I've heard a couple of differing opinions about 29ers ie they're great for taller riders and that they're better than a full suspension 26" bike etc. Should I just buy a Giant Trance and enjoy the upgrade from my XTC or should I jump on a 29er?

My second question is about sizing. The retailer is telling me to drop a size (i ride a hardtail XL Giant) and I'm wondering if the sizing for a 29er really is different or should I ride the same size for the same retailer. Just FYI its a Norco Jubei and I need an XL in the hardtail non 29er norco. Of course the retailer doesn't have the Bike in stock....

I believe 29ers are good for taller riders. You get a more pleasing proportion of frame to wheel size.

I would not say that a 29" hardtail is better than a full-suspension 26" bike. Suspension is suspension. Wheel size is wheel size. Bigger wheels really don't make up for suspension. Maybe in some abstract sense they do, but not when you hit a root on the trail and get your butt kicked by the seat. If you like full-suspension in the 26er size, then you'll want in the 29er size too.

As far as going down a size goes, I would be cautious there. It might depend upon the brand. Start by comparing effective top-tube lengths.

Wheel size being proportionate isn't anything new; I sure don't want to go back to riding 20" or 24" wheeled bikes. OTOH I don't think I'm quite tall enough at 5'10" for a 29er....so I went 650b instead for my "big wheeled" bike, although the rest are 26ers; the 650b wheels work on my current generation Heckler without modification. One day I may buy a 29er frame, but in no hurry; I've ridden one and while a bit different it's not making me want to run out and splurge on a 29er. I know a few guys who ride 29ers and they do say there's something to the bigger wheels needing less suspension compared to their 26ers. The 29er I tried for a good length ride was a friend's fs model, with 80 mm of travel front & rear, but the suspension wasn't really set up for me so hard to say it was equivalent to a longer travel 26" bike or not, nor did I ride a hardtail 29er for comparison.

@bikinfool, you went with 650b? That's interesting. I'm 5'9", have been drinking the 29er Kool-aid for years, and bought my first 650b bike this spring. I have all three sizes now. I'm not planning to throw out my 29ers, but I've decided that my next front-suspension hardtail will be 650b. (the one I bought this spring is a Beasley -- single-speed + rigid).

Here's a pic of the Beckler. Ride it the most of all the bikes, too.

That's nicely done. Hey, are you running a suspension seatpost? It kinda looks that way, but maybe my eyes are being fooled by the background.

It's funny sometimes which bike ends up being the one you ride the most. I've been thinking to post about that. The Beasley has ended up being the one that I grab most often when I just want to ride around the neighborhood. I like the dead-simple aspects of no suspension and no gears. I'm planning to order up some Marathons for it, to make it more pavement-friendly.

It's not what I planned. It's just how things worked out.

thats a gravity dropper. Telescoping, not suspension.

Cool! that makes perfect sense.

I'm 6' 2" and my new 29er (IRO Model 19) is a much better fit than any 26er's I've owned in that I feel more centered within the geometry of the bike/wheels. The rider's weight is lower releative to the wheels than a 26er creating a better handling bike and a more porportionate fit. In addition, I no longer feel that I'm teetering on top of small wheels and can clear obstacles better (ref: angle of attack). The comparison to full suspension bikes comes from the fact that many 29er tires, especially in the 2.4/2.5" width, hold an enormous amount of air relative to a 26" wheel. They hold so much that I run about half the pressure that I used to on my old bikes. The ability of my fully rigid setup to handle rocks, roots, drops, jumps, etc makes me think that ,at least for the XC type of riding that I do, a full suspension would be completely unnecessary with needless weight and maintenance. I know that 29er's are wheel size de jour, but, I honestly can't imagine going back to a "small wheeled" 26" bike. Also, I was told that frame sizes are similar and was advised to buy the same frame that I would in a 26er. For me, that's a 20" bike and it fits perfectly and is the best handling bike I've owned yet.

I ride a 2003 Nishiki X-29, a twentyniner hardtail. I bought a 20" framesize, the same as my 26" bikes are. I'd go for the same seat-tube height you're riding now.
You can't compare a hardtail 29er to a fullsuspension 26er.
My experience with 29" is: more traction, more comfort, a more stable ride, easier climbing, more control downhill, less tire-wear, higher top-speed, easier acceleration when you're already rollin, higher cornering speed due to lower center of gravity and larger tire contact area.
The downsides: a bit heavier, less stiff wheels (or stiff, but heavier), tight turns are more difficult. Not so good on singletrails. Twistin and turnin go slower than on a 26er. Acceleration from stand-still is slower. Less parts available for tuning a 29er bike.

OK, I have seen it mentioned twice in this thread now, and I'm confused. Why would the center of gravity, or riders weight, be lower on a 29 than on a 26? Is the design of the 29 frame geometry such that a lower CoG is the result on 29s?

I am between 5'9" and 5'10". I ride a 17 1/2" Gary Fisher Rig 29er. I could have ridden a 19" Gary Fisher no problem. My twin brother is my size and he has a 19" 29er which he preferes to my size, some of it to a degree is personal preference. I love my 29er. I never ride my 26" mountain bike anymore. I agree with other posts, whatever bike you are considering consider the effective top tube length. You should not have a problem with size on a 29er.

With the higher axles but everything else similar to a 26er, your weight is somewhat lower in that respect....I think that's how the reasoning goes.

I think that's it, too. The axles are higher, but with more bottom bracket drop than a 26er the rider's position is about the same distance from the ground as on a 26er. So relative to the axles, you're lower on a 29er than on a 26er.

FWIW, I'm 5'8" and love my 17" Jamis Dragon 29er. I usually ride a 17" mtb frame, but I tried the 15" Jamis Dragon 29 to see how it felt. I was too cramped on the 15. So for me, with that particular model, I ride the same frame size in a 29er as a 26er.

I just got an 18" Jamis Durango 29. I'm a tad over 5'9". I haven't ridden much singletrack w/it but so far, so good. The standover clearance is less than I would ordinarily prefer, but I sat on the 16" frame and there wasn't much difference between the two standover heights, and the 16" was way too compact in the cockpit. I haven't been on my old rigid trek 930 w/26" wheels but I think that the latter would have a slight edge in tight terrain, but for my type of riding, I like the better rolling, higher riding 29" setup (not to mention getting into the 21st century w/front suspension and disc brakes).