Call me ghetto... but this turned out pretty decent and works great. Thought I'd share my little creation. This was on my Thule rack, may work differently on others.

I had been strapping the tires down tight to the rack which worked for the most part, but any side wind would occasionally blow my tire sideways... not fun going 70 on the highway.

So had to get creative to fix this...

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313202954667.jpg

PARTS:
2 - Polyethylene Internal Coupler, 5" or 4" depending on your tire size (get these at any hardware/home store... home depot, etc.).
4 - 1/4" x 2" bolts.
8 - 1/4" washers.
4 - 1/4" wing nut bolts.
2 - straps of your choice... or get some super cheap snowshoes with the ratched latch (which I used).

You will also need a Dremel or other rotary tool and some zip ties help.




Here are my parts per strap - the coupler, 2 bolts with washers and wingnuts, and the strap from my old snowshoes (cut down).

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313195737007.jpg



First I had to cut out the part shown here in green, so that it would fit snug with the tray. Just notched them out with the cutter.

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313195839385.jpg
DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313200047845.jpg



Next I cut the coupler in 2 pieces, leaving one slightly taller than the other.

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313200459085.jpg



Then I lightly zip tied the taller piece to the rack, threw my bike on top to find the position, and strapped it down tight so it wouldn't slide around.

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313200706131.jpg



Then lay the shorter half inside the other. I found having the two creates a stronger support.

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313201042509.jpg



I drilled two holes with a (bigger than 1/4") drill bit so that it went through the center channel of the thule aluminum tray. This won't effect anything on your thule tray if you want to put your old straps back on some day.

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313201411192.jpg



To help with drilling the second hole, I put the bolt in and lightly tightened. I arranged as bolt head on top with washer, and then bottom of thule tray the other washer and wingnut.

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313201315887.jpg



Once my holes were drilled I removed the inner coupler and layed down my strap. I didn't want to drill through the strap since it was hard rubber that might eventually stretch, so this is how I went about it. This ratchet strap from my old snowshoes fit perfect.

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313201649109.jpg



Then I just put the inner coupler over the top of the strap, put the two bolts in, and tightened it up. I also took the rotary tool and cut all corners nice and round, and got rid of any other sharp areas where things could catch.

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313202627781.jpg



Here is a front view with the two pieces and Bud. You can see the bolts going through underneath. It's a nice snug fit.

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313194900473.jpg



The finished front one strapped down. Side to side movement of the tire is now very minimal.

DIY Fat bike rack tray/straps for 5" tires - write-up with photos-camerazoom-20130313194823194.jpg



Then it's time to go inside and have another beer.