To the Point: Cartridge Bearings
Cartridge bearings are an integral part of the modern mountain bike. From headsets to hubs, bottom brackets to suspension pivots, cartridge bearings can be found on nearly every component whose purpose includes some type of rotation. We often take for granted the stresses and harsh conditions mountain bike bearings endure, rarely thinking about them until they make noise or develop play, typically after countless hours of abuse. To find out more, we spoke with Matt Harvey, one of the owners of Enduro Bearings, an industry leading company that offers an extensive line of bearings specifically designed for bicycle applications.
What are cartridge bearings?
What is the ABEC scale? For bicycles, what are the advantages of using higher rated bearings?
What do the numbers on a bearing mean? For instance, 6802RS.
How water resistant are cartridge bearings? Will washing your bike with a hose force all the grease out?
Why does play develop when a bearing is worn out? Are the balls themselves worn down?
What are angular contact bearings? What are the advantages of this design?
What are the benefits of ceramic bearings? It seems like when they first came out they garnered a lot of press, but now you don't hear as much about them. Any thoughts as to why this may be?
www.endurobearings.com
What are cartridge bearings?In the bicycle industry, cartridge bearings refer to a bearing assembly that can be entirely removed
and replaced into the component such as a hub or bottom bracket. Traditionally, each bearing
assembly in a hub would consist of four separate components; a cup, a cone, a retainer and balls. Each
of these components (with the balls being held by the retainer) would be assembled as individual parts and
then adjusted with nuts and threaded axles on a hub or spindle assembly. Cartridge bearings replace
this four component assembly with one complete unit that is sealed with rubber seals. A radial
cartridge bearing consists of an inner and outer race, a retainer holding the balls and then two seals to
keep the grease in and the elements out. There is no adjustment feature for these bearings as they
are made with internal clearance or play. They are typically mounted by pressing them into a bore,
such as both sides of a hub flange, and then a slip fit axle is run through with stops behind the inner
race of each bearing. Nuts or top caps lock the bearings and axle into place. Again, there is some
internal play when they are tightened down. When the bearings wear out or they get rough or
contaminated, they can be removed entirely for servicing or replacement.
and replaced into the component such as a hub or bottom bracket. Traditionally, each bearing
assembly in a hub would consist of four separate components; a cup, a cone, a retainer and balls. Each
of these components (with the balls being held by the retainer) would be assembled as individual parts and
then adjusted with nuts and threaded axles on a hub or spindle assembly. Cartridge bearings replace
this four component assembly with one complete unit that is sealed with rubber seals. A radial
cartridge bearing consists of an inner and outer race, a retainer holding the balls and then two seals to
keep the grease in and the elements out. There is no adjustment feature for these bearings as they
are made with internal clearance or play. They are typically mounted by pressing them into a bore,
such as both sides of a hub flange, and then a slip fit axle is run through with stops behind the inner
race of each bearing. Nuts or top caps lock the bearings and axle into place. Again, there is some
internal play when they are tightened down. When the bearings wear out or they get rough or
contaminated, they can be removed entirely for servicing or replacement.
What is the ABEC scale? For bicycles, what are the advantages of using higher rated bearings? The ABEC scale and ratings refers to a number of tests and tolerances for radial ball bearings including
measuring their individual components, assembled components, and tests such as high speed
noise testing. Basically, these ratings refer to roundness tolerance of the inner and outer races,
trueness of the raceways, and radial and axial runout of the races. While the ABEC scale traditionally
has been used to pick out the best bearings for high speed applications, this does not directly apply to
bicycle bearings, which are considered a low speed application. But, the scale does give an idea of the
general level of precision and quality of the bearing. There are some other features which are more
important for bicycle application such as ball groove depth, ball complement (diameter and quantity
of balls) surface finish of the raceways, type and quantity of grease, design of seals, etc..., which
are not factored into the ABEC rating. Most high ABEC tolerances require the bearings be mounted
into high tolerance, ground surfaces with highly accurate spindles and bores to take advantage of the
precision level and trueness, which most bicycle components do not have, as they are machined parts.
In general, an ABEC 5 bearing is much more precise and accurate than the part it is being installed into.
