New Vendettanaut

[Greenspeed]

Hello everyone,

Just introducing myself. I have been riding recumbent since 2007. From 2008, solely riding M5 CHR until this April. Bought a new to me Vendetta. Learning to ride Vendetta was interesting. It was a big learning curve for sure. I straight away use a clipless pedals on the Vendetta as I m quite comfortable using clipless on all my recumbent bikes that I had owned previously.

Had one nasty spill earlier in the day when learning to ride Vendetta. I was too confident and that sort of bring me back to reality and respect the diffrence between SWB and MBB FWD. Surprisingly, I was able to ride Vendetta better after my spill.

So far I have clocked more than 500km on Vendetta (probably close to 25,000km on M5). My average has jumped from 21km/hr to 31km/hr this weekend. I am really chuff with the bike and enjoying the experience of being a Vendettanaut.

 

[Charles.Plager]

Welcome!
I'll be very

Welcome!

I'll be very interested to hear your thoughts on the two bikes when you get more experience with the Vendetta.

You sure do own a lot of pretty bikes...

 

[Greenspeed]

Thanks Charles.
Here's what i

Thanks Charles.

Here's what i have posted on Bent Rider.

Has clocked around 500km on the Vendetta so far. Yesterday my average speed was 31km/hr in comparison to 21km/hr on my first outing (few weeks ago). The increased in speed is an indication that I am much more comfortable on the Vendetta. I still can't attack descend yet like I could with M5 CHR. The MBB FWD spinning out can translate to serious instability during descend. I heard with experience, this will improve. Hence, M5 CHR is still way faster during descend. On the flat, they are both about equal for me. Where Vendetta really shine is ascend. This bike just flies up the hill with ease. We are talking a speed different of at least 6km/hr (e.g. 24km/hr for Vendetta and 18 - 19km/hr for M5).

Ride quality of Vendetta is harsher than M5 using the same wheelset, which is not surprising. I have bought a new set of wheels for Vendetta, Campagnolo Zonda, which improves the ride somewhat. Partly I think the wheelset is not as stiff with steel spokes. I debated whether to get Eurus (aluminium spokes - thicker blade), but in the end I got the cheaper Zonda because of the steel spokes.

 

[Ivan]

Thanks for sharing -- keep

Thanks for sharing -- keep posting about your experiences!

I am a Silvio 2.0 rider not a Vendetta. Now about a year on Silvio and enjoying the journey. What I really like, when you get comfortable being more aggressive downhill, is that downhill momentum PLUS the climbing power when ascending really comes together on a rolling hill.

Living in a city, there is a underpass on my commute that I use to benchmark my progress and different techniques. After a couple of months on Silvio I could hit 50kph on the bottom, then come out the top at 32kph -- I was thrilled cos I could never do that on my DF road bike. Now, when I'm feeling energetic, I can lift my butt and use my arms and sprint to 60kph at the bottom and come out at the top 40kph. Great feeling and I know my technique, and of course my fitness, can improve and my speed on this fun little underpass can increase.

 

[Peder Torgersen]

One of things I like about

One of things I like about the Vendetta is passing other riders when climbing.
The wobbling going down hills took a long time for me to master.
Yesterday on my commute to work I pedaled very fast going down a hill because there was rider ahead that I wanted to pass.
It was very windy and I had to stop pedaling because I started to wobble.
Be careful when it's windy.
Today I passed a rider climbing before descending on the same hill today I just coasted down because he was behind me.
There was no wind today but strong side wind can make the handling difficult.

I have had the vendetta for some time but still find it very fun to ride and impressed with the speed capability.
I hope you will also feel more confident on your descents with more riding time.

 

[Greenspeed]

I am getting much better

I am getting much better riding Vendetta. I have changed my front chain ring to 52 Biopace (from 50T) and now is geared better for me. I can pedal downhill but still have plenty of room to improve. I am finding myself choosing to ride Vendetta more than my M5. It is just so fun to ride.

 

[pugwash]

Frame Stiffness

Really interested to see the comment about how much quicker the vendetta is up hills. I think a lot of people including myself have been pleasantly surprised at how well a cruzbike climbs. A few years back for my own amusement, I did some analysis on the effect of frame stiffness. This is one of those perennial arguments ,some people say frame stiffness is important for efficiency, others will say that any energy which goes into bending the frame and drivetrain is returned as the system is unloaded.

I modelled the system as two masses, the rider and bike being one mass the rotating mass of the legs as the other and connecting the two masses by a spring which is the stiffness of the frame and drivetrain, and a gearbox which takes into account the bike's gearing system. I will spare everybody the maths, but the results were interesting. Firstly the energy which goes into deflection of the frame and drivetrain is pretty much all lost. The gear ratio is important, and more energy is lost in lower gears. Finally spinning i.e. reducing variation in torque through the pedal stroke will reduce the losses somewhat.

While the frame of the M5 looks gorgeous, it is also a great big curved spring which I'm sure doesn't help maintaining stiffness.

