Originally Posted by Gallo

There are allot of factors and probably the least limiting factor is the bike. Fitness Talent and skill make up for most speed. If you fitness is good you need to break some barriers. A fitness routine of hill repeats and sprints helps you break fitness barriers. Skill on the mountain bike is no small thing either. As you point out shaving some times around corners and know when to accelerate and when to brake when to weight your front tire when to let it flat out run are key components of speed. Some guys are just plain faster and better and that is talent.

I have a 2008 Stumpjumper Hardtail and a Pivot 429C full suspension. So one big difference is wheel size. Which is a whole nother conversation. On the flats the 29r has an advantage ramps up and rolls faster. On really twisty stuff the 26 is more nimble. Climbing the same routes I have not seen much difference. Descending the full suspension is much better.

Not all of these factors translate to all out speed. Having the full suspension did make me more confident and therefore faster on descents but that skill has translated over to when I ride the hardtail. I am way more comfortable on the full suspension. Less beat up after rides. When I get out on the Hardtail it puts a smile on my face familar as I rode a hardtail for years whippy and fun.

The bottom line is both bikes can be fast you just have to ride them fast.

I think the dropper post and tubeless set up are the two things that improved my speed more than my new bike did.

Bottom line is if you love to ride get a good fs that fits you. If you are worried only about speed your current bike is probably not holding you back as much as you think.

One sure way of getting faster is ride with faster folks and hang on to their wheel for dear life while you suffer.

btw I ride socal canyons lots of short climbing +- 300 vert and chunky sections mostly clay like hard pack

Good luck