Actually contrary to popular belief soft seats don't really help. If problems persist after a few weeks of riding head to your local bike shop and see if you can get fitted for a saddle (they measure your sit bones by sitting on a bean bag thing) and can recommend a saddle. Also some padded bike shorts/liners will help too that's the part you want padded not the seat itself.
Lastly and perhaps most importantly, bike fit. If you haven't yet get a fit done or read up on how your bike should fit. Small adjustments here and there can make a big difference.
Looking for the perfect mountain bike fit? We cover everything you need to know, from frame size to seat height and handlebar width, plus much more.
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Give it a few rides to settle in though, it takes me about two weeks of consistent riding each spring to work everything out to feel comfy again.