Carbon Seat Post Modification UCI Legal

What happens when you find your ideal position, but it’s not in compliance with UCI sanctioned rules? Are you out of the luck? Not always. Read on.

This was the rider’s problem:
before modI ride an ISM Adamo Time Trial saddle in UCI races, so I’m restricted to a maximum fore position of 5cm behind the center of the bottom bracket. I have recently visited for a fit… While I was clever enough to pack my UCI-legal seat post, I forgot the clamp and had to be fitted with the stock seat post (Bontrager #419096) in place, with the 35mm offset post head (Bontrager #419630). The saddle was as far forward as the rails would allow, and I was at about 7-8cm behind the center of the bottom bracket.

When I took the bike in to have it upgraded to Di2, I realized the setback of the UCI-legal post was an additional 23mm further back than the stock post with 35mm setback. That significantly alters my position and negates a lot of what I just did for fit.

That leaves me with two options: sell my bike and buy a new one or modify the seat post. I’m not a product designer or engineer, so I can’t help very much in the final outcome, but I guess what I was envisioning is to cut the top off and possibly “shave” the forward surface of the head, then slide it forward 25-30mm, and fabricate the rest to secure it to the post. Can you do that? Would you have any other suggestions?

We can do that & we did. Below are photos of the final product.

trek bontrager carbon seat post modification
Looking at the above photos, you may think we just cut off the top and glued it at a different angle. It’s not that simple nor structurally sound. We fabricated a piece to fit inside the seat post to strengthen and secure the two pieces in addition to our carbon and resin work. Below is a photo of the piece at one of the construction stages.

bontrager seat post mid stage

From the customer’s Facebook post after he raced on his new post,

First TT of the season was a smashing success. I set a personal record at the Conquer the Canal TT. While it was an individual time trial, it took a village.

Kane Bicycles in NC solved a problem I’ve been struggling with for two seasons by fabricating a custom carbon seatpost for my Trek Speed Concept that’s 100% UCI legal and gets my saddle exactly where it needs to be. Looks better than it did when new. If you’re not losing sleep over a 23mm setback but have a crack in your otherwise awesome carbon frame, these guys can fix it.

My new position shaved more than a few seconds off my time, thanks in no small part to Paraic McGlynn and Stephen Merz at Cyclologic in Scottsdale, AZ. These guys eliminate the guess work and rely on oh-so-precious biomechanical data to dial in your position and extract every available watt. Extremely happy with this fit.

We love working with carbon, fabricating custom pieces, and helping you enjoy riding your bike even more. If we can help you, please do not hesitate to ask us!