Octalink, MegaExo and new Compact Crank
 

I have a circa 2002 Wilier Gerolsteiner team frame, with Dura Ace kit. (No the Italian body has not rejected the Japanese organs as my friends predicted.)

It has an Italian thread BB (no kidding) with Shimano Octalink splines. I want to put on a compact crank. I would be happy to get a non-Shimano crank set (FSA etc). Having built it up from scratch, I am comfortable changing parts.

I think the issue is that Shimano has patented the Octalink, so I can't put another brand on the existing BB. I could easily buy a complete after-market MegaExo CC and BB, but I think most of the standard kits available online (from Competitive Cyclist, Nashbar, etc) come with MegaExo BBs that have English thread.

A new Ultegra CC is about $400. Other than finding a used CC online, is there a relatively inexpensive way to get a compact crankset on this baby? I can't do Boone with the standard crank.

Thanks,

Ian

Pro Bike Kit sells the Ultegra External Bearing BBs w/ Italian threads for under $22 w/ free S+H. As an aside, I recently bought a 105 compact crankset on eBay for $30 lightly used. The weight difference between it and the Ultegra standard crankset I was replacing it with is minimal.

I'd look for an R600 on ebay (or R700 if you want to go 10sp) as they go new for cheap and use modern BB cups. You can find them for around $100 and the cups will run around $30-50 depending on what model you get.

I'll second that.

But the cups should be more like $20

I would highly advise you to stay away from FSA compacts, and any of their cranks in general. Especially given that

a) you're running an all shimano drivetrain already
b) it's dura ace
c) FSA bottom brackets suck

Don't buy into a problem.

There's a reason their cranksets are cheaper, and that they get substituted for genuine shimano/campy/sram cranks, OEM. It's for pricepoint, not performance.

IRD used to make their Impala crank in an octolink version. It's discontinued now I think, but you might bebable to track one down. My first choice would still be the r600/700, but if you didn't feel like changing bottom brackets there is an option.

Thanks, but I need a bit more education.

Is R600 an earlier Shimano compact crank? If it is Shimano, why won;t it fit on the existing OctaLink?

Why would I need to change the cups? Isn't the splining on the center shaft? Not sure why a cup change would help.

Ian

The R 600/700 are Hollowtech II cranksets that use the external bearing BBs. The suggestion is to pick up one of these (pretty cheap on eBay) and replace your BB with the external bearing type.

Right around the time compact cranks became popular Shimano changed their crank/bottom bracket standard from Octalink to Hollowtech II. Short of the IRD I mentioned, I don't know that there is another compact crank that is compatible with an Octalink BB. If you are changing to a compact, you will almost inevitably have to change to the modern outboard cup style bottom bracket system. The good news is that overall the cups are generally cheaper than something like an Ultegra or Dura Ace Octalink BB.

When Shimano comes out with a product that is not in their current lines, they typically give it the R600 designation (or R500, R700 depending on quality level). Since their normal lines (105, Ultegra, DA) didn't have compact cranks available they came up with the R600 for 9 speed and the R700 for 10 speed. A year later they made a compact available in all their lines and the R cranks were discontinued. But they are great deal. Other than the chainring width the only other difference is that the R700 is a little lighter because it has hollow crank arms.

Chainring width did not change between 9 and 10 speed. They remain 3/32 as always.

Only the spacing became narrower.

if you can't find a R600 or R700, since they're discontinued, just go for a tiagra, 105 or ultegra.

Ahh.

Other than chainring spacing the only other difference is that the R700 is a little lighter because it has hollow crank arms.

Ok now?

Thanks to all for the education. I get it now.

One last question. After my rides in Boone, I will probably swap back to my 53/39 cranks. I'd then like to put the R600 on my wife's Bianchi which is otherwise all Campy. It's a safe bet the BB is Italian. Is there a problem putting Shimano chainrings on Campy drive train?

Thanks,


Ian

If you are going to install the entire Shimano crank and bb on your wife's bike, it will work fine with the rest of the Campy drivetrain.

There is a problem if you plan to change just the chainrings. Shimano uses 130 mm bolt circle diameters on their standard road cranks and 110 mm on their compact cranks. Campy uses 135 mm on their standard road cranks and a proprietary modified 110 mm bcd (one bolt is offset out of the 110 mm circle) on their compact cranks. Therefore the chainrings are incompatible between the brands.

BTW, I assume you know this by now but external cup bottom bracket cranks have the spindle built into and a permanent part of the right crank arm. They are not like the the older square taper and Octalink/ISIS bottom brackets that had the spindle as part of the bb itself.

You do have have something else to consider in that both yours and your wife's bike may require derailleur swaps to work right with the compact crank. Pre-compact era FDs were typically not spec'd for 16T jumps. And if you already have a wide range cassette your RD may run out of chain take up capacity. But some components work past their spec. Also, you may need to take a few links off your chains. Maybe somebody here has tried it and can let you know. What campy does your wife's bike have?

Octa-link is so last century,,, external bearings have pushed the other stuff off the podium.

Hmmm, I bought my current Campy square taper crank and bottom bracket in 2006! If Octalink is last century, what does that make square tapers? :)