SKF Bottom Brackets Back in Stock

Bottom brackets are almost invisible, and you only notice them when something goes wrong. When the bottom bracket in my Firefly started to bind after just a few hundred miles, I put in an SKF, and that was the last I thought about it. When the bike was overhauled, the BB was spinning as smoothly as ever. That is how it should be!

How does the SKF last so much longer than other bottom brackets? SKF is a world leader in bearings, and they’ve applied all their technology to these bottom brackets. The two biggest advantages are larger bearings and better seals.

Let’s look at the bearing size first. SKF runs the bearings directly on the spindle and on the shell of the cartridge (above). That way, there is enough room for large ball bearings that can handle the high torque and low rpm of a rider’s pedaling, which is really tough on bearings. On the driveside (left side above), the SKF bottom bracket uses even stronger roller bearings to handle the extra force of the chain.

Most other bottom brackets use premade bearings (also called ‘cartridge bearings’ or ‘sealed bearings’), usually the 6903 size shown above. Using a premade bearing is much easier, as you don’t have to grind and polish the bearing seats. Instead, you simply press the bearing’s inner race onto the spindle and the outer race into the shell. The problem is that the extra bearing races waste space, and then you no longer have room for properly-sized ball bearings.

Bottom bracket shells were originally designed for cup-and-cone BBs that run the bearings straight on the spindle and the cups. They started with 1/4″ balls (6.35 mm) and sized everything up from there, without wasting a single millimeter. Most bottom bracket shells still are that size, even though cup-and-cone BBs now are rare.

When you use premade bearings, you lose about 1.5 mm on each side, plus a little bit more because the sleeve needs some room inside the BB shell. As a result, the largest balls you can fit are 2.8 mm in diameter, less than half the ‘normal’ size. These small balls have a much lower load rating, and they’ll also wear out faster.

The other big issue is that the premade bearings don’t have good seals. They are sometimes called ‘sealed bearings,’ but those black or red rubber seals are intended only as dust shields for indoor applications. They aren’t waterproof at all. You’ll never see a bearing like that exposed on a car, and yet even high-end bottom brackets put nothing but a rubber shield between your bearings and the gritty outside world.

The SKF bottom brackets have labyrinth seals that really do keep moisture out. Once, I cut open an SKF cartridge that I had used on my Urban Bike for a full year of rainy Seattle commutes, and the grease inside was fresh and clean. These seals are truly high tech, and SKF even patented them, because they were designed specifically for this application.

As a result of all this quality, we can offer these bottom brackets with a 10-year warranty that includes the bearings. (Actually, we limit the warranty to 10 years or 100,000 km, whichever comes first.) For most riders, one of these SKFs will be the last bottom bracket they install in their bike, and it’s certainly been that way for me.

SKF had stopped making these bottom brackets, and for a while they were unavailable. We are glad that we now can offer them again in all sizes, with British, Italian and even French threading, as well as in an ISIS version, as a world-wide exclusive from Compass Cycles. Click here for more information about SKF bottom brackets.

About Jan Heine, Editor, Bicycle Quarterly

Spirited rides that zig-zag across mountain ranges. Bicycle Quarterly magazine and its sister company, Compass Cycles, that turns our research into the high-performance components we need for our adventures.
This entry was posted in Bottom brackets. Bookmark the permalink.

49 Responses to SKF Bottom Brackets Back in Stock

  1. Dr J says:

    Nice, but you conveniently forgot to mention that most modern BB bearings sit in outboard cups and as such have actually larger diameter than those in SKF BB.
    Also, they are so inexpensive (~$30, especially compared to SKF BB) that even if they have to be replaced every few years, it’s usually non-issue.

    • There are definitely two approaches to bikes: You can buy five $ 30 BBs that require replacing every two years, and it’ll cost the same as one SKF BB – if you don’t count your time working on your bike, and don’t mind the risk of getting stranded if the BB develops trouble at the beginning of a long ride. Or, for the same money, you can buy one part that lasts five times as long, and you’ll always have a wonderfully smooth BB and the knowledge that it won’t give trouble. Both approaches are valid.

      As to external-bearing BBs, see the other comment below…

  2. larryatcycleitalia says:

    A note on the Italian threaded 111 mm spindle square taper model – I’ve installed 3 or 4 of these to replace Campagnolo BB’s supposedly of the same dimension and found this BB puts a Campagnolo triple crank a bit more “outboard”. This means the front derailleur may need some readjusting. If I knew I would NEVER want to put a Campagnolo BB back into one of these frames I would measure the actual dimension and mill off a bit of the BB shell so the crank would sit in exactly the same place as with a Campagnolo BB. Since I have NOT measured this, but noticed it only after finding the front derailleur needs adjustment, I wonder if perhaps the crank is not being pushed as far onto this spindle vs the Campagnolo? Anyone else have this experience?

