Well the design that I had been using, that worked so well, didn’t. I rebuilt it using steel in all the important mounting areas and it failed to spring…at all! “???” I went back to my original and took a closer look and found that it was failing in numerous locations. It appears that it was giving a softer ride as it was breaking down under my butt.
New design! All the mounting points are steel and my fiberglass is reinforced with extra layers at all the key points. I used the same concept of a base mounted to the frame, and a long thin tongue that mounts to the seat. The difference is that I now have third piece sandwiched between the other two. This third piece is a fiberglass spring formed around a PVC pipe nipple. The overall stiffness of the ride is based on the thickness (number of plys) of fiberglass in the spring. I have found that you can ‘fine tune’ the ride by replacing the PVC pipe nipple with a like sized section of fuel line or steel pipe.
I currently have about 400 miles on it and it is getting the job done. That’s why I went ahead and painted it.
The ride is different. You have a bit of roll from side to side due to the narrow tongue, but not enough to feel out of control in any way. The main difference is a bit hard to explain. Most bike seats deliver the jolt from the road up through the frame into your spine, and add some padding in between. With this set up there seems to be a very slight lag between the jolt that you feel in your feet and hands and movement of your butt down into the seat. This delay seems to cancel out the road bumps and holes. This happens very fast and I’m not sure what is happening, but there is no visible wear on the seat pan. I think that the frame is delivering the jolt to the front of the seat pan and the tongue is acting like a lever which has to catch up. My first solo seat was just a hard pan of fiberglass, but even without foam the ride was a vast improvement on my back. I am including pictures of my new seat. It’s bigger and has a bit of back support. The seat is still just at the foam stage. I’m still playing with the design so no cover yet.
So! What do you think?