Jake’s Musings About Bearings
Technical facts from the world of tribology
Recommendations related to cycling applications
Resources and recommendations for further reading
The “Tier-1” difference
When Jake refers to “Tier-1 bearings,” he’s referring specifically to bearings made by one of four large and highly respected international manufacturers: NTN (including French brand SNR, now formally “NTN Europe”) and NSK, each based in Japan, SKF of Sweden, and INA-FAG (Schaeffler Group) of Germany. As English mechanical engineer Hambini has repeatedly indicated in his excellent website blogs and no-holds-barred YouTube videos, these companies are household brands in serious industry - automotive, factories, aerospace, energy production and primary industries, etc. But the reason they’re sometimes unfamiliar to cyclists is because the cycling industry tends to ignore supply from these companies (“tends to” being the operative word phrase, as a few noble outliers have always existed; Hope, for example, used to spec SKF bearings in their hubs, while hub newcomer Qvists employs NTN bearings and Phil Wood uses NSK). The industry views industrial rolling elements as too expensive and/or outside of the specification needs and cozy supply arrangements desired by cycling brands. Many bike hubs will use cycling-specific sizes such as 17287, 15267, or 15307 (15 x 30 x 7 mm), all non-ISO sizes. However, the Tier-1 makers, firmly committed to the ISO sizing framework for radial deep-groove ball bearings, have little interest in mass-producing (except, perhaps, by custom request) these more unusual cartridges. (In turn, most cycling brands would probably balk at the quoted pricing from the big four.) Cycling is a cliquey industry by any reasonable standard - take it from a proprietor and insider - and so these brands go where the current consumer and insider zeitgeists, and supply in the right niche specs, exist. Enduro Bearings has become the main choice for most premium hub and frame companies, from Hope Tech for most of the last decade to Industry Nine to White Industries and any number of frame OEMs. But, as Hambini has also strongly implied, as a bearing expert completely immersed in the quality difference with Tier-1, Enduro makes a very moderate product when evaluating their range as a whole and in comparison with the true leaders in trobology. We routinely spec Enduro bearings at Hogtown Spokes, as some of their items are absolutely first rate: their XD-15 ceramic flagship bearings, their new solid-lube ABEC-5 units, generally their Stainless Steel bearings (if ordered with green seals/as non-OEM made-for), and most of the ABEC-5 level products. Their MAX suspension bearings are also amazing, kind of an Enduro house specialty. In certain cases, we have no choice but to spec Enduro. Enduro is the only mainstream company that currently makes a 15307 bearing, for example (15x30x7 mm). Industry Nine Hydra and NGB hubs require this peculiar size for their rear Driveside shell slot. The idea with 15307 is to try and massively stiffen a normal 30 mm OD bearing (typically 6903), by increasing the available real estate for - and thus the size of - the actual balls. It’s a commendable attempt.
But wherever we can, we often opt to spec Tier-1 bearings instead or concomitantly, incorporating the super-premium upgrade that Tier-1 represents into our Full Custom or Curated pricing structures for wheelsets. Our experience has absolutely been that Hambini is correct in talking up these brands. They deliver a consistently superior, more refined, stiffer, quieter, and longer-lasting bearing product whenever compatible specs can be found for cycling uses. Tier-1 bearings are like the difference between a beautifully tailored truly bespoke suit, made by a 69-year-old virtuoso named Giuseppe with generational know-how, and a tailored style du jour suit that men in the consumer West can now purchase at chain-style “bespoke” men’s clothiers. The difference is subtle - but also more than marginal with Tier-1. We’re particular, historically, to Japan’s NSK Corporation. Genuine NSK bearings are fairly easy to acquire in Canada (by comparison, NTN bearings are a little harder to get, while FAG bearings are difficult to obtain), affordable given the superlative quality (again, with a slight leg up over NTN), and the range of sizes and enclosures (seal types) is ideally suited to cycling applications. Jake has pursued and passed accreditation in Bearing Basics, Troubleshooting, handling and installation best practices, and product knowledge for the NSK line through the online NSK Academy. Many of the facts mentioned on this page are cited from the NSK Academy, as an outstanding tribology resource.
