29er



J

[email protected]

Guest
Hi All,

I bought a Redline Monocog 29er single speed bike a few days ago (from
the good folks at Yellow Jersey!) and already have 10+ hours on it.

It is great fun. It seems to be the perfect "shut-up and ride" bike.

As an avid fixed-gear road rider, I figured the single speed aspect
would be fine, but I was a bit apprehensive about how the gearing
would be hoplessly wrong at all times considering my gravitationally
challenged build, and the preponderance of steep hills found off-road
compared to the mild grades found on roads. Wrong! The stock gearing
is perfect for my conditions and style.

But what really blows me away is the big wheels. I've read all manner
of things about more easliy rolling over obsatcles, longer contact
patch for better traction, etc. I figured it was all true, but only by
tiny margins. But that does not seem to be the case. It seems to make
a HUGE difference. Is this possible, or am I hopelessly jaded in my
perception? What actuall percantage difference in terms of steep up-
hill traction can the larger wheels make? Being on the tall side, and
thus somewhat top-heavy in terms of wheelies and endos, is the longer
wheelbase making a bigger difference for me than it would for a
shorter rider? Riding into ditches and small streams poses no problems
in places I have endoed on other bikes. Also no wheelis up steep
hills, and wheelspin is practically eliminated.

So quantitatively, how much of a difference does a 29er make with my
100kg perched on a seat 84cm from the bb in terms of resisting endos
and wheelies, and getting power to the ground on steep climbs?

Joseph
 
On Feb 17, 1:47 pm, "[email protected]"
<[email protected]> wrote:
> Hi All,
>
> I bought a Redline Monocog 29er single speed bike a few days ago (from
> the good folks at Yellow Jersey!) and already have 10+ hours on it.
>
> It is great fun. It seems to be the perfect "shut-up and ride" bike.
>
> As an avid fixed-gear road rider, I figured the single speed aspect
> would be fine, but I was a bit apprehensive about how the gearing
> would be hoplessly wrong at all times considering my gravitationally
> challenged build, and the preponderance of steep hills found off-road
> compared to the mild grades found on roads. Wrong! The stock gearing
> is perfect for my conditions and style.
>
> But what really blows me away is the big wheels. I've read all manner
> of things about more easliy rolling over obsatcles, longer contact
> patch for better traction, etc. I figured it was all true, but only by
> tiny margins. But that does not seem to be the case. It seems to make
> a HUGE difference. Is this possible, or am I hopelessly jaded in my
> perception?

The price goes a long way to making the ride feel great. $450 bucks of
giant BMX! Woohoo!
 
On Sun, 17 Feb 2008 11:47:26 -0800 (PST),
"[email protected]" <[email protected]> wrote:

>Hi All,

>But what really blows me away is the big wheels. I've read all manner
>of things about more easily rolling over obsatcles, longer contact
>patch for better traction, etc. I figured it was all true, but only by
>tiny margins. But that does not seem to be the case. It seems to make
>a HUGE difference. Is this possible, or am I hopelessly jaded in my
>perception?

Dear Joseph,

Wikipedia:
<http://en.wikipedia.org/wiki/29er_(bicycle)>

Wiki has links to articles, such as this:
http://www.zinncycles.com/wheels29.aspx

It's hard not to notice the lack of simple geometry and measurements
in most of the arguments.

I wouldn't be surprised if there was a huge difference between your
new bike and your old bike, but I suspect that there's a lot more to
it than the small change in tire height.

Cheers,

Carl Fogel
 
[email protected] wrote:
> Hi All,
>
> I bought a Redline Monocog 29er single speed bike a few days ago (from
> the good folks at Yellow Jersey!) and already have 10+ hours on it.
>
> It is great fun. It seems to be the perfect "shut-up and ride" bike.
>
> As an avid fixed-gear road rider, I figured the single speed aspect
> would be fine, but I was a bit apprehensive about how the gearing
> would be hoplessly wrong at all times considering my gravitationally
> challenged build, and the preponderance of steep hills found off-road
> compared to the mild grades found on roads. Wrong! The stock gearing
> is perfect for my conditions and style.
>
> But what really blows me away is the big wheels. I've read all manner
> of things about more easliy rolling over obsatcles, longer contact
> patch for better traction, etc. I figured it was all true, but only by
> tiny margins. But that does not seem to be the case. It seems to make
> a HUGE difference. Is this possible, or am I hopelessly jaded in my
> perception? What actuall percantage difference in terms of steep up-
> hill traction can the larger wheels make? Being on the tall side, and
> thus somewhat top-heavy in terms of wheelies and endos, is the longer
> wheelbase making a bigger difference for me than it would for a
> shorter rider? Riding into ditches and small streams poses no problems
> in places I have endoed on other bikes. Also no wheelis up steep
> hills, and wheelspin is practically eliminated.
>
> So quantitatively, how much of a difference does a 29er make with my
> 100kg perched on a seat 84cm from the bb in terms of resisting endos
> and wheelies, and getting power to the ground on steep climbs?