Higher ABEC level rated bearings are higher precision and have tighter tolerances.
measuring their individual components, assembled components, and tests such as high speed
noise testing. Basically, these ratings refer to roundness tolerance of the inner and outer races,
trueness of the raceways, and radial and axial runout of the races. While the ABEC scale traditionally
has been used to pick out the best bearings for high speed applications, this does not directly apply to
bicycle bearings, which are considered a low speed application. But, the scale does give an idea of the
general level of precision and quality of the bearing. There are some other features which are more
important for bicycle application such as ball groove depth, ball complement (diameter and quantity
of balls) surface finish of the raceways, type and quantity of grease, design of seals, etc..., which
are not factored into the ABEC rating. Most high ABEC tolerances require the bearings be mounted
into high tolerance, ground surfaces with highly accurate spindles and bores to take advantage of the
precision level and trueness, which most bicycle components do not have, as they are machined parts.
In general, an ABEC 5 bearing is much more precise and accurate than the part it is being installed into.
Higher ABEC level rated bearings are higher precision and have tighter tolerances.
What do the numbers on a bearing mean? For instance, 6802RS.The numbers on a bearing refer to the series, dimension, and then the type of bearing. For instance,
6802 2RS refers to a bearing which is 15x24x5 mm with 2 rubber seals. "6800" is the series beginning
with a 10 mm bore. The increments go 10 (6800), 12 (6801), 15 (6802), 17 (6803), 20 (6804) and then
5 mm bore dimensions from there. A 6804 has a 20 mm bore, a 6805 has a 25 mm bore (5 x 5 mm = 25 mm),
etc. The 6800 series is called Extra Thin Line Bearings and 6900 would be Thin Line Bearings (larger section,
heavier duty bearing. A 6902 2RS would also have a 15 mm bore, but with a bigger ball, and has a 28 mm OD.
Finally, 2 RS literally means: Two (2) Rubber Seals. You may also find bearings with a number like 61802.
Here at Enduro that is how we designate our ABEC-5 line of bearings but dimensionally the 6802 is the same
as the 61802.
6802 2RS refers to a bearing which is 15x24x5 mm with 2 rubber seals. "6800" is the series beginning
with a 10 mm bore. The increments go 10 (6800), 12 (6801), 15 (6802), 17 (6803), 20 (6804) and then
5 mm bore dimensions from there. A 6804 has a 20 mm bore, a 6805 has a 25 mm bore (5 x 5 mm = 25 mm),
etc. The 6800 series is called Extra Thin Line Bearings and 6900 would be Thin Line Bearings (larger section,
heavier duty bearing. A 6902 2RS would also have a 15 mm bore, but with a bigger ball, and has a 28 mm OD.
Finally, 2 RS literally means: Two (2) Rubber Seals. You may also find bearings with a number like 61802.
Here at Enduro that is how we designate our ABEC-5 line of bearings but dimensionally the 6802 is the same
as the 61802.
How water resistant are cartridge bearings? Will washing your bike with a hose force all the grease out? It depends on the grease and the seals that are used. "2RS" means Two Rubber Seals, but there are
many types. The usual 2RS seal is a single lip which runs dynamically on the outer part of the inner race,
the outer lip is static, and fits into a groove of the outer race. Enduro makes an LLB or LLU type, which is a
double lip seal that rides in a machined groove on the inner race. This, along with a water resistant or
marine grease will make it much more difficult for the grease to wash out of the bearing even when pressure
washing. That said, bearings ridden for long amounts of time in the rain or pressure washed again and
again will eventually need to be serviced depending on how often this occurs. Water will creep into any
sealed system given enough time in a wet environment. Using heavy degreasers and soaps will
also cause the grease to break down quicker, so be careful about what you spray on your bearings.
