What options are there to change the saddle mount on an aero seatpost of an Stevens Arcalis 2017 to mount a saddle with non-round carbon rails?

Below you can see the saddle mount that is designed to accept round saddle rails only. Usually 6mm x 6mm or 7mm by 7mm.

Are there any options – specific to this bike or general purpose – to allow that?

Arcalis saddle mount


Stevens Vertriebs GmbH (info@stevensbikes.de) informed me via email

... we are sorry, we don´t have Arcalis saddle clamps for Carbon-Rail available

So stevens does not provide any replacement part for my purpose.

  • I'm guessing it would be cheaper and easier to buy a new saddle with aero rails to fit your clamp. – Criggie Oct 26 '18 at 3:27
  • Or, alternately, if you REALLY like that saddle, buy a seatpost that will fit the saddle you want and the frame. Either option should work fine and likely be easier than trying to munge your seatpost by altering it. – Deleted User Oct 26 '18 at 18:30
  • 3
    A replacement seatpost doesn't look to be an option for this bike. I think it has a proprietary aero seatpost that's specific to this frame, so unless Stevens can sell one with the other rail clamp, he's out of luck. – Carbon side up Dec 7 '18 at 21:46

As the "Stevens Vertriebs GmbH" and other sources on the internet mentioned there is probably no 3rd party solution as of now to mount another saddle which has no round bars.


I sanded down the carbon rails of the saddle to make them fit. When doing this wear a breath protection and protect you and your environment from the carbon particles.

  • 4
    Respectfully, this is a terrible idea, and the rails are at a risk of sudden failure. – Weiwen Ng Mar 27 '20 at 9:53
  • Consider this: the rail is under a lot of pressure from the clamp. It wouldn’t be a good idea to sand down a solid steel saddle rail, as you’re weakening the structure. A solid steel rail, at least, is probably over-engineered for the purpose, i.e. it has more than enough strength. Something like a tubular titanium rail or a carbon rail is just strong enough, so if you remove material, it rapidly goes to not strong enough. There’s the additional complication of possibly causing stress risers or breaking fibers, but I’m not a composites engineer. – Weiwen Ng Mar 27 '20 at 13:11

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