Unexpected Powertap hub noise issue

[makoti]

I just changed a bike over from Campy 10 to 11. Was using a Powertap rear wheel with it. So I just slapped on an 11 speed Chorus cassette & figured I'd be good to go. But when I pedal backwards or the wheel freewheels, I get a sound like something is clicking. Not the RD, because it happens on two bikes. It sounds like something is hitting the spokes, but I don't see anything & it only happens when the wheel is locked down on to the bike. It shouldn't need a spacer, right? Campy 10 & 11 are compatible. Right?
Thoughts?

[nate2351]

Have you made sure the lockring is torqued down all the way?

[makoti]

I'll check again, but I got it as close to what was on the ring (50?) as I could.

[oldpotatoe]

I just changed a bike over from Campy 10 to 11. Was using a Powertap rear wheel with it. So I just slapped on an 11 speed Chorus cassette & figured I'd be good to go. But when I pedal backwards or the wheel freewheels, I get a sound like something is clicking. Not the RD, because it happens on two bikes. It sounds like something is hitting the spokes, but I don't see anything & it only happens when the wheel is locked down on to the bike. It shouldn't need a spacer, right? Campy 10 & 11 are compatible. Right?
Thoughts?

'May' need a 1mm spacer or one of the thinner ones found with Wheels Manufacturing cassettes.

[makoti]

'May' need a 1mm spacer or one of the thinner ones found with Wheels Manufacturing cassettes.

Please tell me these are standard & easy to find...

[oldpotatoe]

Please tell me these are standard & easy to find...

Wheels makes everything from .3mm on up. But I think the cassette is tickling the spokes, so may need a thin spacer on first. Got a decent LBS around?
Might contact PowerTap also.

[shovelhd]

Is your RD hanger straight?

[makoti]

Is your RD hanger straight?

Happens on two different bikes & not with me other wheels, so I'd rule that out.
OP - yeah, they do most of my work (put the 11 on this bike), so I'll ask them Monday when Derrick is in. Not gonna mess with the weekend crew.

[makoti]

To close the loop & if anyone else runs into the problem...
Took the bike in & they put a 1mm spacer on behind the largest cog. End of noise. Got a second one to set up my other wheels the same so swapping wheels will not be a pain.