What if the end of the boom look like this

[ratz]

Ok this might be stupid but I find interesting.
Perhaps this has been considered already.

What would be the implications if the welded on stem clamp were removed from the end of the boom of the Silvo and the Vendetta?

Replacing it would be an Outside slider like on the nose of the Vendetta; it would be short in length just long enough to be stable and allow for some finite length adjustment. Create it in two versions one with a double pivot hinges and one with a single pivot hinge.

• Would that allow for more ergonomic positioning of the handlebars based on the size of the rider?
• How many fit problems could that solve?
• How many steering geometry problems would it introduction?

It could also just be integrated into the upper boom; but it seemed like a second sliding tube might be more practical for mass production, refinement; replacement, and modularity; and could be offered as an upgrade to existing bikes; cut off the end of your boom and slide the new end on. Upgrade done.

Idea inspired by the picture below.

 

[Jeremy S]

Interesting. You can easily

Interesting. You can easily move the handlebars closer/farther (along the axis of the boom) with the current design. If you add a steerer extension above the fork, you can move them higher/lower, so combined you get 2D control. I guess your suggestion is equivalent to a being able to easily vary steerer extension length?

 

[ratz]

Yes an alternative to variable extensions

Jeremy,

Yes that's what led to the idea. There are only a few sizes extensions; and I had been thinking about what would happen if you replaced the tubular arms on the extension with adjustable length screwing bolts with locking positional nuts; then 2 different size extensions could have a variable range of says 50mm-100mm and 100mm-150mm. But I my head keeps locking up on how you keep them squared up once they are adjusted and the damage you could do to the front triangle if they let loose, not to mention the havoc to the chain length, that's asking a lot of a screw thread based adjustment. No in the end the extensions probably need to remain fixed sizes.

So keeping with fixed extension of 100mm and 150mm and maybe the ghetto 50/60mm we've seen; how do you compensate for people that are a close fit but not quite right. How do you fix an aero belly, how do you accommodate someone as tall as Dave who seems resigned to having no option other than bullhorns? What do you do about the rider with freaky short or long arms compared to his legs.

The solution could be you give some vertical control at the handle bars; this give you some extra reach control and vertical control; if you are tall you can get the bars up; if you are short you can get them down. If you have longer than average arms you can tweak them forward of you have shorter than normal you can pull them back. It seems to also open up options for which handle bars you can go with. A version could be offered up that was 35mm and one that was 24mm.... Also being applicable to all parts already sold or in inventory seems attractive...

Perhaps you make the top slider long; leave the middle section short then the water bottle mounts go on the top section and there is no more cutting the boom to make it fit short people. Those people retro fitting would have to cut pipe; but we are a odd crowd already.

 

[ratz]

Missed that;

Yes I missed that; thanks for clarifying. I was thinking about two axis of adjustment; forward and back is mostly there now; I was thinking about movement on the z-axis up and down for fit. That can be done with a single hinge. With the double pivot you can attack Z plus angle of incline and reach and while those can be gotten at in other ways, the the extra pivot point give a lot more positional control and subtle adjustment; might be over kill.

 

[Jeremy S]

Just to be clear Bob, since

Just to be clear Bob, since you mentioned chainstay extensions -- I was talking about a "steerer tube" extension (above the fork), not a chainstay extension. I think John has suggested steerer extensions to people with fit problems. Not sure how flexibly sized they are. They seem to have a large minimum size due to the need to attach to the top of the steerer tube.

 

[mzweili]

BOOM CLAMP

What would you think of a clamp that allows for a height adjustment?

 

[John Tolhurst]

Oh! that's nice. Is that

Oh! that's nice. Is that via solidworks?

Any knuckles, hinges, pivots etc must not be part of the linkages whose stiffness delivers performance.

Handlebar Slider boom BB. This is subject to oscillating positive negative flex. (if I can express it like that)

BB chainstay axle. This is subject to oscillating positive flex - easier to resist perhaps, a telescoping element can function well if tolerances are done right (in my estimation)

So those adjustable stem elements need to go between the fork and the slider, not anywhere else.

