Last January I treated myself to a 70th birthday present of a new seat for my recumbent. Unfortunately due to supply-chain issues, it ended up back-ordered, and I just got it.
This seat is potentially more comfortable because it can recline more. It also should be more aerodynamic. The main purpose of the new seat is comfort, not aerodynamics, so I’ll get good use out of it. But being a retired engineer, my inner nerd was curious about the potential speed advantage.
The seat on the left was the original seat, called the “recurve”. The one on the right is called the “Euromesh”. There is a limit to reclining on the recurve because it makes the front stick up too far and whack into the back of your legs. This is not an issue on the Euromesh because of its shape. The two are shown side by side with the standard incline.
You can see there is lots more room to lower the Euromesh. I tried out the new seat with it reclined a few more inches than the recurve. I did a speed trial on one of my standard Strava routes, the Coyote Creek trail to Bailey Ave and back. Surprisingly, I was a few minutes slower than my best time. It felt like I could not put out as much power. I can push really hard on the seat back of the recurve when going fast, but on the Euromesh it felt like I would waste some energy sliding on the seat.
Professional cyclists on conventional bikes have also run into a trade-off between being more aero and the ability to put out power. But I hadn’t heard of this on recumbents. I know that all the speed records on recumbents are set on very reclined seats.
I’m stubborn and wasn’t ready to give up. It turned out that the length of the stays holding up the seat in the back prevented reclining as far as I wanted to try, even when telescoped to the shortest length. I didn’t want to cut the stays because that would make them unsuitable for the other seat. So I kludged together temporary stays using dowels. If this had worked I could have made it more official by buying some tubing. The “prototype” is shown below.
This position is a lot more aerodynamic but would take some getting used to comfort-wise. I tried doing some short sprints with it to test speed, and again, surprisingly, it was not any faster. But this also might have been because pedaling felt more awkward. This may be just a matter of getting used to the new position and adjusting my pedaling style.
Original source: https://bionicoldguy.home.blog/2023/09/12/belated-birthday-present/