# Educate Me - Carbon rail compatible seatclamps



## j2d (Nov 15, 2010)

I'm eying Williams Cycling new AuroraSLC ( I would post a link but am unable) saddle and I've seen where they say that it can only be used with Carbon rail compatible seatclamps. I've searched a bit online and here and I can't quite identify what that really means or looks like 100%. From what I've gathered the carbon rails are oval shaped and standard rails are round, how can I identify a compatible seatclamp?

Also, do you have any recommendations?


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## PoorCyclist (Oct 14, 2010)

The carbon rails I have used are round and looks just like the same thickness as the metal version (at least it is from the same company, anyway)
So I would imagine the same seatpost clamp would work.


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## j2d (Nov 15, 2010)

The rails on the Williams saddles are flatter with degree/measurement markings on the sides. They aren't the standard round, at least that's how it appears in the images.


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## jkk (Apr 2, 2007)

Not sure if it's still up, but Specialized used to have installation instructions online for their carbon-rail saddles which described criteria for compatible clamps... for example shape (oval vs circular), area of clamping surface on top and bottom, distance between clamp segments. The recommendations vary among manufacturers. I'm using a 3T seatpost which 3T says is carbon rail compatible, yet it doesn't meet all of Specialized's criteria.


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## j2d (Nov 15, 2010)

I'll venture over to their website and see if it is still available.

Thanks.


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## j2d (Nov 15, 2010)

I believe this is what your were referring too.

h.t.t.p.:// service.specialized.com/collateral/ownersguide/new/assets/pdf/Saddle---Carbon-Rail-Saddle.pdf


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## jkk (Apr 2, 2007)

Yes, that's it. I replaced my 2005 Bontrager carbon seatpost with a Thomson Elite to conform to to these specifications when I bought a Romin Pro saddle last year. I also looked at the 3T seatpost but it didn't meet all the specs even though it is marketed as carbon rail compatible.


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## j2d (Nov 15, 2010)

I went by my local bike shop today and asked the same question and even he wasn't completely clear on it. His best advice was to go with the type of seat clamp that sandwiches the rails from the top and bottom as that would most likely provide the best fit.


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## Ryan from Williams (Jan 4, 2012)

*Seatpost Compatibility*

Hi,

My name is Ryan and I work at Williams Cycling. Someone pointed me towards this thread and said there may be some confusion about which seatposts would be compatible with our new SLC saddles that feature carbon rails. 

The main difference between ti or steel rails and our carbon rails (aside from being a different material that's lighter and has better ride qualities) is that they have an oval profile. While they have a standard 7mm width, they have a taller 9mm height. 

Your friend at the bike shop was right, most seatposts that clamp vertically should be fine, as the contours are built to fit the standard 7mm width. Seatposts that clamp horizontally will not be compatible, unless they are specifically designed for 9mm high ovalized rails. You should also be sure that any seatclamp you use is free of sharp edges that could gouge and damage the carbon.

I hope that helps clear things up a bit. I'm happy to hear you're considering our saddles. We've worked hard to make them some of the best in the industry. If you ever have questions about any Williams Cycling products feel free to send an email or give us a call.


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## j2d (Nov 15, 2010)

Ryan,

Thanks for your input and explanation. That pretty much confirms what I begun to think so I'm glad to know I had the right visualization at this point.

I'll already own a set of 30x wheels and absolutely love them so when I saw that Williams was coming out with some knew products I was greatly enthused! 

Thanks again.
Matt



Ryan from Williams said:


> Hi,
> 
> My name is Ryan and I work at Williams Cycling. Someone pointed me towards this thread and said there may be some confusion about which seatposts would be compatible with our new SLC saddles that feature carbon rails.
> 
> ...


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## Hanks (Sep 30, 2011)

*When I think about Carbon Seat Rails*

I think about those thin breadsticks or those thin straw-like cookies dipped in chocolate. 

I can't help it,

Hank :idea:


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## Eric_H (Feb 5, 2004)

I have used Fizik and Selle Italia carbon rails that 7x9 mm with Thomson seat posts and I have had zero problems. One Fizik probably has 20K km on it.

One thing to always verify before installing saddles of any rail construction is that there are no sharp edges or burrs on the seat post clamp surfaces that might dig into the rail. I usually dress the edges of all the Thomson clamps with a fine circular file. Almost all of them are fine from the factory, but an ounce of prevention.....


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## celltech (Jul 21, 2009)

Received my Aurora SLC yesterday and rode it this morning for 30 miles. I have a Neuvation FC500 and was using a Terry Falcon before. The SLC is much less padded than the Falcon. Between the lack of padding and how close the rails are to the shell I had to raise my seatpost 3/8"+. On my luggage scale the seat was truly ~150 grams as advertised.

The SLC is a tad more narrow and shorter than the Falcon. But in the end I loved it. With the thinner padding you fell more connected to the bike, but I think the carbon rails soak up shock better than metal so it's not a harsh ride like I was kinda expecting. The old rump hurt no more/less than with the plusher (and heavier) Falcon. I am 6' and 162 lbs as a point of reference.

As with the Falcon I am sold on the center cut out seats. For me at least it really takes the pressure off the package.

The rails fit easily into my post mount and I don't see any issues with it holding. I felt the edges of the mount first and didn't notice any obvious burrs and didn't bother to file them. I am not sure of the rail construction but they seem compressed as a single unit, almost like a V shape. Looks like Uni carbon and not the braided/weave type. Very smooth and flat looking surface.

Only downside so far is the thinness in the nose. It's pretty pointed so when you come out of the saddle and slide back down you better clear it or it will grab your shorts. And standing at a stop light it hurts to let it poke your butt.

Still early, but highly recommended so far...


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