My concept is a link between the existing parts. Something that connects to the pivot clamp as the slider does, and on the other end connects to the slider clamp as does the pivot clamp.

And dont' forget that with any extension fitted to the pivot clamp, the clamp itself can be flipped over.

 

[ratz]

Flexi flexi

Ok how to organize these thoughts.

John, the the flex issue that makes sense, definitely don't want to be draining out power by introducing parts that flex. Now you mentioned flipping the pivot clamp; is that something you think the part in the drawing suddenly makes possible? The comment led me to think about rotating the pivot mount 180 degrees; would that also give another adjustment and range or does it mess with stability and clearances? (it's not obviosu when I eyeball the bike). A curve in the boom seem acceptable at the BB. What if the cockpit end had a slight 5 degree bend; that would allow an additional two orientations; curved up and curved down; that would provide adjustment without adding flex but might be crude. So you don't think a telescoping extension is crazy; just hard to do right?

Marc, nice work!. Instead of The long slot adjustment that could potentially slip; perhaps multiple holes at even spacing intervals? The tension clamp might need to be out of the way of the cable routing maybe rotated 10-15 degrees off of vertical allowing for the lowest possible settings to be used without cable interference.

I see that bracket having multiple applications. (1) by moving the boom angle in opposition to the extension, it potentially allows a 100mm extension function on the range of 50-100mm and 150mm one to work on the range of 100mm-150mm. (2) without an extension it can further open the cockpit further for large and tall riders.

Fascinating because it's making adjustments in the opposite direction of my thoughts; and it works perfectly to get to the end result.

Any chance you can model up the bullhorns if I have you dimensions?

 

[Rick Youngblood]

Bob, I like the idea of the

Bob, I like the idea of the cockpit end bar clamp having a slight bend to it, to drop the bars down about 2" (for me that would work perfectly), which is what I need. But I can see a problem for John is this may work for you and I, but maybe not the next guy or gal - the big question is how can you make the cockpit handle bars adjustable without compromising the stiffness (maybe that's coming up with a variety of custom handlebars, just thinking out loud). One of the many attributes that I like about the Silvio is the simplicity in it's design, the downtube straight from the handlebars to the BB.

I too need for my hands to be below my shoulders, but I like a slight bend in my arms, so as I bring the bars back to my body, they raise up higher.

 

[ratz]

Simplicity is good.

Rick,

I'm with you, I understand what buttons I'm pushing. The conversation is certainly shaping understanding and refining idea. As I think through it like you, I keep going: "well that won't work for the next guy" but then I stop and really think hard about what I don't understand. The next guy/gal is going to be taller or shorter and skinner or heavier so obviously they have diffrenet needs. But..... then I realize that when the bottom the bracket moves to accommodate another person, then the cockpit also moves in a sympathetic manner. That is the beauty of the design in most cases it almost self-corrects. Small tweakability seem to be all that's missing to dial it in for personal preference of the last 10% of comfort.

If you look at photos of people on their Silvio 2.0's and Vendetta's most of the ones we have show people with very similar positions depending on their size. I am coming to believe that positional tweaking is a subtle adjustment for everyone; and John almost has 1 size fits all. It seems like they are really really close and far more so than most recumbents san maybe the Meta. I

I'm closing in on a solid belief that 3 things and lead to a refined fit (Without talking seats)....

(1) The existing 100mm and 150mm extensions. Maybe add a 50mm.

(2) A stem bracket like what Marc drew; that can work in opposition to the extension to reduce it's impact and add viability for tall people. Removing the need to have many extension sizes

(3) A short list of dropbars and bullhorn that have 0mm, 40mm and 60mm of drop in their shoulders

Those three adjustments seem to cover most of what we have seen discussed and really open up the fit adjustments without sacrificing the simplicity and performance.

 

[Rick Youngblood]

Bob, with those three things,

Bob, with those three things, and then add the curved handle bar clamp that works in conjunction with Marc's bracket, fine tuning could make a perfect fit, no?

