I carry an 18" long 2"x10" piece of planking, beveled on one end. Rolling up on it raises the car enough to get my little scissor jack under the frame. I also watched a u-Tube comparison of stop leak products and Slime proved to be far superior to the aerosol Fix-a-Flat product. The testing was done with 1/4" punctures and was pretty extensive. Now, I carry a big bottle of Slime and pitched the large can of F-A-F I'd carried for years. I do also carry a plug kit and a 12v air compressor. Of course, a side wall puncture will make AAA pretty much the only cure. (personal experience
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