REVIEWS DEALS BIKESHOPS TRAILS

26" vs. 29" SS: Inherent rotating mass advantage?

4115 Views 50 Replies 19 Participants Last post by Speedub.Nate, Jan 14, 2010

mlloyd007

Discussion Starter · Dec 27, 2009

The Niner Air 9 Carbon is tempting me, but when I compare wheel weights on a 26" wheel vs. a 29" wheel, it looks like 29" wheels (Industry Nine) are at least 100 grams heavier. That's rotating mass, so for climbing it appears there's an inherent energy disadvantage with the 29er. I can see that with technical terrain that disadvantage could be overcome somewhat by lower rolling resistance of the larger wheel over obstacles. So am I correct in assuming that a 26" bike will climb better on smooth terrain due to lower wheel rotating mass, while a 29" bike would climb better with increasingly technical terrain?

Your informed thoughts appreciated.

1 - 20 of 51 Posts

Schmucker

· #2 · Dec 27, 2009

Momentum. Acceleration is the only negative. It takes more to spin the weight up. It is more weight to carry up a hill if all else is equal, however. The momentum is especially useful on a single speed, obviously. All the pros easily outweigh the cons.

Speedub.Nate

· #3 · Dec 27, 2009

Couldn't you also phrase your question, "Since the 29er wheel spins 10% slower than the 26" wheel at any given speed, don't they have an advantage?"

Or you could ask, "Since the energy to spin up wheels represent only about 3% of the total energy required to propel the bike and rider forward, do small weight changes really make a noteworthy difference?"

After all the flawed 26 v 29 tests that have been performed, I have this theory: as more and more 29er riders enter competitive events in various classifications, we'll either see a dominant "fastest" wheel size emerge, or it'll be a wash as the podium is shared by the two wheel sizes.

AlexRandall

· #4 · Dec 27, 2009

The Niner Air 9 Carbon is tempting me, but when I compare wheel weights on a 26" wheel vs. a 29" wheel, it looks like 29" wheels (Industry Nine) are at least 100 grams heavier. That's rotating mass, so for climbing it appears there's an inherent energy disadvantage with the 29er

Then the tyres are heavier, as are tubes (if you run them), the frame has more heft due to the larger amount of tubing, forks have more lowers length etc etc.

SS riding isn't really about the weight, but about the flow. I can only assume that 29ers roll over things and cushion better than a 26er, because lots of nutters seem to like riding 29ss rigid bikes - and the last time I was foolish enough to ride rigid on the 26er I found it hard to grip for the next day or so.

Polk

· #5 · Dec 27, 2009

I have actually rode both 26" and 29" SS on the same trail, so I can give my experience.

Both bikes were steel framed with rigid forks. The 26" bike climbed steep, rough climbs easier and accelerated a little easier. The 29" biker was smoother, and at the end of the trail I felt a little less beat-up. Lap times were similar, but I never did any careful comparison of times. In the end I settled on the 29er; the ride difference trumped the acceleration difference for me.

pieterp

· #6 · Dec 27, 2009

(Keeping) Momentum and flow are the key words when riding SS. The big wheels hold the momentum for longer, the make line choice less important (since they roll over 'everything')so you can keep your flow more easily.

Zanetti

· #7 · Dec 28, 2009

The whole 29" thing is selling very well at the moment, and the hype is at an all time high. It'll be intesting to see what the mood towards them will be five to eight years from now. If I know the bicycle industry, they'll be hyping these new, super lightweight, fast accelerating 26" wheels.

boomn

· #8 · Dec 28, 2009

Zanetti said:
The whole 29" thing is selling very well at the moment, and the hype is at an all time high. It'll be intesting to see what the mood towards them will be five to eight years from now. If I know the bicycle industry, they'll be hyping these new, super lightweight, fast accelerating 26" wheels.

personally I disagree. In some regards I see an interesting parallel to when full suspension bikes were first introduced. Lots of people thought they would never perform well and would possibly even die off because of the power loss when pedaling and overall poor performance. As things advanced many people got over some of the disadvantages while other disadvantages disappeared as designs and technology caught up with the new challenge.

Also, like FS bikes, as 29ers become more prevalent and commonplace people will come to a better understanding of how they are simply a choice that has nice advantages within certain scopes but in others isn't necessarily the best choice.

Whafe

· #9 · Dec 28, 2009

I will go so far to say that I doubt any companies (large corporates) will be making hardtail 26inch wheel bikes in 5 years

Speedub.Nate

· #10 · Dec 28, 2009

Zanetti said:
The whole 29" thing is selling very well at the moment, and the hype is at an all time high. It'll be intesting to see what the mood towards them will be five to eight years from now. If I know the bicycle industry, they'll be hyping these new, super lightweight, fast accelerating 26" wheels.

