Here is a verbal diarrhea of mine taken from that group explaining my thoughts on this issue.
Please add scenarios I haven't thought about and point to holes in my 29er fanboy logic.
"I've thought a lot about this exact issue, and still can't decide where I fall philosophically.
I'm a current owner of both a Surly Troll and a (it-doesn't matter) 29 inch mountain bike.
I don't think I'll be touring on a 26" bike.
I'm normally a very practical person, but not in this instance.
So here is how I (poorly) rationalize it.
I am a tall guy, and I have more fun on a 29" bike. It feels faster and deals with obstacles better.
Perhaps its because my 29" bike was built custom ground up by me, and so there's some subconscious attachment to the way I set it up, while the Troll was built up by somebody else with a much heavier and less playful build.
My thinking on the availability of 29er parts is this:
"What if I’m touring in Timbuktu and I need a new rim-tire-wheel? We have researched this. There’s no bike shop of any kind in Timbuktu. There’s what amounts to a general store, but it doesn’t sell bike stuff."-from Rivendell's page regarding 650b replacements.
... it's my belief that if a part fails on me in the middle of nowhere, I will be in the middle of nowhere, where not even 26 parts are available.
For this reason, I believe wheel size is irrelevant, and a rider's reserve of spares and mechanical skill is more important.
Additionally, start out with bombproof parts, maintain them, and put as little stress on parts as possible by packing light.
Some scenarios:
Tubeless 29er tire, despite surviving hundreds of punctures, fails upon receiving a sidewall cut. Possible solutions:
1. Do an emergency boot and run a tube. Note: 26er tubes work just fine in 29er tires.
2. Do a more robust Tire Sidewall Repair, fill with sealant, and run until tire finally quits. Some techniques here (
http://www.bikepacking.net/forum/index.php?topic=2781.0)
3. Install spare tire as last resort. (order new one posted to forward location).
29er spoke breaks:
install spare spokes.
Hub Fails:
Build new wheel with first rim, first spokes, and new hub sourced in local country.
Catastrophe: Rim completely fails.
1. MOST Ghetto: Ride a 26" wheel sourced locally with widest tire (and widest diameter) available. This will severely affect the geometry, and likely make riding on trails or anything but pavement impossible.
2. Source a local 29er rim/wheel: Difficult, but possible depending on location.
3. Mail-order new wheel/parts. Likely very expensive after import taxes and shipping, but companies like Chain Reaction Cycles ship to many countries all over the world. Spend your time waiting on the new parts exploring whatever local you land in. Backpack, work on a WWOOF farm, volunteer, stay with a workaway host. This may not be an option on shorter trips, but when crossing continents, I believe I'd be okay slowing down for a week or two.
Lastly, here is my most irrational opinion regarding this issue.
I ride a bike because it is fun. I don't really have much fun on my Surly Troll. 26 wheels are certainly much more agile on trails, but they feel agile to the point of making me struggle to keep the bike upright. I ignore my obvious lack of riding ability, and blame the 26" wheels, because I feel much more stable and confident on a 29er.
My belief is: Ride the bike you like the most!"
