I have 3 Arc ZS, all strung at 28lb. No problems so far (touches wood). Just make sure the grommets are in good condition as they would help reduce the stress on the frame. Some of the gromment near the top of the ArcZS frame don't stay flush very well when stringing, so pay attention to them when tensioning.
I used to run mine at 29, never had a problem. Tago had 35 in his! As @R says, be careful of the grommets at 2 and 10 o'clock.
I understand what flush means, but does it meant by the grommet head 'sinks in' into the frame? I'd read somewhere in the thread that some forumer replace the single grommets at top of frame with U-shape grommets. Is this a good practice?
My stringer did this last time, too. Put a U shape grommet at 12 O'clock. I think that this question is not easy to answer. If you have a bad stringer or only a 2 point support, he can break your racket @ any tension. I think that every high end racket can take 27lbs+ and more. At around 30lbs you must count in broken racket due weakening the frame after some years.
No, it's not sinking in. The grommet is actually pulled/dragged out of it's hole as you tension the string. I can't remember which exact hole, but it's around the 2 and 10 o'clock position as MarkA said. I seem to remember it's one of the "additional" holes that Yonex introduced to prevent hole sharing. The way I get around it is I tension very very slowly whilst holding the grommet tightly with my finger. It just needs to stay in place until the tension is applied. It's not the grommets at the 12 O'clock position. But putting U shaped grommets at this position won't do any harm and may even help with durability.
Thank you for the clarification.. I checked mine (thoroughly check), didn't find any.. by the way, my z-slash was tensioned at 27lbs with nanogy 98.
Just restring my z-slash (2nd time stringing) with 66UM at 27lbs. The 2 and 10 o'clock grommets were "popped out". It was the same when I first got it stringed with the same string and tension.
i've strung BG85 @ 28lbs on the z slash and it didn't crack. but as the rackets get worn out, the grommets are loose within the holes. what i would recommend is that once you see the grommets get a bit worn out, replace them with new ones, or else your racket will suffer. i've strung it for the same customer a few times and so far so good.
This happened on the brand new NR-ZSP's I strung as well. I can only suggest the stringer tries to hold those grommets in place with your finger while the relevant string is being pulled.
For those who have a 6-point machine, either try and hold the grommet in whilst tensioning. Or post stringing, you can put the racquet back onto the machine, clamp down, using the string puller, pull the string to one side (so that the string is parallel with the grommet) and push the grommet in with you fingernail. Keeping constant pressure with your fingernail, pull and release the string gently and repeat this several times. I found that the grommet will sometimes move back in very slowly. Also as the grommet is bent to one side, on the next restring, turn the grommet around 180°.
Why? because the grommet has come out or the string is protruding? This is a problem with the design of the racquet imo. The recess for the grommets is shallower on the ArcZS than most other racquets and the angle at which the grommet is positioned and the spacing makes it prone to moving when the string is tensioned. Due to the shallow recess the grommets appear higher, and any string that overlaps the grommet head are unprotected. It doesn't happen all the time but it is a trait of some racquets (my MXJJS does this sometimes) - not necessarily a sign of a bad stringer.