Here are the 4 variations of seal design that Enduro offers, LLU being the most effective at keeping water
out and contaminating the bearing:
many types. The usual 2RS seal is a single lip which runs dynamically on the outer part of the inner race,
the outer lip is static, and fits into a groove of the outer race. Enduro makes an LLB or LLU type, which is a
double lip seal that rides in a machined groove on the inner race. This, along with a water resistant or
marine grease will make it much more difficult for the grease to wash out of the bearing even when pressure
washing. That said, bearings ridden for long amounts of time in the rain or pressure washed again and
again will eventually need to be serviced depending on how often this occurs. Water will creep into any
sealed system given enough time in a wet environment. Using heavy degreasers and soaps will
also cause the grease to break down quicker, so be careful about what you spray on your bearings.
Here are the 4 variations of seal design that Enduro offers, LLU being the most effective at keeping water
out and contaminating the bearing:
Why does play develop when a bearing is worn out? Are the balls themselves worn down?Most times, it is the bearing raceways that are worn out when play develops. While the balls can wear
too, they are generally harder than the raceways and will wear the races out first. This is especially true for
ceramic balls, which are seven times harder than the raceways. This can be avoided by maintaining a proper
amount of grease in the bearing.
too, they are generally harder than the raceways and will wear the races out first. This is especially true for
ceramic balls, which are seven times harder than the raceways. This can be avoided by maintaining a proper
amount of grease in the bearing.
What are angular contact bearings? What are the advantages of this design?Angular Contact cartridge bearings (A/C) more closely resemble the traditional cup and cone bearings
referred to back in point #1. While they can be made as cartridge bearings, until recently they could
not be removed and replaced as cartridge bearings because they would come apart into three pieces when
removed. This made servicing difficult, and if installed backwards, potentially disastrous. Enduro's newly
patented A/C bearings eliminate these problems with a unique design in which they can be removed and
replaced as other cartridge bearings without coming apart. A/C bearings do require a preload system being
either a threaded axle with no inner axle stops, or a spring or wave washer system with no inner axle stops.
With an angular contact hub or axle system designed to use these bearings, they can be adjusted to remove
wheel play. As play develops, they can be readjusted to remove it. While the same can be done with radial
bearings, these will wear out prematurely as the ball is rolling on a thin part of the race. A/C bearings are
designed internally to have the ball located at a 15º angle when preloaded. Because all of the balls are always
loaded on the races, there is always even load distribution.This is not true on a radial bearing with internal
clearance, where some of the balls are carrying all of the weight as the wheel spins. In this way, A/C bearings
will last longer.
referred to back in point #1. While they can be made as cartridge bearings, until recently they could
not be removed and replaced as cartridge bearings because they would come apart into three pieces when
removed. This made servicing difficult, and if installed backwards, potentially disastrous. Enduro's newly
patented A/C bearings eliminate these problems with a unique design in which they can be removed and
replaced as other cartridge bearings without coming apart. A/C bearings do require a preload system being
either a threaded axle with no inner axle stops, or a spring or wave washer system with no inner axle stops.
With an angular contact hub or axle system designed to use these bearings, they can be adjusted to remove
wheel play. As play develops, they can be readjusted to remove it. While the same can be done with radial
bearings, these will wear out prematurely as the ball is rolling on a thin part of the race. A/C bearings are
designed internally to have the ball located at a 15º angle when preloaded. Because all of the balls are always
loaded on the races, there is always even load distribution.This is not true on a radial bearing with internal
clearance, where some of the balls are carrying all of the weight as the wheel spins. In this way, A/C bearings
will last longer.
What are the benefits of ceramic bearings? It seems like when they first came out they garnered a lot of press, but now you don't hear as much about them. Any thoughts as to why this may be? Ceramic Hybrid bearings (steel races with ceramic balls) are still very popular and are here to stay. When
they were first discovered by the bicycle industry, there was a lot of press because they were new. Suddenly,
many companies were offering ceramic hybrids, but like anything, there were some very good ones, and some
very bad ones. There was also a lot of misguided press claiming they would last forever. While they can last as
long as standard steel bearings, in general, good ones will last the same amount of time as an all steel bearing.
