C Law

I have been using 26'' mb wheels my whole life and have a few questions for anyone who can shed some light on them if they please.

1. Don't heavier wheels and tires make 29'' bikes handle more slugishly?
I mean, xcounty riders spend mortgage pmts on lightening their bikes, especially rotating weight, aren't larger wheels and tires generally heavier?

2. Does the extra momentum generated by the larger and heavier tires really make a big difference?

3. How much smoother does it make the ride vs 26'' wheels?

4. Does the larger contact patch really improve traction dramatically?

Any other big differences I should know about?

Thanks for the help

Quasi

1. Larger wheels are generally heavier because of the heavier tires and tubes/goop. Sluggish? Well that depends on what you are doing with them and how strong you are. If you have weak lower body muscles, you would be better off riding 26" or BMX bikes. 29er wheels take a bit more force to get going. But once you get them going, they keep going with less effort. So if you are doing something in which you expect to constantly start and stop, choose smaller wheels, espeicially if your legs tire easily.

2. Again, it depends on what you are doing. I find that in going uphill, the extra momentum makes a huge difference. Going downhill it is not so great, maybe a disadvantage. Going downhill you have gravity pushing you rather than your legs. Nevertheless, the smaller wheels will accelerate faster than the big ones. So in a course where there are a lot of short uphills and short downhills, the quick accelerating smaller wheels will have the advantage. But if there are long uphills, long downhills the momentum of the bigger wheels will be best, especially on the uphills.

3. Can't say about a smoother ride, you would have to have identical bikes in both large and small wheels to make any determination. The flatter arc of the tire will make it easier to overcome high AOA objects.

4. Dramatically, I doubt it. But of course it depends on what you are going through. Any increase in contact patch will help in slippery situations, unless the tire needs to cut through some kind of a layer to get at a harder layer for traction, then narrower wheels would be better (like an oil slick maybe?).

I believe 29ers are much less likely to launch their riders over the bars. This may have to do with the increased gyroscopic effect of the wheels, or maybe the lower relative center of gravity. I don't know. It is only my experience.

MichaelW

Wheel size should be judged relative to the rider. A 4'10" woman and a 6'6" man do not have the same riding experience when using std 26" MTB wheels.
I think that 29" is a useful option for big riders and gives them advantages of reduced rolling resistance. The disadvantages of a heftier wheels are not so important for big riders.

Buzzbomb

1. First thing to realize is that wheels are only marginally heavier, and can be just as light. Tires are heavier, although some are edging into pretty light weights this season. Tubes can be really heavy, if you are that worried about weight either go Stan's with a steel beaded tire and a rim that works well, there are some combinations that are known to work well, or use a lightwieght 26x2.1 tube. About the only time I notice the extra weight is when sprinting.

2. I really feel the momentum, especially on the downhills. I ride with a guy who was significantly faster than me on the downhills, and once I switched to a 9er I found myself right on his tail and riding the brakes. I would say in a course with a lot of short up and down hills the 9er will give you an advantage due to the retention of momentum.

3. My 9er hardtail is really plush compared to my old 26" bike. What really helps is the fact that on trails that I used to have to run around 40 psi to avoid pinchflatting, I can now ride at 26 - 27 psi. This gives greater compliance which results in an even larger contact patch, and helps a lot on techy climbs. In fact, I can climb stuff out of the saddle without breaking loose that I used to struggle for traction on in the old days. Another key consideration is that most 9ers have at least an inch more BB drop than a 26" bike, and this results in a bike that, for me, feels a lot more stable.

4. IMO, YES.

Big grin factors for me. These things can work for you, but you need to try one out, and not just a parking lot demo, give it a try on a trail. Fisher sometimes has demo days and usually they have a few 9ers to try. If you are into XC, and not too concerned with hucking or trials, I'd say the 9er may be a good option for you.

Quasi

We are talking about wheel momentum here right? Not bicycle momentum? IMHO wheel momentum important where the wheel contacts the ground. Imagine that you are spinning golf ball attached to a 13-inch long string over your head at one revolution per second. You reach up with your other hand and catch it. Ouch, that hurts. It hurts because the ball has momentum. The ball just imparted its momentum into your other hand, just as your bicycle tire imparts its momentum into the contact patch (well, sort of). Now grab a 14.5-inch long string and do the same thing. OUCH, that hurts even more. This is what happens when you pedal a 29er, you get more leverage on the ground. But when you are going down hill and you are not pedaling, I don't see any advantage other than the wider circumference of your tire makes it easier to roll over some objects. But then again, the 26 inch wheels will be spinning faster (assuming the bike is going the same speed as a 29er) so they might be able to claw their way over things better. I hope you are right about 29-inch wheels helping on the downhill. If so, I see a bright future for custom DH bike builders, cause I don't see any around right now. Maybe they are afraid 29 inch wheels are weaker, surely DHers aren't afraid of a little extra weight.

Buzzbomb

First off, we aren't talking about imparting energy to a static body (golf ball meets hand), and I'm not going to get into a physics discussion, you can google a million of em, and in lots of them there are guys way smarter than either of us on both sides of the fence. 9ers don't apply to DH, where the stiffest, strongest wheelset rules, regardless of weight. Check out the wheelsets those guys are using - they aren't concerned with weight. Besides, the trend with them is going to smaller wheels. No, I offered anecdotal evidence based on my three years of experience with 9ers. My real world results have led me to sell my uber light 26 inch bike (You know - the kind with a $600 wheelset, yada, yada, yada) for cash to acquire yet another 9er. Your mileage may vary. I don't see 9ers replacing 26" wheeled bikes, rather I see them as an increasingly valid choice for those who get most of their kicks riding singletrack, what with more forks, wheels, and tires being offered every season for the last three years. Bottom line? Ride one. If you don't like it don't buy it. They aren't for everyone.