    • The tolerances of the square tapers are so tight (because of the angle, even 0.1 mm move the crank significantly inward or outward), that you often need to adjust the front derailleur slightly when replacing BBs, even when it’s the same brand and model. Fortunately with these, you won’t have to do it often!

  3. “cup and cone” bottom brackets are by far the most common in use today. Only bike snobs ignore the vast majority of mass market bikes.

    • All the mass-market bikes I’ve seen lately had cheap cartridges. Cup-and-cone bottom brackets require skilled labor to adjust. The skills are hard to find in the countries where bikes are assembled these days, which is the main reason why cup-and-cone BBs became (almost?) extinct.

      • Matthew J says:

        I have a couple NOS Campagnolo Record cup and cone sets. They are beautiful enough even non-cyclists notice them on my book shelf.

        From time to time I’ve thought about putting one to work on my road bike. Then I consider how easy it is to install a cartridge and how little I have to worry about maintenance and wind up leaving them on the shelf.

  4. Shu-Sin says:

    Just checked availability on the JIS-BSC square taper 116mm, and it says it’s out of stock. Is this size not available at all?

  5. Tbone408 says:

    Do they make external bearing bb’s? It would sure be a nice offering especially for mountain bikes.

    • We don’t offer external bearing bottom brackets, but if you need one, the Chris King ones seem to have a good reputation.

      I am not a fan of external bearing BBs – it’s basically a work-around to make the existing BB shell larger. Screwing the bearing seats onto the outside of the shell, you get alignment issues, because the shell is never faced 100% perfectly. Furthermore, most current designs have bearings that are still much too small, since the spindles now are huge and take up all the extra space. With a carbon frame, you should just make the BB shell larger, since you need that volume anyhow for the huge tubes. With a steel frame, the larger shell will negate any weight advantages of the large-diameter, thinwall spindle…

      • Adem says:

        I’m a fan of the WheelsMFG external bearing BBs.

        I’ve never had issues with BBs of this type for 24mm spindles, but the bearings definitely end up quite small on the BBs for 30mm spindles.

  6. james says:

    Campag UltraTorque BB and cranks has been the best I have ever owned. Mine is about 10 years old now, and have likely carried me 100,000km already. I have replaced the bearings once about 5 years ago, but 5 years from a BB for me is at least 5 times longer life than anything I’ve used before. Also, the bearings I put in 5 years ago are showing no signs of wear yet.

    • You are lucky! Most riders around here get at most a year or two out of the modern Campy BBs. Campagnolo resisted the move away from square taper as long as they could, because they knew that square tapers work just great. But in the end, as a mainstream manufacturer, they felt they had to follow the general trends…

  7. Simoen says:

    I’m a bit confused about what BB to use for TA cranks.
    For example their Carmina crankset and Pro 5 Vis are both ISO square taper according to their website. Compass however says it’s JIS? Sheldon also lists TA as ISO.
    What am i missing?

    • What most people are missing is that JIS is not a Japanese standard at all, but it’s in fact the old French standard. The Japanese makers copied Stronglight and TA (and perhaps René Herse). Later, this became the Japanese Industrial Standard (JIS). This means that French cranks use JIS bottom brackets.

      Campagnolo also copied the French, but they didn’t copy exactly. In those days, few makers offered square-taper cranks and BBs, so Campy was expected to work only with Campy. Nobody would put a Campy crank on a Stronglight BB or vice versa… So it didn’t matter that the Campy standard was a little different from the French. The Campy standard then became ISO.

      Where things get confusing is that TA stopped making cranks for a while, and when they restarted, they needed new tooling, and they made that to ISO standards. This means that older TA cranks – I’d say until the 1980s at least – are JIS. Newer TA cranks, including the most recent Pro 5 vis, are ISO.

      What makes all this even more confusing is that the two standards are so close (both use the same angle, just the spindle is thicker on JIS) that the tolerances overlap: A thick ISO spindle actually passes as a JIS one. (I have a JIS Campy Record BB spindle from the 1970s that works perfectly with Stronglight cranks!)

      The full story of BB standards is in this blog post.

      • Gert says:

        I have a relatively new TA Vortex compact bought in 2013 and a two new TA Carmina compact bought 2015 and 2017. They all fit a JIS bottom bracket.
        By mistake I received an ISO bottom bracket once. The left crank arm came on so tight that they could not turn.
        So I would definately say new TA cranks are JIS

      • Interesting. TA claims they are ISO…

      • Matthew J says:

        Peter White (whom I believe is now the US importer) says JIS as well. Mariposa – Canadian custom builder company that has been working with TA for years – also says JIS.