 

[Charles.Plager]

I modelled the system as two

I modelled the system as two masses, the rider and bike being one mass the rotating mass of the legs as the other and connecting the two masses by a spring which is the stiffness of the frame and drivetrain, and a gearbox which takes into account the bike's gearing system. I will spare everybody the maths, but the results were interesting. Firstly the energy which goes into deflection of the frame and drivetrain is pretty much all lost. The gear ratio is important, and more energy is lost in lower gears. Finally spinning i.e. reducing variation in torque through the pedal stroke will reduce the losses somewhat.

For what it's worth, this is what I would think the case is. Some people believe that the energy stored in the frame will be returned ( e.g, constructive interference), but I think that's very unlikely. They're also forgetting that if the timing is just right, the energy stored in the frame could work against you ( e.g., destructive interference). In general, I'd expect it to be lost.

And I think it makes sense that when spinning, which reduces the variation in torque, the effect would be less.

 

[Kim Tolhurst]

re--stored Energy

this is not a PUB bike, (passive upper body) but you can if you like!

Kim.

 

[BentAero]

Be it a road race motorcycle,

Be it a road race motorcycle, a motocross bike, or a nascar stock car, a chassis that flexes is a chassis that's slow. It will likely be more comfortable, but it'll be slow.

 

[John Tolhurst]

Nice one pugwash!

Nice one pugwash!

 

[pugwash]

Some people believe that the

Some people believe that the energy stored in the frame will be returned (e.g, constructive interference)



The natural frequency of the bike frame would be much higher than a riders normal cadence. So any kind of virtuous tuned response is highly unlikely.

Perhaps one way of visualising the maths is to think of a one-dimensional system, which isn't perfect but gives the idea. Imagine the heavy mass (bike & rider) connected to the small mass (feet and pedals) by a piece of elastic (fexie bike frame and drive chain). The small mass is in turn pulled by our cyclical force. The critical moment is when this force goes to zero in the spring will accelerate both masses but more of the energy will be transferred to the smaller mass. In reality most of the energy will go into accelerating small mass in the opposite direction which can't be recovered, because our elastic string goes slack. On the next cycle, the cyclical force users energy to accelerate the small mass back up to speed, and provide the energy required to extend the spring. As I said, all this energy is pretty much a dead loss.

In general a stiffer chassis will be better until the additional weight outweighs the benefits. Part of the brilliance of John's design is realising stiffness in the geometry and layout rather than just throwing carbon fibre at an existing solution. With the latest Silvio and the Vendetta, there is more to it than just the MBB arrangement. The really impressive part is that John and cruzebike have actually been able to bring these bikes to market and continue development.

I dips me lid.

 

[Charles.Plager]

The natural frequency of the

The natural frequency of the bike frame would be much higher than a riders normal cadence. So any kind of virtuous tuned response is highly unlikely.

Agreed.

 

[Ivan]

A good explanation by pugwash

A good explanation by pugwash indeed! The genius of the Cruzbike triangulated FWD design may not be immediately appreciated by the first time observer but it certainly is there. I love curvy carbon frames too, but it is exactly right what pugwash says, that the M5 is a spring along it's length, compressing with each pedal stroke!

If a curvy carbon Cruzbike materialized one day, it would not have this problem due to the innovative FWD front triangle!

 

[Greenspeed]

I have to chime in here in

I have to chime in here in regards to the comments on "springy" M5 frame.

http://m5ligfietsen.nl/uploads/Itemizer/popups/1364.8.jpg

http://m5ligfietsen.nl/uploads/Itemizer/popups/1364.6.jpg

The main frame on M5 CHR is chunky square carbon tube which lend itself much of the stiffness of the frame. It is more compliance than the Vendetta but not to a point that it is a soft noodle. Carbon just deaden the road buzz better too. Just have to clear misconception that the M5 frame compresses with each pedal stroke.

 

[John Tolhurst]

Just have to clear

Just have to clear misconception that the M5 frame compresses with each pedal stroke.

? there is no misconception. It does flex with every pedal stroke. So does the Vendetta for example, but no where near as much

M5 have done a great job of controlling it with the box frame.

 

[pugwash]

Carbon frame

One of rules of thumb used to convert aluminium boat masts to carbon fibre, is to make the mast same size and thickness as you would in aluminium. The reason this works is that contrary to the hype, carbon fibre composite has about the same stiffness or, to use the jargon elastic modulus, as aluminium: 70 GPa, the carbon mast works out at the same stiffness, it should be a little stronger and not quite half the weight.

I didn't mean to pick on the M5, we just had a pretty picture in the thread. But the point remains, that just making a bike out of carbon will not necessarily make it stiffer. Rather than making the comparison against marine aluminium alloys, which I have to do for corrosion reasons, John has the luxury of using some of the more high tensile aluminium alloys which makes carbon harder to justify. If money is no object, the carbon frame will be better, but the dollars per kilo saved against aluminium are quite high.