What makes bikes handle differently? Can a bike be too light?

[Eric Bazan]

(big snip ...)
> It is especially not common on hills, steep or otherwise. The type of pedaling you describe isn't
> sustainable for any duration. Unless it's a finish line sprint, it's posing -- inefficient,
> dangerous, and hard on the bike.
>
> http://www.sheldonbrown.com/standing.html

I'm back. Just checked out Sheldon's article. He made some good points, but I'm sticking to my guns.
Standing is good. As another poster noted, it feels good. My bike likes it when I stand on it.

Also, Sheldon mentioned (at least twice) the bike must be in 'excellent mechanical condition' before
attempting to stand and pedal. Say what? If any bike is in such poor shape that it's going to break
by merely standing and pedaling it, that bicycle shouldn't be ridden. Period.

-Eric B

 

[Eric S. Sande]

>If any bike is in such poor shape that it's going to break by merely standing and pedaling it, that
>bicycle shouldn't be ridden. Period.

How would you know ahead of time.

--

_______________________ALL AMIGA IN MY MIND_______________________ ------------------"Buddy Holly,
the Texas Elvis"------------------
__________306.350.357.38>>[email protected]__________

 

[Tom Sherman]

"B. Sanders" wrote:
> ... I'm afraid that is quite wrong. Sprinters use their whole body to power the bike forward. This
> necessitates swinging the bike from side to side, transferring force exerted by the arms and upper
> torso into extra downward force against the pedals.
>
> This is especially important while climbing steep hills. Try climbing a steep hill without using
> your upper body, and keep the bike from moving side-to-side. Then try it again using your upper
> body and allowing the bike to move freely. I can almost guarantee that you'll see a speed increase
> with the latter technique. This might explain why it is so common.

Here is another explanation on the advantage of rhythmic lateral oscillation of the bicycle while
climbing out of the saddle. < http://asb-biomech.org/onlineabs/NACOB98/219/ >

Tom Sherman - Quad Cities USA (Illinois side)

 

[Andrew Bradley]

Terry Morse :

> > It is especially not common on hills, steep or otherwise. The type of pedaling you describe
> > isn't sustainable for any duration. Unless it's a finish line sprint, it's posing --
> > inefficient, dangerous, and hard on the bike.
>
> There is not much upper body effort required, but one moves the bike naturally from side to side
> when standing to counteract the torque of the pedals that would otherwise tend to tip the bike
> over. Using arm muscles to force the bike to stay upright is possible, but uncomfortable and
> inefficient. All experienced riders tip the bike when pedaling off the saddle, using only a tiny
> amount of arm force.

Of course it is natural to move the bike about, if you don't you have to go "up-and-over" the bike
on evey stroke.

As I see it the only inefficiency in flinging the bike around occurs at the tyres, heavy bike or
light bike.

The energy you put into moving bike-weight to one side (angular acceleration required) is fed into
the drivetrain on deceleration via increased pedal-force at the pedal you are leaning on.

If you don't pull hard on the bars though, you can't expect much extra power from riding out of the
saddle. The "lightly tipping" mode you mention is useful for avoiding a gear change and giving
certain muscles and other body parts a bit of respite. I'd guess this mode is used aerobically.

Andrew Bradley

 

[Andrew Bradley]

"Peter Cole" :
>
> We generally finish our club rides with a sprint, with riders trying to break away from a fast
> pack on a flat stretch. It's mostly done seated. For one thing, if you stand, you generate a lot
> more drag.

This is an interesting point, however sprints on unlimited gears are always done standing in races.
This is surely less aerodynamic, so there must be significant extra power available from the upper
body while out of saddle.

> It's very uncommon for cyclists to climb faster standing. Climbing is cardio-vascular limited, and
> standing pedaling is slightly less efficient for most, enough so that the sustained maximum pace
> is a bit less.

On long climbs,yes. But on short hills, in a race, everyone will be out of the saddle.

Andrew Bradley

 

[Tom Sherman]

Peter Cole wrote:
> ... I can't recall being chased by a dog in several years, don't know why that would elicit
> sympathy....

I wish that were true of the places I have ridden. Rural agricultural areas typically have lots of
dogs that treat the section of roadway adjacent to the farm buildings as their territory.

