Totally in an xc race the power delivery, acceleration out of corners and weight can be make or break on an xc course....
Same riders on a rough technical Ungroomed trails would likely run a FS rig.... I know I do...

probably your best value is an aluminum 26 inch wheel bike with front suspension only. I have been using full suspension lately and like it for real rough trails but for the money a hardtail 26 wheel with a decent fork is hard to beat. The tubeless tire setup is a nice upgrade. If the trails are only rolling and not super hilly, you may find a 29 inch wheel fully rigid single speed is a nice way to go, the bigger wheels soak up a lot of the shock and you can go pretty fast with one gear, it's easier to maintain and save weight, just a thought.

Get disc brakes at least, the rim brakes were a pain in the neck.

26 or 29 inch wheels are fine, I like the smaller wheels myself having used both a lot but most of my friends use the bigger ones and love to drone on about how great they are

Wheel size is based on use. Generally speaking, for joe recreation, either size is fine. For racing, 27.5 is the perfect median. Outside of that you need to pick base on course. Lot's of climbing and tight = 27.5 or 26. A trail that flows strong and not very tight = 29er.

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The curious task of economics is to demonstrate to men how little they really know about what they imagine they can design.

riders win the Olympics and world cups on all different wheel sizes. Middle aged men sit around and debate about it.

Dangle writes a great post. I also spend more time on my MTB than on a tri or road bike.

I have been recommending friends (and my kids) buy a hardtail (front suspension only) with hydraulic disc brakes. Hydraulic matters because they are largely maintenance free. Fit is most important, and any of the wheel sizes work well on the trails, if you have a longish stretch of road or a lot of flat sections of trail, a 29er will be faster.

Brand doesn't matter that much - all will be good quality in a bike shop. Look for something with Shimano SLX or better (Acera ->Deore -> SLX -> XT -> XTR) or SRAM X5 (X5, X7, X9, ...).

Single chainrings are the 'new thing' (especially on burly Enduro or downhill bikes), but for a new rider a double is probably best. If you live in steep terrain areas, a triple may make sense but they tend to be buggy shifting so avoid it if you can.

Examples would be a Giant Talon, Specialized Rockhopper, Trek Stashe or maybe a Niner EMD if you want to get away from the mega brands...

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" I take my gear out of my car and put my bike together. Tourists and locals are watching from sidewalk cafes. Non-racers. The emptiness of of their lives shocks me. "
(opening lines from Tim Krabbe's The Rider , 1978

Every time I see folks arguing about wheel sizes for MTBs and saying one is better than the other for various uses, in my mind I see the arguments REALLY being about frame geometry :-/

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Cool. Then I have a fun problem for you. Take a model of a wheel as a simple hoop (pretty reasonable for the wheel sizes we're discussing. i.e. all of the differences are at the outer edge). Solve for the kinetic energy of that wheel traveling at a fixed tangential velocity (fixed road speed). You don't even need to plug in values. Just look at the equations using variables. Don't forget to simplify ;-)

So...look at that and tell us: does the kinetic energy of that hoop vary with the mass, the radius, both, or neither? Report back here with your findings.

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Science and physics go both ways. We don't only try to make predictions based off of known scientific concepts. We also make observations, then use scientific concepts to quantify what's going on. The observation is, 29er is faster on x-c trails.

But, the wheel diameter wasn't the only thing varied in what you "tested", so it makes no sense to attribute any differences you observed to simply that one change. Not only that, but if you do the exercise I outlined above, it might give some insight into which variables matter and which don't.

Humor me...it's a good way to get intuition for the situation...at least in regards to the common "larger wheels have higher inertia and thus roll over objects easier" meme.

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Back to back to back to back rides of mine while swapping bikes says otherwise.

So faster for some while not faster than others.

Perhaps still another 29er with different geometry would work better but I haven't found it yet.

jaretj

That doesn't really matter. If it's not the wheel diameter, then it's all the other variables, and the result is the same. The 29er is faster.

So then what's stopping you from doing those other variables with other wheel sizes?

It's not about the wheel diameter.

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The result is not the same. I've beaten loads of 29ers in races on a 26er and a 27.5. Now my perspective is based solely on mountain bike racing, not recreational mountain biking. Assuming the same engine strength, a 29er will not accelerate as fast as a 26er. A 29er will not do a dead climb as fast as a 26er. If a 29er is the fastest bike, then why are we seeing the rise of the 27.5? The 27.5 mutes the differences and is an extremely fast bike.

