Thursday, November 15, 2007
NJS bike; What's going right; crankset (kinda)
When I was looking for a NJS crankset, I decided I did not want a Sugino; way too common. I was perusing ebay and found a Suntour Superbe Track Crank; but only the right side. It was NOS and absolutely beautiful, so I bought it. Why do I do these things. Had I waited I would have come up with a set, now I need to search (probably in vain) looking for the left arm. But in the mean time, I found a Dura Ace left arm, in 165mm (the same as the Suntour) That should work in the mean time. There was a problem with this plan however. The Dura Ace was JIS and the Suntour ISO. Now I knew this when I bought the Dura Ace, but it was only $25 and NOS.
When dealing with cranks and bottom brackets, usually there are problems. Since I was dealing with square taper, there are two standards, JIS and ISO. They are not incompatible, but they are different. JIS is the Shimano standard, except for track cranks. ISO is Italian and Track. These are generalities, but for the sake for this discussion it will work. The difference between the two tapers are the ISO is slightly smaller and shorter. Generally an JIS crank will mount about 4 mm farther on an ISO spindle (see http://www.sheldonbrown.com/bbtaper.html for more info).
I wanted to mount the crank on my fixed gear bike to see how it looked. I scrounged around and found a used bottom bracket with Shimnao NJS cups and bearings, and a Campagnolo ISO spindle. Track Spindles tend to be narrower than standard spindles, usually in the 107-108.5 range. This is meant to achieve a chainline of 42mm; this is compared to 46 mm of the standard road double. The Campagnolo spindle was stamped "68-SS-120". I am told this means the spindle is for a bike with a 68mm bottom bracket housing, a double chainring, with 120mm rear hub spacing.
The Spindle itself measured about 112mm. This would seem too long but it is asymmetrical. When installed in the proper fashion it would give you a 46 mm chainline, turn it around and the chain line was 42mm; nice! I put the whole thing together and it looked like this.
Since the Dura Ace arm was new, the difference on how far it mounted was only about 2mm. I also Dremel ('d) out the corners of the inside of the square taper so the crank could mount farther down the spline. Add that to the fact that the spindle was a little longer on the non-drive side and you have a perfect fit. If I someday do find a mate the Suntour right side I may go with an NJS spindle, but for now I'm quite happy with the result.
I've gotten the rear wheel back and it looks just as nice as before, but now it's 4 cross. I am also expecting the new Vittoria CX tires in the next 2 days' and Lickbike still hasn't credited my VISA (I think I'm done doing business with them). Next is the frame. I had toyed with the idea of getting a Keirin frame but all I would be doing is hanging my pretty new parts on a used banged up frame. Okay they are very nice, all lugged and custom made, but it wasn't made for me. It would just be one more Keirin track bike where I would have to compromise somewhere in the size and/or color. So I looked around and settled on a Soma; a 55cm in pearl white. I called American Cyclery (the Soma distributor in San Francisco) and they'll have one for me in 2 days. I told the wife and she wants a road trip to China Town (she's so good). The only custom part will be having the fork steerer cut and threaded; they come 1 inch threadless. I have a very nice Tange chromed steel headset I bought for just the occasion.