Jake uses the term “Tier-1” to refer to these bearings as an apt analogy with elite military professionalism. The West’s most capable and professional special-operations forces exist outside of the respected command structures of the Green Beret (Special Forces) Groups or ordinary Navy SEAL Teams. America’s best are instead specially attached to the independent Joint Special Operations Command (JSOC) and enjoy the super-elite mantle of being Tier-1 SMUs: “Special Mission Units.” In Canada or Britain, the equivalent parallels are JTF2 and the SAS, SBS, and SRR commando formations. Almost any bearings used in reputable bike hubs will be of generally high quality; this includes Enduro’s offerings or TPI’s offerings, plus others like Black Bearing, NBK, and ISB. But the Tier-1 bearings perform on a pedestal all their own. They’re Tier-1 - aka the absolute best of the best.
Bearing enclosure types (sealing designs)
Differences exist in the nomenclature for different brands, when it comes to sealing efforts. Within the designator “2RS” - for 2x Rubber Seal, the standard design needed to meet the demands of cycling and other applications where environmental contaminants are constant realities - there’s a variation in possible designs. But these efforts routinely group into two broad categories: contact seals, offering the best protection but with more friction in use (and therefore limits in high-speed industrial applications - which cycling is not); and non- or light-contact seals, offering lower protection especially against water but noticeably less rotating friction (and therefore permission for higher rotational speeds), both in the hand and once mounted. Generally speaking, we consider contact seals ideal for rear wheels, for mountain wheels, or heavier riders who will already tax a bearing’s limits that much more than lighter folks and need all the help they can get from a cartridge design. We suggest non-/light-contact seals for front wheels, road and some gravel wheelsets, and lighter riders. Within the Tier-1 Japanese coterie, our anecdotal experience is that NTN contact seals (always finished with the rubber bright red) drag a little bit more than NSK’s equivalent (always distinctive maroon in colour), while the two companies are virtually neck-in-neck on the non-contact side. With SKF, a simple “2RS” designation typically means contact seals. SKF’s contact seals drag somewhere between NTN’s and NSK’s, in the hand. The same applies to INA-FAG’s version, historically labelled “2RSR” when the type is contacting. Note, crucially, that each of these bearings become extremely fluid once installed and loaded in the hub slots of a built wheel. The loaded state, of course, is what actually matters.
Among the reputable Tier-2 companies, labelling practices assort but serve the two overarching design groups.
NTN SPECIFICS
LLU - NTN’s contact rubber seals bear this designator. Two precision-engineered seals make contact with lip grooves machined into the lower race of the bearing (all decent bearings, from any maker, have machined grooves in the outside or upper race). LLU units are excellent at keeping out moisture and all types of contaminants; in cycling, durability against ingress is a major aspect of bearing performance. LLU units are almost always available (and supplied by Hogtown Spokes) with CN (ISO “Normal”) internal clearances. NTN’s contact bearings are extremely well made but can be slightly deceiving for the uninitiated. The effectiveness of the sealing makes them feel sluggish in the hand, despite the evident high quality. While they do operate with a designed-for increase in drag versus non-contact or light-contact bearings, this hand sluggishness is superficial and should be ignored. These bearings will come into their smooth own once loaded in a built wheel (or fitted into a bottom bracket) and rotated at speed. These are the most ideal bearings on the market, in our opinion, for the heaviest riders and worst conditions. They also make for possibly the best custom bottom bracket bearings available. Hogtown will sometimes customize and sell such bottom brackets, typically in BSA 68/73 mm.
LLB - NTN non-contact rubber seals are listed in this manner. These bearings feature incredibly low drag and strong resistance to most contaminants; water is really the only contaminant that cycling users should be mindful of as a vulnerability with LLB. This doesn’t mean that these bearings can’t be spec’d on mountain bikes or in wet climates. But it does mean that hubs taking these bearings for such uses need to come with excellent external sealing provided by their machined end caps (eg, Hope NDS rear caps, Industry Nine or Koozer labyrinth front caps, etc). NTN LLB bearings offer phenomenal performance front and rear in road wheels. With well-designed hubs, our perspective is that a rider looking for an upgraded front wheel - in any cycling discipline - might give these some serious consideration. Front wheels (and this logic also provides the case for ceramic front bearings) are self-sustaining in that they can’t rely on the direct momentum driver of the drivetrain, as with a rear wheel. Thus front bearings need to be that much smoother for maximum riding efficiency. A front wheel sets the efficiency tone and pulse of a wheelset and provides a great place for light-contact seals.