Tom Sherman - Quad Cities USA (Illinois side)

 

[Tom Sherman]

"B. Sanders" wrote:
> ... Of course, the rider can get used to almost anything. We humans are supremely adaptable. So,
> after a few rides every spring, my body re-adjusts to the quirks of each bike, and my favorites
> once again emerge. They're usually the same:
>
> 2000 RANS Rocket SWB recumbent 2001 Klein Attitude Race 199? Bianchi Brava single speed conversion
>
> These are all lightweight bikes. Low weight produces a benefit that I call "flickability."
> Flickability means that the bike responds quickly and effortlessly to tiny side-to-side rider
> input forces....

Barry,

The Rocket is hardly lightweight by upright road bike standards, but it is lighter than most other
steel frame recumbents. I believe the handling of the Rocket is more due to weight distribution and
steering geometry than weight. Ride a RANS Rocket and a RANS V-Rex [1] back to back and you will
find the Rocket to be much more responsive feeling. (I did this for several hours at a bike shop,
and ended up taking the Rocket home).

[1] The two bikes should only differ by a pound or so in weight.

Tom Sherman - Quad Cities USA (Illinois side)

 

[Tom Sherman]

eric bazan wrote:
> ... Standing while going up hills makes it possible to push a bigger gear and use a lower
> cadence....

Is there any advantage to doing this, unless one is already using the lowest gear on the bicycle?

Tom Sherman - Quad Cities USA (Illinois side)

 

[Captain Dondo]

On Fri, 18 Apr 2003 15:36:47 +0000, Stephen Harding wrote:

>
> Neither do I see why banking the bike back and forth while standup pedaling would be especially
> bad for the bike. Perhaps putting more lateral forces on frame (frame weakest in lateral
> stiffness), but a quality bike frame shouldn't be too upset with such forces.
>

I ride with an ex-linebacker. This guy tips the scales at 260# + with power to match. If you're
drafting him and he gets up to sprint, you can see the frame and the rear wheel flex. I mean the
rear wheel gets out of line by about 3 inches with the front, due to frame flex.

He completely trashed several Trek frames, due to excessive flex. Trek simply doesn't make frames
strong enough for a rider like that. No frame failure, but simply a substantial loss of rigidity in
the frame.

So yes, a big powerful rider can overpower a bike or frame, and excessive flex can be hard on a
quality frame.

-Dondo

 

[Andrew Bradley]

Tom Sherman :

> Here is another explanation on the advantage of rhythmic lateral oscillation of the bicycle while
> climbing out of the saddle. < http://asb-biomech.org/onlineabs/NACOB98/219/

Explanation? All they seem to do here is measure joint angles during out-of-saddle work and draw
strange conclusions.

Anyone who has seen footage of Pantani, Virenque, Ullrich, Armstrong, Zulle will know that "style"
ain't what defines the elite bike rider.

They also claim that it is primarily because you move forward to go out of saddle that the
ranges of joint-movement change. It isn't. It is because the hips are no longer at a fixed
distance from the BB.

Andrew Bradley.

 

[Tim McNamara]

In article <DqYna.515526$F1.72830@sccrnsc04>, "Peter Cole" <[email protected]> wrote:

> You can toss the bike violently from side-to-side, or not at all. Obviously the side-to-side
> thrashing is harder on the bike

In what way?

 

[Tim McNamara]

In article <[email protected]>, "Captain Dondo"
<[email protected]> wrote:

> On Fri, 18 Apr 2003 15:36:47 +0000, Stephen Harding wrote:
>
> > Neither do I see why banking the bike back and forth while standup pedaling would be especially
> > bad for the bike. Perhaps putting more lateral forces on frame (frame weakest in lateral
> > stiffness), but a quality bike frame shouldn't be too upset with such forces.
>
> I ride with an ex-linebacker. This guy tips the scales at 260# + with power to match. If you're
> drafting him and he gets up to sprint, you can see the frame and the rear wheel flex. I mean the
> rear wheel gets out of line by about 3 inches with the front, due to frame flex.

Are you sure that's not just a perspective illusion from the bike being thrown from side to side and
weaving a bit down the road?

> He completely trashed several Trek frames, due to excessive flex. Trek simply doesn't make frames
> strong enough for a rider like that. No frame failure, but simply a substantial loss of rigidity
> in the frame.