My current setup is pretty darn close to perfect for me. I've been able take 3 hour rides and feeling comfortable. As spring and summer comes I will be upping that to 4-5 hours and a few here and there up to 8.

 

[mzweili]

STEM BRACKET 2nd

I refined the initial idea, taking care of possible slippage and clearing the cables.
I'm still questioning myself about the loads this particular part sees. Maybe by beefing it up I could get a sufficiently sturdy part printed in ABS.
PS.: John, yes I'm designing with Solidworks.
PS.: Bob, send me a sketch of the handlebar you imagine, I will see what I can do (3 dimensional curves are a little tricky)

 

[Eric Winn]

Pinch tabs and light mount

Rotate the pinch tabs on top and, besides being symmetrical with the riser tabs instead of offset, you might be able to also use it for a light mount - with an aero housing of course.

-Eric

 

[mzweili]

Light Mount

not sure that a light up there would be very useful. It would light your legs and project a nice shadow play in front of you.

 

[ratz]

to add locking position

Rather than beefing up the arms. Make the outside surface fine grain serrated. Then add a small plate with a matching serrated face surface to slide the bolt through on each side. Once the bolt engage the serrated surfaces would lock together giving a super rigid vertical hold.

As for the light. I just got the Dinotte $14 light bracket mentioned in another thread. Seems to be the perfect solution to mounting a light on the nose. Still would like a bolt on solution but I think this will work.

 

[Ivan]

With Marc's bracket, one

With Marc's bracket, one would be able to fully adjust handlebar position independent of BB height. This height adjustable bracket would be an elegantly simple solution to refining the cockpit adjustment. I heartily agree with Ratz' 3 points for refined fit. The other thread on bullhorns and drop bars complement this thread for fit refinement.

This discussion is very exciting! The refinement we are talking about here is at the ultra end of the comfort scale. I am now doing century rides in previously unimaginable comfort. Further refinements to my position is towards the needs of ultra-cycling and tweaking what is already exceptional on Silvio and Vendetta.

 

[mzweili]

CLAMP WITH LOCKING

That is what it would look like. To get a reasonable cost, this part would have to be molded, machining it would be far too expensive. The washer could be made from an extruded bar, or maybe stamped. In any case, both parts require some investment in costly tooling.

 

[Ivan]

Stem Raiser

I was thinking...wouldn't an off the shelf stem raiser provide similar functionality of this custom bracket? Perhaps not so fine-tuned but if someone had a high BB and not much room with the handlebars (like Talleyho), then a stem raiser would do the trick.

http://m.ebay.com/sch/i.html?_nkw=Bicycle+stem+raiser&_pgn=1

 

[Nanda Holz]

3D print it

Check out www.ShapeWays.com they even 3D print in certain kinds of metals. Got lots of accessory ideas I plan to try this year for various bikes and trikes

 

[super slim]

The best option for a new

The best option for a new Silvio, is one with a long head stem and the existing light weight V2.0 head stem clamp, and cut the headstem to the required length.

If wanting to raise the steerer tube at the headstem on an existing Silvio 2., then this is a option, to use head stem spacer rings on an adaptor that bolts to the existing V2.1 Head stem clamp.
see the attached PDFs

?This option is about two times the weight of the existing V2.1 option, so about the weight of the V1.0 clamp arrangement.

Existing headstem spacers are all 36 mm OD and normally 29 mm ID, varying in height from 1 mm to 15 mm or greater.
I assume that 5 to 50 mm high spacers could be purchased and also corresponding M6 set screws 40 mm long for no spacer and 90 mm for 50 mm spacer.

The top machined part is located on the machined plate on its the inside of the groove, and the spacers locate on the outside of the groove. Only one spacer can be used and be located on its bottom and top.
If more spacers are required then a 1 1/8 OD (28.75 mmOD ) 0.6 mm thick? ss tube is required to locate the spacers.

Super Slim