However, recently Enduro introduced XD-15 nitrogen steel races, and these will last much longer than steel
bearings with ceramic balls. This steel alloy holds up to the hardness and non yielding ceramic balls, even
without lubrication and exposure to any kind of elements. The Enduro XD-15 bearings will run just as smoothly
a year or two later as the day they were installed, even without service.
they were first discovered by the bicycle industry, there was a lot of press because they were new. Suddenly,
many companies were offering ceramic hybrids, but like anything, there were some very good ones, and some
very bad ones. There was also a lot of misguided press claiming they would last forever. While they can last as
long as standard steel bearings, in general, good ones will last the same amount of time as an all steel bearing.
However, recently Enduro introduced XD-15 nitrogen steel races, and these will last much longer than steel
bearings with ceramic balls. This steel alloy holds up to the hardness and non yielding ceramic balls, even
without lubrication and exposure to any kind of elements. The Enduro XD-15 bearings will run just as smoothly
a year or two later as the day they were installed, even without service.
www.endurobearings.com
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Member since Feb 1, 2009
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Few things:
1) Don't buy bearings from your LBS, they charge you +300%. Also, your OEM bearings will probably be expensive. Measure it out w/ digital caliper, measurements go out to (example): 21.5x31x7mm, Never 21.233x31.344xetc (usually in .25 increments) Decent bearings can be had for around 10 dollars each, not $50 each (for crappy ones)...Chances are, your OEM bearings may be worse than the ones you'll end up buying online (hubs,BB). Once you get the measurements, type it in a "bearing finder" and it'll come up with all the bearings in your size.
2) Ceramic is very nice...but once again, totally not needed. Steel do the job fine! Just as along they aren't super cheapy and are designed to take on physical loads.
3) Sealing job is pretty much the key to the lifespan of a bearing. 2x Lipped w/ Labyrinth. Purchase some Lucas's Heavy Duty Marine Grease (sludge) and slap it on there. If you can, putting a very thin of flimsy plastic cut out to the bearing's dimension and laid over the bearing w/ grease can help a lot in hubs or some BB's.
Try 10-6.50=3.5, 3.5/6.50 = .538
Sooo you're 10 dollar bearing is actually being sold at a 54% margin. Still not 300%... which is a little over the top, but that's a pretty healthy margin. I however, say that margin is fair, and everyone should shop at their LBS.
And that's your LBS, California over here = everything is jacked up in price right from the start.
--> Remember that Margin (difference between Retail/Cost) is different equation from mark-up which: 3.51 = X*6.49 -> 3.51/6.49 = .54 x100 = 54% Markup
My bearings are 80(70+10) for a pair from OEM or through LBS. I find the same ones, for $20 for pair. Same design/stamp on the bearings (brand atleast), 2x Lipped, Decent ABEC, everything good.
$80-$20 = $60/20 = 300% Markup.
Quick recap: we charge $9.99 on bearings that cost us $6.49. So, what is 9.99*0.35? Answer: 3.50. That means that $3.50 is 35% of $9.99, which means we are making a 35% margin, which is exactly what I said. What's 3.50/6.49? Answer: 0.54. That means we are marking up the bearings by 54%, which is what you said, but incorrectly labeled as "margin". So a 35% margin is the same as a 54% markup. Totally confusing, but key terms in the retail environment.
@Spicy-Mike's got it. Good find if you got those bearings for 1/4 of the price your LBS is charging! That's some crazy markup for sure. I bet you got them cheaper than they can, though. There's nothing in our shop that we charge more than 50% margin on, that's 100% markup for those of you following along. Not even clothing, which is usually the highest margin inventory item in most bike shops.
Yeah..the price difference is nuts..just a quick search on Google w/ dimensions yields a good range of price/bearings!
And Ceramic usually can tolerate much higher RPM's and the Ceramic balls (not race) itself is usually more "accurate" + stronger . But, think about, what on your bike has high RPM's? We are talking at the very minimum of 1-3K+ RPM. The only thing that spins completely are hubs and BB's.
