Both are 160's and it looks to be as heavy, etc. Here's the web site with the same rotor for the Winzip brake that is used on the Sun trikes. (I hope nobody thinks I work for that site, like I was accused of not to long ago. It's the only place I've seen the Winzip brake/rotor.) http://www.bicycledesigner.com/defau...umber%3D505202

Nothing was changed to install the Avid rotor...it just bolts on like the old rotor did. I almost didn't pull it when I got the Avid, but it was a little warped. Here's a picture of how the rotor goes on the trike. In this they are using an Alfine trany...but it bolts on the same way on the stock hub. http://www.utahtrikes.com/RECENTTRIK...Sun_X3_SX.html

Yeah, it's the Roundagon.

Thanks,
Mr Gnome