I was cool to "fat 700x54" at first. I found the 'twenty nine'
nomenclature cutesy or silly and didn't see the point.

But now, having done some really nice quality bikes for 'the big guys' I
feel they are proportional and a good idea. Look at a Medium Italian
guy (like me!) with normal road wheels and then a Big Guy with fat '29'.
Everything just looks proportional I think. Even moreso comparing 26
mountain wheels under a regular guy to 29-inch under tall fellows.

p.s. thx for the plug!
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 
On 17 Feb, 21:39, A Muzi <[email protected]> wrote:
> [email protected] wrote:
> > Hi All,
>
> > I bought a Redline Monocog 29er single speed bike a few days ago (from
> > the good folks at Yellow Jersey!) and already have 10+ hours on it.
>
> > It is great fun. It seems to be the perfect "shut-up and ride" bike.
>
> > As an avid fixed-gear road rider, I figured the single speed aspect
> > would be fine, but I was a bit apprehensive about how the gearing
> > would be hoplessly wrong at all times considering my gravitationally
> > challenged build, and the preponderance of steep hills found off-road
> > compared to the mild grades found on roads. Wrong! The stock gearing
> > is perfect for my conditions and style.
>
> > But what really blows me away is the big wheels. I've read all manner
> > of things about more easliy rolling over obsatcles, longer contact
> > patch for better traction, etc. I figured it was all true, but only by
> > tiny margins. But that does not seem to be the case. It seems to make
> > a HUGE difference. Is this possible, or am I hopelessly jaded in my
> > perception? What actuall percantage difference in terms of steep up-
> > hill traction can the larger wheels make? Being on the tall side, and
> > thus somewhat top-heavy in terms of wheelies and endos, is the longer
> > wheelbase making a bigger difference for me than it would for a
> > shorter rider? Riding into ditches and small streams poses no problems
> > in places I have endoed on other bikes. Also no wheelis up steep
> > hills, and wheelspin is practically eliminated.
>
> > So quantitatively, how much of a difference does a 29er make with my
> > 100kg perched on a seat 84cm from the bb in terms of resisting endos
> > and wheelies, and getting power to the ground on steep climbs?
>
> I was cool to "fat 700x54" at first. I found the 'twenty nine'
> nomenclature cutesy or silly and didn't see the point.
>
> But now, having done some really nice quality bikes for 'the big guys' I
> feel they are proportional and a good idea. Look at a Medium Italian
> guy (like me!) with normal road wheels and then a Big Guy with fat '29'.
> Everything just looks proportional I think. Even moreso comparing 26
> mountain wheels under a regular guy to 29-inch under tall fellows.
>
> p.s. thx for the plug!
> --
> Andrew Muziwww.yellowjersey.org
> Open every day since 1 April, 1971

One look at the Monocog on my hatch-back mounted rack on my Fiat Bravo
shows how big the bike is. I actually laughed when I saw it.

Joseph

PS: I find the 29er tag somewhat embarrasing too.
 
On 17 Feb, 21:16, [email protected] wrote:
> On Sun, 17 Feb 2008 11:47:26 -0800 (PST),
>
> "[email protected]" <[email protected]> wrote:
> >Hi All,
> >But what really blows me away is the big wheels. I've read all manner
> >of things about more easily rolling over obsatcles, longer contact
> >patch for better traction, etc. I figured it was all true, but only by
> >tiny margins. But that does not seem to be the case. It seems to make
> >a HUGE difference. Is this possible, or am I hopelessly jaded in my
> >perception?
>
> Dear Joseph,
>
> Wikipedia:
> <http://en.wikipedia.org/wiki/29er_(bicycle)>
>
> Wiki has links to articles, such as this:
> http://www.zinncycles.com/wheels29.aspx
>
> It's hard not to notice the lack of simple geometry and measurements
> in most of the arguments.

Yes, there are lots of anecdotal claims made everywhere, and my own
experience was quite similar to Zinn's, but where are the numbers?

My 26" bike is a full suspension 27 speed regular XC type bike. The
new bike has no suspension, and single speed. On my ride today in
particular I rode up 2 of the steepest (short) climbs around here. On
the 26" bike it takes a lot of effort to balance wheelieing and
traction to get up these hills. Today I thought, "No way. I'll be way
overgeared and have to walk from half-way, if I don't spin out first."
Not the case at all. I stood and just rode right up. On one of them, I
even stopped midway in a track-stand for some horses I hadn't seen
when I started the climb.

> I wouldn't be surprised if there was a huge difference between your
> new bike and your old bike, but I suspect that there's a lot more to
> it than the small change in tire height.
>

There must be some explaination, because the difference is very great
indeed.

