Oh yeah also when i was trying to tighten the front bumper i noticed that one of the nuts was not tightening and just turning around. I noticed also that this is really bad and must be fixed before you strip the cf base. To do this you need to take a pair of plyers and a flat screwdriver. This sort of only works well if you have the type of nut that it would be imposible to take off at this point with the bolt loose. Pull with the plyers and slowly rotate and then pull. Repeat and then eventually the bolt will pop into place… unless you forgot to file away a square and then you have issues… once it pops into place put the screwdriver under the nut and pull up. While keeping up the pressure with the screwdriver slowly tighten the nut untill the screwdriver cannot fit at all then tighten slowly the rest of the way. If you do not do this you will strip the square filed out spot in the base and i dont know what you can do then except hope that the handle is strong enough with the remaining bolts.
Hope that helps anyone who finds themselves in this spot.
I think that’s the most perfect think I’ve ever seen in my life. My dirty, scruyy, dog eared trials unicycle is nothing on that! It’s a patchwork up upgrades and mends but that thing… Band spanking awsome!
I bet in 2 months, someone’s gonna post asking about how to build a carbon fibre saddle. Just like every week someone asks about all kinds of repeated things. No-one’s fault but wouldn’t an archive of these repeated questions be really useful for everyone!
You did such a detailed write up of the process with crystal clear pictures Why not get this thread hosted on unicycletips.com? At least put the text with the images. Give the host an email!
What kind of file did you use? Can you take a picture of the file?
Finding a suitable file is the most difficult part of making a CF saddle. It is easy to find triangular files that are small enough. But triangular files are not good at making square holes or 90 degree corners. I made three CF saddles using a triangular file. Not fun. I finally just recently found a square wood file that is small enough so next time I make a CF saddle it will be easier.
Could you just use a dremmel instead of a file? I’m sure there is an attachment that would work? Like a really small pin drill/sander tip or a small grinding disk?
One thing that you may want to add that I have seen in other CF tutorials that I didn’t see in there was adding a piece or rubber or plastice inbetween the seatbase and the seatpost so that the post won’t damage the cf.
For a file i just used a triangular file that was as wide as my carraige bolts so that i would know when i was getting close. It was pretty hard but they turned out alright. I could give you a pic but its just a triangular file looking thing.
Im not sure about a dremel. Could work i guess if you are very carefull.
About the piece of rubber: I might have to add one of those but i dont know how exactly could you explain it or show a picture.
I used ducttape to hold the bolts in and it would definitally be helpfull and prevent stripping the square holes in the carbon fiber but im glad i didnt use one because i had to change all of the front bolts because they were too short. So if your sure that you have the right length bolts and want to make it completely permanent then id suggest using some epoxy if you know how but if its your first time making a seat id do a less permanent way of attaching the bolts to allow for error.
Yesterday i went riding to test out the new seat. It worked very well but i noticed one thing very painfully: the side that doesnt have the tubing acts as a dull saw on your other leg when jumping seat out. So I suggest putting a second peice of tubing or something to smooth the edge of the cf base so that you dont have to be in so much pain.
Also while doing unispins i noticed another source of pain. The bolts need to be longer since the 3/4" dont fit but the 1" stick out so that you hit your fingers on them. It is pretty painfull so i used some end caps that i found in the bike section of ACE. I had to cut them a bit since they were too long now they fit well but i wish they were black:(
Cut a rectangular piece of rubber from a thick inner tube and put the rubber between the seatpost bracket and the carbon fiber base. Another option is to put large fender washers between the seatpost bracket and carbon fiber base (that’s what I use).
The reason is that the seatpost bracket makes contact with the carbon fiber at points (corners) or 90 degree edges. Those points and edges will dig in to the carbon fiber and cause weak spots where the carbon fiber can crack. The rubber takes away the points and edges. The big fender washers do the same.
If the curve of the seatpost bracket fit the CF base exactly and the edges and corners of the seatpost bracket were radiused then this wouldn’t be necessary.
There have been a few people who have cracked carbon fiber seats. As far as I know the ones that have cracked are ones that didn’t have a piece of rubber or something similar to spread out the stress points. But even with that a CF seat isn’t going to be indestructible. They do have a finite life.
Okay so I put in a piece of rubber in my seat. Heres a few pics illustrating the process sortof. Heres the rubber cut out with the holes punched out. Basically i took off the washers on the seatpost and with a sharpie marked where the bolts came through the seatpost. I then put the peice of rubber up to the seatpost and drew an outline of the shape and put dots where the bolts came through.
To punch the holes i used this punch and a hammer. Its sort of obvious but use a scrap block of wood to do the pounding on because the hammer makes huge dents before it punches through the rubber.
