Engineering bicycle part by part

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Komarov
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by Komarov

MrCurrieinahurry wrote:
Sat Feb 06, 2021 9:19 am
Excellent ImageImage
Hey, sorry to reply here to your DM, but the policy of these wonderful forum doesn't allow me to even reply in the DM since I'm "newly registered".

We will test the mounting in house for static and cyclical loads - analize the real characteristics and compare them to calculated ones.
If everything more or less consistent - we will start "field testing" and may need some feedback on the prototypes :wink: So hit me with your adress in DM and we will look how it comes out :lol:

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erik$
Posts: 147
Joined: Sat Nov 15, 2008 5:26 pm
Location: Veneto, Italy

by erik$

Thanks for putting this out there, Komarov!
I really like the cross section view of the seat post and how one can clearly see the material placement to cope with the tensile and conpressive stresses. Seems like one needs quite a bit of material to withstand buckling.
The solid molded parts of the head look very well compacted, could you explain briefly how you do this, or is it part of the secret sauce? Compression molding of the head first and then bonded in when laying up the main part of the post, maybe?

Komarov
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by Komarov

erik$ wrote:
Sun Feb 07, 2021 8:19 am
Thanks for putting this out there, Komarov!
I really like the cross section view of the seat post and how one can clearly see the material placement to cope with the tensile and conpressive stresses. Seems like one needs quite a bit of material to withstand buckling.
The solid molded parts of the head look very well compacted, could you explain briefly how you do this, or is it part of the secret sauce? Compression molding of the head first and then bonded in when laying up the main part of the post, maybe?
Thank you Erik!

The body of the seatpost actually isn't so thick all the way around, but it has significantly more material in front and in the back of the tube comparing to the side walls. And since it was cut along the axis of the bike - the thick walls got into crosssection. I'll remove 1/4 of the part to show the side's thickness also.

The head is moulded in 1 part with the body and consists from the same fibers the cylinder is made from. They just go all the way from the bottom into the "hooks".
We use the pressure around 30 bars during the moulding of most of the parts so all the material and epoxy is pushed into any free space available inside the mould simultaneously pushing the air bubbles away.
We create such a pressure by different ways, in case of the seatposts it's kinda our know-how :) Nothing extra-secret or rocket-science (well, kinda rocket-science but not by us :D :D) ,I know only 1 bike company which uses similar technology to produce really high quality bicycle tubing and it seems like the technology is rather expensive (it really has a price to pay :wink: ) or complicated for bicycle industry to be widely used.

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MrCurrieinahurry
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by MrCurrieinahurry

Man this is exciting stuff love it..
Formerly known as Curryinahurry

Cycomanic
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by Cycomanic

This is really interesting thanks a lot for posting!

Knightyboy27
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by Knightyboy27

What is the min insert of your seatpost please?

From your photos, I would assume that given the constant thickness of the post, there is no specific insert range unlike other brands?!

erik$
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Location: Veneto, Italy

by erik$

@Komarov
Thanks! Good job on getting the process to where you are, always nice to do the whole moulding in one go.

Komarov
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Joined: Thu Jun 13, 2019 2:46 pm

by Komarov

Knightyboy27 wrote:
Mon Feb 08, 2021 5:20 pm
What is the min insert of your seatpost please?

From your photos, I would assume that given the constant thickness of the post, there is no specific insert range unlike other brands?!
Hi!
Actually there is insert range for the seatpost. Its just the seatpost on the pictures above is 200mm long and so short that as you noticed it basically consists from the clamping zone and thereby has almost constant thickness. Also part of the reinforcements along the seatpost ends in the middle of the tube because the higher it gets - the lesser the lever of the load.

This is another cross section btw
photo_2021-02-08_23-44-35.jpg
But for longer posts we make 200mm clamping zones for 400/350mm long seatposts and 150mm zones for 300/250mm seatposts like on the picture below - on the right couple of finished seatposts with matte clamping zones. (actually the real lay-up for clamping zone goes 220mm up but matte zone goes only for 200mm just in case :D :D )
Снимок1.PNG
Truth to be told - the post will be just fine in most cases even if clamped in the wrong place,
I cut the holes for the bolts by cnc-mill to make them precise and in order to do that - the post has to be clamped as high as possible:
Like on this video: https://www.instagram.com/p/CAgGGL_Fm6-/
(sorry, I'm too lazy to upload something on Vimeo for the minute of cnc mill cutting carbon fiber :D :D so here is the instagram link)

Of course the tube is weaker in places without layers of carbon which go around the tube, but I tested it for the x3 loads of clamping which occurs when I set the post into the cnc mill and it was just fine. But of course the post which was clamped in the wrong place and broken won't be warrantied - we are small company and don't sell much but no one was smart enough and managed to break one yet) In worst case scenario with seatback, long post and the saddle pushed as far back as possible the post sustains 300kgf of load and then the saddle's rail breaks or bends if its made from steel. If rail is clamped for the middle - the post breaks around 400kgf of load.
And we make custom lay-up with longer or shorter clamping zones for free, so its not a problem anyway))

On the other side - I (and any other sane person) would recomend not to insert the post less than 70mm into the frame because it possibly will just break the seattube of the frame and that would be a real pain in the ass.

Knightyboy27
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by Knightyboy27

Many thanks for such a detailed response.

Just trying to work out the taxes and duties involved in shipping a saddle and seatpost combo to the UK now.

Komarov
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by Komarov

Knightyboy27 wrote:
Mon Feb 08, 2021 10:38 pm
Many thanks for such a detailed response.

Just trying to work out the taxes and duties involved in shipping a saddle and seatpost combo to the UK now.
I dont manage the shipments, but as I understand - we usually ship to UK and the customer don't has to bother himself with custom's fee or any delivery issues at all :wink:

Geoff
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Location: Canada

by Geoff

Not sure how I missed this. Really great work!

cajer
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by cajer

Have you thought about making something like the new wide pad aero bar that were used in the hour record?

Komarov
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by Komarov

Geoff wrote:
Wed Feb 10, 2021 11:40 pm
Not sure how I missed this. Really great work!
Thank you!
cajer wrote:
Thu Feb 11, 2021 9:22 am
Have you thought about making something like the new wide pad aero bar that were used in the hour record?
I designed the extensions for one bikefit studio in Moscow. When the serial production and sales will be launched and if both go well - guess it would be rational to make the base bar, pads and mountings to form the whole cockpit.
So we may design them on our own or per order from studio which will be quicker way to do it since we are busy developing our own products and its easier when someone else does the research and just gives you the specification :D

Kumppa
Posts: 469
Joined: Mon Oct 13, 2014 10:05 am

by Kumppa

Nice work!

How wide is that carbon loop on the Garmin mount? Any plan when you might get these for sale? Looks promising alternative to replace the original plastic one.

by Weenie


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Komarov
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Posts: 66
Joined: Thu Jun 13, 2019 2:46 pm

by Komarov

Kumppa wrote:
Thu Feb 11, 2021 11:50 am
Nice work!

How wide is that carbon loop on the Garmin mount? Any plan when you might get these for sale? Looks promising alternative to replace the original plastic one.
Thx! The loop is 10mm wide (I believe the standart Garmin mount is 12mm), I hope to at least have some prototypes in March or April, but you always cant guess where the delay might happen in these things

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