Hi, I have two bikes that i use interchangeably. First one is a trek slash 7 2015 small sized which i use for downhill and some gnarly trails. Second one is a mondraker vantage RR 2015 small sized which i use for mellower trails. The vantage is quite long and is longer than the slash for about 58mm on the ETT... i compensated it with a shorter stem of 30mm for the vantage, the slash has a 50mm stem. Will using two different bikes with almost different sizes and feels affect my skill progression, as I am currently still an intermediate rider with just 2 years of riding experience?
It will probably make you a better rider if you can feel the differences and adjust your riding style ! I have 2 bikes ( meta V4 and a Scott voltage) , just take a few minutes and I'm good !