Hi there.
Have been looking on several forums, but couldn't find an answer...
Well, as my lousy skills slowly progress, I find this mechanical dead zone more and more annoying, expecially when changing car's directions, there are those few degrees of rotation when the wheel doesn''t respond as it should. Yesterday I made many laps with the RAC and it was quite obvious that this is a major problem.
Being my first wheel I didn't notice it right away, and I've got accustomed to this "feature" (which has always been present).
There is no dead zone in the calibration, wheel runs steady and smoothly, but I feel that something in the inner mechanism (FFB belts...I guess) has a bit of "play", and the problem is present only when FFB is set > than 0%.

I don't even know if mechanical dead zone is the right description for these symptoms...anyway the question is: is it a known issue ? Is there a way to fix it ?
I mean is it possible to open the wheel and tighten something ?

I haven't noticed a dead zone in the rotation detection, but there is a dead spot in the middle of the FFB. Perhaps that is what you are talking about?

If so, this seems to be present on every logitech wheel. however, I haven't realy noticed it on my DFGT, it seems like it's actualy smaller than on the G25 I used a while ago.

There realy isn't a way to make it go away, it's just the nature of FFB motors. Some companies deal with this problem in different ways, logitech seems to use a very simple design that makes it very noticable.

From the DFP I recalled the same problem. It has a 'dual stage' transmission, i.e. wheel, big cogwheel, to small cogwheel, to big cogwheel to motor small cogwheel.

Every gear/gear 'contact' has some play, and the second gearing is amplified; if the gear ratio is 8:1 and the second stage has 0.5 degrees of free play, you'll feel 8*0.5 = 4 degrees of play at the steering wheel.

A G25 has a single transmission where this problem is probably some 8x less bad..