Ah, so his frame went soft under his massive power?

> So yes, a big powerful rider can overpower a bike or frame, and excessive flex can be hard on a
> quality frame.

"Hard" in what way? Failure of the tube or the joints? Permanent deformation of the frame?

 

[Tim McNamara]

In article <[email protected]>, [email protected] (Andrew
Bradley) wrote:

> This is an interesting point, however sprints on unlimited gears are always done standing in
> races. This is surely less aerodynamic, so there must be significant extra power available from
> the upper body while out of saddle.

People stand to sprint in order to use their weight on the pedals, not because there's "significant
extra power" available from the upper body. Most bicycle racers don't have much of an upper body to
get power from.

Watch the pros race. Many of the top sprinters do most of their sprint sitting down; this is even
more apparent in track sprinters. Standing for 200-300 meters of all-out sprinting is not effective
for most riders (Abdujaparov being a notable exception). Amateurs tend to be more likely to sprint
standing, but the sprints tend to only be 50-100 meters long.

 

[Mark Hickey]

"B. Sanders" <[email protected]> wrote:

>"Mark Hickey" <[email protected]> wrote in message

>> Having just built up a fixie (nothing's lighter than a fixie...) I can say I did notice the
>> bike's tendency to "bounce around" a bit more when I'm out of the saddle. But though it feels
>> like it's more likely to crash when the back wheel skips to one side or the other, the force
>> necessary to bring it back where it belongs is less as well.
>
>Nonetheless, it is interesting, isn't it? The rear wheel on my titanium hardtail positively
>skitters over small bumps. But wait, I thought rigid frames are all the same - no vertical
>compliance, right? How is this possible? If the total weight of bike + rider is so similar (less
>than 1% variance), how can such a large difference be felt at the rear wheel? (BTW: Yes, I've tried
>different tires and air pressures, different wheels, etc.)

When your rear tire hits a bump, it tries to displace the rear of the bike vertically, while the
tire is at the same time doing its best to absorb the energy by flexing.

With a really light bike, the rear end of the frame will be displaced (though not "flexed") more
than a heavier bike.

This is easy to visualize with the rider out of the saddle, but even with a seated rider, the same
principles apply, but the movement of the frame is bounded by the suspension of the saddle (and
rider's butt I suppose).

A good every day example of this phenomenon is the difference between the ride of a car or truck
with just the driver, as opposed to heavily loaded. Put a ton of rocks in the back of a small pickup
truck, and it's suddenly much more difficult to get the rear wheels to bounce off the ground on bad
road surfaces... ;-)

Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame

 

[Mark Hickey]

"Captain Dondo" <[email protected]> wrote:

>I ride with an ex-linebacker. This guy tips the scales at 260# + with power to match. If you're
>drafting him and he gets up to sprint, you can see the frame and the rear wheel flex. I mean the
>rear wheel gets out of line by about 3 inches with the front, due to frame flex.

You need to do an experiment. Sneak over to the linebacker's house, and get his bike. Now wedge it
between a couple solid objects and pull on the back end until it moves three inches "out of line".

Now run like hell, because you just permanently destroyed a really, really big strong guy's
bike... ;-)

>He completely trashed several Trek frames, due to excessive flex. Trek simply doesn't make frames
>strong enough for a rider like that. No frame failure, but simply a substantial loss of rigidity in
>the frame.

'Splain me, Lucy. How does the structure of the metal change without failing?

>So yes, a big powerful rider can overpower a bike or frame, and excessive flex can be hard on a
>quality frame.

A big powerful rider can experience excessive flex, and it's possible excessive flex can cause a
failure in a frame eventually. Just don't get your knickers in a twist over your frame "going
soft"... it simply doesn't happen.

Mark Hickey Habanero Cycles http://www.habcycles.com Home of the $695 ti frame

 

[Peter Cole]

"Tom Sherman" <[email protected]> wrote in message news:[email protected]...
>
> Here is another explanation on the advantage of rhythmic lateral oscillation of the bicycle while
> climbing out of the saddle. < http://asb-biomech.org/onlineabs/NACOB98/219/ >
>

It's not really an "explanation" at all. From the article:

"The range of bicycle tilt was also similar between groups although an analysis of maximum (3.72 ±
1.66°) and minimum (-6.60 ± 1.17°) values did show an asymmetric tilt pattern for elite cyclists."

