11 speed spacing

[Rueda Tropical]

Campy 11 speed chainrings are available now so you can convert a 10 speed crank to 11. I know the 11 speed teeth are narrower -is the spacing the same between 10 and 11 speed cranks? I recall having to switch spacers going from 1st gen 9 to 10.

[Dave]

The spacing is about .6mm closer and the teeth are .1mm narrower. I would not bother with a chainring swap unless your chainrings are shot. I've had no trouble using my 10 speed crank with 11 speed.

The spacing change was done in the same manor as the only other spacing change in 2000 (.4mm for 10 speed). The mounting surface of the big ring is machined thinner to bring the big ring closer to the little ring.

Since one of the bolts attaches the chainring to the back of the crankarm, it would make sense that a thin shim washer should be required between the crankarm and the chainring, since the big ring is located further to the left. I would assume it needs to be .6mm thick. I have three 11 speed cranks and none of them have any washers, so apparently the 11 speed crankarms were made to fit the new rings without any spacing washer.

[oldpotatoe]

Campy 11 speed chainrings are available now so you can convert a 10 speed crank to 11. I know the 11 speed teeth are narrower -is the spacing the same between 10 and 11 speed cranks? I recall having to switch spacers going from 1st gen 9 to 10.

Like using a '9s' crank on a '10s' system/chain, no need to swap rings for 11s. I have ridden a Chorus 11s with a Record 10s compact crank w/o any problems.

[Rueda Tropical]

Could someone put a caliper between the inner and outer 11 spd chainrings and get a measurement?

I've found Campy ergo will shift just about anything up front (it seems 11 will be like 10 in this respect) but I'd like to get it set up to spec.

[Tobias]

Since one of the bolts attaches the chainring to the back of the crankarm, it would make sense that a thin shim washer should be required between the crankarm and the chainring, since the big ring is located further to the left. I would assume it needs to be .6mm thick. I have three 11 speed cranks and none of them have any washers, so apparently the 11 speed crankarms were made to fit the new rings without any spacing washer.
Dave, does this not assume the new rings to be of same thickness as before, and also the spyder tabs? Have you measured the new crankarm and ring mounting surfaces' thicknesses? I'd be interested in knowing what the differences are. Also if either new ring is dished to move them closer. :)

[oldpotatoe]

Could someone put a caliper between the inner and outer 11 spd chainrings and get a measurement?

I've found Campy ergo will shift just about anything up front (it seems 11 will be like 10 in this respect) but I'd like to get it set up to spec.

"The spacing change was done in the same manor as the only other spacing change in 2000 (.4mm for 10 speed). The mounting surface of the big ring is machined thinner to bring the big ring closer to the little ring."

Yes, LH ERGO starting in 2009 is like the LH shifting of 2006 and older(all levels(and Record/Chorus of 2007/8). Any FD will work. I just installed a 2008 FD onto some Rotor rings(the egg shaped ones) and 11s Chorus ERGO, works fine.

[Dave]

The problem with trying to take some of the proposed measurements is the chainrings are not uniform in thickness, so there is no point where you can just take insert calipers and take a spacing measurement.

The teeth are quite a bit thinner than the ring. The teeth can be cut off-center to alter their position relative to the mounting surfaces. Campy's teeth are located close to the right face of each ring.

When I first got an 11 speed crank, just a visual inspection showed that the area where the big ring bolts to the spider was cut quite a bit thinner to move that ring closer to the little ring. That's always been Campy's method of altering the spacing.

With the crank on the bike, the best way I have to check the tooth spacing is by measuring from the side of the downtube to the tip of a tooth on each ring. I use a precision machinists scale with .01 inch increments. I come up with the tooth spacing of .30 inch or 7.6mm. I have an FSA crank that dates back to 2003. It's got a nearly identical tooth spacing of .310 inch tooth to tooth.

Edit: I just found a Campy drawing for a UT crank and it shows the left side of the teeth to be positioned 4.6 and 12.3mm from the face of the BB for a difference of 7.7mm. It shows the shifting ramp to be located 10.3mm from the BB face. Unfortunately, there are no dimensions to the chainrng mounting surfaces.

About the only advice I can give to someone wanting to try 11 speed rings on a 10 speed crank is to buy them and mount the big ring. I'd check the ring for runout before installing the bolt behind the crankarm. If it runs true, then see if there's a gap to be filled where the ring mounts to the crankarm. It might require a thin washer, but maybe not.

I measured the aluminum spacer that goes between the big ring and little ring, at the crankarm mounting bolt and found it to be .151 inch or 3.84mm thick. This should be the same thickness as the spider arm mounting tabs. AFAIK, Campy has never altered this thickness to reposition the chainrings. When 10 speed came out, the info I've read claims that the big ring mounting surface was just machined .4mm thinner than 9 speed. I did my best to measure that thickness with both 10 and 11 speed cranks on the bike and came up with a thickness that is .6mm thinner.

[Tobias]

I measured the aluminum spacer that goes between the big ring and little ring, at the crankarm mounting bolt and found it to be .151 inch or 3.84mm thick. This should be the same thickness as the spider arm mounting tabs. AFAIK, Campy has never altered this thickness to reposition the chainrings. When 10 speed came out, the info I've read claims that the big ring mounting surface was just machined .4mm thinner than 9 speed. I did my best to measure that thickness with both 10 and 11 speed cranks on the bike and came up with a thickness that is .6mm thinner.
Thanks Dave. Does this difference mean the chainring bolt length also changes?

[Dave]

Thanks Dave. Does this difference mean the chainring bolt length also changes?

I have no idea. I don't have a Campy 10 crank left to measure.

[oldpotatoe]

Thanks Dave. Does this difference mean the chainring bolt length also changes?

I measured the chainring bolts this morning, from SuperRecord and 10s Record. The main 4 chainring bolts are the same width, both mail and female. The one hidden one under the crank arm is .4mm shorter for the 11s one.