Help me understand this Seat Mast Topper

[weisan]

One of the things that puzzles me till this day is the design of the seat mast topper of my french Cyfac carbon bike.

I hate to jump to any hasty conclusion or malign the good name of this venerable french framebuilder without first seeking some clarification. Perhaps some of you here is familiar with the design and can enlighten me.

As far as I can tell, the only way to set up the saddle is to tighten the bolt from the top. But that requires a saddle that has a cutout in order to access the bolt. Lucky for me, my saddle of choice is a Specialized Toupe and it does have a middle cutout which allows me to access the bolt. Now it begs the question, what happens if someone is using a saddle that doesn't come with a cutout, how are they going to be able to tighten up the rail clamp?
I am not the smartest guy around so maybe I am missing something.

Please take a look at the following pictures to get an idea what I am talking about....

http://alicehui.com/bike/cyfac/IMG_7124.jpg

http://alicehui.com/bike/cyfac/IMG_7126.jpg

http://alicehui.com/bike/cyfac/IMG_7125.jpg

http://alicehui.com/bike/cyfac/IMG_7127.jpg

Please refrain from using harsh language, just state what you know, any observations and stick to the facts. The purpose of my thread is not to let you insult a reputable bike company. It doesn't help anybody. Thank you.

[Clean39T]

It looks to me like at one point there were two bolts and a different top cradle, which is not so different from other designs. I think someone lost some of the pieces and McGuyver'd it into what you now have.

Either that, or the French just assume that all male riders wish to maintain their Rule V (https://www.velominati.com/comment-page-8/#:~:text=%2F%2F%20Obey%20The%20Rules.,it%20is%20ne ver%20good%20enough.) status, on and off the bike, and therefore ride cut-out saddles exclusively...

[BRad704]

Similar to Cleans idea that the clamp is not original, any chance there's a hole inside the clamp, so you would tighten from the bottom before mounting to the seat post?


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[Hindmost]

Similar to Cleans idea that the clamp is not original, any chance there's a hole inside the clamp, so you would tighten from the bottom before mounting to the seat post?


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If those clamp parts were supposed to work are they simply inverted?

[ultraman6970]

Knowing french doesnt surprise me at all that the thing tights from the top only. Their ingeneering in some of the simplest things sometimes goes overboard and well things like this happens.

THe shape of the seatpost mast is not rounded??? Personally I would try to find another stubby from another bike with a more friendly design.

[gbcoupe]

Is this a 1 or 2 bolt clamp? Guessing 2. Should be a dial up top for adjustment and a bolt under in the back for clamping.

Also, that cradle doesn't look like it's making complete contact on the underside.

Agree that this is not original.

[Vientomas]

https://forums.thepaceline.net/showthread.php?t=188133&page=4

https://www.bikeforums.net/road-cycling/998253-frustrating-ridley-saddle-clamp.html

[dave thompson]

Specialized makes a seatpost with the same feature, the adjustment bolt is only accessible through the saddle cutout. Maybe it’s Spec’s sales incentive to buy one of their saddles.

[happycampyer]

It’s hard to tell, but your topper looks different from the one in this review by Pez.

https://pezcyclingnews.com/amp/technspec/cyfac-absolu-2/

That definitely looks awkward. And I thought the clamping mechanism on PMP seatposts was hard to adjust. Regardless, Cyfacs are beautifully crafted bicycles.

[Blown Reek]

I think someone lost some of the pieces and McGuyver'd it into what you now have.

Someone went parts shopping at the co-op to make this system (sort of) work.

Also, that to cradle doesn't look like it's making complete contact on the underside.

Double the torque in the front to compensate for the lack of clamping in the back, you know.

[Black Dog]

https://pezcyclingnews.com/photos/tech/cyfac/cyseat2.jpg

https://pezcyclingnews.com/photos/tech/cyfac/cyseat1.jpg

https://pezcyclingnews.com/photos/tech/cyfac/cyseat3.jpg

[weisan]

http://alicehui.com/bike/cyfac/IMG_7139.jpg

http://alicehui.com/bike/cyfac/IMG_7140.jpg

http://alicehui.com/bike/cyfac/IMG_7141.jpg

http://alicehui.com/bike/cyfac/IMG_7142.jpg

[jc031699]

Hey Weisan-pal,

Have a look at this. It may have a mechanism that matches your topper.


https://www.ebay.com/itm/184435681290


Clearer pics of the original styles here

https://www.ebay.com/itm/174368548367

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[happycampyer]

This picture from the Absolu eBay listing shows the mechanism more clearly than the photos in Charles' review. It seems as if someone made an aftermarket modification.

https://photos.smugmug.com/photos/i-vMJCDB8/0/87fee2be/L/i-vMJCDB8-L.jpg

The standard (i.e., not a topper) seatpost in the other eBay listing has a slightly different mechanism, with the front adjustment dial in a higher, more inaccessible location.

[weisan]

Thank you JC, thank you Happy. I am still not 100% sure how this works.

[Vientomas]

There are 2 versions. One is a single bolt, like yours. The other is a double fastener. Your pic from the old thread shows the original bolt which can be tightened with a spanner wrench under the saddle. Apparently you have replaced the original bolt with a hex and no longer have the ability to tighten the clamp without the use of a hex wrench.

Apparently you never had the joy of attaching a saddle to one of these:

https://www.ebay.com/itm/CAMPAGNOLO-NUOVO-RECORD-SEATPOST-TWO-BOLTS-27mm-80s-VINTAGE-OLD-SUPERLEGGERO-/303295145508

[Pegoready]

Weisan, you having a senior moment ;)?

You replaced the bolt yourself then complain about the bad design, hehe

OG pic with the bolt you can adjust with a spanner like the old Campy post linked above.

[Mark McM]

Apparently you never had the joy of attaching a saddle to one of these:

https://www.ebay.com/itm/CAMPAGNOLO-NUOVO-RECORD-SEATPOST-TWO-BOLTS-27mm-80s-VINTAGE-OLD-SUPERLEGGERO-/303295145508

Campagnolo produced a special seatpost wrench that was bent to reach up and under the saddle to tighten the bolts:

https://i.pinimg.com/474x/df/8e/d8/df8ed858dfe4534171328ddcc9551f8f.jpg

[Pegoready]

Campagnolo produced a special seatpost wrench that was bent to reach up and under the saddle to tighten the bolts:

https://i.pinimg.com/474x/df/8e/d8/df8ed858dfe4534171328ddcc9551f8f.jpg

Flex head ratchet is money for this style of post. Almost makes owning an old Campy post a joy.

https://images.homedepot-static.com/productImages/5a961671-2185-425e-9a8a-cbb98bdf3988/svn/gearwrench-combination-wrenches-9908d-64_1000.jpg

[jc031699]

Thank you JC, thank you Happy. I am still not 100% sure how this works.


With the two bolt system like in the two eBay posts, the finger dial bolt sets the angle and the Allen bolt tightens it down.

Like with an old two bolt American Classic post.

https://www.thebicycleguys.com/products/american-classic-road-bike-set-back-aluminum-seatpost-27-2-x-240mm


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[ls1togo]

Same topper used on older Ridley Helium integrated seat posts, I had several just like yours..Unfortunately, I have no solution for you as I use Selle SMP saddles so tightening through the top was the method I used...The only issue I found was that the clamp would allow slippage on the rails after time...