I believe there is a bit off a pendulum effect, but that we're beyond the early "hype" stage as the wheel size has proved itself to be competitive, which drives sales. I do think a lot of non-29 riders are seeing the successes of 29ers on the podium and in the mags and hopping on, and that that may correct out when some decide to switch back to 26 when the time comes for a new bike.

Guitar Ted

· #11 · Dec 28, 2009

Zanetti said:
The whole 29" thing is selling very well at the moment, and the hype is at an all time high. It'll be intesting to see what the mood towards them will be five to eight years from now. If I know the bicycle industry, they'll be hyping these new, super lightweight, fast accelerating 26" wheels.

Your avatar inspires me to paraphrase you in the following manner:

"The whole suspension thing is selling very well at the moment, and the hype is at an all time high. It'll be interesting to see what the mood towards suspension forks will be five to eight years from now. If I know the bicycle industry, they'll be hyping these new, super lightweight, rigid forks next."

Imagine someone saying that circa 1993 when your Mag 21 was new.

And I did hear that then. Obviously, we all know the result.

Point being that 29"ers aren't going away, and neither are 26"ers.

Horses for courses.

Speaking of which, in terms of single speeding, my take is that momentum is a precious commodity. 29 inch wheels conserve momentum longer than 26 inch wheels do. The big wheels also roll over things with less energy loss, they have lower rolling resistance, and because of the differently shaped contact patch, you can corner faster, and lose less momentum than on 26 inch wheels.

Finally, the gyroscopic effect of the bigger wheel stabilizes the bike more so than with smaller hoops. You can downhill with more confidence and speed, plus that stability factor opens up geometry possibilities not possible with 26 inch wheels.

26 inch wheels also have several advantages that may appeal to other riders, like quicker acceleration, the ability to build a really small bike with correct geometry, and the ability to build up lighter, stiffer wheels. Not to mention the choices in components far outweighs that of 29"ers.

I think that for folks unfamiliar with 29"ers, it might prove useful to think about what it would be like to go from a 26"er to a 24 inch wheeled mountain bike. That "difference" is similar to what you gain from going up to a bigger diameter from 26 inch wheels.

There are trade offs, but many of us feel the advantages far outweigh the negatives.

See less See more

Speedub.Nate

· #12 · Dec 28, 2009

Guitar Ted said:
"The whole suspension thing is selling very well at the moment, and the hype is at an all time high. It'll be interesting to see what the mood towards suspension forks will be five to eight years from now. If I know the bicycle industry, they'll be hyping these new, super lightweight, rigid forks next."

...

Finally, the gyroscopic effect of the bigger wheel stabilizes the bike more so than with smaller hoops. You can downhill with more confidence and speed, plus that stability factor opens up geometry possibilities not possible with 26 inch wheels.

Worth noting that just a couple of years ago, MBA called the hardtail dead. We all laughed. Again reading the pendulum, there's been a "correction" back towards fully rigid -- maybe a bit of an over-correction as measured by sustained bike sales? The good news is there is room for all kinds of bikes, as long as there is room in our collective garages!

Re: gyroscopic effect, let's not overlook the improved center of gravity, or rather, higher front axle height, which reduces the endo factor, also inspiring rider confidence.

Zanetti

· #13 · Dec 29, 2009

Guitar Ted said:
Point being that 29"ers aren't going away, and neither are 26"ers.

Horses for courses.

I agree 100% with you on that.

Guitar Ted said:
Speaking of which, in terms of single speeding, my take is that momentum is a precious commodity. 29 inch wheels conserve momentum longer than 26 inch wheels do. The big wheels also roll over things with less energy loss, they have lower rolling resistance, and because of the differently shaped contact patch, you can corner faster, and lose less momentum than on 26 inch wheels.

Finally, the gyroscopic effect of the bigger wheel stabilizes the bike more so than with smaller hoops. You can downhill with more confidence and speed, plus that stability factor opens up geometry possibilities not possible with 26 inch wheels.

26 inch wheels also have several advantages that may appeal to other riders, like quicker acceleration, the ability to build a really small bike with correct geometry, and the ability to build up lighter, stiffer wheels. Not to mention the choices in components far outweighs that of 29"ers.

I think that for folks unfamiliar with 29"ers, it might prove useful to think about what it would be like to go from a 26"er to a 24 inch wheeled mountain bike. That "difference" is similar to what you gain from going up to a bigger diameter from 26 inch wheels.

There are trade offs, but many of us feel the advantages far outweigh the negatives.

All that theoretical stuff sounds fine and good, and I'm sure it sells plenty of bikes, but after two years of riding side by side with several of my riding buddies (who are on 29ers) I fail to see any real world advantage. You simply can't cheat the laws of physics. For every advantage the bigger, heavier wheels have, there is an equal and opposite disadvantage.