It's hard to understand exactly what they mean by a maximum and minimum, but it appears that they're
saying the average cyclist swings the bike 10 degrees or so. That's a very small amount.

They didn't offer any biomechanical justification or analysis for the measured amount of swing, they
just observed it. Some cyclists swing the bike a lot, some not at all, I still don't see any proof
of efficiency or anything like that.

 

[Captain Dondo]

On Sat, 19 Apr 2003 16:28:50 +0000, Mark Hickey wrote:

> You need to do an experiment. Sneak over to the linebacker's house, and get his bike. Now wedge it
> between a couple solid objects and pull on the back end until it moves three inches "out of line".

I'm talking lateral flex. The front wheel tracks true; the rear wheel tracks in an S curve... Some
of it may be line of sight stuff, but any frame will flex under enough power. His far more than
most. Trek frames aren't built for that kind of weight...

> 'Splain me, Lucy. How does the structure of the metal change without failing?

Aluminum makes a lousy spring. You bend it enough times, it loses its strength. No single point
failure, just goes soft as a noodle. That's why springs are steel. I've had one alum. frame end up
that way after about 5 hard seasons. The frame just loses its liveliness.

> A big powerful rider can experience excessive flex, and it's possible excessive flex can cause a
> failure in a frame eventually. Just don't get your knickers in a twist over your frame "going
> soft"... it simply doesn't happen.

I've seen it happen. In my somewhat limited experience, Trek frames are great but not built for
big riders. Klein and some others do much better for big guys. Nothing against Trek; they make
great frames.

-Dondo

 

[Peter Cole]

"Terry Morse" <[email protected]> wrote in message
news:[email protected]...

> All experienced riders tip the bike when pedaling off the saddle, using only a tiny amount of
> arm force.

The article cited in this thread measured (seemingly) 10 degrees or so of swinging arc. That's not a
lot. I don't think I swing even that much, but such small angles are hard to estimate.

 

[Peter Cole]

"Mike S." <mikeshaw2@coxDOTnet> wrote in message news:Gb3oa.1592$366.810@fed1read06...
>
> Sprinting is one of the things I love about cycling. The speed, the power, the rush, the sense of
> accomplishment when you're done. Just riding along (JRA) doesn't have nearly the same effect. I
> understand that not everyone is like me, so YMMV when it comes to enjoying sprinting. But just
> like green eggs and ham, try it, you may like it!

Believe it or not, I have done the occasional sprint, but thanks for the condescension anyway. My
comments weren't about sprinting, but thrashing the bike from side-to-side.

> Hmmm, the SDBC ride here in San Diego does about the same thing, but is always won by a guy
> standing up sprinting for the last 50-100m. Towards the late spring/summer, I'm actually one of
> the ones up there sprinting "for the win." You ever see Cipollini take an all out sprint seated?
> He gets the big tow to the line seated, but for that last explosive burst to the line, nothing
> beats the standing sprint.

I'm sure you and Cipollini are both impressive sights. Our finish sprints tend to be much longer,
and usually seated.

> ...and when was the last time that happened to you? A chain skipping isn't going to cause a crash
> unless you're completely "equilibriumly challenged." Basic maintenence takes care of the rest...

Last time for me was several years ago, new chain, worn sprocket, MTB with very low bars...

I've seen quite a few of these though over the years, mostly pedal pull outs, but even when riders
haven't gone down from a chain skip, if they're standing, they often wobble violently. I've seen a
few pack crashes caused that way.

> Hell, you might as well worry about some idiot in a car hitting you if you're worried about a
> chain skipping or a pedal falling out. In the likelihood category, both occurences are very rare
> for a decently maintained bike.

Chain skips and pedal *pull outs* aren't all that rare in my neck of the woods.

 

[Peter Cole]

"Tom Sherman" <[email protected]> wrote in message news:[email protected]...
>
> Peter Cole wrote:
> > ... I can't recall being chased by a dog in several years, don't know why that would elicit
> > sympathy....
>
> I wish that were true of the places I have ridden. Rural agricultural areas typically have lots of
> dogs that treat the section of roadway adjacent to the farm buildings as their territory.

I think it's a regional thing. I do lots of riding in rural New England, and virtually never see a
loose dog, never mind an aggressive one.