Weight Weenies

I have a bicycle with Chorus 12 speed including a 48/32 crankset and the position of the crankarms seems to be different from my 11 speed Campagnolo (50/34) cranksets even though all of them supposedly have a q-factor of 145.5mm (the bicycles are set up identical regarding seat height, distance to handlebars, etc).

After riding two ("hard") days in a row with a 11 speed crankset I switched to the bicycle with the 12 speed Chorus (for an "easy day").
Immediately something felt weird with the right foot: it wasn't in the "correct" position.
After maybe 5 minutes that feeling was gone, the right leg had "adjusted" to it. But after 60 minutes the right knee started to hurt -- so something
is different wrt the crankset.

I checked the distance from the center of the seattube to the inside of the crankarms (at the level of the pedal insert).

12 speed: drive side 62mm, nds 58mm
11 speed: drive side 60mm, nds 60mm

Is this normal for a Chorus 12 speed crank or just for the 48/32? Could it be that the smaller chainrings require more distance from the seat tube / seat stays?
(which might also apply to the new "SRW" cranks which is why the q-factor is bigger?)

Could someone who has a 12 speed Campagnolo crankset please measure
the distance from the middle of the seattube to the inside of the crankarms
(both sides) and post the information here (including the size of the rings and whether it is SR/Record/Chorus etc)?

Thanks!

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Chorus 12s 172.5mm crank here, 48/32 chainrings. As near as I can measure, the backside of pedal insert is equidistant from the seat tube.

Is it possible that you put the wavy washer on the drive side of the BB?

Thanks for measuring and posting!

darkmother wrote: ↑

Tue Jun 06, 2023 3:21 pm

Is it possible that you put the wavy washer on the drive side of the BB?

Then the drive side would be further out, not closer, right?

claus wrote: ↑

Tue Jun 06, 2023 2:56 pm

Could someone who has a 12 speed Campagnolo crankset please measure
the distance from the middle of the seattube to the inside of the crankarms
(both sides) and post the information here (including the size of the rings and whether it is SR/Record/Chorus etc)?

Thanks!

The technical document for the crankset has the measurement spec
Does not mention any asymmetry

My bottle cage is in the way so I measured from centre of screw (hopefully it was centre of seatpost)

Got 60.5mm both L and R on vernier Record 50/34 170mm crank..measured to where pedal attaches

claus wrote: ↑

Wed Jun 07, 2023 4:26 pm

Then the drive side would be further out, not closer, right?

12 speed: drive side 62mm, nds 58mm

Yes. That is what you posted.

There shouldn't be any asymmetry by design.

in Ultra-torque the Hirth joint can't adjust the distance between crank arms so if the BB shell is out of spec, you could end up with them slightly to one side. However, I wouldn't expect as much as you're seeing.

I'd suggeset:

1) as suggested already, take cranks off and check location of wavy washer
2) measure width of BB shell to check is in spec

Thanks for the cluestick...

There was no wavy washer on the DS -- but none on the NDS either.

After adding one to the NDS it seems to be ok.

the wavy washer in campag systesm is for accomodating different tolerances. If it was missed out and there wasn't play in the cranks, seems like your bb shell could be on the over-large side

It's like gravel chainring combos.
I use Wickwerks 44/34 and 11-36 with my 6870 Di2.
You just need an adapter to lower the FD and also drill another tension spring hole in the RD.

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