Every stationary trainer lifts up the rear wheel to enable to spin the wheel.
If you train in this strange position, you will have to apply unnecessary force to the handlebar to support your upper body. It's not good for effective training and for learning correct riding position. You should sit on the saddle and relax the arms.
Mag Riser is a plastic block to level the bike by putting it under the front wheel. There are two different grooves on the upper side. Wide & shallow groove is for MTB's fat tire, and the narrow & deep groove is for 700c road bike tire.
Part Number: 400-3231-00
Barcode: 4944924403935
Product Code: MIN TTD A RIS