Joseph
 
[email protected] aka Joseph Santaniello wrote:
> [...]
> PS: I find the 29er tag somewhat embarrasing too.

Better "29er" than "69er", e.g.
<http://www.trekbikes.com/us/en/bikes/2008/mountain_hardtail/69er/69er3x9/>.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful
 
[email protected] wrote:
> On 17 Feb, 21:16, [email protected] wrote:
>> On Sun, 17 Feb 2008 11:47:26 -0800 (PST),
>>
>> "[email protected]" <[email protected]> wrote:
>>> Hi All,
>>> But what really blows me away is the big wheels. I've read all manner
>>> of things about more easily rolling over obsatcles, longer contact
>>> patch for better traction, etc. I figured it was all true, but only by
>>> tiny margins. But that does not seem to be the case. It seems to make
>>> a HUGE difference. Is this possible, or am I hopelessly jaded in my
>>> perception?
>> Dear Joseph,
>>
>> Wikipedia:
>> <http://en.wikipedia.org/wiki/29er_(bicycle)>
>>
>> Wiki has links to articles, such as this:
>> http://www.zinncycles.com/wheels29.aspx
>>
>> It's hard not to notice the lack of simple geometry and measurements
>> in most of the arguments.
>
> Yes, there are lots of anecdotal claims made everywhere, and my own
> experience was quite similar to Zinn's, but where are the numbers?
>
> My 26" bike is a full suspension 27 speed regular XC type bike. The
> new bike has no suspension, and single speed. On my ride today in
> particular I rode up 2 of the steepest (short) climbs around here. On
> the 26" bike it takes a lot of effort to balance wheelieing and
> traction to get up these hills. Today I thought, "No way. I'll be way
> overgeared and have to walk from half-way, if I don't spin out first."
> Not the case at all. I stood and just rode right up. On one of them, I
> even stopped midway in a track-stand for some horses I hadn't seen
> when I started the climb.
>
>> I wouldn't be surprised if there was a huge difference between your
>> new bike and your old bike, but I suspect that there's a lot more to
>> it than the small change in tire height.
>>
>
> There must be some explaination, because the difference is very great
> indeed.


"All else" isn't "equal"
Suspension is heavy and also wastes climbing effort by repeatedly
compressing an unloading the boingers (hence, the popularity of
'lockout' forks for climbing).
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 

> Joseph
>
> PS: I find the 29er tag somewhat embarrasing too.

So change it into metric dimensions....
 
On Sun, 17 Feb 2008 13:02:33 -0800 (PST),
"[email protected]" <[email protected]> wrote:

>On 17 Feb, 21:16, [email protected] wrote:
>> On Sun, 17 Feb 2008 11:47:26 -0800 (PST),
>>
>> "[email protected]" <[email protected]> wrote:
>> >Hi All,
>> >But what really blows me away is the big wheels. I've read all manner
>> >of things about more easily rolling over obsatcles, longer contact
>> >patch for better traction, etc. I figured it was all true, but only by
>> >tiny margins. But that does not seem to be the case. It seems to make
>> >a HUGE difference. Is this possible, or am I hopelessly jaded in my
>> >perception?
>>
>> Dear Joseph,
>>
>> Wikipedia:
>> <http://en.wikipedia.org/wiki/29er_(bicycle)>
>>
>> Wiki has links to articles, such as this:
>> http://www.zinncycles.com/wheels29.aspx
>>
>> It's hard not to notice the lack of simple geometry and measurements
>> in most of the arguments.
>
>Yes, there are lots of anecdotal claims made everywhere, and my own
>experience was quite similar to Zinn's, but where are the numbers?
>
>My 26" bike is a full suspension 27 speed regular XC type bike. The
>new bike has no suspension, and single speed. On my ride today in
>particular I rode up 2 of the steepest (short) climbs around here. On
>the 26" bike it takes a lot of effort to balance wheelieing and
>traction to get up these hills. Today I thought, "No way. I'll be way
>overgeared and have to walk from half-way, if I don't spin out first."
>Not the case at all. I stood and just rode right up. On one of them, I
>even stopped midway in a track-stand for some horses I hadn't seen
>when I started the climb.
>
>> I wouldn't be surprised if there was a huge difference between your
>> new bike and your old bike, but I suspect that there's a lot more to
>> it than the small change in tire height.
>>
>
>There must be some explanation, because the difference is very great
>indeed.
>
>Joseph

Dear Joseph,

Er, notice that you've moved from wondering whether it's possible to
insisting that the difference is very great indeed.

But that's human--whether it's there or not, it's nice that you like
your new bike.

But think about the idea that any reasonably geared single-speed MTB
bike is somehow going to let you outclimb a 27-speed MTB bike, with
trackstands in the middle of the climb.

