These are new grommets I just put in.
Uh huh... as I suspected (and hence why I immediately inquired).
I'm willing to bet that (in replacing the grommets) you've installed the side grommet piece (which runs from 10H all the way down to 10T) upside down.
You may not think it makes a difference because, at first glance, that side grommet piece
appears to be symmetrical, but it's not.
The very last hole/tube in that side grommet piece is bigger at one end (to accommodate 2 strings), and smaller/regular sized at the other end (to accommodate only 1 string).
You
must orient the end with the bigger hole/tube towards the throat of the frame, and
not the head of the frame.
This is because 10T is a tie-off location (for the bottom cross) and you need to have this bigger grommet barrel going into 10
T, and
not into 10
H.
Otherwise, it will cause multiple problems with the grommets fitting correctly.
Yes, I know that the mains don't even run through this side piece whatsoever.
So, you may be thinking "even if this piece
is upside down, what difference would that even make when I'm pulling tension on that 8th/last main?"
Just because
none of the MAINS actually pass through that side piece, don't fool yourself into thinking it couldn't possibly make much difference (after all, the mains actually only pass through the grommet piece along the lower shoulder).
It's hard to put into words but, take my word for it, it
does have an effect.
If/when this side grommet section is oriented
incorrectly, the end with the smaller grommet barrel will be down at 10
T and the end with the bigger grommet barrel will be all the way up at 10
H. Having the bigger grommet barrel up at 10
H will pose an even
bigger problem at the junction where the side grommet piece meets up with the grommet strip section that resides in the bumper guard (between 9H and 10H).
If the big grommet barrel is up at 10H, then it will not want to fit all the way into/through the actual drilled hole in the frame. This will cause the grommet(s) to awkwardly bulge outwards.
The grommet at 10H won't sit correctly within the frame. Therefore, one of two scenarios will occur. The grommet junction outside the frame (between 9H and 10H)...
- will not have a loop of string over it, and the grommet strip ends will bulge badly outward (as if someone is pulling the end of the grommet strip up with invisible pliers), or...
- will have a loop of (cross) string over it, thus the bulging effect will expose this section of string to court scrapes (the string will now be above what the bumper guard can protect).
The 2 scenarios above are dependent on which side of the frame the bulging grommet happens to be on... as well as which side of the frame the crosses were started on.
And... if the side grommet piece in installed wrong, you will
also encounter troubles in attempting to tie off the bottom cross at 10T (because the smaller barrel grommet is now at 10T, rather than the larger one).
You'd find yourself wondering why it was difficult to get your tie-off string through that smaller grommet (after all, it wasn't meant to have 2 strings passing through it).
I didn't have any problems on the other side for the 8th string.
Now, the reason you didn't have any problems with the other side of the frame is because, in all likelihood, you simply got lucky and installed that side grommet section correctly (bigger grommet tube being at 10T, instead of up at 10H).
Additionally,
even when the grommets are installed properly, certain racquets (especially Babolat) have a tendency for the grommets to pull out/away from the frame when tensioning some of the mains.
Namely, whichever main first exits the bottom grommet at the lower shoulder of the frame (if the frame has 6 holes in it's throat bridge, this would be grommet 4T... if the frame has 8 holes in it's throat bridge, then this would be grommet 5T). The angle of the pull will sometimes try to make the end of the grommet strip pop out.
The same thing can sometimes also happen when tensioning other outer mains too (just like when you were tensioning that 8th/last main).
It is a very good habit to always hold these grommets in place, with your fingers,
just before AND during tensioning of these main strings.
This exact technique can been seen from 4:25-4:32 in the following video by
@Richard Parnell. You'll notice that it is the 8th/outside main that he is tensioning, while holding the grommets in the frame with his fingers.
And also here, from 6:50-7:17, whilst tensioning each of the 4th mains exiting from 4T.