NSK SPECIFICS
DDU - This bearing is our first choice for contact seals for a vast majority of riders and bikes. Our first-hand experience is that they offer very close to the same weather hardiness as the NTN LLU equivalent (ranking one higher would amount to splitting hairs), but with noticeably less drag in your hand and also less drag when loaded and in use on some hubs. These bearings are easy to identify, based on their distinctive dark-maroon seals. This is a wonderful product for heavy riders, rear wheels, wet riding conditions, and even for a particularly burly or all-season road wheelset. The NSK DDU is Hogtown’s favourite contact bearing. These are sometimes supplied by Hogtown in the “CM” variation - meaning special low-noise design. The CM design features reduced tolerance ranges within the CN (Normal) clearance class and is interchangeable with the same-dimension typical CN bearing.
Hogtown-edited images (seals): nskeurope.com
VV - VV is NSK’s answer to NTN’s LLB non-contact sealing. These are appropriate for the exact same cycling use conditions as the NTN products, described above. The low-torque design is effortless and instantly noticeable with VV-series items. VV bearings make for a wonderful front wheel pairing with NSK DDU rear bearings; they also work beautifully for a low-friction complete road wheelset. Furthermore, VV bearings make for a fast-spinning bottom bracket (for those who don’t ride in utter muck). We’re big fans at Hogtown Spokes.
DDW - This is NSK’s in-between or light-contact seal type. These bearings are harder to obtain in Canada and won’t typically be sourced by Hogtown.
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TIER-2/ENDURO
Enduro bearings copy the labelling used by NTN. Therefore Enduro’s contact units are labelled LLU, while their light-contact seals are labelled LLB. Enduro deserves credit for a clever approach with some of their bearings, which come half LLU/half LLB. These bearings are designed to be installed with the hardy “business” end - the LLU side - facing outward, toward the elements. They essentially function as lower-torque, lower-resistance contact bearings or, looked at differently, as more durable light-contact bearings. Enduro’s excellent 15307 ABEC-5 steel bearing, standard in the Industry Nine Hydra rear hub, employs this strategic design. The light-blue seal faces outward on the Driveside of a Hydra (or NGB) rear hub.
Most of Enduro’s all-LLU bearings will be confined to the MAX full-complement designs specific for suspension pivots, although ABEC-5 cartridges suitable for hub use are, at least in theory, also available as all-LLU. Our experience is that Enduro’s LLB units can be hit and miss. The Stainless LLB models and ABEC-5 models tend to be high quality, although this isn’t guaranteed. Hope’s OEM custom Enduro Stainless LLB bearings for the Pro4 hub models operate smoothly but lack the critical Tier-1 thoughtfulness feature of machined grooves for the lower races (I can absolutely prove this claim). The ABEC-3 LLB units vary in quality much more widely, depending on a given batch, in our experience. In general, versus NTN’s LLB or NSK’s VV bearings, Enduro’s light seals are lower quality. Attention to production execution is much less meticulous on the regular. The accuracy of the shaping and fitment of these seals is less precise and less confidence-inspiring; uneven micro gaps sometimes exist around the seals’ fitted inner circumference, while, as noted, lower races often lack grooved receiving channels for the rubber seals - a major difference versus the Tier-1 big four, whose bearings always have this critical weather-focused feature. With seals that don’t make full contact, and therefore make hubs’ rolling elements more vulnerable, companies shouldn’t ever get the design, let alone execution fit and finish, wrong - especially for what Enduro bearings cost shipped!
However, since the quality level is generally commendable in the ABEC-5 precision class from Enduro, and because 440c Stainless bearings offer advantages for corrosion-resistance (albeit at a rated 20% lower load capacity versus bearing carbon steel), we’ll almost always tell customers that Enduro is worth trusting and offers an upgrade in the ABEC-5 range. From Hope, which has Enduro Stainless bearings made custom for their hubs, the seals are black. Aftermarket Enduro Stainless bearings come with green seals - and the green version do have machined lower-race grooves. Buy these.
TIER-2/TPI
TPI bearings use a variation on the NTN/Enduro nomenclature. TPI bearings, made in Taiwan and elsewhere in Asia, say either “LU” (contact seals), “LB” (non-contact seals), or, as with Enduro, both LU and LB. The latter offer the same best of both worlds proposition as the Enduro versions. TPI bearings are very high quality overall, one of the closest Tier-2 makers to entering the Tier-1 club in terms of quality-assurance and performance reliability. Additionally, TPI bearings offer a wider temperature window than NSK bearings: from -25*C to 120*C, in operational use. TPI bearings are standard in DT Swiss hubs, Race Face Vault hubs, and partially in Spank Hex Drive hubs, among other standout hub brands and models. The TPI LU/LB units, in our experience, run with slightly lower torque (less resistance) than Enduro’s version and with more consistent tolerances in the execution of the seals and raceways. The reduced friction may be due, in part, to the different lubricant fill; Enduro’s units have a hefty and thick Mobil (distinctive blue) greasefill. We recommend TPI LU/LB bearings for road rear wheels, mountain wheels, and for any rider looking for extra water-resistance.
