Brief Update

[John Tolhurst]

Vendetta is faster than Silvio both up hill and down dale. I am happy with the image of the bike also. But I am not yet satisfied with the handlebar ergonomics or the cabling solution - my heart wants internal cables within the handlebar and boom as far as the pivot clamp over the headset.

And I wonder, yes I do, how much farther back I can recline the seat and not corrupt the ridability.

And I worry, yes sir, I worry about what rough chip seal surfaces do. They are not my friend and I would like to imagine a softer lighter rear suspension system than Silvio has on the back, indeed I have imagined it and drawn it but I don't know if the problem warrants prototyping my solution. How much faster would the bike be if I could prevent road vibrations from entering the body, it could be as much as 5% and is a lot to leave behind.

Or should I stop toying and bring the sweet beast to market??

(reposted from Silvio thread)

 

[Mark B]

Tough call, indeed. Listen to your heart.

Mark

 

[zivl3]

On my regular commute there is a long, straight, slightly uphill section of road that is pretty rough. One part of it was repaved last year. On all my bikes, I can easily accellerate to a faster speed and cadence as soon as I get to the smooth repaved section. The increase in speed is noticeably greater on the non-suspended bikes, often times I'm able to pull a bigger gear. With my Silvio, I can ride at a higher speed over the rough section so I don't get a big jump in speed on the smooth pavement. Unfortunately, I can't quantify the difference between the Silvio and the rigid frame bikes. Plus, it's not just a speed difference. It isn't obvious how much I tense up on the rough pavement until I hit the smooth pavement and my entire body relaxes.

When I first started riding the Silvio, I wasn't sure that the suspension did much for me but when I take any of the other bikes it always amazes me how rough the road feels in spite of the significantly narrower and higher pressure tires on the Silvio.

Anyway, regardless of the weight penalty, I vote for suspension on any surface that is rouger than a velodrome. I think it will allow you to concentrate on riding smoother and more effeciently.

 

[JonB]

John Tolhurst wrote: Vendetta is faster than Silvio both up hill and down dale. I am happy with the image of the bike also. But I am not yet satisfied with the handlebar ergonomics or the cabling solution - my heart wants internal cables within the handlebar and boom as far as the pivot clamp over the headset.

And I wonder, yes I do, how much farther back I can recline the seat and not corrupt the ridability.

And I worry, yes sir, I worry about what rough chip seal surfaces do. They are not my friend and I would like to imagine a softer lighter rear suspension system than Silvio has on the back, indeed I have imagined it and drawn it but I don't know if the problem warrants prototyping my solution. How much faster would the bike be if I could prevent road vibrations from entering the body, it could be as much as 5% and is a lot to leave behind.

Or should I stop toying and bring the sweet beast to market??

(reposted from Silvio thread)

What improvements are you going to do in V2 ?

Is the time to market right? I mean, if you stop now, how soon can it be on the market? Does it matter to the market if you come out in X months, or in X+Y months. I would think that comming out with a racing bike in the fall in europa/america does not mean much, but comming out after xmas, in januar, when people buy stuff for the new bicycle season... As for Australia, i suppose you can race all year long. Where are your other markets?

I would suggest that you come out when it is good enough to sell well, but now you already mentioned it, and people knows it is comming, this might mean they do not buy Silvio.

 

[dennis234]

Is it longer wheelbase than the Silvio? Lower seat height or the same?

 

[John Tolhurst]

Same wheelbase, slightly lower seat - about 40mm - and far more reclined.

 

[Manalive]

I'm sure this has occurred to you, but it seems that keeping the Vendetta rigid will help differentiate it from the Silvio, and stop them treading on each others' toes... The more 'macho' spec may appeal more in continental Europe, where (I believe: this may be worth further investigation) the 'recumbent' demographic is younger. Get the rigid Vendetta to market, and then work on a suspended Vendetta as a Silvio replacement?

I've been riding round London on a rigid conversion for a few weeks now, without problems (and nothing's overtaken me yet!), but that's on 60psi tyres... Mk 2 will be full-suss, but that's because I want a full-on XC bicycle.

God bless,

Alex

 

[kidneyboy]

i say let it loose and see how it flies.

if you need more testing done send one to my house

 

[MrSteve]

John Tolhurst wrote: Vendetta is faster than Silvio both up hill and down dale. I am happy with the image of the bike also. But I am not yet satisfied with the handlebar ergonomics or the cabling solution - my heart wants internal cables within the handlebar and boom as far as the pivot clamp over the headset.

And I wonder, yes I do, how much farther back I can recline the seat and not corrupt the ridability.

And I worry, yes sir, I worry about what rough chip seal surfaces do. They are not my friend and I would like to imagine a softer lighter rear suspension system than Silvio has on the back, indeed I have imagined it and drawn it but I don't know if the problem warrants prototyping my solution. How much faster would the bike be if I could prevent road vibrations from entering the body, it could be as much as 5% and is a lot to leave behind.

Or should I stop toying and bring the sweet beast to market??