If you like, post the tire circumference, crank length, and sprockets
for both bikes, and I'll post what the overall gearing works out to.

***

If you want some numbers for endos, there's an obvious pitfall.

If you jack the front and rear axles up from the height of a 26" MTB
to the height of a 29" MTB, the front contact patch stays right under
the front axle.

But you're also jacking the center of mass up just as much as you
raise the axle.

So there's no change in the braking leverage.

That is, a line drawn from the new center of mass through the new axle
height will be parallel to a line drawn from the old center of mass
through the new axle height:
http://i28.tinypic.com/c0u14.jpg

So there should be no change in braking and endo-potential . . .

Unless, of course, the new frame has the bottom bracket at a different
height or a different wheelbase, which would change the center of
mass.

In other words, it's very unlikely that anyone changes _just_ the
wheels from 26 to 29. The frame is usually different, so is the
suspension, the tires and wheels are likely to be heavier, and so
forth.

In fact, you'd have to change the gearing, since the 26" would have
noticeably lower gearing with the same sprockets than the 29".

You may be noticing the difference between a lighter, unsuspended bike
and a heavier one with suspension and gears. Apart from the weight,
suspension can rob a surprising amount of power from a bicycle trying
to go uphill, not to mention the wallowing that affects handling.

If you look at bicycle trials, the bikes have solid frames, no
suspension:
http://en.wikipedia.org/wiki/Bike_trials_riding
http://en.wikipedia.org/wiki/Image:Zona_zip.jpg
http://en.wikipedia.org/wiki/Image:Megamo.jpg

They can stop to stare at horses a lot better than full-suspension
bikes.

Cheers,

Carl Fogel
 
On Feb 17, 6:33 pm, [email protected] wrote:
> If you want some numbers for endos, there's an obvious pitfall.
>
> If you jack the front and rear axles up from the height of a 26" MTB
> to the height of a 29" MTB, the front contact patch stays right under
> the front axle.
>
> But you're also jacking the center of mass up just as much as you
> raise the axle.
>
> So there's no change in the braking leverage.

Dear Carl,
I'd have to go with Joseph on this one. I switched to a 29er a year
and a half ago and found the same remarkable differences that he is
describing (and which are often described by 29er riders). True, the
specs on my older "26 inch" MTB and my newer 29er were not identical,
but they are VERY similar in basic layout. My first ride on my 29er
(which was also my first ride on ANY 29er) was an absolute
gigglefgest. I felt like I was cheating. Despite my technical skiils
having lapsed from having spent far more time on a road bike than off-
road, I was very comfortably riding some familiar techincal terrrain
at least as easily as I had ever done. The benefits of the "small
change in tire height" are quite noticeable.

But for the sake of discussion, it would also appear that many endos
are less likely on a 29er for reasons other than just the larger
wheel's ability to roll over and/or through obstacles. In many (but
not all) such endo events the pivot point is the axle-line of the
front wheel (Not the case if the front wheel is locked by the brakes).
On a 29er the axle IS higher, therefore more difficult to pivot over.
Taken to the extreme, if the pivot point were higher than the rider's
CG no endos would be possible.
This is not to say that a 29er can never be endoed. I have first hand
experience to the contrary. But you'll just have to take my word for
that.

But even wihen the front wheel is locked and the pivot point becomes
the contact patch, your comments make one very basic and erroneous
assumption that I have heard numerous times. It is that, because of
the larger wheels the center of gravity (of rider and bike) must be
higher. Not true. The rider position (and CG) is essentially set by
(or directly related to) the bottom bracket height which, with
appropriate design, is not necessarily higher than on any other bike
regarldess of wheel size. On my 29er it is actually a bit lower than
my "26er."

DR
 
On Sun, 17 Feb 2008 19:59:31 -0800 (PST), DirtRoadie
<[email protected]> wrote:

>On Feb 17, 6:33 pm, [email protected] wrote:
>> If you want some numbers for endos, there's an obvious pitfall.
>>
>> If you jack the front and rear axles up from the height of a 26" MTB
>> to the height of a 29" MTB, the front contact patch stays right under
>> the front axle.
>>
>> But you're also jacking the center of mass up just as much as you
>> raise the axle.
>>
>> So there's no change in the braking leverage.
>
>Dear Carl,
>I'd have to go with Joseph on this one. I switched to a 29er a year
>and a half ago and found the same remarkable differences that he is
>describing (and which are often described by 29er riders). True, the
>specs on my older "26 inch" MTB and my newer 29er were not identical,
>but they are VERY similar in basic layout. My first ride on my 29er
>(which was also my first ride on ANY 29er) was an absolute
>gigglefgest. I felt like I was cheating. Despite my technical skiils
>having lapsed from having spent far more time on a road bike than off-
>road, I was very comfortably riding some familiar techincal terrrain
>at least as easily as I had ever done. The benefits of the "small
>change in tire height" are quite noticeable.
>
>But for the sake of discussion, it would also appear that many endos
>are less likely on a 29er for reasons other than just the larger
>wheel's ability to roll over and/or through obstacles. In many (but
>not all) such endo events the pivot point is the axle-line of the
>front wheel (Not the case if the front wheel is locked by the brakes).
>On a 29er the axle IS higher, therefore more difficult to pivot over.
>Taken to the extreme, if the pivot point were higher than the rider's
>CG no endos would be possible.
>This is not to say that a 29er can never be endoed. I have first hand
>experience to the contrary. But you'll just have to take my word for
>that.
>
>But even wihen the front wheel is locked and the pivot point becomes
>the contact patch, your comments make one very basic and erroneous
>assumption that I have heard numerous times. It is that, because of
>the larger wheels the center of gravity (of rider and bike) must be
>higher. Not true. The rider position (and CG) is essentially set by
>(or directly related to) the bottom bracket height which, with
>appropriate design, is not necessarily higher than on any other bike
>regarldess of wheel size. On my 29er it is actually a bit lower than
>my "26er."
>
>DR

Dear DR,

Please re-read my post--you're repeating my point.

Briefly, if you raise nothing but the axles, then there's no effect on
braking because the center of gravity rises just as much.

So either there's no effect on braking and endos, or the bottom
bracket has to be moved, changing the center of gravity.

Cheers,

Carl Fogel
 
On Feb 17, 9:08 pm, [email protected] wrote:
> On Sun, 17 Feb 2008 19:59:31 -0800 (PST), DirtRoadie

> Dear DR,
>
> Please re-read my post--you're repeating my point.

I am? I asserted that a 29er is likely to have a clear benefit in
avoiding endos. But you appeared to have taken just the opposite
position, suggesting that it is likely the over-exuberance of a new
29er owner in "feeling" such things.

> Briefly, if you raise nothing but the axles, then there's no effect on
> braking because the center of gravity rises just as much.

You have created a nonsensical "strawman" by merely (in theory)
putting larger (29") wheels on the same (26") frame. That hardly
helps explain OR challenge what may be happening on a frame which is
purposely built to accomodate the 29" wheels.

> So either there's no effect on braking and endos, or the bottom
> bracket has to be moved, changing the center of gravity.

The point is that the bottom bracket is NOT likely to have been
significantly "moved" relative TO THE GROUND if the bike in question
has been designed for the larger wheels (as I believe most 29er's have
been). As I pointed out, it is a very common misperception that ALL
29er's have a higher center of gravity simply because of their larger
wheels. Your disscussion seemed to be largely in line with that
misperception.

DR
 
In article
<[email protected]>,
landotter <[email protected]> wrote:

> On Feb 17, 1:47 pm, "[email protected]"
> <[email protected]> wrote:
> > Hi All,
> >
> > I bought a Redline Monocog 29er single speed bike a few days ago (from
> > the good folks at Yellow Jersey!) and already have 10+ hours on it.
> >
> > It is great fun. It seems to be the perfect "shut-up and ride" bike.
> >
> > As an avid fixed-gear road rider, I figured the single speed aspect
> > would be fine, but I was a bit apprehensive about how the gearing
> > would be hoplessly wrong at all times considering my gravitationally
> > challenged build, and the preponderance of steep hills found off-road
> > compared to the mild grades found on roads. Wrong! The stock gearing
> > is perfect for my conditions and style.
> >
> > But what really blows me away is the big wheels. I've read all manner
> > of things about more easliy rolling over obsatcles, longer contact
> > patch for better traction, etc. I figured it was all true, but only by
> > tiny margins. But that does not seem to be the case. It seems to make
> > a HUGE difference. Is this possible, or am I hopelessly jaded in my
> > perception?
>
> The price goes a long way to making the ride feel great. $450 bucks of
> giant BMX! Woohoo!

Woohoo indeed. I do notice that my cyclocross bike is quite an
entertaining ride off-road, and has some of that "go over anything"
feel, though I notice it more in contrast to my road bike than my MTB.

I made a pretty picture to illustrate the differences:

http://www.flickr.com/photos/rcousine/2272842143/sizes/o/

Note that this shows nominal 29" and 26" diameter wheels. I've included
some reference "obstacles".

I'm not sure what it means.

But my feeling is that the aesthetics of 29er and 26er bikes are quite
difference. As to the climbing performance, I'd point out that a 29er
effectively forces lengthening the wheelbase and particularly the
chainstays. This may help the bike feel more connected during climbing,
but I'm no expert on mountain bike geometry.

