I got these two balls this week so this is a short comparison with little use but I thought worth a look.  Rob Herman suggested some layouts for a Track arsenal and my driller looked at them and tweaked them a bit for my stats. which are in my profile.

920T 50 4" 45 X hole at P2
715C 55 5" 40 no X hole


Both balls in OOB surface. After last night (5 man league)...920T is a rolly arcing ball.  Good on fresh mediums and up.  Rolly arc because of the box surface 4000 ab and layout plus it''''''''s a traction ball.  715C surprised me while it has some control built in and not a skid flip ball but if you get it to the friction it is angular more so than I thought it would be again because of the OOB surface 2000 ab and Powerhouse factory finish.  I could knock off the polish with a 4000 ab pad but then I think it would be closer to the 920T.

BTW.....lane condition used these balls on is a 39 ft. THS 19.7 ml with what I term semi-poor lengthwise taper with too much volume in the backend that seems to carrydown faster than many centers probably part of the reason is the 15 year old Bruns Anvilane panels.  
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Scott





Edited on 10/22/2010 8:27 AM