Don't invest in ceramic, they won't be noticeable better. Steel bearings w/ good sealing system + decent race/ABEC grade will be wayyyy more than enough and should last very very long. Key part is to get some really heavy duty Marine grease and use that liberally on the bearings/around.
something else to consider about ceramic bearings (as we are on Pinkbike which is predominantly mountain biking) is that many bearing manufacturers actually warn end users about using ceramic bearings in any application with high impact loading (sudden shock)
their reasoning is that ceramic bearings whilst being harder and truer, are actually much more brittle, and this can cause damage to the bearing race
for road bikes and tri bikes they kind make sense (well, not really...its psychological but people like "fast" equipment, especially for extra $100) but for MTB's should never be used, especially for wheel hubs, bottom brackets and suspension pivots which all experience high impact shock loading
And on the ceramic note, from my personal experience, ceramic bearings spin waayyyy nicer than steel. A lot more expensive, but it's pretty sweet when your wheel legit takes like 10 minutes to stop spinning haha
thanks for the information, always good to learn more
most of the "ceramic" bearings I have seen have been the complete ceramic units, its good to know the 'hybrid' units are more durable for shock loading
In my experience, the most reliable cartridge bearings are the ones with the largest gauge balls. Big balls last, small balls fail. Anybody remember the Pig DH headset, it had big balls and lasted forever. The Bearings in my E13 bb use tiny little balls, and I have to replace the bearings every four months or they will SEIZE COMPLETELY.
The Saint loose ball hubs are great if they are maintained and occasionally overhauled, but most riders don't have those skills and even alot of mechanics will over tighten the cones and damage them during the adjustment process so you really have to know what you are doing.
If you still have original saint hubs are you still rocking that direct mount reverse derailleur?
Any mechanic that cannot adjust a cup and cone hub properly should be retrained, that is the first thing you learn at any shop/school. Its more difficult to find the 22mm cone wrenches than it is to adjust the hub.
BTW: I have quality Shimano hubs and... if you don't have time to service them - they are pain in the ass... otherwise love'em! At least with quality cartridge bearings after servicing once a year - you don't have to adjust them, only to readjust them, when the grease gets pushed out after few first rides after the service. People having no "technical savoir-vivre" like patience, feel, curiosity to understand how stuff works, someone to ask for advice - should stay away from Shimano hubs, sell them right away or no later than 1 year after purchase
Anyone here had the experience of removing bearings only for the shell to remain lodged whilst all the innards fall out?
And im talking 6 month to a year frames.
from what I have understood for some years, Enduro is NOT a bearing manufacturer but a bearing re-seller? Having their "name" stamped into the rubber shields, and choosing the bearing package and other features like shielding?
I would always go with SKF, GMN, etc.
I am not a fan of full complement bearings (which Enduro made good business from) as they don't offer advantages on mountain bikes
but offer the disadvantage of premature bearing failure once they are contaminated
(the bearing retainer in non-complement bearing, actually adds a degree of lubrication when a bearing "runs dry" as well as preventing the run dry by resisting 'wash out' retaining more grease), as we found with many full complement bearings especially those fitted to RF products
Of course it applies to some parts, but for the most part, you're better off upgrading to a better but cheaper system.
I currently have a single-pivot Sinister Gruitr that has 2 needle bearings and 2 thrust washers, total. I don't miss that stupid 12-bearing FSR one bit.
Despite your reassurances, I would maintain that a majority of bike mechanics who adjust loose ball hubs do indeed over-tighten and damage the cones, races, and seals during the adjustment process. If you think it's easy and simple to not do any damage then I challenge you to explain your complete hub adjustment technique right here and give me the opportunity to critique it.
I have a feeling that some of the mechanics who think it's easy to not over-tighten during the adjustment process might actually be the ones who are over-tightening during the adjustment process...
You would be amazed the times ive seen a rear hub "adjusted" rather than ensuring regrease and full strip
That's why the diameter of head tube / BB got larger.
And you have to note that; bike components must be light, efficient because it is powered by man kind.
As for ceramic, balls in a steel race not a huge advantage in my opinion, but balls in a stainless race = big advantage as alot of wear in MTB bearings comes from the water contamination causing rusting and therefore premature wear.
Just my thoughs, not gospel though.
with the fsa ceramic bearings- at -10c - much easier to crank over definitely- spin freer.
so what does that mean in terms of watts savings?
have no idea - but for me - im always going to stick with ceramic bearings .
they are also on my road bike as well.
just my 2 cents (if its worth that ! )
A modern example (not to name names) would be a company that makes hub shells for several 'brands' that offer mechanically identical hubs in anodised, painted and plain/cnc'd, but does not ensure the bearing surface is cleaned of excess paint or allow for any changes in preload when the bearing is pressed in to the shell.
