I work as a tour guide, so am on road bikes ad nauseam. To help rekindle my love for cycling, I'm getting back to my MTB routes and am looking to purchase a new 29er HT.
It has been about 5 seasons since I raced off-road, but I always preferred a smaller bike. I am 1.92m (6'4"), but I never seem that tall. I realize that last statement is weird, but I pedal with my heels down, so run a very low saddle, with a lot of setback too (as I must accommodate femurs and 'full-length' feet into my pedalling position - see 2nd photo). My only off-road bike for the last few years has been a Cannondale Bad Boy, in size L (20"), on which I run a 140mm stem at +5deg - as pictured below.
My position over the pedals and my reach to the bars both feel right on this bike, and mimic what I had been racing previously, but there is no denying the fact that I am stretching it a fair bit.
Looking at the spec of 'modern' bikes, it seems the stem lengths have gotten shorter - especially on 29ers. As an example, if I wanted to maintain my current position on a Specialized Stumpjumper HT, I would end up with the following two options:
I would certainly prefer to avoid the use of a -17deg stem, and I'm concerned that the longer FC & wheelbase of the 21.5" frame would feel more sluggish and not allow me to flick the bike as I'm used to... these are the same sensations that I disliked previous larger 26" frames too. I suppose the flip-side of that is that I'm curious if running a 135mm (or most likely 140mm, as I'm aware that 135 doesn't really exist), would 'mess up' the intention of the geometry, if such a notion exists.
For context, I'll be riding/racing this bike on mostly fast, dry terrain, with some technical rocky bits.
So I guess my request is to have some feedback on stems & wheelbase from more experienced 29er riders, especially XC racers, and have some opinions on the two set-up options shown above.