The quality level is so good with TPI overall that these bearings usually aren’t worth replacing even for a rider prepared and determined to spend for Tier-1. Certainly we would make this point with smaller, less load-bearing bearings such as freehub units (eg, 6802). In such cases, we would advise only splurging on a Tier-1 front bearing set - something like the NTN LLB or NSK VV - and leaving TPI LU/LB bearings installed rear, at least in the freehub and perhaps even in the shell slots. TPI replacement bearings are pretty straightforward to obtain in Canada, as original equipment in DT Swiss hubs.
TIER-2/BLACK BEARING
French company Black Bearing provides another strong Tier-2 bearing option. Admittedly their website lists only basic technical information (en français), but these bearings perform great. These are go-to units for Hogtown Spokes in the slightly esoteric 15267 (15x26x7 mm) size. Most available Black Bearing units say “2RS” but are effectively LLB light-contact. We like Black Bearing because their LLB units are as smooth as Enduro’s version - or smoother - but with more consistent seal quality and machined lower-race grooves.
TIER-2/ISB SPORT
ISB bearings, based in Italy, are extremely similar to Black Bearing and recommended by Hogtown Spokes. Their basic steel bearings typically come with distinctive green contact seals. ISB makes a predictable, reliable, quality bearing product.
NOTABLE MENTIONS (STEEL BEARINGS)
Rain and Dew - Rain and Dew is an ISO-certified Chinese bearing company making impressive non-/light-contact (LLB) steel, Stainless Steel, and hybrid-ceramic bearings. Most of their items come at least described as ABEC-7 (high precision), albeit with nylon versus pressed-metal retaining cages for the balls. (By contrast, the Tier-1 Japanese companies use metallic cages for greater stiffness and durability, especially in precision bearings.) Rain and Dew presents an impressive, affordable option and is recommended and frequently used by Hogtown Spokes.
Fushi Bearing (certain models only) - Fushi quality can vary widely, from commendable to outright disappointing, but this Chinese company also makes some strong hybrid-ceramic and steel bearings. Their ABEC-5 precision line is small and needs to be larger, but where available it’s worth installing in some hubs. Fushi precision units generally offer non-contact sealing, however often lack lower-race grooves.
EZO - EZO bearings are made in Japan and generally offer a very impressive option. Our experience is that their smaller units (6802 or 6803) tend to be extremely competitive and are often available with contact seals, simply labelled “2RS” (as with SKF). EZO is a Tier-2 company that punches above its weight and is worth investing in for a hub performance improvement. These are serious bearings.
S&S - This underrated Asian bearing company supplies many of the upstart Asian wheel and hub companies, such as China’s Koozer (stock cartridges on the newest models). S&S copies the Enduro/TPI approach of split sealing with many of their bearings, including as now standard for Koozer. S&S makes some extremely good unusual bearing sizes - such as 15268 for hub use - and is relied upon regularly by Hogtown Spokes. Really importantly, S&S seems to always employ machined lower-race grooves in their units.
NBK - NBK is the third of the impressive Tier-2 bearing brands, alongside EZO and TPI. Asian-based, they make handsome, durable, typically light-contact bearings for a number of hub companies, from Koozer historically to China’s ELITE Wheels and iCAN. NBK also offers serious, professional bearing information on their website - load capacity, lubrication requirements, rotational limits, etc. We’re extremely impressed with the value from NBK. NBK bearings almost always employ machined lower-race grooves, to improve sealing even in a light-contact bearing design.
Some words of wisdom from the experts at NSK
The online NSK Academy features excellent information about troubleshooting and handling bearings; like any serious, engineering-driven manufacturing company, NSK aims to study failures in the field and apply these lessons-learned to educating their customer base and business partners. The Academy soundbites a number of key maxims in the training modules. Four of these, in particular, are worth referencing here:
>>Don’t cook - or freeze - your bearings; NSK temperature range
NSK’s rubber-sealed bearings have an effective operating temperature between -10*C and 100*C.
