[SuspectDevice]

Alright, after much poking and prodding from many people to try a full 29 bike, I made some (very crude) dropouts that gave me clearance to run a 29" wheel on the back of the Mustang. This made the BB way to high (13") and the stays pretty long (17.75"), but I mostly wanted to feel the acceleration and rolling properties, and not so much the handling, as obvioulsy I would want to build the entire frame around a 29".

The bike does get slightly more climbing grip, and smoothed out the trail a little bit, but the heavier, larger diameter wheel really just doesn't accelerate well enough for me to want to race on one. I would love to have a big ole touring bike built around a dual 29" setup though.

Carrying 2 different tubes is a pain in the butt though.

The great thing about just running a single 700c wheel in the front is if you have the ability to build custom forks you can just slap the bigger wheel on in lieu of a suspension fork. I feel like I get the same amount of grip with my 2" Karma as I got with my 2" 26" Karma and a 63mm Sid, with less weight and more reliability...

 

[MMcG]

Are you able to build your own forks?

I ran my Karate Monkey last night with the Reba pretty much locked out the entire time (just the miminal travel from the blow off valve or whatever RS calls it) and I liked how it worked in that mode vs. getting full travel. Perhaps I need to stiffen up the fork with more PSI or something.

Any photos of your 69er that you can share?

 

[N8 v2.0]

It would seem to me that a "69er" is neither fish nor fowl...

 

[jbogner]

Spend some more time on a 29" rear wheel, and you might discover what I did- that I can stand and torque without losing traction in situations that would have me walking my old 26" hardtail, that the additional traction is good on steep rock slabs as well as dirt, and that the overall conservation of momentum provided by both 29er tires makes me faster.

Of course, it really does matter what tires you're running. Try a set of Ignitors...

 

[SuspectDevice]

Don't have a camera to snap a picture of my butchered bike, but let's just say it's not pretty.

I whipped the unicrown steel fork up out of tubing I had laying around. It is both heavy and flexy, but I wanted to try something that was signifcantly shorter than the Karate Monkey forkthat I have to preserve the handling of the bike.

 

[Leethal]

A 26" tube works perfectly fine in a 29" wheel..

 

[Cloxxki]

I've written this elsewhere (well, all over the web) before.

I simply cannot comprehend how people can be turned off by an increase of the rear wheel weight by 150g, to the point of it being a deal killer.
Because that's what sits between 26" and 29" XC wheels of identical quality :

26"
tire 500g
tube 150g
rim 400g
spokes 180g

29" : add 10%, some 133g.
Throw in 17g for 4 extra spokes to bring wheel stiffness to the same level, voila, 150g.

What, calculated in Watts, becomes utterly insignificant to propel a bike, magically becomes an anchor in the rider's head when it's grams another setup could have saved.

Mount your bike in the trainer, tire running free. Hook bike computer to rear wheel. Engage biggest gear.
Half a second of maximum effort, from standstill.
I bet you reach 30mph. How long does it take you with the rear wheel on the ground, and the whole bike and rider having to be propelled forward? Heck, the flick of a hand can propel a wheel in the repair stand to 20mph. Compare that to 5 seconds of full-body sprinting to accelerate in real-life. The 150g of the larger rear wheel (0.2% of complete weight, even for a racer boy on a light bike) is lost in the measuring precision.
Hey, even if a 10% larger wheel only rolls a tiny bit faster (why else go big on a road bike, the largest available is the world standard) the rolling resistance will overcome the weight increase of the larger wheel.

Still, people do get turned off by a 29" wheel, "it's so slow". I think the mind is what's slow, in adapting to new things.
Explain how it "just feels slow" to a NASA engineer. Those folks don't care for that, they care for what's really best for acheiving their goals.

My theory is that wheel flex (not getting the 4 extra spokes) and innecessary slalomming under accelleration are what's eating up energy people are sensing as "slow". If not, it's just between the ears and there is no cure.

There ARE super valid arguments for 26" wheels over 29", even out back, but I have only heard them from BMX and DJ riders. And no, it's not stiffness, weight, or durability. For XC and DH, I'm not aware there are any valid arguments that cannot be simply turned around by unlocking a 26"-specific parameter.

 

[fubar5]

Sweet post Cloxxki.

I see you posting at lot of places on the net about 29ers..What line of work are you in??

 

[NapalmCheese]

Explain how it "just feels slow" to a NASA engineer. Those folks don't care for that, they care for what's really best for acheiving their goals.

Best line ever! (considering I'm a NASA engineer)

 

[Cloxxki]

Ah, happy to stick that feather up your behind

If you must know fubar5, I'm in Europe, posting during breakfast and at evenings. I currently work in the chemical industry after saying goodbye to bike bizz (which I refer to as a hobby club rather than a business).
I manage to squeeze in perhaps 2 posts during lunch. For the better also. And believe it or not, bikes are no longer my first sports passion.

 

[mastercycleman]

taking wieght off the components, wouldnt be noticable compared to taking wieght off the wheels, as it is rotating mass, which is why they have more momentum, but less acceleration.

 

[Cloxxki]

The effect of rotating mass is sub-factor 2 of static weight, and only during change of speed. Considering bike+rider tend to go toward 200lb, and rotating weight being ~5lb, adding a percentage to that ~5lb does very VERY little to acceleration. And no, radius is not a factor.

 

[A.P]

Mickey, you really dont need to carry around 2 different tubes. A 26 tube would be fine.

Hell, in an emergency I have fitted a 20'' x 1.95 bmx tube into a full 26'' 2.5 casing downhill tire at jeepeater. I rode it for weeks.

 

[MMcG]

Ah, happy to stick that feather up your behind

If you must know fubar5, I'm in Europe, posting during breakfast and at evenings. I currently work in the chemical industry after saying goodbye to bike bizz (which I refer to as a hobby club rather than a business).
I manage to squeeze in perhaps 2 posts during lunch. For the better also. And believe it or not, bikes are no longer my first sports passion.

What is that first sports passion Cloxxki?

 

[Cloxxki]

I'm setting an off-topic record attempt, so all please ignore.

It's not yet taking off due to lack of proper gear (and plain laziness), but I have gotten the idea in my mind that I just might not suck at XC Skiing, Winter Triathlon or even Biathlon.
To train for XC Skiing, I need to do lots of running anyway. It also fits into cyclo-cross which I hope to bring to a more solid #3. With the running at more decent level, I might have fun in a winter triathlon. Running the snow, biking the snow (which traithlete is going to beat me at that?) and skiing.
The past 4 summers, I've had a nasty brochitus/allergic astma kind of thing, limiting my results. I figured as I'm strong as an ox even on a lazy winter morning, I might as well learn to xc ski (never tried) and have fun in the snow (which we have 24hrs per year here).
So, geeky rollerskiing as a training tool is in my future. I've already found it to give a superb base for cycling, after 2 weeks off the bike I pretty much kicked ass in a national series beach race.