Silvio 1.0 Chainstay Extension - Photos

[randyspann]

-- Here's some pictures of my Silvio before and after installing the short chainstay extension. My goal is to raise the BB height to get a more "closed" body position. As you can see I raised the BB height by 6". Haven't had a chance to test ride, it's cold and icy here in New England. But feels good on the trainer.

Pre installation:

BB 21.25" 54cm
Seat 23.25" 59cm

Post installation:

BB 27.25" 69cm

What the extension looks like:

 

[ak-tux]

Definitely  looks more Aero!

Definitely looks more Aero! Does it add any noticeable flex?

 

[John Tolhurst]

Just have to make sure the

Just have to make sure the alignment is good, a nice straight flat path from BB to axle, before doing up the ring clamp bolts.

 

[John Tolhurst]

seat height would be 21.5?

Seat 23.25" 59cm
..
Where did you take that measurement to? Across all our bikes, I have consistently measured from the ground up to the join between the seat back and seat pan, and at that point your Silvio would be 21.5" If you have a moment, would you like to confirm that for me?

Thanks for the informative pictures.

 

[ak-tux]

John, probably the measurment

John, probably the measurment was taken with the bike mounted on the trainer and the back wheel on what looks like piece of wood which I estimate is about 2" thick.

 

[dalehough]

It would actually be a inch

It would actually be a inch and a half it looks like a 2x6 to me.

 

[randyspann]

seat height

-- John you are correct on the seat height. When I measured, I did account for the height of the trainer, but I wasn't sure where on the seat to measure. Flex? Don't notice any flex. Seems the same as before.

 

[romuald.josien]

Flex, weight, and boom length

What is the material used for the chainstay extension? Moderated extra weight?
Why not an extended chainstay itself? really more costly?
Does the boom lenght needs to be adjusted? extended?

I'm interested by this chainstay extension, not for the higher cranks position but for better extending my long legs, yet I'm already at limit of the boom length.
I'm afraid by the possible flex it can bring when pushing hard in uphill.


Thanks for your comment and feedback.

 

[John Tolhurst]

Romuald, 
The extension for a

Romuald,

The extension for a long leg person allows a little more overlap of boom and slider. That is important to reducing flex in those parts. Therefore, the extension reduces flex in those cases.

The extension weights, I forgot. 80 to 100 grams. Its made from heat treated 7005. The flexing stress it is under is constant, always in one direction, whereas teh boom it is occilating with each pedal stroke. You will have no concerns about flex.

As before, I will stress that the extension must be aligned with the axle. If the extension/chainstay is even slightly cupped it is possible when going over a bump for the chainstay to kink irreparably.

 

[romuald.josien]

Flex, weight, and boom length

Hi John,

Thanks for the clarification.
...and regarding the idea of providing a longer chainstay option instead of this extension part?
it would be a more elegant solution for tall men like me

.

 

[John Tolhurst]

I hope to do that

Yes, it would be more elegant, here's the 'thing':

• 
  respecify the thickness and stiffness of the chainstay
• 
  new mold low thousands of dollars
• 
  new testing regime
• 
  not reversible
• 
  increased cost of whole CF chainstay versus extention
• 
  or split models, increasing stock holding costs and stock out problems

So yes I agree, and I'll be happy if we grow to realse that approach.

 

[randyspann]

testing the chainstay extension

-- Tested the chainstage extension this weekend. No problems with flex! Also added a stem extension like Jim Parker did on his Vendetta. I wanted a little more knee clearance. The ride is now dialed in for me, very happy with the mods. (6' 6" tall). With the chainstay extension, I'm more aero (1 to 2 mph faster) and climbs like crazy, kind of obsoletes the granny chainring.

 

[unc99]

Were you able to use a single

Were you able to use a single chain with the extension or did you have to piece two chains together? I just received a 100mm extension but haven't had time to play with it yet. Obviosuly my existing change will not work, but I can't remember if a new chain comes long enough to work with the extension

 

[mickjordan]

SINGLE CHAIN

Although I gave up on the extension as I couldn't get the fit right, I did need two Shimano 6600 chains with the Ultegra triple setup when I had it installed.

 

[randyspann]

Update on chainstay extension

Update - Well after a few hundred miles on the Silvio with the chainstay extension, I have to say I am very pleased. No flex even super powering up hills. This makes the geometry of the bike perfect for me. I am continually amazed how well the Silvio climbs! Much better than my very light DF!