If you have spent any time at all reading this blog then you are aware that I, Guitar Ted, am a 29"er nutcase. I am pretty adamant that this wheel size is better on a lot of levels than a 26 inch wheeled bike for alot of people. Not all people, mind you, just alot of us. So, it always makes me shake my head when I see a "96er", or what I have settled on calling it: a 50/50 bike. You know, one of those 29 inch front wheeled, 26 inch rear wheeled half breed bikes. I saw another example of one on mtbr.com recently and felt compelled, again, to say something. (Perhaps I'm in need of intervention?) At any rate, this is what I have concluded about this whole 50/50 bike idea.
Here is the deal. People think that they are "getting the best of both wheel sizes" when they go with a "96er", or 50/50 bike. This notion is so misleading. Even I didn't see through it until recently. Follow the logic here for a minute. If by saying that you get the best of both wheel sizes with a 50/50 bike, then the rear wheel of a 29"er and the front wheel of a 26 inch wheeled bike are somehow deficient in comparison, right? If this is the case, it would make sense then to compare a 26" rear to a 29" rear to see what really is "better". Let's see then. The touted benefits of a 26 inch rear wheel are the following: spins up to speed faster, is lighter, is stronger, and is the accepted standard. Am I missing anything there? Let's see about the 29"er rear: better roll over, less rolling resistance, better grip, and more comfortable. Okay?
Now, let's take a few closer looks. 1. On the acceleration factor: It has been discussed on various levels that the actual acceleration/weight "advantage" of a 26 inch wheel may not be as great as once thought. Actually, there is some evidence that shows that the smaller/ lighter wheel is actually a disadvantage! Mavic has been doing extensive tests that were recently alluded to in an article on velonews.com by Leonard Zinn. Apparently, Mavic found that the flywheel effect of a slightly heavier wheel may in fact increase uphill climbing efficiency! The article quoted a Mavic official as saying, "The lightest wheel doesn't always win." This is interesting for the 29"er in that the momentum saving attributes of the larger, slightly heavier wheel may in fact be an advantage versus a 26 inch rear wheel. Yes, it may be harder to get past the initial moment of inertia of the big wheels, but coming to a near dead stop is the only time that this should really be a problem. 2. Lighter/ stronger? Well, a 29 inch rear wheel might be heavier than it's similarly equipped 26 inch cousin, but the difference should only be about 10%. In fact, there are several wheel builds out currently that are on par with 26 inch wheel weights, and in some cases are super light. Strength? Look, if you can build a wheel that can survive Paris-Roubaix in a 700c format using 100 plus psi. tire pressure in skinny tubular tires, then what do you think the chances are that a wheel with a 2.1 inch wide, high air volume tire will fare in the same size? Even off road a 29"er should be quite strong enough to last if built properly. 3.While 26 inch tires are standard and are widely available in several different tread patterns, the 29"er will be on par with that in about a year or so.
Okay, so advantage #1 is dubious and #'s 2 and 3 are either false or you can disallow them because you are using a 29 inch front wheel on the 50/50 bike anyway. If 29" rear wheels are not good enough for reasons #2 and #3 then the same should apply for the fronts, no? Anyway, the advantages of the 29"er rear far out weigh these "advantages" of the 26 inch rear.
Tomorrow, I'll cover some more thoughts I have on these 50/50 bikes and reveal my plans for testing my theories.