Track Crank Information, Looking for Real Numbers.

[Jamie Medeiros]

I am looking for information on Dura-Ace and Campagnolo track cranks. More specifically the x and y values of the chain rings and crank arms. I have been unable to locate any numbers for either. Shimano doesn't list any track info in the Products Technical Information Manual, and I have never seen a Campagnolo Technical Manual. (Does anyone know if such a book exists, and what needs to be done to obtain one?)

Thanks,

[benson]

Did you look on the Campagnolo website for the Technical manual?
The official Campagnolo web site - Bicycle Parts and Components Cycling - Technical documentation

[Jamie Medeiros]

For some reason the PDF wouldn't load this morning. It works now, it is good but still no track information in any of the three years of Technical manuals listed. Pages 25 and 26 of the newest one lists the type of information I am looking for but nothing on track parts anywhere.

[Too Tall]

I am looking for information on Dura-Ace and Campagnolo track cranks. More specifically the x and y values of the chain rings and crank arms. I have been unable to locate any numbers for either. Shimano doesn't list any track info in the Products Technical Information Manual, and I have never seen a Campagnolo Technical Manual. (Does anyone know if such a book exists, and what needs to be done to obtain one?)

Thanks,

Boss, can you repeat the question once more in english?

Are you talking BCD? If that is the case it is 144 > BUSINESS CYCLES: Track Components

[benson]

This is all I can find.
I guess that you didn't need to know all that other stuff back in the days when steel frames had lugs and 7/8" chainstays, .

[Jamie Medeiros]

Thanks, that confirms my research that the chain line is 42.5mm and I can do the math for the different tooth chain rings. Now all I need to find is the distance between the inner faces of the crank arms, which probably varies a bit depending on the maker. I have a Dura-Ace crankset arriving today so I will wait and measure it.

[Too Tall]

MasiSpecial, that graphic is from Business Cycles and is right on. James, Sheldon also has good info. to calculate the spec.s you are after: All About Bicycle Chainline

[Jamie Medeiros]

Yes, I looked at that. The thing I cannot seem to locate is the distance from the inner face of the crank arm to the center of the frame. With regards to their road and mountain cranks, both Shimano and Campagnolo give all the information I am looking for. They just give me nothing on the track equipment. For instance if you scroll down to page 19 in the Campy manual (page 11 of the PDF) http://www.campagnolo.com/repository...UAL%202011.pdf they give the distance between the left crank arm and the face of the drive side BB as 91.5mm and the distance to the same point for the right crank arm as 23.5mm. Track crank arms have a low "Q" factor and I am worried about the arms actually contacting the chainstays out where the pedals attach, not just the chain rings. I have built a gauge I call the Shimanolator that mimics a Dura-Ace road crank arm and various size rings, I am trying to make another to mimic track cranks. Someday perhaps I will build a mountain gauge.

[Tom Kellogg]

Over the last five years or so, these issues have gotten a lot worse to deal with. There are now a lot of SS crank sets out in the market and the range of centerline dimensions is huge. Just to give you one example, the SRAM Omnium crank set uses standard Piste chain line numbers as it should, but the thickness of the spider arms at the crank bolts is such that you need to build in quite a bit more spider arm clearance than you would need to do for either Campy , Shimano or Sugino cranks. And it is not just a little bit with some of the cranks out there.

Anothger issue is that the numbers that some of the companies give you for ring and arm clearances are not in fact what the cranks have. When I used to design for Merlin, they had AutoCAD templates that made it easy to copy them into a chain stay elevation for clearance checks. They made these templates directly from Shimano's spec. sheets. Sounds like a good idea, but it doesn't work. Shimano seemed to give very conservative numbers and we always ended up with more clearance than the drawings indicated. With Campy, it has traditionally been the opposite. Their cranks always seem to fit in a bit tighter than their specs, at least on road cranks.

Having said all that, what we do is have dummy set of cranks such that the "bottom bracket" slips into the BB shell with a crank set attached. Then we can see exactly what we are going to have in the real world.

Finally ... trust but verify.

[benson]

MasiSpecial, that graphic is from Business Cycles and is right on.

Nope, that graphic comes from the Campagnolo #18 Catalog

[suzyj]

Track crank arms have a low "Q" factor and I am worried about the arms actually contacting the chainstays out where the pedals attach, not just the chain rings.

I've had this happen. The combination of Campagnolo Record cranks, LB106 BB (which is built more for touring applications, with a large gap between chain stays), short chain stays, and LR15 socketed dropouts (which locate the inside end of the chainstay in the same plane as the inside dropout face) resulted in about 1mm clearance between the pedal end of the crank and the chainstay. Once I actually rode the bike and sprinted, the cranks would tap the chainstays, resulting in the cranks coming loose in surprisingly short order.

Not a good look.

[Andrew Cooper]

I do generally dummy the cranks if I am not able to get the information. That is if I have them on as dummy's or purchased them early in the build to check