My 596cc TT Rep runs with a 21T gearbox sprocket. All the other sprockets are as standard and this gives a top gear of 4.8:1. With a 3.25 x 19 rear tyre this gives a speed of 72ph at 4000 rpm, 90 at 5000 rpm. I would like to try a 22T sprocket but I think this would be close to over gearing it
My 498cc 2 Speed Sports Squirrel also has a 21T drive sprocket and a 3.00 x 20 rear tyre but in this case 4000 rpm is 80mph due to different rear and high gear sprockets giving a 3.93 high gear. This is possibly slightly over geared.
Oddly enough on my track sessions at the VMCC Mallory Park event I felt happier at using the TT Rep at high revs than the 2 Speeder. I held the 2 Speeder back on the straight when I could have gone faster (65 – 70mph?) whereas on the TT Rep I think I sometimes touched 80. As I was only demonstrating I was more interested in the cornering than out and out speed