Today mountain bike trails are being built for the 29er, meaning they flow very well. They are designed to hold momentum. Historically, mountain biking was done on trails built for multi-purpose, thus the 26 we designed for those trails. For joe average, the 29er is the best option. For joe racer, the 27.5 will be the best option. For joe budget, a 26er is the best option.

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The curious task of economics is to demonstrate to men how little they really know about what they imagine they can design.

24 Solo is much more fun then IM (having done a few of both...)
The fellow racers are much nicer and don't mind having a solo drafting for a bit. I've even been offered a wheel to follow a few times. Now if you're on a team and try drafting off me? Different story :)

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Vale!
Tracy T
http://www.thelencoaching.com
Some light reading::: http://www.tracythelen.blogspot.com

The other variables are there to accommodate the larger wheel size, 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. 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. 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. 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.

Now if smaller wheels are always better, why aren't we all riding road bikes with 650c wheels, or even 24-inch wheels? Why aren't off-road jeeps, rock crawlers and baja trucks running 18"-20" wheels instead of 33"-35"?

My girlfriend is big into the MtB scene. She convinced me to pick up a steel 29er hardtail.

I could not be happier. The whole MtB thing has made riding a bike fun again. Sure. I fell down a bunch. But, it is just so, so, so different from TTing, racing crits, and even CX.

Buy something, ride it, have fun.

Oh. And go race it too. MtB racing is way chill. A triathlete can learn a lot about being a better human being before a MtB race.

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Twitter @achtervolger

If you consider 5 to 6 cm BB drop the same as even with the axles then yes the bottom bracket is essentially the same height as the axles.

Truth. I think gold, silver, and bronze at the men's race in London were all on different sized wheels. I think it all comes down to preference, riding style, and the kind of trails you ride.


EDIT: OP should go to the local LBS and see what they say and sit on some bikes and see what works. They'll be much more useful than a bunch of internet strangers.

i'm not even sure if you can buy higher end 26 wheel stuff in shops. That's partly why I like it, I can buy nice frames and wheels at fire sale prices

Here you go:

Men
Gold = 29" FS, Silver = 27.5" HT, Bronze = 29" HT

Women
Gold = 26" HT, Silver = 27.5" HT, Bronze = 29" HT

Old ones are especially soft!

Youtube the trails in Sedona and you'll see why an FS is the way to go. The pros here all ride FS too, and there are plenty.

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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.

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.

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

So, what you're saying is its a psychological effect...got it. There's a reason I called them "placebo wheels" above ;-)

And all you mention above has to do with frame geometry and not the wheel sizes...despite what everyone has been sold.


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


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.

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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The jeep analogy holds, you are just neglecting other variables that also apply to bikes, such as contact area and approach angle.

Funny how people refuse to accept that 26" is for all intents dead. It is like 2000 when the holdouts were arguing against disc brakes.

Tech moves on. For 90% of riders a 27.5 or 29 is the best solution.

But it has been pretty entertaining to watch triathletes argue about it...
26" is still alive and well in the DH arena, but not so much in the XC. Some all mountain bikes do still have 26 - Stumpjumper Evo comes to mind. Maybe in a few years when everyone has converted to 29 or 27.5, the bike companies will go "look! We found the perfect size wheel!"

To the OP - forget all the blather about wheel sizes and find a bike that fits you and you feel comfortable riding. Doesn't matter what the wheel size is - if the bike doesn't fit it won't be fun. Test ride as many different styles as you can. You might like the stability of a 29er, but find the geometry of the smaller wheels fits you better. I've been on both and have flipped from 29ht to 26fs in the middle of 24 hour race - so I'm neutral in the whole wheel debate.

You'd be better off getting a newer bike and spending a little more money then a bargain from the early 2000s. Technology changes very quickly and finding "antique" components for that old farm might be hard or more pricey. A HT will give you more bang for your buck, but will required a steeper learning curved for fun. The FS will make the every day riding fun, but will hide and compensate for some of the basic skills needed to ride smoothly.

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Vale!
Tracy T
http://www.thelencoaching.com
Some light reading::: http://www.tracythelen.blogspot.com