C Law

Buzz, your responses are kind of up the alley of what I have been thinking. I am a large (6'2 185) guy who rides singletrack. I think a 29er would be right up my alley. I don't have the funds this year but I am yearning to get a 29er single or fixed gear going off road in the near future.

But I also had a thought that It is just another reason (from the bike companies) to get a new bike. That is really the reason I asked the question.

thanks for your guys input

Quasi

No we are not talking about imparting energy to a static body, but we are talking about using the same principle, combined with friction, to propel a movable object on a relatively static surface: leverage.

Of course we are only giving our own opinions about how 29ers perform. But I am sure you agree that our opinions might be wrong, there might be other reasons for performance advantages that we see in 29ers. I find total weight to be the major factor in downhill speed, are you sure your newfound downhill speed wasn't attributable to a heavier bike? Or maybe your friend lightened up his ride, or he is dieting.

I am a great advocate of 29ers. But there are many claims about how 29ers do this or that better than smaller wheels. Too many claims, it is becoming more like a religion and one is ostracized when they question any of the claims. IMHO this only alienates people thinking about entering the 29er world.

Buzzbomb

I keep repeating that the change is an incremental one, an evolution not a revolution. Actually, to be more precise it is a devolution, as 700c was the worldwide standard size til the Schwinn paperboy type bike's appearance. We are on the same page. I think that for every claim of an advantage there is an equally valid counterclaim of the inevitable disadvantage, on both sides of this particular argument. Weight/momentum, speed/acceleration, whatever. In some applications, for some people, they work quite well, other people don't like them. I say, viva choice!

Buzzbomb

I think a 9er would work well for you. Check out MTBR, there is a strong presence of 29" bike riders there. As far as 29" for a new product, I think the big players are using full suspension to fit that need. 29" bikes are for the most part being built by small independent guys. The major players in the cycling industry have yet to jump on board, and have snubbed requests for bikes that take the bigger wheel.

SquatchCO

bigger riders mean bigger bikes, right?

I'm 6'9", 235 lbs. Well into the clydesdale category. I'm pretty sure I want to go with a 29er, but I was wondering if there were any designed for big riders. I know Kona has their Hoss line, and I really liked the Sugar 293/2. I was wondering if there was a bike that was a combination of the two: tough and overbuilt, with 29 inch wheels and cross-country/all-mountain design. Any ideas?

LordOpie

Next time you're in Boulder, talk to Walt.

https://waltworks.com/dev/index.php

SquatchCO

yeah, I've heard of him. Only thing is (and I'm sure I will get a lot flak for saying this) I'm kind of leaning towards full suspension. And I doubt I'll see anything but hardtails from him.

willtsmith_nwi

A 29er rim is the same size as a road rim.

Road riders are just as interested in fast response time. The moment of inertia on a road tire will suffer proportionally as much increase as that on a mountain tire.

If either of these were a major issue, wouldn't we see a drive by roadies to use 26 inch rims. Wouldn't they be SOOO much faster.

The truth is that you have to look at the inertia of your BODY vs the moment of inertia of your wheel. What you will find is that your body weight is the NUMBER 1 factor to getting your bike moving. Seriously, I used to have this debate with skaters who argued against 90mm wheel for the SAME reason. Now I see that higher performance skates are now using 100mm and 110mm wheels.

Wheels to not exist individually for the load they carry. The LOAD is the issue, the wheels for our bikes are VERY secondary.

Now the larger wheel does effecitvely change the gearing ratio. Any bike will seem "sluggish" if you attempt to accelerate in too tall a gear.

willtsmith_nwi

I think if you measure the force of gravity vs the moment of inertia of a 29er wheel, you'll find that the wheel is negligible. I think you'll further find that most off hill downhills involve a LOT of braking.

But it is very true that 29ers may be inappropriate for children and small riders.

willtsmith_nwi

There are monster trucks out there with 5' tall tires. The rigs are 3 tons. There is nothing inherint to a 29er that makes it incompatible with downhill. One simply must build a thicker rim, use taller hub flanges and up the spoke count. Yes, that makes the wheel heavier, but that doesn't matter so much in downhill.

Check on mtbr.com on the 29er forum, there was a story recently on a 29er builder riding a FULLY RIGID 29er in a major downhill event. Lenzsport is coming out with a downhill 29er soon.

Honestly, I think that if 29ers can crack the downhill market, they would take over VERY quickly.

willtsmith_nwi

Gary Fisher uses VERY lightweight racing frames. I'm sorry my friend, but you would probably trash it VERY quickly.

In a hardtail, you could probably build up a steel Karate Monkey. In titanium, Lenz makes a killer full suspension called the Leviathon. Check on mtbr.com on their 29er forums. You'll probably get some guidance there.

jo5iah

I'm 220 and drop my Fisher 293 3' on a regular basis, without problem. I have not trashed it do so for ~800mi. I wouldn't characterize the 292/3 as a VERY lightweight frame either.

My only problems with the Fisher are BB height (better when the rear shock is all aired up, and the travel is set to 4.2") and the headset. Hairpin turns are a little sluggish, but only about 11% worse

I find that the biggest advantage my 29" wheels offer is that they roll over larger obstacles. Second biggest is that I can climb up steep slick surfaces better than I used to. After that, I do not launch myself superman style nearly as much, which is good and bad (flying is fun, no?).