are removable and reusable, if removed carefully.
the old grease can be flushed out and replaced.
the time consumed doing so, compared to the cost of the new bearing, is the determining factor to most folks as to whether it worth doing or not.

if the bearing is rough to turn, notchy, or "loose but gritty"... trash it, get a new bearing.

try measuring the bearing, then searching around for the same size with the same seal configuration... "RS" means one rubber seal, "2RS" means two rubber seals, (there are steel "sealed" ones too, actually just dust covers!))etc. Bicycle parts suppliers tend to put the standard, easily sourced, bearings into their own packaging, then nearly double the cost of those common bearings... Headset and some Crank bearings, are the tricky ones to find aftermarket.... Wheel bearings are at large hardware and auto parts stores even, sometimes

all that said... high impact side loading of ANY ball bearing assy. WILL DAMAGE the bearing... the degree of that damage may be below someone's threshold of detection, but it WILL be there.... the very tiny balls and races in external crank bearing designs, and headsets? those little things will almost certainly be damaged if pounded on at just the inner race, when seated on the outer race.ball bearings don't like heavy side loading... there are special designed (deep channel) ball bearings for higher side loads, but they are expensive due to the hassle in constructing them.... they still wont like being beat on.

wschruba

I definitely agree that there is little benefit to be had in 'servicing' a cartridge bearing outside of simply replacing it. It is not hard to tell by feel if a cartridge has grease left in it/has excessive wear. Outside of the (sometimes) specialized angular contact bearings (sometimes) found in hubs, headsets, and bottom brackets, radial cartridge bearings are not expensive to replace.

But, consider: in almost every [cartridge bearing] hub on the market, 3/4 of the bearings typically found in a rear hub (hubshell bearings, outer freehub bearing) are accessible from one side for removing a bearing shield. Probably close to 90% of that number have a shield available to be removed on all four bearings. There is little to be gained in completely removing the bearing cartridge and both shields to clean it.

Kontact 

The "inspection" is feeling how the hub axle turns. If it doesn't feel smooth, it is time to replace the bearings.


The difference between a cup and cone hub and a cartridge bearing is that the races of the cup and cone aren't sacrificial. If you wait until the hub feels bad, you have damaged the major components of the hub. With a cartridge bearing it doesn't matter how damaged the races get - they are disposable. And cheap. And usually last longer than the overhaul interval of a cup and cone.


Removing cartridge bearings and tearing the seals out is like removing the grease from a loose ball system and then stuffing it back in. All you're doing is shortening the life of the cartridge bearing and doing unnecessary labor when there is zero downside to just letting the cartridges wear out.




This is a similar problem to solvent cleaning chains. Sure, you can feel like you are really a maintenance super-star, but all you're actually doing is rinsing the deep lubrication out of the rollers. I sincerely doubt banging cartridges out, opening the good seals and replacing a little grease is doing anything but shortening the life of the bearings.

HerrKaLeun

I have no idea where the 5th is. But look at page 20 for the D202SB and it says 5 bearings, 4 pawls. Also their 177mm hub next to it has 5 bearings.
Ironically some months ago i took the hub apart (described here) but didn't think of caring baout bearings at all on an all new bike.

I think you and almost everyone else convinced me to just leave them as they are. chances are with the cleaning procedure (degreasing etc.) there is some chance to screw it up by leaving some degreaser in, or by diminishing the seal etc.

If I ever need bearings, how do I find the correct size? Ideally I order them before taking the old ones out. The hub catalog says 2x6902 and 1x15267. This brings me to 15x28x7mm bearings on amazon etc. I assume 15 mm is inner diameter, 28mm outer and 7 mm is thickness. But the TA is 12 mm (this is rear hub, not front). Am I missing something? Shouldn't it be 12 mm inner diameter?

And is there a special grade or standard to use? Or can I just buy any industrial bearings of the correct size? Like for cup/cone I use Grade 25. Or what brand is good? I see $1.99 and $10 bearings.

