Climbing speed comparison: Silvio vs. Vendetta

psychling

Well-Known Member
balance issue

In response to Eric Winn's post (below):

The riding characteristics of a recumbent vs a DF that Dan Fallon describes In a 300k brevet from Flagstaff to the Grand Canyon on his blog along a dangerous route section is interesting but I'm curious if Dan was riding one of his Cruzbikes or one of his other recumbents and if the Cruzbike FWD, MBB configuration makes this issue easier to deal with?

I've linked Dan's complete post above. Below is the part of his blog post I'm referring to. How would the Vendetta handle this vs the Silvio? Quest? Sofrider? Any significant differences between bikes when gusting cross winds are involved?

"This section is difficult for any recumbent bike. Add to it the 3 - 5% incline and a gusting 20 mph wind from the west and it is more than difficult; it is potentially lethal.

The upright bike has far more balance capability than the bent. The upright rider can get out of the saddle and rock the bike back and forth with minimum of difficulty in order to ride a straight line.

The bent rider doesn't have that option. By design the recumbent bike and the rider are one unit. Under difficult conditions the bent rider has to be far more careful of road conditions, weather conditions and crosswinds."

This also brings my Motorcycle Safety Foundation training to mind where they train you in maneuvering around obstacles where one of the key points is to not focus on what is immediately in front of you but focus through the path you need to take, e.g. focus more on the exit out of a curve in front of you instead of the entrance to that curve. Does this apply in Dan's scenario and more generally woud following this technique help mitigate some of the wobbles that new Cruzbike riders experience?

-Eric

Eric ...

A 30 mph cross wind is going to push a bicycle and rider sideways, no matter what platform (upright or 2 wheel bent). The rider can `focus through on the path you need to take' all s/he wants but that won't inhibit the laws of physics. Whether on an uphill, flat or downhill crosswinds have to be respected.

I've observed in the last few months a few cyclists (upright and 2 wheel bent) getting seduced into the `thrill' of fast descents and then `reduced' to mortal collections of road rash and broken bikes.

It wouldn't have mattered if I had ridden a Cruzbike or any other recumbent.

As I mentioned in the section you quoted, there is a difference between how a cyclist can handle crosswinds (not to mention `ribbed' roads on a screaming descent):

The upright bike has far more balance capability than the bent. The upright rider can get out of the saddle and rock the bike back and forth with minimum of difficulty in order to ride a straight line.

The bent rider doesn't have that option. By design the recumbent bike and the rider are one unit. Under difficult conditions the bent rider has to be far more careful of road conditions, weather conditions and crosswinds.



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Eric Winn

Zen MBB Master
Thanks Dan,
I'm trying to


Thanks Dan,

I'm trying to live vicariously through your stories to learn and understand the ins and outs of recumbents. In reading about your experiences on your blog and these forums it looks like you have a more detailed and nuanced approach to exploring riding characteristics so I value your insight and advice.

To date the only recumbent experience I have is about 45 minutes to an hour of test riding a Silvio but I placed an order for a Vendetta yesterday so I am looking forward to many years and miles of riding to come. BTW, would love to come visit the Prescott area some day and try some of the dauting looking riding you've blogged about.

I totally agree with you about the need to recognize and deal compently with the dangers of crosswinds, speed, road hazards, etc. but because of the amount of riding you've done on different bikes I was really curious if you could discern if the Cruzbike design (FWD, MBB, very stiff geometry) made any measurable difference in dealing with those issues as compared to other designs.

For example, a lot of discussion surrounding Cruzbikes are the ability to engage your upper body during climbing or rapid acceleration to do some of that same rocking back-and-forth albeit not quite in the same manner as an upright bike.

I had two thoughts on this:

  • The heavier MBB front end and resulting issues with moments of inertia might make the Cruzbike more susceptible to control issues in a cross wind

  • The upper body power-rocking of the Cruzbike and the heavier MBB front end and resulting issues with moments of inertia might make the Cruzbike less susceptible to control issues in a cross wind.
It sounds like it might be a wash from your description and cross winds are just particularly bad for recumbents period.

I am beginning to grok the recumbent bike and rider as one unit, especially after riding the Silvio - that was so cool. I felt like I was banking an airplane rather than riding a bike. I don't really grok anything else about recumbents because I haven't ridden them - but this will change with my Vendetta purchase.

I did a poor job of expressing my thoughts relating to the MSF "look through/past your path" as I wasn't thinking of it in relation to having a crosswind to deal with but just for dealing with maneuverability in general and perhaps more specifically as an aid to learn how to ride a Cruzbike for the first time. This concept combined with Charles Plager's advice to take your feet off the pedals when things started getting dicey both seemed to help me on my first exposure to the Silvio. I found looking through and past my turns was really helpful and was soon comfortable doing u-turns with the Silvio after only a few minutes of riding. The most useful thing however was taking my feet off the pedals when things were getting weird - thanks Charles!

-Eric
 

psychling

Well-Known Member
Experience

Eric ...

Much of what we're discussing can only be appreciated `from the neck down.' And I've learned that my `neck down' is different from other's `neck down.'

My suggestion is that you put lots of miles and hours on the bike. You'll likely learn things through your fingers and toes that none of our talking about will teach.

BTW: a crosswind is a crosswind. Whether you're on an upright, a recumbent or an 18 wheeler. No. I have not experienced any deficit or benefit in dealing with a crosswind on a front wheel or a rear wheel drive recumbent. The only difference in a crosswind is whether you get `slapped' off the road or just `pushed' off the road.
 

MrSteve

Zen MBB Master
Aerodynamics

I thought I'd point out what seems obvious to me, so (bear with me)
here are a few points I'd like to point out...
before I get to the point:

-The aerodynamics of the machine is important when speeds increase.
This thread has been about climbing.... Now we seem to be descending!

-Of course, if there is a headwind, then aerodynamics is also important
when you're climbing.

-The Vendetta, the Silvio and the Sofrider are all short wheelbase,
moving bottom bracket and front wheel drive bicycles.
They all differ in detail but all share the same basic design.

My Sofrider (with me on it) never felt solidly planted at high speeds.
I'm guessing that I have never truly been able to relax.

This is how I solved my nervous bike:
I installed wheel disks on my rear wheel.
The extra area behind the Center Of Gravity (C.O.G.) acts like the vertal fin,
the rudder, of an aircraft.

The rear wheel disks react to side gusts, of course, but they also provide
self-centering forces (on my bike, for me) when side gusts try to deflect the path of
my bicycle.

As an added benefit, my bike has a higher top speed with the rear wheel disks
installed.

You may find the same aerodynamic benefit -of more area behind your C.O.G.- as I do,
if you have a rear fairing, a rear bag or rear panniers installed on your bike.
You may even benefit with a deep-rim Zipp style rear wheel.

Or not.

After all, your riding style is your own and our experience on our Cruzbikes
may be different.
Nevertheless, aerodynamics is a factor to consider!




Descend safely,
-Steve

 
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