Actually, if you look/think about the design of the stringway mounting, you'll realize that this is a "user error" (or a mounting adapter design issue).
The babolat adapter is designed for the thin throat bridge piece to sit in the middle of the adapter. This may seem obvious, but the adapter doesn't sit at the correct height for the frame due to the hold down design of the stringway mounting stocks. Basically all that needs to be done here is either not torque the frame down all the way (keeping an eye on where the throat bridge meets the adapter) OR take an old leather belt (or plastic) and use them as a spacer beneath the racquet and THEN torque the frame down.
If you think about it -- the hold down mount design of the stringway itself does not provide ANY support for the frame. It's only used to keep the frame in touch with the white plastic mounting stocks.
My 2c.
Thanks to everyone who replied to my post. If nobody else has any problems I must be doing something wrong...
The problem is that even when trying to apply the tips, carefully mounting the racquet (while thinking ;-)) I am still having problems.
Case in point: Strung a Radical MP today using the normal throat supports. I decided to not use my normal workaround and mount in accordance with the tips given in this thread:
- Observing that the throat supports contact the frame and are symmetrical (same for tip supports).
- Very gently securing the hold down supports. I mean
very gently.
- Making sure that the center of the bridge was sitting at the correct height given its beam width compared with that of the racquet tip.
Proceeding to string as normal I made the following observations:
- The screws that hold the throat supports have a little play in them allowing them to tilt forwards.
- When tillted slightly forward this, together with the slight taper of the bridge cross section makes the racquet climb on the throat supports when the mains are installed.
- As the racquet climbs it begins to transfer load to the hold down supports. The load on the hold downs transfers to the mounting plate causing it to bend upwards where the hold downs are secured.
As a consequence, the frame is allowed to compress when the mains are installed. In this case the compression was 6mm. After installing the crosses the racquet was 2-3mm shorter than unstrung length.
Over the years I have owned the machine I have noticed that it is easier to work with box (or rounded box) beam/throat racquets since the throat on these racquets are far less prone to climb on the throat supports (for obvious reasons).
The problems I noted above are about the same as those I have with the Bab retainer. The main difference is that I have found a workaround that can be applied when using the normal supports but are difficult to apply successfully with the retainer. The workaround involves taking as much play as possible out of the system prior to stringing, even going as far as stretching the hoop approx. 1mm when mounting.
Also, regarding the retainer: I disagree that it is impossible for it to tilt when it makes contact with the bridge above and below the center. Since the center of the V-notch is above the anchor point (screws) a lever arm exists. That, along with the slight play in the screws that hold the throat supports is enough to start the problem. Once started it becomes self-reinforcing.