Singlespeed & Fixed Gear - Surly Fixxer and XTR Hubs issues - Need help...

I have a Surly Fixxer on my XTR hub and for whatever reason I'm getting some annoying rotation when track standing, accerlating, or braking. The cranks at the pedal are only moving 1/4" to 1/2", but it is enough to drive me nuts. I've checked the cog, lockring, etc, all tight. I can see the fixxer body move against the hub.

Can anyone help?

Is your chain tension snug enough?

Is your chain tension snug enough?

very tight. The weird thing is I can see the fixxer moving, and the hub body is not. It's like the interface between the two is too loose. Not sure how to fix it. I might shoot the boys at Surly an email.

I would contact surly. Sounds like a compatibility issue.

Are many street fixie riders using the Fixxer?
Doesn't it screw into the hub? Wouldn't that unscrew itself anytime you put a lot of backpressure on it, like skids/skips/trackstands/backward circles?
I thought that would be an issue like the freewheel adapters that screw on the disk and trispokes.

this is not uncommon with the fixxer.

Are many street fixie riders using the Fixxer?
Doesn't it screw into the hub? Wouldn't that unscrew itself anytime you put a lot of backpressure on it, like skids/skips/trackstands/backward circles?
I thought that would be an issue like the freewheel adapters that screw on the disk and trispokes.

+1...those things should have a disclaimer, i also bought one just for an easy conversion. not sure about the surly ones, though, i'm guessing they'd be targeted more toward street riders. i could be way wrong, though.

Doesn't it screw into the hub? Wouldn't that unscrew itself anytime you put a lot of backpressure on it, like skids/skips/trackstands/backward circles?
I thought that would be an issue like the freewheel adapters that screw on the disk and trispokes.

Not how it works at all. Shimano cassette bodies use a female star interface so there is nothing to unscrew.
If I were you, I would put an alumnium shim along the edge of the splines before re-installing the fixxer and being sure to tighten the 10mm fixing bolt to the reccomended torque (very very tight).

JB weld ould also work there too, not to stick the two pieces together, but to take up the space that's creating the play.

Not how it works at all. Shimano cassette bodies use a female star interface so there is nothing to unscrew.
If I were you, I would put an alumnium shim along the edge of the splines before re-installing the fixxer and being sure to tighten the 10mm fixing bolt to the reccomended torque (very very tight).

JB weld ould also work there too, not to stick the two pieces together, but to take up the space that's creating the play.

The shim idea is a good one, well so is the JB Weld one too. The whole issue is more annoying than dangerous. Thanks for the ideas.