I was looking at the current Scalpel which has a 69.5° HT angle

Thanks for your thoughts on it

I recently purchased a "modern geometry" mountain bike with a 66.5 degree HT angle, long reach, very short chainstays, a steep seat angle and a 50MM stem. Riding this on the trail has been a revelation for me: it's more stable, more comfortable and much more confidence inspiring. I personally really like the "long and low" design on many bikes these days. My last mountain bike prior to this one was purchased in 1993, so it's been a while. That older, more upright bike (with a useless elastomer-based fork) was really tricky to ride with any kind of confidence on a rough trail.

Regarding full suspension vs. hardtail. I personally feel that full suspension is faster, more comfortable and makes riding tough trails far easier. However, maybe making things more comfortable/easier is not what you're looking for. Personally, I'm a hardtail guy. I prefer the simplicity, I like the feel while climbing and I'm not exactly racing EWS or shredding Downieville. That means an alloy hardtail with 1x11, a Fox 34, nice wheels and a remote dropper for me. YMMV.

RMT really hit it on the head with suggestions. As (almost) always, ignore jimatbeyond.

There's not a perfect number, but keeping the stem in the 50-70mm range will probably make more sense than the 80-100 range. Yes, even if it's an XC bike. I think you have the right idea overall from reading through this thread. Regarding the stem length vs. bar width, 100mm width = 10mm on the stem is not the number most people work with. 2:1 (20mm width increase equals 10mm stem decrease) is a much more popular figure. It's not perfect, but it's probably a bit closer than the 10:1 suggestion. Stems are cheap, so experiment. It seems most people would rather have their reach in the frame and not the stem.

One thing not talked about much with finding a mountain bike is finding a bike that helps you with your weak areas. Do you pass people on the climbs and then have people on your tail while descending? Maybe a bike with a touch more travel, wider tries, slacker head angle, longer wheelbase or *gasp* a dropper post may help your overall speed. It took me a long time to realize I was faster on a 30lb bike with 5" on each end than my 21lb hardtail with 100mm on the front. For some with more handling than horsepower, the smaller wheelbase, quicker handling, lighter weight argument would make more sense.

Get on as many bikes as possible. 5 seconds on Google shows mountain bike demos from all sorts of brands. "xxxx demo days" can find things like Giant, Trek, and Specialized events all over the country.

In the end, nobody can really tell you what you prefer though.

Thanks for your thoughts.

Personally I'm looking for a FS bike not for the comfort but because, like you, I think they are faster

Thanks, I taking in everyone's thoughts.

I've been told that I'm an all-arounder and a very smooth rider but if I had to say where I was weakest, I'd say long climbs.

I'm going to look for more demo days like you suggest, I don't want my next bike to be an impulse buy.

jaretj

Here's one more for you.

I'm 5'5" on a 650b M Scott Spark with a 50mm stem and 750mm bars. I went shorter and wider than what the bike came with, and it became easier to control on stuff that was difficult for me. It was easier to turn the bike through tight tree gaps and sharp switchbacks. Also, not getting as easily hit off my line when going downhill through gnarl.

One thing that I haven't seen anyone mention here is how nice and comfortable a full suspension make climbing over gnarly rooty ground. Plus, the Spark has the suspension lockout mounted on the handlebar, so it's easy to flick on and off.

Thanks, which model of the spark do you have? I'm looking at the 720.

I've got the lowly Spark 750

Nothing wrong with the 750, thanks for your insight.

Only just seen this - I also ride a Spark as my 'faster bike'. I have the 700 Premium, alongside my 160mm travel enduro bike. The Spark is a heap of fun, super quick up but quite capable as a trail bike as well. Have you got any further with your dilemma?

I'm going to ride the Anthem/Pique again this weekend.

I'm looking for someone that has a small spark to try out, I'd probably go with the 710 or 720. The medium Contessa Spark at 20mm longer (432mm) may be a better fit than the small men's though since I'm currently riding with a total reach of 490mm (BB to center of bars)

I haven't seen a small Scalpel anywhere but then I really haven't tried yet. The stem(s) I need to get my fit appear to be available.

I added the Trek Fuel to the mix but those are hard to find, the small is a bit short on length and the medium is tall. it appears that the 2018 bikes are taller and that doesn't work for me. If I come across one that I like and it's a good deal I might go for it.

The Anthem and Spark are easy to get right now, I'll most likely go with one of those bikes. I might be able to find something when I go to Utah for Xterra USA or at least look at things cuz I'd really like to buy local but if I come across a good deal I'm not going to pass it up.

Things that I want:
Shimano M8000 cuz I like to be able to shift with my thumb and index finger and not just my thumb but that's not a deal breaker.
Fox 32 CTL fork cuz I just like Fox
I like to stay with 1 1/8 stem but that also not a deal breaker.

I'm going to make an appointment with a local fitter that I trust and make sure of the sizing I need although I'm pretty sure I'll be throwing money away.

I have time and I don't want this to be an impulse buy. I have a capable bike but it's starting to make some noises and I really don't want to throw $300 of bearing, bushings and pins to keep it going. It would be just fine for someone tooling around on my local trails.

Again, thanks to everyone that chimed in on this, it gave me many things to think about.

Thanks again to everyone that helped me.

I bought a small Scalpel today.

A mechanic at a local bike shop has one and he brought it in for me to see. I made measurements, did some calculations and rode it around a bit.

It was much smaller than I thought it would be, and more like I'd hoped. I can easily fit on this bike and I don't have to slam the stem like every other bike on my list.