Yes, a 1.25 inch roller is a good all-around size, but the 'best' roller size depends on motor HP, rider weight, top speed required, and terrain...
A heavy rider, in hilly terrain might be better off using a 1 inch or even 7/8 inch roller, whereas a featherweight rider on flat terrain could go with a 1.5 inch roller.
Yes, a 1.25 inch roller is a good all-around size, but the 'best' roller size depends on motor HP, rider weight, top speed required, and terrain...
A heavy rider, in hilly terrain might be better off using a 1 inch or even 7/8 inch roller, whereas a featherweight rider on flat terrain could easily go with a 1.5 inch roller.