(reposted from Silvio thread)

Internal cables, at least down to the pivot clamp, right?
Just pull a sleeve over the lot.
You know, 1/8" thick neoprene or a Lycra/Spandex tube.

How far back can you recline the seat... you ask?
No further than zero-angle (flat/horizontal)!
It depends on how tall your chain stays are, doesn't it.

Suspension, now, hmmm.
Are your wheels laced with radial spokes?
Are your wheels a sort of "mag."?
Like, Zipp or other composite spoked aero wheels?
Are they disc wheels?
If so, then they're pretty rigid & I might consider incorporating
some sort of elastic in the rear triangle, between the seat pan and the rear wheel.
Maybe make the suspension removable... or incorporate a suspension lock-out
feature.

If your wheels are laced, X2 or X3 pattern?
Maybe forget suspension.

Or just grin and do what yer gonna do anyway and surprise us all!
:twisted:


-Steve

 

[gannet]

John Tolhurst wrote: ...
And I worry, yes sir, I worry about what rough chip seal surfaces do. They are not my friend and I would like to imagine a softer lighter rear suspension system than Silvio has on the back, indeed I have imagined it and drawn it but I don't know if the problem warrants prototyping my solution. ....

Well, I'm no engineer, so if I can think of things then the better minds will have already done so, but still....my 2c worth:

So you want to lose the weight of the springs in the Silvio, but keep the springiness...

Rear wheel travel (rwt):
DF's manage some with curved seat stays (but how much?) and Titanium (Ti) frames get a bit more ( again, how much?)
An Aussie review of a Ti framed Cube Litening raved about the comfort (relative to a race DF at least) Lynskey frame, I think.

Vendetta pictures show a very straight stay - is that locked in?
Given that one Silvio 'big advantage' over boring ordinary race bikes is due to just 12mm rwt(?)
then how much is needed to get the vendetta to 'work' ?
How much if you exaggerate the seatstay curve, and how far can you push that ? Might 6mm
be enough to give it some edge? 6-9mm range? If seatstays could be bolted on, you could have a choice, but with a weight penalty.

As for the front ?
If still using a trailing arm like the current carbo yoke, then some sort of curved curved fork ( similar to the curved seat stay), something like the leading link suspension on old motorbikes perhaps?

 

[Doug Burton]

gannet wrote:

John Tolhurst wrote: ...
And I worry, yes sir, I worry about what rough chip seal surfaces do. They are not my friend and I would like to imagine a softer lighter rear suspension system than Silvio has on the back, indeed I have imagined it and drawn it but I don't know if the problem warrants prototyping my solution. ....

Well, I'm no engineer, so if I can think of things then the better minds will have already done so, but still....my 2c worth:

So you want to lose the weight of the springs in the Silvio, but keep the springiness...

Rear wheel travel (rwt):
DF's manage some with curved seat stays (but how much?) and Titanium (Ti) frames get a bit more ( again, how much?)
An Aussie review of a Ti framed Cube Litening raved about the comfort (relative to a race DF at least) Lynskey frame, I think.

Vendetta pictures show a very straight stay - is that locked in?
Given that one Silvio 'big advantage' over boring ordinary race bikes is due to just 12mm rwt(?)
then how much is needed to get the vendetta to 'work' ?
How much if you exaggerate the seatstay curve, and how far can you push that ? Might 6mm
be enough to give it some edge? 6-9mm range? If seatstays could be bolted on, you could have a choice, but with a weight penalty.

As for the front ?
If still using a trailing arm like the current carbo yoke, then some sort of curved curved fork ( similar to the curved seat stay), something like the leading link suspension on old motorbikes perhaps?

I've been priveledged to have some input on this design (I have one of the two first prototype frames here), and when you see it, it will knock your socks off!

John spent huge time and resources creating the Silvio, and it really shows when you try to "compete" with it in developing a new design. The "12mm" of suspension travel work wonders in dissipating the eyeball-rattling high-frequency input that chipseal produces with high-pressure tires, and it makes a difference over long distances, as Maria Parker ably proved last October.

The overall approach to Vendetta is "pure energy" - all compromises have been re-balanced to maximize ergonomic input and cut waste in aerodynamics, weight and power transmission. Goal: all the rider's energy passes through the frame to the road without being dissipated in the frame, drivetrain and atmosphere. Consequently the frame elements are quite rigid.

Curved stays are difficult to capitalize on in aluminum, where there is a finite cycle life to bending parts and the fatigue damage accumulates over a power curve, as opposed to steel or Ti, where the fatigue life is much more forgiving.

I think John will probably move forward very soon. Stay tuned!

Best,

Doug

 

[Tom Roberts]

Any updates on this bike?

 

[Nanda H.]

Great update John!!! Maybe just leave room for a 28-32mm rear tire, and that should offer enough passive plushness for those that feel the need. Are you running a 23mm tire right now?

 

[Dano]

I say bring it to market now and continue to work with it and offer it as an option down the road.
Lack of suspension seems to be the norm for a lot of bikes purportedly built for speed. Although I have to admit that I sold my Bacchetta because I wasn't comfortable with the ride on chipseal.