Hi, Chile!
When we had our road bikes fitted by a knowledgeable bike shop guy, we asked about our mountain bikes. We were both surprised that the fit should be the same - including seat height. We both adjusted our mtb's as best we could to match the fit we'd gotten on our road bikes and were really pleased with the feel. The higher saddle will help your climbing a lot, and, unless the steep is really really steep or loose and technical, should not get in the way when descending. I say go for the longer seat post and enjoy your riding and the increased speed!
Hugs and butterflies,
~T~



Reply With Quote