When you truing the wheel you do the truing 100%. 100% truing the wheel can happens with the eye and truing stand park tool Ts-2 or TS-2.2 or is need dial indicator to use for the wheel is be 100% prefect round.

There is no 100%. Lots of folks talk about half a millimeter as a standard to shoot for but, if you are working with a used rim or even a lower end new rim, that's probably not going to be possible.

I've often said that I sometimes feel like an analogue guy who has been trapped in a digital world. Dial indicators for wheel truing are just a way to quantify what my eye sees so I don't need one.

I use my eye, and I can almost always true a rim to much better than half a mm.

Granted, I'm only on my sixth or seventh wheel, so this is just beginner to beginner. I shoot for roughly a half millimeter of truth. Once it's there, then I figure that I'll probably have to re-true it at some point in the future, even if a pro could have made the same wheel stay true forever. I've also re-trued factory built wheels. What I've learned since I built my first wheel, is the importance of getting the spokes up to a good tension. That, and washers on the spokes for my old Sturmey Archer hubs, have eliminated spoke breakage for me.

I build hundreds of wheels a year, and although I have a dial indicator, I never use it for wheel truing. I keep my feeler gauge handy and shoot for .2mm but sometimes have to settle for .5mm. It really is good enough for any application.

At the final truing stage, I usually give priority to correct even spoke tension, and then try to get the truing as close as possible without compromising the even tension.
I prefer correct even spoke tension to perfect truing <0.5mm
YannisG

This is the thread's best post. A stable wheel which doesn't break spokes is FAR more worth while then a wheel within .020". Andy.

+infinity