InWyo wrote:
The other variables are there to accommodate the larger wheel size...
And of the ones that matter (wheelbase, trail, head tube angle) there's nothing stopping frame designers from using the same values for 26" wheels as for 29". The reverse isn't true, obviously. You want a 26" wheeled bike that handles like a 29er? Just give it a longer wheelbase and longer trail.
InWyo wrote:
... and the larger wheel size accommodates other changes. For example, where the bottom bracket is located relative to the axles. On a 29er, the bottom bracket is essentially the same height as the axles. If you do that with a 26er, you'll be striking your cranks on every single obstacle you come by.
Ummm...you may want to investigate that a bit more. What you are referring to is known as "BB drop" and is a measure of how far the BB is below the axles. From what I've seen, 29er frames typically have BB drop values 30-35mm larger than equivalent 26er frames. In other words, the 29er BBs are LOWER relative to the axles than a 26er. This is done to keep the height of the BB relative to the GROUND in approximately the same location, thereby minimizing differences in the height of the center of mass of the bike+rider system.
InWyo wrote:
Also, having the BB set at the same height as the axles minimized how much it "swings" as you lean the bike over in a turn.
Again, see above about BB height vs. the ground...the bike rotates laterally about the tire contact patches, not the axles, and the height of the BB relative to the ground is approximately the same for both. You may want to re-think this one as well
InWyo wrote:
It also seems to give you the feeling that you are "in" the bike, as opposed to "on top" of the bike. For me, this give me a ton of confidence.
So, what you're saying is its a psychological effect...got it. There's a reason I called them "placebo wheels" above ;-)
InWyo wrote:
Is it as nimble as a 26er (having the ability to flick it from one side of the trail to the other)... absolutely not. But it doesn't need to be, because you can choose more forgiving lines.
And all you mention above has to do with frame geometry and not the wheel sizes...despite what everyone has been sold.
InWyo wrote:
Now if smaller wheels are always better...
That's a straw man. I never said that one size wheel was better than the other in regards to the wheels themselves. Now then, certain sizes make certain geometry choices easier to accommodate, but that's usually in the smaller sizes
InWyo wrote:
why aren't we all riding road bikes with 650c wheels, or even 24-inch wheels?
Simple. Because it's been shown that using smaller wheels on a road bike doesn't impart any performance advantages, so it makes no sense to go away from a well-established standard. The only exception is for fitting purposes for smaller riders, which is why you typically see 650c wheels on small sized road bikes. It's too bad this didn't happen in regards to MTB wheel sizes as well.
InWyo wrote:
Why aren't off-road jeeps, rock crawlers and baja trucks running 18"-20" wheels instead of 33"-35"?
As the owner of a Jeep that's taken off-road, I can tell you that the choice of tire size is all about axle-ground clearance and body clearance for a given suspension lift. Even so, there are gearing and axle strength trade offs that need to be considered when fitting larger tires. Your analogy falls down here as well...
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