If not, would anyone like an article about retaining compounds and thier various applications?
Good ol' Roger Durham at Bullseye had a great theory on why his hubs (with noticable end-play, once tightened in frame/fork) were more efficient due to the very fact that not all of the balls were in contact when loaded. I wish I could find the notes (was pre-internet) but it was an interesting read and I'd like the industry opinion as well.
I wanted to add that there are 2 types of bearings. Bearings with retention clips (which separate the balls by a small amount). Bearings that are max compliment (no retention clip). Because there is no space between the balls in max compliment bearings, they can put an extra couple of balls into the bearing (the more balls, the more the load is distributed). The balls in max compliment bearings rub against each other however, increasing wear in high RPM applications. For wheels and bottom brackets and any bearing that spins a lot, you would want to use a bearing with a retention clip separating the bearings. For frame pivots and headsets that really don’t spin at high speeds, use max compliment bearings.
Enduro sells both types, and is the only company I have ever purchased replacement bearings through. There has not been a bicycle bearing I have not been able to find through Enduro, and I have replaced a fair number of frame bearings. They even carry those funky knuckle bearings on ends of the shock units from the older model Epics.
Ya, I wanna know what the recommended grease is? I'm using good 'ole Phil Wood brand.
Just wanna say to everyone... regardless of where you ride or how often, every few months inspect your sealed bearings.
that's the truth
ceramics should never be used for MTB where shock loading impact is too common, whether in suspension pivot, hub or BB
ideal for road bikes, if you want to waste your money...
In the user manual they actualy advise you to clean the bike as little as possible
its true, bikes do not enjoy being washed!!
the understanding I have learned is to always wipe down bikes with a clean rag, or if really mucky, then use warm soapy water and sponge / brush and rinse with cold water but never with pressure washer or even water hose
the issue of chain cleaning is something I learned from discussion with KMC and Shimano technical people, they always advise wiping with rag, lubing and wiping with clean rag again, you can get a chain very clean using this method
if really dirty on MTB then some warm soapy water, but NEVER degreaser, chain cleaning machine or any solvents as it just f*cks the chain and then the transmission
the problem for mechs working in bike shops is that customers expect "factory clean" when servicing and bike shops use parts washers (which ruin chains...) despite the mech knowing that surface dirt on a chain is better than flushing all lubricant from chain rollers as it can never be replaced
SRAM Tech actually use a military-grade Marine grease for all their servicing, said it was easily the best they have found and not stupid money either
that's the thing really? you often find better solutions outside of what the bike industry is trying to sell you...which is often 're-badged' generic greases and oils
I can buy motorbike suspension oils and DOT brake fluids for 1/4rd of the price that "mountain bike" brands charge, and the company here in the UK (Rock Oil) that manufacturers and retails these substances under their own brand name, also has a very healthy business doing 're-badge' work for much bigger known "brands"
Bearings generally only come 1/3 packed and the gaps invite water over time which, in my experience, is the primary cause of failure.
For high-rotation bearings, I'll use Inox MX-3 or TSI301 and just brush an light coat of marine grease on the external surfaces.
Teflon-based PTFE grease can also be really handy for anything in between heavy-duty, eg bottom bracket etc, and (relative) high rotation, eg wheel bearings.
For chain lube, I've been using TSI301 for about four years and find it works really well as it gets into the microscopic nooks and crannies in the metal and lasts better than anything else I've tried.
thanks for your input
I would add from my experience, that re-packing bearings with quality grease is ideal for bearings seeing limited angular rotation like pivots on suspension frames, or headset bearings
for bearings used in wheel hubs or bottom brackets (which are actually rotating constantly, rather than limited "back and forth" rotation like suspension pivots or headset bearings) you don't want to pack in too much grease as it can cause accelerated wear to the bearing from hydrodynamic over-pressure
getting 'just enough' grease in a wheel or BB bearing is always preferable to 'over packing' that bearing