Not that this should stop you from enjoying your 29er, but in 2006
serious endurance MTB racer Dave Harris did a comparison between his
29er and 26er by racing both during a 24 hour race:

<http://www.cyclingnews.com/mtb.php?id=news/2006/mar06/mar03mtbnews>
<http://teamhealthfx.com/blogs/dave_harris/archive/2006/02/21/571.aspx>

Even Dave notes that he enjoys the feel of the 29er, though it appears
to be a bit slower (when comparing watts and lap times) or to require
more energy at the same speed.

Of course, if you've already chosen a singlespeed, lap time arguments
will fall on deaf ears.

I daresay that one thing that mountain biking has figured out is that
there are tons and tons of bikes out there that are avowedly not
designed to be the fastest possible bike over any course. The entire 6"
suspension category, all 29ers, singlespeeds, rigids, and others, exist
because while they're not faster than the alternatives, they're more fun
or they feel different.

--
Ryan Cousineau [email protected] http://www.wiredcola.com/
"In other newsgroups, they killfile trolls."
"In rec.bicycles.racing, we coach them."
 
On Sun, 17 Feb 2008 20:47:14 -0800 (PST), DirtRoadie
<[email protected]> wrote:

>On Feb 17, 9:08 pm, [email protected] wrote:
>> On Sun, 17 Feb 2008 19:59:31 -0800 (PST), DirtRoadie
>
>> Dear DR,
>>
>> Please re-read my post--you're repeating my point.
>
>I am? I asserted that a 29er is likely to have a clear benefit in
>avoiding endos. But you appeared to have taken just the opposite
>position, suggesting that it is likely the over-exuberance of a new
>29er owner in "feeling" such things.
>
>> Briefly, if you raise nothing but the axles, then there's no effect on
>> braking because the center of gravity rises just as much.
>
>You have created a nonsensical "strawman" by merely (in theory)
>putting larger (29") wheels on the same (26") frame. That hardly
>helps explain OR challenge what may be happening on a frame which is
>purposely built to accomodate the 29" wheels.
>
>> So either there's no effect on braking and endos, or the bottom
>> bracket has to be moved, changing the center of gravity.
>
>The point is that the bottom bracket is NOT likely to have been
>significantly "moved" relative TO THE GROUND if the bike in question
>has been designed for the larger wheels (as I believe most 29er's have
>been). As I pointed out, it is a very common misperception that ALL
>29er's have a higher center of gravity simply because of their larger
>wheels. Your disscussion seemed to be largely in line with that
>misperception.
>
>DR

Dear DR,

My point is that the wheels alone are not going to cause the change.

You have to change other things, such as the frame and gearing.

Joseph, the original poster, seemed to be asking about the wheels and
wondering if the wheels alone were causing wonderful improvements,
looking for numbers and geometry.

Cheers,

Carl Fogel
 
On Mon, 18 Feb 2008 04:47:36 GMT, Ryan Cousineau <[email protected]>
wrote:

>Woohoo indeed. I do notice that my cyclocross bike is quite an
>entertaining ride off-road, and has some of that "go over anything"
>feel, though I notice it more in contrast to my road bike than my MTB.
>
>I made a pretty picture to illustrate the differences:
>
>http://www.flickr.com/photos/rcousine/2272842143/sizes/o/
>
>Note that this shows nominal 29" and 26" diameter wheels. I've included
>some reference "obstacles".
>
>I'm not sure what it means.
>
>But my feeling is that the aesthetics of 29er and 26er bikes are quite
>difference. As to the climbing performance, I'd point out that a 29er
>effectively forces lengthening the wheelbase and particularly the
>chainstays. This may help the bike feel more connected during climbing,
>but I'm no expert on mountain bike geometry.

Dear Ryan,

Your drawing shows that why a larger wheel will roll more easily over
obstacles. That's why ox-carts have wheels seven feet high.

But it may exaggerate the effect for the two wheels in question, since
most MTB riders aren't trying to pedal up steep slopes littered
end-to-end with sharp 4 to 12 inch steps.

Real obstacles on trails tend to be rounded.

They also tend to compress when actually measured.

A lot of "4-foot ledges" and "waist-high logs" that I rode in trials
competition had an annoying habit of shrinking to under 36 inches and
to less than knee-high under the weight of a tape-measure.

I do think that there's the obvious but slight rolling advantage to a
slightly larger wheel, but I suspect that different frames, gearing,
suspension, tires, and other equipment (as well as the new bike effect
and rider expectations) account for just as much of the improvement.

Until it's pointed out, few riders "notice" that the bigger wheels and
tires must be heavier and should accelerate more slowly, even though
they often "notice" that a recently purchased lighter bike climbs much
better and that slightly lighter wheels accelerate faster.

Joseph seems convinced that his new bike is wonderfully better, which
is good to hear and may well be true. I'm just skeptical that the
impressive climbing improvement is purely a matter of a pair of
slightly bigger wheels when there's also a change to a solid frame and
to single-speed gearing.

I doubt that the two bikes in question are quite as comparable as we'd
like, but again it's nice that Joseph is having so much fun.

