If you had your choice…
19 lb compliant Hardtail, or 22 lb 100mm dual suspension for Xc , and Xc marathon 50-75 milers.
What would you pick and why? Assuming groupset etc all the same. And also that each can lockout the suspension via handlebar lever.
Full Suspension. Faster and more fun.
Why? Because I raced a 19 pound hardtail for several years on marathon XC and now I’m on a full suspension and I’m faster and having more fun 
In all seriousness though, full suspension bikes now are so good on the climbs and they give you so much in return in rougher terrain for being able to go at speed, especially with the new geometry, that the only reason to pick a hardtail is weight at this point at 22lbs, you aren’t really giving much up there either.
I made the switch from Carbon hardtail(Pivot LES) to a FS(Yeti SB100) and I dont know that I could ever go back. The first few rides felt slower, but after getting it all dialed in all my PR’s started to fall at a lower RPE then before. I had a 2009 Giant Anthem FS bike for awhile, and it was so sluggish and I hated it and swore to never go FS again, but as @stevemz said, modern FS is so damn good I hardly notice it moves under me.
The SB100 really is such a fun XC/trail bike. It’s really the best mountain bike I’ve ever owned, and I’ve owned a lot of them.
full suspension
why? because I’m getting older and that level of travel, albeit limited on a XC bike, has a huge benefit in terms of comfort and therefore freshness over a long distance event.
BUT
That is assuming all things are equal because there are factors that are as important as FS v HT to your overall performance - head angle, pedal bob, chainstay length, seat angle etc.etc.etc
Rear suspension adds cost, complexity and more maintenance, but I’d still go with FS.
I have a hardtail for similar types of racing…reason? Cost…I have five kids and just can’t swing a FS at this point
Full sus for me. Definitely more comfortable. And may also be faster, depending on the terrain you are riding on.
I have both, I think its pretty necessary for short xc races. Both my bikes take he same race wheels, ie I scrimped on one set of race wheels, and one set of training wheels with cheaper tyres, one stages power meter that goes on both bikes. Three years ago I would use my hardtail for 8 out of 10 races, this year its 2 out of 10 using the hardtail. But on certain courses its defiantly the correct option. So if I had to choose it would be FS.
training is mostly done on the HT, less maintenance, and it can go on the trainer.
I have a 21lb hard tail and a 33lb FS… quite sure I am still faster on the FS through anything remotely rough. Climbing is not as big a difference as I expected it to be. even with my FS bobbing something terrible ( it’s old with no lockout) I can still sit and spin that puppy up the same hills at roughly the same pace I can move my HT.
Both, of course. 
I got just got a new Procaliber 9.8 SL to round out the stable. Nice to have as a throwback bike and work on trail skills again, like the old days.
That and my Top Fuel 9.8 cover the racing end and my Stumpy as the play bike on the Springer side.
The Procaliber is great. I wish the 34SC had been available when I was racing on it, because part of the reason I got rid of mine was that I hated the Sid.
I still have a crazy side project rolling around to build up a single speed hardtail for the next time I make a run at Leadville.
Something like this is the only thing that would tempt me back to the hardtail
That’s killer. A riding buddy got last years Procaliber too, and went single speed with it. He loves it. I want to try geared for now, bit might play with SS eventually.
I just need to get the dropper and it will be ready to play.
I went full rigid for my singlespeed, probably the best bike for some of the local weeknight race series around here. Mine is only 20 lbs though since my wheels are still 32 spoke and i decided to go with a dropper post. I’m still a little bit skeptical over 19 lb claims without pictures since a cassette shifter derailleur and suspension fork should be more than the penalty I’m getting from the dropper post and a little bit heavier wheels.
My main bike is a Jet9 though so i gladly give up much more than the proposed 3 lbs in the op for a fs bike. Climbing rougher terrain on a fs feels better but isn’t always faster.
Hi all!
I need help deciding between two bikes - sorry for bumping a 3 year old thread for the same old story!! but would love some advice as i am completely new to MTB.
I have an opportunity to trade my 2022 cube reaction pro c:62 hardtail (XT) 2000EUR with a very good condition aluminium giant anthem 29 2 from 2020 full sus (SLX) 2800 EUR.
The Cube probably weights 11.5kg maybe 12 with dropper where as the giant is likely closer to 13.5kg without dropper.
I race and ride XCO (35-45 mins) mainly on ‘natural trails’ - so very rooty, slippy and Techy. I do tend to lose a lot of speed, particularly on Rooty sections where I get bounced all over the place. I generally take this as inexperience but also probably a hardtail doesn’t help.
I do use my hardtail for a good bit of riding to and from the trail, and some longer road rides on weekends, I really enjoy it for that.
I am 66kg, 26 years old, 4.5wkg and new to MTB, started in January 2022. I generally finish top 10. Some guys are way faster, even on old hardtails - so i have no excuse either way!!
Thanks
I wouldn’t upgrade to full sus unless you are going for a carbon fibre frame. Id save and buy something more expensive down the line.
If you want bang for buck performance, especially for such short races, upgrade your hardtail. New carbon wheels perhaps?
Digging up and old post here….
How did he make his Procal single speed? I’ve been dying to but the math doesn’t work out for an eccentric bottom bracket?
He use one of those Shimano chain tensioners.
Thanks!
