Are all NJS hubs forged?
Are all NJS hubs forged?
..nope, a few of them are genuine.
no only yours are counterfeit.
my real answer is: all the ones i've ever seen are forged,
that is to say not cnc-machined. but i don't know if they are
cold or hot forged ...i would assume hot.
I read somewhere once that some arent or werent.
It seems to me that with the NJS certification that there would have to be some sort of leveled manufacturing for all of them to comply with NJS. Unless maybe the rules changed at some point.
Basically i wanted to know if theyre all forged but i guess more specifically whether or not my Sansin hubs are forged.
This has been covered before, but NJS hubs (and equivalent hubs in other drillings) are actually manufactured by a technique called metalspinning. A blank is put in a metalworking lathe and spun rapidly. A relatively dull tool is then pushed against it and causes the metal to flow gradually to form the shape of the hub, much like one would push clay into shape while spinning on a potter's wheel. You typically make a separate blank for each side and then put them together and use spinning to fuse the two halves together. You will occasionally see signs of this fusion joint at the centerline of the hub.
Metalspinning works out the stresses and any flaws in the metal extremely well so the hubs have very low failure rates from cracking. It also allows the hub flanges to be made very thin (i.e., lightweight) without compromising strength. Spinning doesn't compact the metal structure like forging so it doesn't offer the strength of forging, but forging isn't really relevant for hub design -- spinning is actually a better method. Forging works better for products taking strikes (such as hammer faces) or for products facing lever forces (wrenches, crankarms, etc.). And forging works much better when many forging steps are used (the top Sugino crankarms are forged something like 23 times while 75's are only forged about 6-8 times, for example); on hubs, there isn't much opportunity to do to many forging steps. If one uses a stress-relieved billet of aluminum and then mills (CNCs) it you can get the same net performance as with spinning but you have to leave more metal in place so CNC'd hubs tend to be heavier.
Very interesting. Thanks!
since we are on the subject, how many of the cranks out there are forged as opposed to cast?
Nice one 11.4
somewhat related (since Sugino cranks came up):
I was talking to a representative from Sugino a few weeks back and asked about comparative stiffness between the 75's and Mighty's. He said the 75's were stiffer by design. The Grand Mighty are made to be a bit more pliant. He said experienced riders with very smooth cadence appreciate the slight flex on the Mighty and don't suffer from much power loss since they are efficient, while riders who are sloppier or sprinting more aggressively should benefit from the stiffer 75's.
Good info Nate.
My hubs are from the 80s too and im thinking they didnt have this hi-tech process back then. Same with the campys im guessing.
Weird. I would have thought that NJS would have required all hubs to be made with the same process.
It is a very interesting process, there is a pretty big metal spinning shop just down the way from mine.
I could sit and watch for hours, they can do huge domes and stuff... here is a clip although not the best camera quality.
So, I'm still confused. I'd seen that quote about the Sherrif Star hubs being lathed - which is not the same as forged - and yet, it is possible to buy Sherri Star NJS hubs - which begs the question, are the Sherrif Star NJS hubs manufactured to NJS standards (ie forged) and therefore a far better hub than was sold outside of Japan?
The Sheriff's Star Campy C-Record hubs are milled (same method as CNC but not computer driven). Campy equipment at that time had huge status in the keirin circuit and riders with rare Nuovo Record track components were envied. Women married them for their Nuovo Record track groups.
Well, this certainly helped get an NJS stamp for the C-Record track ensemble. Here's a good example of how NJS certification doesn't really mean you have the best equipment -- like with the Shimano Dura Ace 7410 seatpost, C-record components just weren't all that good, at least in their early configurations (think about the aero seatposts breaking, about the problems with Delta brakes, and the early C-Record cranks). But the equipment did get a certification. It's identical to non-stamped equipment (except for the stamp of course). There's no piece-by-piece testing when it leaves the factory, but when you build up a NJS wheel and plan to race it at a parimutuel keirin track, the wheel is then subjected to stringent testing. You have to pay a fee for every piece of equipment that gets stamped, which is why Campy only did a fairly small amount of the stuff. The word got out in Japan eventually that the C-Record stuff was pretty but not as reliable as Sanshin, Suntour, etc., and demand withered. Campy didn't really bother to pursue that market again. They were at the low point in their manufacturing history and it took a few years to get back in stride. Today they hardly care about track and offer just a paltry range of dimensions in some very dated equipment. They haven't spent a dollar on track equipment design in fifteen years. They simply see the road market as their focus.
Not to mention the sheriff star hubs had a habit of blowing up.
Mes compaingnons cui j'amoie et cui j'aim,... Me di, chanson.
The C-Record hub also had the useless cosmetic dust covers on the ends of the hubs. They needed a special Campy cap puller that's of course no longer made and very expensive when you find them. Alternatively, you can make do with a couple hacksaw blades, but you risk dinging a hub every time you want to service or adjust the hubs. The only redeeming grace is that the dust covers had a tendency to loosen a bit over time and either fall off on their own (or rattle incessantly while riding). Italian design at its best -- like a 1970s Fiat. Thank heaven that Campy came back from that debacle.