Cheers,

Carl Fogel
 
On 18 Feb, 06:52, [email protected] wrote:
> On Sun, 17 Feb 2008 20:47:14 -0800 (PST), DirtRoadie
>
>
>
> <[email protected]> wrote:
> >On Feb 17, 9:08 pm, [email protected] wrote:
> >> On Sun, 17 Feb 2008 19:59:31 -0800 (PST), DirtRoadie
>
> >> Dear DR,
>
> >> Please re-read my post--you're repeating my point.
>
> >I am? I asserted that a 29er is likely to have a clear benefit in
> >avoiding endos. But you appeared to have taken just the opposite
> >position, suggesting that it is likely the over-exuberance of a new
> >29er owner in "feeling" such things.
>
> >> Briefly, if you raise nothing but the axles, then there's no effect on
> >> braking because the center of gravity rises just as much.
>
> >You have created a nonsensical "strawman" by merely (in theory)
> >putting larger (29") wheels on the same (26") frame. That hardly
> >helps explain OR challenge what may be happening on a frame which is
> >purposely built to accomodate the 29" wheels.
>
> >> So either there's no effect on braking and endos, or the bottom
> >> bracket has to be moved, changing the center of gravity.
>
> >The point is that the bottom bracket is NOT likely to have been
> >significantly "moved" relative TO THE GROUND if the bike in question
> >has been designed for the larger wheels (as I believe most 29er's have
> >been). As I pointed out, it is a very common misperception that ALL
> >29er's have a higher center of gravity simply because of their larger
> >wheels. Your disscussion seemed to be largely in line with that
> >misperception.
>
> >DR
>
> Dear DR,
>
> My point is that the wheels alone are not going to cause the change.
>
> You have to change other things, such as the frame and gearing.
>
> Joseph, the original poster, seemed to be asking about the wheels and
> wondering if the wheels alone were causing wonderful improvements,
> looking for numbers and geometry.
>
> Cheers,
>
> Carl Fogel

I meant the wheels and requisite changes to accomodate those wheels.

Joseph
 
On 18 Feb, 05:47, Ryan Cousineau <[email protected]> wrote:
> In article
> <[email protected]>,
>
>
>
> landotter <[email protected]> wrote:
> > On Feb 17, 1:47 pm, "[email protected]"
> > <[email protected]> wrote:
> > > Hi All,
>
> > > I bought a Redline Monocog 29er single speed bike a few days ago (from
> > > the good folks at Yellow Jersey!) and already have 10+ hours on it.
>
> > > It is great fun. It seems to be the perfect "shut-up and ride" bike.
>
> > > As an avid fixed-gear road rider, I figured the single speed aspect
> > > would be fine, but I was a bit apprehensive about how the gearing
> > > would be hoplessly wrong at all times considering my gravitationally
> > > challenged build, and the preponderance of steep hills found off-road
> > > compared to the mild grades found on roads. Wrong! The stock gearing
> > > is perfect for my conditions and style.
>
> > > But what really blows me away is the big wheels. I've read all manner
> > > of things about more easliy rolling over obsatcles, longer contact
> > > patch for better traction, etc. I figured it was all true, but only by
> > > tiny margins. But that does not seem to be the case. It seems to make
> > > a HUGE difference. Is this possible, or am I hopelessly jaded in my
> > > perception?
>
> > The price goes a long way to making the ride feel great. $450 bucks of
> > giant BMX! Woohoo!
>
> Woohoo indeed. I do notice that my cyclocross bike is quite an
> entertaining ride off-road, and has some of that "go over anything"
> feel, though I notice it more in contrast to my road bike than my MTB.
>
> I made a pretty picture to illustrate the differences:
>
> http://www.flickr.com/photos/rcousine/2272842143/sizes/o/
>
> Note that this shows nominal 29" and 26" diameter wheels. I've included
> some reference "obstacles".
>
> I'm not sure what it means.

To me it means that at a given speed over for example the 10cm brick
the larger wheel has more time to lift the bike up over the obstacle.
This reduced the upward acceleration, and at the very least makes for
a smoother feel. Whether it makes any difference in terms of energy, I
don't know.

>
> But my feeling is that the aesthetics of 29er and 26er bikes are quite
> difference. As to the climbing performance, I'd point out that a 29er
> effectively forces lengthening the wheelbase and particularly the
> chainstays. This may help the bike feel more connected during climbing,
> but I'm no expert on mountain bike geometry.

This is also a place where I think the longer contact patch could be a
factor.