      • Simoen says:

        Gert, are you happy with the Carmina cranks and the quality of shifting? Thinking about ordering a 46/30 for myself but can’t seem to find a lot of experiences online.

      • Gert says:

        Shifting is a problem for me going from the small chain ring to the large. It tends to shift beyond, if I am not careful, but I also run 36-48, and the front derailleur preferably likes a difference of 16, so that is probably the reason. But it is not the same on both the bikes I currently use them on. So some of it may be caused by inadequate alignment of the front derailleur
        On both bikes I use TA Zephyr chainrings.
        So I woud assess that 90 % at least of the shifting problem is caused by me and the 36-48 combination.
        Regarding the 30-46 combination, I have the compact version with Bolt Circle Diameter of 110mm
        As far as I have seen the smallest chainring for that is 33. So I do not think 30-46 is possible. It might be possible in the carmina version with a separate spider, but I do not know.
        Rene Herse cranks have the 30-46 combination
        I only use TA cranks for the crankarm lengt of 185mm, so if crank arm length is not an issue then the Rene Herse might be the answer

      • marmotte27 says:

        I bought one of the Pro 5 vis 70 anniversary cranks. TA claims as you say they’re ISO (they don’t say if it’s the older or the newer 2015 ISO standard…). As there aren’t many bottom brackets available in the necessary 125 mm spindle length for a double (that’s an understatement, there aren’t any except TA’s own Axix model) I measured them on a Shimano square taper. It slides 14mm onto the JIS taper, leaving around 4mm between the end of the spindle and the screw (I didn’t tighten the screw like a madman, so there might still be half a mm or so in there.) The crank was far from bottoming out on the taper. That to me looks just fine to use JIS bbs with the TA crank. Maybe buy a 123 mm spindle length.

  8. Adem says:

    I’m curious about the taper length/profile on these BBs.

    I purchased the 107mm JIS Square Taper BSC version of this bottom bracket in March of 2016; after 2500+ miles I noticed that the driveside crank (an old Shimano FC-M737) had developed a teensy wobble. Upon disassembly, I noticed that the crank had bottomed out against the base of the taper during installation.

    This was NOT the case with my old Shimano BB-UN7x cartridge BBs, nor is it the case with the Phil cartridge BB that I installed in place of the SKF unit. Visually, the SKF BB looks like it has a “JIS low profile” taper than a standard JIS taper. Any thoughts or comments?

    • That is surprising, because our experience is exactly the opposite: The SKF spindles tend to run at the upper end of the tolerances for JIS cranks, so the cranks usually sit a millimeter or so further outward. That is why we recommend the 110 mm SKF bottom bracket for our René Herse cranks, but 113 mm with most other makers.

      What is more likely is that the crank’s taper has enlarged over time, and the SKF spindle has a shoulder where it transitions to the larger bearing seats that you don’t have on the Phil Wood with its smaller bearings. Hence the crank bottomed out on the SKF, but has a little more life left on the Phil. (Eventually, the crank bolt will bottom out on the end of the spindle inside the crank extractor hole…)

      It’s something you can check by removing the crank bolt and checking how much the spindle is recessed inside the crank. If you do believe that the SKF is out of spec, please return it, as it’s still within the warranty period. Then we’ll have a look.

  9. Nestor Czernysz says:

    Sorry, I’m a little unclear on the manufacturing issue. SKF is producing this B.B. currently or this is a big stash? Thank You.

    • Everything in the bike world is made in batches. Factories tool up for one component, make a good supply, then retool for another. The components are warehoused until they are sold to distributors. When warehouse stocks run low, a decision is made whether production is restarted, or whether the product is discontinued. In other words, when a product is discontinued, it’s not like somebody goes and switches off the assembly line, but it’s simply a decision of not to make any more once the existing stocks are sold.

      This is different from cars, which roll off the assembly line every minute or so, and the only way to adjust production is to run more shifts or idle the factory.

      So while I don’t think the production line is currently running, we can say that these BBs are currently in production, in the sense that there will be more when they are needed. So there is no need to stock up because you fear they’ll soon become unavailable in the next year or two.

  10. Samuel Atkinson says:

    Will the silver BSC left cup be re-stocked?

  11. zigak says:

    Does somebody have any recommendations for mtb cranksets that will fit skf isis or square taper bb? Preferably 3x or 2x.