Thanks for all the replies, good discussion and I learn a lot.

maddog34

find quality name brand bearings... Fafnir, Timken, F.A.G., NKS, Koyo, SKS... all good. NO brand name seen? AVOID THEM!
PRICES vary quite a bit... i go to Bearing Distributors to buy bearings... yes, they sell to the public also.
tell them into what you will be installing them into... sweat fit bearings are looser before install, press fit a different tolerance, and so forth... bicycle uses are a loose press fit.

i regularly remove the "seals" from ball bearing assys. to change the grease out for more and better grease... some arrive nearly empty. the "seals" are usually not waterproof , and are called "dust covers" on a parts list.
Seriously, a DUST COVER... water can and does migrate right past the seals. They can be gently prised out of the bearing, then pressed back in with your fingers after regreasing the bearing... this is 40 years of experience talking, not rumors or what some magazine article or blog printed.

tap the bearings out with as little force as possible... i use either a three point tapping, or four point... top, bottom, then left, right.... don't get greedy, work slowly and evenly...the smaller the balls in a bearing, the more likely it is to be damaged during removal... some inner races will collapse enough that they pop right out, tiny balls rolling all over the place!

The single most common cause of premature bearing failure? PRESSURE WASHING the machine in question.... the machine sure looked shiny afterward though!
A good quality bearing that is installed correctly, and not overloaded in it's use, will last many years.
Shoot 3000lb/sq in. water at it, and you might as well order fresh bearings immediately... 'cuz you gonna need 'em soon.........

modern external bearing Bottom Bracket bearings are TINY balls, in a fairly shallow channel, with tiny, weak seals... they fail about once a year... they are overloaded, and experience higher side loading than recommended. I found i could slow the failures by adding fresh grease via a GREASE NEEDLE, and smearing the outer dust seals with good waterproof bike grease every month or so... GXP BB and crank set, CX bike.... the Shimano BB's hold up longer than the GXP BB's... about twice as long, actually... i finally convinced that rider to quit pressure washing his bike after we refreshed both wheel bearings... and then, one week later, i pulled the front apart right after he had P. washed that bike... the hub was full of water again........ Fresh Ultegra hubs and re-lacing a wheel is not cheap, eh? Ultegra hubs of that age feature a sophisticated seal design.....

cyccommute 

I have no idea what the numbers stand for but they are linked to the size of the bearing. A "6902" is the 28x15x7 (ODxIDxthickness) mm bearing. The "15267" is a 26x15x7mm. The 26mm OD bearing is probably for inside the freehub which needs to be a little smaller.

The 15mm ID diameter is fairly standard in my experience when it comes to the axle for bicycle wheels. TA may be measuring the ID of the axle but that seems a little weird.

As to the cost, I doubt that it matters all that much. The $10 bearing is probably ceramic and might last longer but the cheap $2 bearing is probably going to last roughly 50,000 miles any way...again based on my experience...so going cheap isn't going to cause any problems just as going with the more expensive bearing isn't going to break the bank.

Dave Mayer

If you can clean out and regrease the cartridge bearings in-place, then this is absolutely what you should do. It will take minutes to perform, and potentially add tens of thousands of miles of life to the cartridges.

I've done this dozens of times on many different parts assemblies. All you need to pull this off is a tiny flat-blade screwdriver to pop the seals, some good degreaser (nothing water-based), some replacement grease, and a little patience.

Spending a few minutes on this will avoid having to deal with replacement of the carts a year from now, and then having to make multiple trips to multiple bike shops so that you can beg them to take $100 of your money to replace a couple of bearings that they’ve sourced direct from China for $5.

Reynolds 

As said above, pulling cartridge bearings by the inner race doesn't damage them if done properly, IME.

ThermionicScott 

That's interesting. The disc brake mount is so far away from the left flange, I wonder if there are separate bearings to support each.

fietsbob

If you Press the bearing out, then it wont be damaged, <guess> they likely used a press to install it..

Arbor Presses are a tool Shops use, one in many Auto service and machine shops.