"energy-sucking handlebar-on-a-stick" ???

[Charles.Plager]

Ya know, Eric, I don't know

Ya know, Eric, I don't know if that one counts as I'm pretty sure I screwed that up last time I tried to talk about it too...

 

[John Tolhurst]

It is not really one thing

It is not really one thing twisting over and above another. It is all of them adding up to the total movement, and that includes the boom and slider as well. The best place for a brace is from the middle of the grip (amputate a finger, sorry) down to the BB shell (knee amputation too?). Failing that you have to remove elements; stem, steering extension, pivot clamp ... attach the handle bar to the top of the slider. You've seen this of course in the Silvio and Vendetta implementations (patented).

 

[billyk]

I'm sure John's right, of course, but ...

I'm sure John's right, of course, but today I tried holding the brake while pulling the bar and pushing the pedal hard. There was noticeable bend in the handlebar. So while it won't solve the whole problem, I'll work on a beefy replacement bar and hope for a significant improvement. 50% better would make a big difference climbing hard.

The Quest is such a great bike, they're definitely gonna keep making it better, so we can expect a different handlebar on the Q4. Right, John? Right? (As a coffee drinker, I pay no attention to tea leaves).

BK

 

[John Tolhurst]

The bar end may be moving,

The bar end may be moving, but does most of that movement originate in the bar itself? My point is that what you see moving at the end of the bar is a mapping of the accumulated flex of the whole system.

 

[Charles.Plager]

Hey BK,
Put a horizontal

Hey BK,

Put a horizontal sticker on the stem and see if you can see it twisting...

 

[richa]

A possible test


As a test, a bar-end could be attached at the top of the riser (right below the handlebars) pointing forward (and angled down) and a pipe stuck on that sticking out forward to a point somewhere near the bottom bracket. ideally, it would all be ridged.

Then ride and watch to see if end of the pipe moves relative to the bottom bracket. If it doesn't move then there's no flex in the system from the BB to the top of the riser tube, and all the flex is in the handlebars.

Rich

 

[ratz]

Flex is flex

So the Quest showed up today; assembled it tonight. Nice only took 30 minutes without a manual. Little easier than the Silvio Should be perfect for teaching the kids and my folks to ride FWD MBB.

But of course because of this thread I had to see if there was flex. I live on a steep hill so that was a pretty easy test. Didn't seem too bad if I spun up the hill; but if I mash; yeah the there's lots of flex.

This is a Q2 so I could see the front suspension move; and it wasn't so much the extension that flexed as it was that the huge leverage of the extension causing flex in the frame and the headset stack. To my mind that's not something that's going away. Tightening the headset stack to help fix that will just give steering that is going to be too tight and binding. I didn't see any real flex in the handle bars themselves; anytime they moved something else move with them.

Not sure what the big deal is though; the bike is bouncy and nice gooshy suspension and feels pretty smooth on the road. I'd expect as much power loss on this as any good fully suspended bike or trike. Spinning is the easy answer and one the knees will appreciate. Clipless pedals would certainly help that.

If I was trying to make it a stiff speed bike aka Turbo Quest. I might....:
1) tip the seat half way to all the way reclined
2) lose the front suspension fork
3) lose the steering extension bar
4) put a tiller type bar on it so the steering was down in the lap hamster style.

That might make for a fun bike put you'd definitely pick up frontend wheel flop in the steer, and you'd loose efficiency from the tiller angled connected at the top of the steer tube unless you braced that to the front boom with some sort of diagonal strut. Yeah probably wouldn't bother, just get a Silvio..... However as I stare at this frame there are a number of interesting ideas that do come to mind for several different configuration. Food for another thread on another day. But that front suspension fork is going to get replaced; that's just too much suspension.

 

[billyk]

THAT is a good idea! (Rich)

Rich - THAT is an excellent idea, and easy enough to do. I'm off to a meeting for the next few days, but will try this soon. BK

 

[Charles.Plager]

Oh sure....
I suggest the

Oh sure....

I suggest the sticker and Rick expands it to a "stick" and he gets all the credit. Hmmmph.

Well, in that case:

* Use a stick (or a hanger) as Rick suggested.
* On the handlebar end, mount a (cut metal) hanger such that it also points over the boom and over the Rick stick.

You'll get a better idea of how much comes from riser and how much comes from handlebars.

 

[MrSteve]

Now For Something Completely Different

Think about changing or altering, the way that you apply power.
If your pedaling technique is bending or warping parts of the bike, why not
consider pedaling in such a way as to minimise bending or warping parts of the frame?

If you're warping and bending frame parts, you're wasting power that could have
been used to push through the air a bit faster.

A stiff, stable connection between your hands and your feet is ideal, of course.
The lighter and simpler, the better... look what Mr. Tolhurst has done with the V.

Now, this is what I do, to limit loading/torquing the frame of my bike:
Rather than apply counter-force to each pedal-stroke, I lean the bike left-to-right/
right-to-left, to counter any remaining pedal-steering.