>>“10% additional load reduces bearing life by 25%”
What this means for riders is that being heavier does matter - and, effectively, that if a bearing wears out prematurely under a heavier rider (or inside the wheels of a bikepacking rig or e-bike) than this will not necessarily be the fault of the bearing; it will be due to the increased load presented. As a precaution, riders with larger physiques or really heavy bikes should only consider hubs with larger bearing specs: 6903 (17x30x7 mm) or bigger on front MTB wheels and a minimum shell size of 6902 (15x28x7 mm) for rear MTB bearings (road wheels take less stress and so these minimums are perhaps more flexible on tarmac). Such hubs also demand smarter, stiffer axle designs that resist torsion, since misalignment also increases bearing wear. A good fit for a larger rider would be a Koozer or Hope hubset, for example (18307 & 6902/6804 front bearings & 6902/6903/17287 rear shell bearings, respectively). Despite all of the other strengths in DT Swiss products, most DT Swiss hubsets would not present a viable option for a larger rider or bikepacker (the Hybrid hubs being an exception), as DT bearings are comparatively smaller than competitor units. Hogtown Spokes has a responsibility to all customers to accurately recommend hubs and bearings based on expected loads and use conditions; customers, in turn, have a responsibility to answer Hogtown inquiries thoroughly and honestly.
>>“As little as 0.1* misalignment can reduce bearing life by 50%”
Granted this statistic is informed by NSK’s experience across all of their products - many of which are used in heavy industry - but nevertheless a large kernel of this brutal fact applies to single-row deep-groove ball bearings used in cycling. This reality is why Hogtown takes pains to correctly install all bearings. We have no time for the quick, conceited industry method of blindly installing bearings and assuming perfection simply because an expensive press was used. Installing fast is the cheap brag of the amateur; professionals take pride in taking time. We use appropriate tools and methods for the job, and Jake has developed ultra-sensitive bearing senses: he’s acutely aware of how a bearing should feel (vibration), sound (noise), spin (torque efficiency), and how it should look when correctly bottomed-out inside a hub’s shell housing. We’re meticulous. We’re at times asked by customers why we don’t, as a formal Condition of Sale, allow clients (or random bike shops) to tinker with their own bearings. The quote above is exactly why not! There’s far too much that can go wrong.
>>Preload has benefits for optimal bearing life - but only very carefully
The graph below (credit: nskacademy.com) shows that the most optimal bearing life (Life Ratio) is reached at a slight level of internal negative clearance in microns - or approximately -9 microns of bearing preload. Conversely, when clearance is extended and the bearing has no preload, bearing life decreases. But not as precipitously as when a bearing is overly preloaded: bearing life becomes absolutely terrible in that situation. Hogtown Spokes avoids adjustable-preload hubsets partly for this reason - user error by the rider can surge preload, as can thermal expansion of bearings in operation. We’re careful with fixed preload hubs to only select wisely. We also know what to look and feel and listen for and will even correct a hub before assembly if something is off. Cycling will never be rocket science or high industry: exactly predicting and quantifying (professionalizing) bearing performance on bikes will probably never be achieved. This is due to the weak link in the whole enterprise: manufacturer parts tolerances within the cycling industry. But we do the best that anyone can, and our goal is always to ensure that neither the bearing products themselves nor their installation are responsible for any shortened use cycles with our wheelset parts. Getting preload right is an area for meticulous custom wheelbuilding practices, across the board.
The Dark Arts: anti-counterfeiting measures
Hambini has a lengthy blog on his website referring to the scuzzy trade in counterfeit or “B-grade” Tier-1 bearings, many of which come out of Asia (along with a lot of first-rate product from the region). The fact is that these bearings are so coveted that disreputable individuals or syndicates have started actively knocking them off and selling the items as authentic. Some of the response language from the Tier-1 consortium is a little dramatic. But there can be no doubt that they’re right in protesting this illegal behaviour and making the point that counterfeit or B-grade items won’t last as long or perform anywhere near as well as the real thing. All of the Tier-1 companies make the same first-principle point to avoid getting counterfeits by accident: to ensure certainty, only source your bearings from reputable suppliers. We take this to heart at Hogtown Spokes, only sourcing our Tier-1 bearings from a respected, lawful, completely legitimate large European distributor authorized by NTN, NSK, SKF, INA-FAG, and others.
