Bike Stability Feeling vs. Rider Position

I had an interesting ride the other day. I was on my Black Mountain Cycles Monstercross, on my way to see my mom. The BMC has a pretty normal cross geo, which in itself is pretty close to road bike geo going back before I was born. I had it setup with a Velo Orange Granola handlebar:

What was interesting was how bad this all felt.

See, it had rained recently, and being September, the paved bike path was covered in spots with wet leaves. Coming into a wet, leafy corner, I instinctively drew back on the bars to grab the brakes in case I needed to slow down. But doing that shifted my weight off the front wheel, leaving the front end very light and vague feeling. This is not what I want when I may be braking and steering in a sketchy situation.

Of course, this is my fault: I'm using that old road geo with a handlebar not made for it. With a drop bar, I would go down into the drops in a sketchy situation, giving me a lower center of gravity at the same time it weights the front wheel at the same time it gives me the best braking. But sometimes a drop bar just feels like overkill when I'm riding on a bike path to see my mom.

That started a Facebook conversation with online friend Tim (current owner of my black Jones LWB) about riding position and stability. I posited that companies like Jones and Riv are working on newer bike designs that give stability with an upright position and good controls access at the same time.

Me being me, having just sold four bikes, I'm immediately thinking about how this will impact my next bike purchase. I've owned several Jones and Rivs, so now I'm looking at a Hudski Doggler on sale. It's a modern fat tire gravel/hybrid bike, but with geometry heavily influenced by the "long, low, slack" modern mountain bikes. Kind of like my Giant Trance, in fact. Thinking about this, I took my Trance on a paved bike path ride. How did a bike with a 67 degree head angle and over 100mm of trail do while out of its element? 

It was... fine! Fun, even. I was comfortable, yet easily confident in any wet corner. A bike designed for security when pointed down a slick, rooty mountain bike trail laughs at bike paths. I oversteered a few corners when I wasn't paying attention and didn't corner hard enough, but that's a normal adaptation.  It probably doesn't have Jan Heine's favored "mid corner line adjustment", but with 2" tires, you can just roll over stuff instead.

I took some photos of me on the bikes to try to understand this better:

The first photo is the Trance in my riding position. The second is the BMC on the grips, and the third is the BMC on the forward loops. This is my normal riding position when I don't need to be on the brakes.

The blue lines are just to let me align and scale the pictures. I tried to line everything up by the bottom bracket.

A couple of observations:

- the front center (red lines) of the Trance is much longer (about 150mm) than the BMC. Having the front wheel so far out really contributes to the stable feeling. Of course, trail is also a huge impact to steering. The Giant has about 50mm more trail. That's a lot. But I'm thinking now that front center is an underappreciated aspect of handling.

- the amount I'm leaned forward (as shown by the green lines lined up to my ear) changes as well. I'm most leaned over on the forward loops of the BMC, and most upright on the grips on the BMC. The Giant is in between, but closer to the forward lean of the BMC's loops. This is really interesting because the Giant feels (and looks) much more upright than the BMC loop position. This is because the steeper seat tube angle of the Giant pulls me closer to the bars without arcing my back so much. Look at the difference in back angle between photo #1 and photo #3.

So the Giant's more modern geo allows:

- a long front center to provide stability

- a steep seat angle to balance the rider's weight between the axles, while still putting the rider in a more upright, relaxed position.

Might be time to start getting more serious about that Hudski.