For most, these are projects which simply push the edge of design; to see how far you can push the envelope before certain limiting factors don't allow you to build any bigger. I for one, will go out and say that while I think that 29ers are amazing bikes, I still see room for a larger wheeled big brother.
Will they be for everyone? No. Just like some short people will never find a 29er to suit their form (although we are now seeing many top female riders who are short riding the 29ers). However, once you do reach a certain threshold, smaller wheels, or in the case of the 36er, larger wheels might be the best answer.
Being tall at 190cm (6'3"), I am definitely on the larger wheeled side of things. I also have a strong upper body and long legs which give me a fairly high centre of gravity. While I find that the 29er is above and beyond and 26er, I still feel that I could go bigger.
One of the things I've noticed of all the 36ers built thus far is that they have all been built for an average height rider. Thus, I think the bikes do look a bit ridiculous due to the small frame, short seat tube, negative stems and bigger than life wheels. I can't help but thinking that wheels of this size built on a frame like mine, or someone way taller, would in effect, look.... well, normal.
There is no denying that these bikes look like an absolute blast to throw a leg over. Anyone who is lucky enough to ride one talks on about the perma-smile they get and how they feel like a kid all over again. Having wheels of this size obviously has design limitations especially on suspension. Thus, anyone who would actually want a bike with this wheel size would do so fully rigid. That being said, you would likely need no suspension whatsoever due to the super low angle of attack of the wheels. After all the years of suspsension, people would go back to full rigids. This would be similar to the fact that many people switching to 29ers are going back to hardtails after swearing off them forever once they got their first 26 inch full suspension bike. Those wheels must weigh a ton? You could never race on that thing! The current answer is that, yes, the wheels are extremely heavy and not practical at all for racing. There is a reason for this though
The only 36er rims and tires currently made are designed for unicycle use.
Thus, one wheel is designed to support the weight of the entire rider. The lightest rim and tire currently made are the following:
Nimbus Stealth Rim: 1116g
Nimbus Nightrider Tire: 1660g
In order to really get a 36er movement rolling fast, you would need rims and tires actually designed for mountain bike use. These would shave at least a third of the weight off the above setup. I would imagine that a good all-purpose aluminum disk-only rim with eyelets would be in the 700-800g range with a WTB Nano-wrapter 36er coming in around the 800g mark. These would be respectable weights; maybe not for the smooth XC race scene but for technical all-mountain riding where you keep the wheels on the ground... this just might be the next bike if your on the tall end of the spectrum.
Will the 36er actually take off as a viable option?
I think it actually will as now that we have the 29er, I think the taller riders out there see the advantages and would want an even larger wheel size. However, maybe the 36 inch wheel size is simply too large. Maybe a 32 inch wheel size would give the best reduction in endo factor, improved traction and rolling smoothness for most tall folk. Also, I have no scientific backing for this, but it seems to me that the taller (and generally heavier) you are, the more traction you require. Thus, a larger rider needs a larger volume tire, a grippier tire, needs to use lower pressure, or larger wheels in order to get the same wheel to the ground grip as someone smaller.
If the amount of grip I have is fine, why would I want larger wheels?
Well, going to a larger wheel size would allow you to run tires with less tread, run higher pressures and give you lower rolling resistance all the while giving you the same amount of traction. In the end, this may negate the effect of the additional weight (just as many 29ers claim over 26ers).
The only reason that the 36 inch wheel size is even entering the mountain bike domain is simply this; because it was already available for another application. Thus, it seems most likely that if another large wheel size is standardized in the bike industry, it just might be the 36er. I definitely think there is a market and room for it in the industry. The main issue right now though is that no one produces a true mountain bike rim and tire for the 36er. However, I see this limitation as being less than the problem that 29ers had when they first entered the marketplace as there were no full-suspension models and limited fork options. With a 36er, no one will want front or read suspension. Thus, a basic chromoly fork (easily made by most custom shops and relatively cheap) and a carbon fork option would satisfy most riders.
So, Bontrager give me a RaceLite 36er rim and WTB, give me a nano wrapter 36 and I'll jump on the train. Till then, the guys at Black Sheep will have to wait to build up my next ride!
Think all of this is complete rubbish and that a 36 inch mountain bike is a completely ridiculous idea?
My bet is that you're shorter than me.