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

[Robert Holler]

I have never noticed that

I have never noticed that much flex in the front ends of these bikes unless on an extreme climb where i was left with nothing else but to mash and counter-steer. In a good pedal rhythm there should not be any need to pull or push on the bars at all.

In fact I am normally as relaxed in my upper body as when on a RWD recumbent unless I have to lay down the power for a sprint or a climb. The key is to practice riding until:

1. You are working the upper core and legs in sync and together - not against one another.
2. You can ride without your hands on the handlebars.

The fact alone that you can ride these bikes without holding on to the handlebars says huge things about their stability, and that you do not need to be constantly engaging your upper body in a battle for power dominance over the MBB.

 

[Shahmatt]

@ Jim Parker,
Interesting

@ Jim Parker,

Interesting experiment and interesting results.

I am curious to know what length of the handlebars were under load, since the handlebar widths between the Sofrider and Vendetta are different. Were the extreme ends of the handlebars used for load application?

It seems to me that the comparison results are quite good really. The Vendetta's deviation/distortion of 16.7% less under "heavy" loading seems like quite a small difference between the two bikes.

The Sofrider 0.95 degrees deviation also seems pretty good. What is the real world distortion of the system for this angle? If I assume a boom length of 70cm that's about 1.16cm deviation from the feet to the handlebars (70cm x Sin(0.95)) . That doesn't sound too bad.

 

[billyk]

engaging the whole body is the point!

Various people here have commented as Rose City above, that in many/most riding situations, the upper body is relaxed, to the point of being able to easily ride no-hands. And I agree.

Certainly in those situations there is no issue of handlebar flex.

But the other point of the Cruzbike design is that when you want to apply power, they are way more capable than other recumbents. I can make the Quest just jump ahead when I need to, even uphill. But then I am most definitely pulling hard on those bars, engaging the whole body (hopefully not mashing). That's when flex becomes an issue. That's when I want maximum power and am apparently losing a fair fraction to bending metal.

Sorry I haven't had time to do the nice test suggested by Rich above. Will report when I do.

BK

 

[MrSteve]

A Few More Observations

How often do you check your bike?

Remember to include the nuts, bolts and bearings of the front end
of your bike in your weekly going-over-the-bike check.
This is most relevant for bikes equipped with front suspension.

If any of the pivoting points develop a little slop, a little play,
some of your power will be sucked away by the play.

If your front wheel is not tuned properly, the loose-ish
spokes in your front drive wheel will eat up some of your power.

Most common:
your tire is a bit deflated. Make sure you check the pressure!

Next-most common:
Your brake pad(s) are rubbing the rim(s).

----

One day, after a long ride full of sprinting and climbing strongly,
mixed in with some DF chasing/passing games, I found that my
TFT was warped off-centre and the chain stay pivot bolts were a little loose!
The clamp that ties the TFT to the steering tube had crept out
of alignment by a few degrees.

Maybe some bolts were not torqued quite enough:
I torque by feel, so that's possible.

Maybe, by some miracle, my legs were actually making some power?
Hey, anything is possible!

Whatever the reason, after loosening the entire front end, relubing and retorquing,
the bike felt as fast as it ever did!

Conclusions?
-any movement of the power train (when under power that does not transmit
your power to the pavement) robs power.

Have fun,

-Steve