If you think you're faster on a 29er, you're right.

If you think you're faster on a 26er, you're also right. :thumbsup:

Zanetti

· #14 · Dec 29, 2009

Speedub.Nate said:
I believe there is a bit off a pendulum effect, but that we're beyond the early "hype" stage as the wheel size has proved itself to be competitive, which drives sales. I do think a lot of non-29 riders are seeing the successes of 29ers on the podium and in the mags and hopping on, and that that may correct out when some decide to switch back to 26 when the time comes for a new bike.

That's pretty close to the point I was trying to make. But I do think the 'hype' is still upon us.

I remember 1996 pretty well. I was working as the Service Manager for a Trek dealer and the Y-bikes were all the rage. The Trek versions were flying out the door as well as the GF Joshuas. Just because the marketers and the magazines tell you it's the greatest thing ever, and sales are at an all time high, it doesn't automaticlly mean the product has merit.

Zanetti

· #15 · Dec 29, 2009

Whafe said:
I will go so far to say that I doubt any companies (large corporates) will be making hardtail 26inch wheel bikes in 5 years

I've been following the bicycle industry for the past twenty years, and I spent a little more that half of that working in it, and I'd have to say you're dead wrong.

http://www.bicycleretailer.com/news/newsDetail/3172.html

Speedub.Nate

· #16 · Dec 29, 2009

Zanetti said:
I remember 1996 pretty well. I was working as the Service Manager for a Trek dealer and the Y-bikes were all the rage. The Trek versions were flying out the door as well as the GF Joshuas. Just because the marketers and the magazines tell you it's the greatest thing ever, and sales are at an all time high, it doesn't automaticlly mean the product has merit.

I remember '96, too. I was the proud owner of a 1996 Fisher Joshua Y. Replaced it with an '01 NRS. Two ends of the full suspension realm (from "living room sofa plush" to "I don't really want suspension" harsh). Both fads in a sense, although many will argue that. Point being, they had their one or two years of popularity, and the industry moved on as they languished in decline.

29" bikes, on the other hand, have been around about as long as Avid mechanical disc brakes, Rohloff Speedhubs, or RIM's Blackberry. The wheel size has transcended brands and categories. It would be tough to argue that the wheel size isn't firmly established or doesn't have merit.

Guitar Ted

· #17 · Dec 29, 2009

Zanetti said:
I agree 100% with you on that.

All that theoretical stuff sounds fine and good, and I'm sure it sells plenty of bikes, but after two years of riding side by side with several of my riding buddies (who are on 29ers) I fail to see any real world advantage. You simply can't cheat the laws of physics. For every advantage the bigger, heavier wheels have, there is an equal and opposite disadvantage.

If you think you're faster on a 29er, you're right.

If you think you're faster on a 26er, you're also right. :thumbsup:

Well, you seem to be in a place where you believe 29"ers aren't what they are cracked up to be. So be it.

2 national championships, a third at world's, UK single speed champ, and a host of other top racers are proving that 29"ers aren't a "theoretical exercise".

Thousands of racers, riders, and recreational cyclists seem to find something about 29 inch wheels that makes them happy, and more secure in riding off road. Does it matter to them if there is "hype"? No, it doesn't. It matters to them that the wheels work.

You can believe what you want to believe, and I am not going to try to change your, or anyones mind. But there is validity in the claims that gets proved everyday by riders all over the world.

If it didn't work, the wheel size would have died five years ago.

Happy trails...............

Whafe

· #18 · Dec 29, 2009

Zanetti said:
I've been following the bicycle industry for the past twenty years, and I spent a little more that half of that working in it, and I'd have to say you're dead wrong.

http://www.bicycleretailer.com/news/newsDetail/3172.html

I could well be wrong, and am happy to be, but I still feel that I am right on this one.... 26er HT bikes are on the way out.....

And I am not sayign that just to stir people up, fully believe it.

Of all the pro's and con's, a 26er HT is inferior to a 29er HT. (A statement I know, but fully believe it)

AZ

· #19 · Dec 29, 2009

32ers will render all other wheel sizes obsolete .

mlloyd007

Discussion Starter · #20 · Dec 29, 2009

The fact is that the more product diversity in the channel, the more net revenue the channel will generate. That's been proved amply in every type of consumer product channel. So there's a very strong economic imperative to diversify the product offerings through innovation and reintroducing older product ideas. Combine that with the fact that the vast majority of mountain bike purchasers are casual users who aren't able to differentiate product quality at the margin, and you have an ever-expanding set of products.

The bottom line is that it's pretty unlikely a whole product category (26" HT) will go away, and much more likely that more and more niches will develop as the category continues to mature. Just look at the number of distinct categories in MTBR now compared to what would have been the case 10 or 20 years ago.

1 - 20 of 51 Posts

This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.