Instructables
Picture of GoPro camera bicycle under-seat mount
Homemade under the seat mount for GoPro camera in order to take videos of the riders behind you.

This took me about 15 minutes and was free with things I had laying around the garage.

This was very fast and easy.

I think this works better than a seatpost mount because you can locate the camera farther back and reduce the capture of your legs or butt in the shots.
 
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Step 1: Materials and tools

Picture of Materials and tools
Materials:
  • I used two 4" x 4"  1/2" thick Corian solid surfacing samples which I got free from work. I also made an earlier version out of wood, but opted fro the solid surfacing material so I wouldn't have to worry about the wood cracking when the mount was tightened to the seat rails. A strong, tight-grained wood would work well.
  • 1/4 -20 short bolt for securing tripod mount to seat mount
  • 1/4" clamping bolt with washer, lock washer and wing nut
  • GoPro tripod mount (see my other GoPro Instructables, I use this mount for a lot of things) OR a GoPro flat sticky mount
  • (If I was to make another out of wood, I would use a piece of 3/4" wide x 1/8" aluminum top and bottom to spread out the load of the clamping bolt so as not to squeeze the wood too much and crack it.)

Tools
  • Drill press with 1/4" bit
  • Round file(s)
  • Band saw, scroll saw or jig saw.

Step 2: Seat rail slots

Measure the diameter of the seat rails and the spacing between the rails. Mine measured 1/4" diameter with a spacing of approx. 1 5/8", which I assume is industry standard, but check anyway.

If using 1/2" solid surfacing, tightly clamp the two pieces together and drill two (1/4") holes into the joint between the two sheets at the appropriate spacing. I didn't pay particular attention to the plumbness of the Corian stock against the drill bit so my holes were deeper in one sheet than the other.

If using wood, utilize a piece of stock about 1" - 1 1/4" thick and drill the holes in the center of the 1" thickness. Then saw the thickness in half, down the center of the holes.

Trim down the sheet material as shown in the picture. The smaller piece must fit on top of the seat rails. In my case, my seat sits back and allows for a decent amount of exposed rail to the back. The larger piece sits underneath the rails with a tongue that projects backwards for the camera mount.

Test fit pieces on the rails and use a round file to adjust as necessary.

Step 4: You are done

Mount the GoPro tripod mount (shown) to the tongue using a short 1/4"-20 screw or bolt. If the screw/bolt is too long, use some washers. Screw it on tightly.
OR
Mount the flat sticky mount to the underside of the rear tongue.

Use a 1/4" bolt with washer, lock washer and wing nut to clamp the mount to the seat rails.

Here are two videos I shot using this mount.
I am very pleased with the results. Rode over some rough terrain without a problem.

http://youtu.be/auUZH1r9Eqw

http://youtu.be/QzCDseKaCHo

Step 5: Updated with slight modifications

I made a few adjustments for a mount for a friend.
He did not have as such exposed seat rail length as I did, so I made the following modifications:
  • Reduced the width of the top piece to 3/4" due to the smaller length of seat rail available to clamp onto.
  • Added 1/8" x 3/4" wide aluminum flat stock on top of top piece to distribute load and prevent Corian from cracking. Filed the drill hole to a square shape to accommodate the use of a carriage bolt for the clamp bolt
  • Used double-sided tape to secure flat stock to top piece. Let some of the tape overlap the drilled hole to help hold clamp bolt when not secured.
Also, I tried a piece of Avonite instead of Corian.
This particular Avonite selection had a course granular composition which made it look like quartz. This product did not seem to machine as well, for this particular application. I would stick with solid surfacing products that have a much finer grain.
Steeler1 year ago
great work I'll definitely build one of these
marple200 (author)  Steeler1 year ago
This is the best mount I have.
It's really simple to make and the shots are great as well.
Very nice job, would make a great light mount also. Love the use of the material Corian you chose.
kjones52 years ago
Nice use of alternative building materials. At first glance I thought it was aluminum and thought, "Over kill!"  

I like mounting the camera to the frame of the bike to let it's weight dampen the shot. I've mounted to the front forks, as well. It looked good until started to do a lot of turning or pumping the bike. Then it not so much.

I like getting the tire in the shot to see the suspension work.  It really adds to the feeling of the trail.

One shot I liked but haven't perfected with the very-low-to-the-rear shot.  My feet keep hitting the camera and knocking it out of whack.  It's a cool shot though.
awesome, keep em coming! how many go pro's do you have? are you going to be shooting front and back at the same time? if you have two, you should try to build a stereo mount! that would be so cool!
marple200 (author)  amandaghassaei2 years ago
Just one camera so far. Who knows what the future will bring, however.