    • Conrad says:

      I think the common sense gearing for mountain and allroad bikes is a 46/30 double. Unfortunately there are not many of them. The Compass one is far and away the best but expensive. I recently bought an IRD defiant that seems nice but I haven’t installed it yet. Otherwise I guess you hope your older silver square taper cranks last forever!

  12. Steve Green says:

    How does facing the bottom bracket affect the accuracy of fitting external bearings? Surely the bearing housings are located by the bottom bracket threads?

    • Threads always have some play, otherwise, you wouldn’t be able to screw them together. What locates the bearing cups is the facing of the ends of the bottom bracket shell. With cup-and-cone bearings, the tolerances are reduced, because you move inward from the BB faces. With external bearings, they are increased, because you move outward.

  13. Andrew Burton says:

    Very curious as to what BB bound up after a couple hundred miles? You choppin’ wood out there, Jan-dog?

    • It was a sleeveless modern BB, which relies solely on the cups to locate the pre-made bearings. The alignment of that always seems a bit dicey… When I took it out, it spun freely, but when I reinstalled it, it was binding again. Instead of messing with it more, I just put in an SKF and replaced the cranks with our René Herse model, which also allowed me to improve the chainline, reduce the Q factor and shed some weight.

      • Steve Green says:

        I bought a second-hand bike with an ” upmarket” sleeveless sealed bearing bottom bracket; the driveside bearing was binding so badly that it unscrewed while I was riding.
        The bearings were located in aluminium cups, and the spindle was titanium… I replaced it with a cheap, all steel, cartridge unit. It’s still going strong after several years. In that time my wife has got through three sets of Hollowtech bearings. I think that I should get round to fitting SKF bottob brackets!

      • Andrew Burton says:

        interesting — i’m not familiar with sleeveless bottom brackets. good to know

  14. Julio says:

    I agree that modern external bb cups on standard bb shells are not an ideal solution. However, they have worked extremely well for me. 10 years on my racing bike with maybe 50.000 kms on them and still going strong (Ultegra). 4 years on the touring bike with quite a few kms on them and all going well. They are much easier to install and service that square taper and also lighter, when paired with hollowtech II cranks there is a great deal of weight savings.
    Not the same opinion about cartridge bearings on hubs though. There I prefer cup and cone bearings.
    On carbon frames making the bb shell larger and fitting a hollow spindle with reasonably sized cartridge bearings is the best solution, imho.

  15. Adette says:

    Hi, what is your recommend of SKF BB JIS length for Miche Primato Advanced track crankset JIS?

    By Miche spec, they recommend 107mm of their own JIS 107 BB JIS, I was fitted mine with Miche 107mm and its work perfectly.

    I want to try SKF BB but unsure about length. I heard taper square BB even they state its the same length, its can still be varies…. SKF BB sure looks very promising upgrades for my bike but just wonder about BB length.

    Thanks in advanced.

    • Adette says:

      Also, I’m curious.

      In term of “fixed”, you can’t coast so I wonder if I upgrades BB will give me noticeable performance?

      Freewheel may not notices it much because you can coasts and rolls. But fixed wheel? I think its should be worth upgrades? smoother and better BB = less drags on fixed = faster over all??

      Any opinions input would be appreciated.

      • As much as we’d love to sell you an SKF bottom bracket, you probably won’t go faster on it. Even a badly worn BB doesn’t slow you down – until it stops working altogether! However, on a fixed gear, you’ll probably feel the smooth feel of a good bottom bracket even more than on a geared bike.

    • The 107 mm probably works fine. You are right, the square taper can vary a tiny bit, but it’s not enough to cause problems with the chainline of a fixed gear.

  16. Jack Luke says:

    I’m a big fan of all things cup and cone — is there a modern C&C bottom bracket out there that you could recommend for day-to-day road use, or is it a pointless indulgence for the sake of enjoying fettling with them?

    • I think cup-and-cone bottom brackets are great if you have time to tinker with your bike. If you overhaul them about once a year, they’ll last forever. I got 60,000 miles out of a Campagnolo C-Record one, and it’s still on the bike. But when I let the grease dry out on the one I had on my next bike – I was having less time for working on my bike – the BB was finished within two years…

      For really good cup-and-cone BBs, you’ll probably be looking at the NOS market. And since bottom brackets are wear items, I don’t expect them to be inexpensive.

  17. Adette says:

    Another question.

    Do you needs grease or any kind of pre-prep before install this? Did SKF BB came with proper greased out of factory?

    I think its probably silly question lol I plan to install it right away without to “disassemble” it and put greases myself.

    Some BB does not greases properly or way too low greases out of factory, that’s my concern. I knew this SKF products have 10 years guarantee so … I guess it is?

Comments are closed.