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Seat clamps and saddle rails?

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Seat clamps and saddle rails?

Old 04-04-11, 05:38 AM
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lazerzxr
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Seat clamps and saddle rails?

In my search for a seatpost with enough set back for my lanky legs I have just ordered a deda superzero post with 21mm set back. It arrived in the post along with a nice new selle italia kit carbonio flow saddle with carbon rails.

Problem is that the clamp on the seat post is longer than the distance between the clamping limits on the rails. In other words, if i use this post and saddle, I have to clamp outside the limits on the rails. On checking my other saddles i notice that the clamp is longer than the distance between limits on all of them, steel rail, ti carbon, whatever!

I suspect that the critical case for a saddle rail is posts with small clamps, such that using a larger clamp would if anything reduce stress in the rails and make limits less important but since I have never seen this stated anywhere, I dont know for a fact.

I also noticed that for totally unknown reasons, deda decided to make the channels on the bottom half of the clamp the same radius as the rails so they fit perfectly together, but the radius on the top part of the clamp a larger radius so it only contacts at a point in the middle of the rail. This goes against all of the saddle manufacturers clamping advice that has ever been supplied with any saddle I have ever bought.

So the question is:
1) Is anyone else using this post and what are your experiences?
2) is anyone else using this seat and clamping outside the limits?
3) if not using this post or seat, what would you do anyway?

I know the seat is comfortable and dont want to change it and the post looks fantastic and finishes the rest of the deda kit off nicely so i dont want to change that either.

Cheers Lazer

Last edited by lazerzxr; 04-04-11 at 06:12 AM.
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Old 04-04-11, 06:49 AM
  #2  
MrTuner1970
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Originally Posted by lazerzxr View Post
Problem is that the clamp on the seat post is longer than the distance between the clamping limits on the rails. In other words, if i use this post and saddle, I have to clamp outside the limits on the rails. On checking my other saddles i notice that the clamp is longer than the distance between limits on all of them, steel rail, ti carbon, whatever!
This isn't making sense to me, but I'm only halfway thru my coffee. Got any pics you could put up?

I have used a Deda Zero 100 seatpost, and the clamp looks similar to the Superzero. I used Toupe and Arione saddles with it -- didn't notice any problems.
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Old 04-04-11, 10:52 AM
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kleinboogie
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I think you're saying that the front and back clamps go beyond the STOP marks on the saddle rails? It looks like its because the Deda clamps are angled rather than straight up'ish. If Selle Italia is serious about the stop marks then it sounds like you're out of luck unless you want to risk it. My Antares doesn't have marks like that so I assume I can use the whole rail. GL

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Old 04-04-11, 09:06 PM
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^^^yep thats what I mean. The clamp is longer than the space between stop marks. So i can line up one or the other, but not both. Selle Italia put the same limits on their metal rails too and tell you your clamp needs to be longer than 30mm. I can see with a small clamp aligned with the forward stop mark and finishing in the middle of the rail, there would be a lot of bending in the back of the rail, but if the entire flat section of rail is supported, would that really matter. I might assume its something to do with the carbon layup in the marked area making it suitable for clamping but like i say they do it on their metal rails too...

Im wondering if its more to prevent poor clamping with small clamps?
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Old 04-04-11, 10:04 PM
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Nick Bain
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psh carbon.
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Old 04-05-11, 06:40 AM
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21mm of setback on a post is small.

You need the FSA K-force with 35mm and that will mount the saddle within the desired range.


On the other hand, if you can achieve the setback number you want with the Deda post, then I think what you are describing is ok but then again nobody on a forum is going to tell you they are certain it's good at the risk of being wrong.
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Old 04-05-11, 07:00 AM
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Can you contact someone at Deda customer service (if there is such a thing)?
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Old 04-05-11, 07:15 AM
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lazerzxr
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Originally Posted by himespau View Post
Can you contact someone at Deda customer service (if there is such a thing)?
As far a i can tell, no such thing. I have tried selle italia instead.

I was hoping to stick with the deda post as I have deda bars and stem. I have noticed my toupe has far longer rails and actually has no limits on them at all so i might have to change the seat instead maybe. Not sure what i'll do but will wait for reply from from selle first.
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Old 04-05-11, 08:42 AM
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I had the same issue. You need to clamp the rails so you go over the stop marks equally in front and back. You will not have any more room for adjustments. Do not overtighten.
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Old 04-05-11, 05:42 PM
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lazerzxr
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Originally Posted by UCIMBZ View Post
I had the same issue. You need to clamp the rails so you go over the stop marks equally in front and back. You will not have any more room for adjustments. Do not overtighten.
Thanks for your input, how did you decide on that? The manual says a minimum 30mm long clamp, using that would leave the back edge of the clamp 10mm off the the stop if the front was aligned with the stop. I figure so long as the back edge is within 10mm of the stop it should be ok. I have contacted support but heard nothing.

Anyway I take it yours has been ok? Any problems? Are you using the same post as me? thanks for your reply
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Old 04-05-11, 08:07 PM
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afraid i can't help much, but selle italia has good customer service IME. i was trying out an SLR with carbon rails and wasn't sure if it was ok with my seatpost. i called them, got a real person without much trouble, and that real person was actually very polite and helpful. i was pleasantly surprised. so i'm not sure how you tried to contact them - sounds like you may have sent an email - but definitely give them a call and i bet they can give you some advice.
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Old 04-05-11, 09:05 PM
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ok cool i'll try that, thanks
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Old 04-06-11, 03:22 AM
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ok they replied to my email before i got chance to call. BIG thumbs up to Selle Italia customer service I explained exacly what I want to do which basically involves sliding the seat back further than the indicated limits allow. I gave all proposed measurements and clamp size and was told that due to the size of the clamp it will be fine to clamp beyond the marked limits. Basically just keep the clamp on the flat section of rail.

So with that response I am good to go I highly recommend contacting their customer service with any of these sorts of concerns if you find yourself in a similar position. As i suspected it is the small clamps that govern the design.

Their response was specific to my question, so dont blame me (or them) if you bust your rails without asking.
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