I just purchased a Brooks C13 saddle (7x9 oval carbon rails, the more recent version with no tape) and was hoping it would fit on my existing post (2016 Jamis Coda Sport - it's a top/bottom clamp with a single bolt) but found that the rails don't align well, so I think I need a different post.

Does anyone have any experience pairing this saddle with a Ritchey comp 2-bolt seatpost? It says it is "compatible with multiple rail types" and boasts good contact area with the saddle, which I believe is what I'm looking for. Or could anyone recommend a different seatpost option that they've paired with the Brooks C13? I'm ideally looking for a lower cost solution.

Also, this is my first time installing a carbon rail saddle and understand that this may need greater sensitivity - is it critical that I invest in a torque wrench to do this properly?

  • Can you clarify, perhaps with a photo: the rails don't align on the clamp how? If the rails aren't aligned with themselves then your problem isn't with the seatpost, but I'd guess that's not what you meant.
    – Weiwen Ng
    Jun 19, 2020 at 18:44

2 Answers 2


Carbon saddle rails are made oval to increase strength and reliability, and you can get these types of adapters for some seat posts. I am not sure how cross-compatible those adapters are, but it may be an alternative to spending more money on a new post. I do recommend using a torque wrench any time you apply force to a carbon component just to avoid over-torque. I looked at the spec sheet on Ritchey comp seat posts, I didnt see anything that led me to think it would work any better than the post you already have, but I have always been a big fan of Ritchey's products, and they have great customer support so it wouldn't hurt to give them a call or shoot an email and ask. You might consider a Thomson Elite post as I think you can buy the post with whichever clamp best suits your needs and the clamps are interchangeable which I find nifty. I love these posts, I have three of them and they never die or malfunction, and they are almost as light as carbon, easier on the wallet too.

  • 1
    Arguably the biggest benefit of a carbon seatpost isn’t the weight reduction, but the comfort gain due to the carbon’s flexibility.
    – MaplePanda
    Jul 20, 2020 at 5:49
  • 1
    If you can notice the subtlety. I have some alloy posts and some carbon posts, and on the trails I ride I am usually out of the saddle when I might otherwise feel any difference. I do have a carbon Campagnolo record post on my favorite steel road frame though. I hope it dampens the vibes a little, butIm not sure.
    – bradly
    Jul 23, 2020 at 17:58

Saddle rails converged on a 7mm diameter round rail and stayed there for quite some time. You can make them out of solid steel, or tubular steel, or solid or tubular titanium. Then we came to the carbon fiber era. I don't have solid documentation of this, but I'd guess that 7mm round carbon rails can't be made durable enough.

So, we came to the 7x9mm standard. I don't have my hands on such a saddle. However, it seems like (as stated on forum threads like this one, this one, or this one) these rails are 9mm tall, but 7mm wide. The tops and bottoms of the rails are circular, and many seatpost clamps should fit them.

Now, why many and not all? Many seatpost clamps cover the rails on top and on the bottom. Some clamps enclose the rail entirely. For example, Enve's clamp is shown below:

enter image description here

Thus, they ship two separate clamps for 7mm round rails and 7x9mm rails with each post. Alternatively, Kent Eriksen's titanium seatpost doesn't fit oval rails at all, and they say so on the product page. Basically, any seatpost where the bolts clamp side to side are not likely to work unless specifically designed (e.g. Enve). Or, sometimes a saddle's bolts won't offer long enough threads to engage fully if you put a carbon-railed saddle in there. I'm not able to find specific documentation for this, but I believe Thomson seatposts may sometimes be in this situation. Thomson offer a 7x9 (or 7x10) clamp on their site, but I have heard people say their stock clamps work fine. In any case, I believe the Ritchey clamp should work, as it clamps from above and below the rails.

So, why does the OP's original seatpost not work? That's a mystery, as it seems like it should from the description. Some photographs might be helpful if the OP wants to diagnose the issue.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.