In addition to this advice, the Tier-1 companies have developed increasingly sophisticated measures to ward off fakes. The World Bearing Association, NSK, and NTN have developed apps that allow users to scan their products to verify authenticity. These are important tools. But it should be noted that because they’re so new they’re also imperfect tools. Older-production-run bearings, some sizes, and some precision classes are excluded for now. NSK, for example, per their online Academy, for now only offers their tool for scanning bearings ending in an “N” to the right of the product code: typically only high-precision industrial bearings. NSK seemingly intends to expand the app coverage for their products into the future. NTN’s app, called AuthentiBear, is more evolved at this point. The app, shown below, is to be used in conjunction with a 3-step post-purchase verification scheme involving an app scan, checking the product packaging, and checking the holographic NTN security labels used on the individual bearing boxes. Hogtown Spokes scans all NTN bearings - whether supported in the system as valid or likely to turn up as currently unsupported - and we retain original packaging for quality-assurance purposes for our customers. We’ll stay on top of the latest developments and anti-counterfeiting best practices in tribology.
Bearing precision (class conversions)
Bearing quality is a multifaceted animal: quality of the steel and steel-hardening; quality of the finishing, precision, fitment, and materials used in the sealing enclosures; expected useful life; quality and appropriateness of the lubrication used; as well as tolerances and precision class. Nevertheless, many riders and cycling mechanics use precision class as a shorthand for bearing quality. While over-simplistic, there’s some validity to this argument in that higher-precision bearings undeniably feel stiffer, quieter, and run smoother. They’re also trusted for higher-stakes industrial applications far removed from biking, where laser precision and low noise and vibration are required (eg, CNC multi-axis cutting machines, precision power tools, or medical instruments like dental drills).
The cycling industry uses a common statement to explain away classes with bearings - and the statement is only half right. Common cycling bearings (eg, from Enduro) typically max out in precision quality at ABEC-5 (ABEC is the American ABMA system of bearing designation). The industry loves to say that this is because riders will never need more than ABEC-5 to have a good cycling bearing, due to the modest speeds involved. This is largely true. But it’s also our perspective that if and when you can find even higher precision, remotely affordably, and appropriate to cycling specs, then why not. Take it where you can get it, or take its effective equivalent. The attuned rider will feel the difference, in our firm opinion. The industry also sometimes makes the same argument about ABEC-3 bearings - and here we flatly don’t accept it. Much more so than with ABEC-5 bearings, which are legitimately “precision” (if not “high” or “super precision”) units, the argument as applied to ABEC-3 bearings is purely self-serving and cost-driven by the cycling industry. Some ABEC-3 bearings are quite impressive and worth using; many in the cycling industry manifestly are not. They’re too often noisy, vibrate too much, and are poorly sealed by comparison with precision bearings. It really depends on the batch and the manufacturer in question.
As noted, American tribologists use the ABMA designations. The Japanese use the JIS Classes. The Germans use DIN. The chart below, from the NSK Academy, shows the conversion equivalencies among this international group. NSK and NTN use JIS, of course. Oddly, it’s really not easy to pinpoint the exact precision rating for NSK and NTN deep-groove ball bearings. Officially, NSK says that bearings coming with unlabelled boxes are nominally “Normal tolerance (P0)” bearings - but this doesn’t pass the smell test, and in a good way. Every NSK or NTN bearing that we’ve ever unpacked is smoother in the hand and in use than Enduro’s specifically labelled ABEC-5 units - and often in the apples-to-oranges comparison of DDU versus LLB seals! This doesn’t mean that Enduro is lying; instead, it appears to be an error/miscommunication in NSK literature or older labelling practices. To get to the practical truth here, we rely on Hambini. He’s worth quoting: “In reality, an unclassified bearing from one of the large manufacturers and specifically NTN tends to be class 4 as a minimum.” This means that NTN and NSK products are effectively ABEC-5+ or high-precision bearings. And it shows. SKF and INA-FAG bearings are typically superbly made ABEC-5 equivalents (eg, “61802”), and in my experience these will be the best specifically designated “ABEC-5” units you will ever receive.
Further Reading
hambini.com - The Robin Hood bearing guru himself offers must-read blog content and authoritative guidance on Tier-1, especially NTN, bearings
nskeurope.com - The European portal for one of Japan’s two august bearing makers offers an excellent jumping-off point for their catalogue, tech info, and bearing literature
cycling.endurobearings.com - Enduro offers a clear, concise description of their seal types and lubrication practices
tpi.tw - Customarily excellent information, about deep-groove ball bearings, from cycling’s Tier-2 “quiet professionals” when it comes to rolling elements
nbkbearingusa.com - NBK’s thorough website is a testament to their strong products, professional seriousness, and amazing value proposition overall
-JAKE BRENNAND, November 22, 2023