>
> Not that this should stop you from enjoying your 29er, but in 2006
> serious endurance MTB racer Dave Harris did a comparison between his
> 29er and 26er by racing both during a 24 hour race:
>
> <http://www.cyclingnews.com/mtb.php?id=news/2006/mar06/mar03mtbnews>
> <http://teamhealthfx.com/blogs/dave_harris/archive/2006/02/21/571.aspx>
>
> Even Dave notes that he enjoys the feel of the 29er, though it appears
> to be a bit slower (when comparing watts and lap times) or to require
> more energy at the same speed.
>
> Of course, if you've already chosen a singlespeed, lap time arguments
> will fall on deaf ears.

Indeed. No contest the geared FS bike would be faster over just about
any course I could ride.

>
> I daresay that one thing that mountain biking has figured out is that
> there are tons and tons of bikes out there that are avowedly not
> designed to be the fastest possible bike over any course. The entire 6"
> suspension category, all 29ers, singlespeeds, rigids, and others, exist
> because while they're not faster than the alternatives, they're more fun
> or they feel different.
>

That's just it. Very strange.

Joseph
 
On 18 Feb, 02:33, [email protected] wrote:
> On Sun, 17 Feb 2008 13:02:33 -0800 (PST),
>
>
>
> "[email protected]" <[email protected]> wrote:
> >On 17 Feb, 21:16, [email protected] wrote:
> >> On Sun, 17 Feb 2008 11:47:26 -0800 (PST),
>
> >> "[email protected]" <[email protected]> wrote:
> >> >Hi All,
> >> >But what really blows me away is the big wheels. I've read all manner
> >> >of things about more easily rolling over obsatcles, longer contact
> >> >patch for better traction, etc. I figured it was all true, but only by
> >> >tiny margins. But that does not seem to be the case. It seems to make
> >> >a HUGE difference. Is this possible, or am I hopelessly jaded in my
> >> >perception?
>
> >> Dear Joseph,
>
> >> Wikipedia:
> >> <http://en.wikipedia.org/wiki/29er_(bicycle)>
>
> >> Wiki has links to articles, such as this:
> >> http://www.zinncycles.com/wheels29.aspx
>
> >> It's hard not to notice the lack of simple geometry and measurements
> >> in most of the arguments.
>
> >Yes, there are lots of anecdotal claims made everywhere, and my own
> >experience was quite similar to Zinn's, but where are the numbers?
>
> >My 26" bike is a full suspension 27 speed regular XC type bike. The
> >new bike has no suspension, and single speed. On my ride today in
> >particular I rode up 2 of the steepest (short) climbs around here. On
> >the 26" bike it takes a lot of effort to balance wheelieing and
> >traction to get up these hills. Today I thought, "No way. I'll be way
> >overgeared and have to walk from half-way, if I don't spin out first."
> >Not the case at all. I stood and just rode right up. On one of them, I
> >even stopped midway in a track-stand for some horses I hadn't seen
> >when I started the climb.
>
> >> I wouldn't be surprised if there was a huge difference between your
> >> new bike and your old bike, but I suspect that there's a lot more to
> >> it than the small change in tire height.
>
> >There must be some explanation, because the difference is very great
> >indeed.
>
> >Joseph
>
> Dear Joseph,
>
> Er, notice that you've moved from wondering whether it's possible to
> insisting that the difference is very great indeed.
>
Ok, I should have said "perceived difference" ;-)


> But that's human--whether it's there or not, it's nice that you like
> your new bike.
>
> But think about the idea that any reasonably geared single-speed MTB
> bike is somehow going to let you outclimb a 27-speed MTB bike, with
> trackstands in the middle of the climb.

That's just it. I was dumbfounded. On the 26" bike I need to sit to
get enough traction (even with double lockout). I then need to lean
way forward to keep from doing wheelies, and I need a low gear in that
position. The low gear may exacerbate slippage. On the 29" SS, I just
stood up and stomped up the hills with zero drama.

>
> If you like, post the tire circumference, crank length, and sprockets
> for both bikes, and I'll post what the overall gearing works out to.
>

The gearing is no problem. Maybe the higher gear used on these climbs
with the SS results in less torque at the wheel so less slippage. Like
driving in a high gear on ice in a car.

I'll have to weigh them, but I think there is only a minimal differnce
between the two bikes.


Joseph
 
You must log in or register to reply here.

Similar threads

Spunky99
29er vs. 27.5" for aggressive trail riding?
Replies
31
Views
344
Cycling Equipment
ttechnoholic
ttechnoholic
jessevan
29er or 27.5” - Which wheel size for my riding style?
Replies
33
Views
439
Cycling Equipment
visual_infinity
visual_infinity
R
Converting my old 29er to a road bike.
Replies
2
Views
1K
Cycling Equipment
dabac
dabac
K2CURIOUS
NEED INFO ON ..K2 ZED 4.9 29er MOUNTAIN BIKE
Replies
3
Views
17K
Cycling Equipment
CAMPYBOB
CAMPYBOB
S
Re: 29er vs. 650B
Replies
0
Views
486
Cycling Equipment
Scott Gordo
S
Top Bottom Back