Most pedal-steer disappears before I notice it, anymore.
Why?
Experience has given my legs enough muscle memory to take care of pedal steer.

Try to grip your handlebars close to the stem.
Ideally, grip the bars on either side of the stem.
This way, you will have no leverage and it will not be physically possible for you to bend/warp the frame.
You will learn to accommodate with body english... what I call, 'leaning the bike.'

Keep in mind that your hands, if they're gripping the bar close to the stem,
are not instantly available for either braking or shifting.

May you work with the force... and fight it not.

-Steve

 

[jphipps]

Headset adjustment

I agree with the comment "The handlebar stem is clamped tightly to the steerer, preventing the upper collar from moving upward. As the upper collar is compressed by the binder bolt, it squeezes the lower collar downward, taking up any slack in the headset bearings." if we are talking about a single piece steerer tube.
In the case of the Quest we have a two piece steerer (steerer + extension). When the binder bolt squeezes, it pushes the lower collar down AND it pulls the extension tube up, which causes the steerer and extension to slightly separate. Then the extension will rock slightly when pushed or pulled.

 

[richa]

extension is clamped just as stem would be


I think the extension simply takes place of the stem. It's clamped on and give the upper collar something to push against.

That said, mine keeps coming loose as well. I think maybe the issue it it's hard to get the extension clamped tight enough with the quick release things. Tightening the binder bolts on the quick releases after their clamped down helps but I'm not sure how tight it's safe to make these. I'd hate to break off the bolts.

Are other's tightening those, and if so, how tight can you make them?

 

[Rampa]

Maybe mount the bars on the boom tube?

Perhaps just a regular headset and a stem and bars mounted to the upper end of the boom tube. Try and keep them as short as possible. It would also allow for a straighter arms. Knee clearance might crop though.

 

[Charles.Plager]

Hi Rampa,
Do you mean like

Hi Rampa,

Do you mean like the Freerider handlebars?

Cheers,
Charles

 

[Rampa]

That is pretty close to what I was thinking. Good catch!

Those Free Rider bars are kind of long, and would be flexy. I was envisioning a threadless stem attached at the very top of the boom, just in front of the headset. I figured that would give the shortest, stiffest bar option, and eliminate the steerer tube extension. I suspect that extension is the biggest culprit of all the joints that are causing flexibility.

 

[hurri47]

+1 for Steve's rocking

+1 for Steve's rocking suggestion. That's the technique I adopted/invented when moving my bars down and back forced me to ride with bent arms. It should be equally effective in reducing steering flex.

-Dan

 

[billyk]

Rocking as a means to avoid flex? (some doubt)

I do the rocking Steve describes as well, and it does take stress from the handlebars, but I think at the expense of ability to apply power.

Isn't this the same thing we do when riding no-hands? I do this for miles on end, absorbing pedal-steer by rolling my shoulders rhythmically against the seat back, so the force is partly diagonally across the bike: left-shoulder-to-right-pedal, then right-shoulder-to-left-pedal. (Thanks to yakmurph's videos for teaching me this some months back).

But first, though I can climb a few percent grade like this, it is much less powerful than the usual Cruzbike whole-body involvement. Second, one wonders if the diagonal force produces a similar frame flex as pulling on the bars. As John T said above, the flex includes the whole structure from handlebar to bottom bracket. Why would this kind of rocking not do the same thing?

BK

 

[billyk]

Maybe most important ...

Maybe most important is that frame flex is mostly an issue when climbing or accelerating hard. Then I doubt if rocking is enough to counteract pedal steer. At least not for me.

BK

 

[Jim Parker]

LASER data on handlebar flex

Hi All,
This past December, I did a series of laser lab experiments with our forks and handlebars. In this particular experiment, I compared the amount of torsional flex of the Sofrider vs. the Vendetta handlebar, while securing the front wheel in a trainer and bracing the BB by clamping a 2x4 to it and bracing the 2x4 to a nearby brick wall. I measure the torque with a digital scale and deviation with a laser attached to the handlebar. What I found was the VN handlebar demonstrated about 17% less flex than the SR. By securely fixing the front wheel axle and the BB-axle, I believe I largely isolated flex to the handlebar/stem apparatus (as much as reasonably possible). While some of the extra flex in the SR handlebar comes from torsional flex in the steerer extension tube, keep in mind that the VN handlebar itself has a 24% wider handlebar diameter (25.6 mm vs. 31.8 mm), and is mounted by a clamp that is 50% wider. Below is the data from this experiment.

I applied a little over 30 ft-lbs of torque (42 N*m) to the handlebars. I would point out that in normal riding, this much torque should never be needed by an experienced rider. Beginner riders, especially when starting from a stop, probably apply this much, or more, torque.

Jim

 

[Vargas]

It all moves...

It seems Eric message was unnoticed. This Quest has front suspension!