Originally Posted by Austinthecity
What does the tubing around the o-ports do? (as seen on Isner's frame)
What is tubing generally used for?
Tubing is generally used today to replace broken grommets. This keeps the string from rubbing on sharp edges. In Isner's case, the tubing is used because O-port frames tend to have some less than rounded edges, and as a result, snap strings. If you recall, last year, Isner was having a lot of problems with his strings continuously snapping. The easy fix was to tube his frame, but is is a major pain in the rear. ken did a great job with his frames.