Recently we've had some threads on the Smiths speedometer and its bouncing needle. Last week, out of the blue, my reverse Smiths speedo starting having some pretty good bounce. Like 120 degrees of bounce, that would come and go, and then went away for a while, came back, but not as bad. It always had some bounce below forty miles an hour or so. Plus, the speedometer has always been off a little, but I really didn't care that much because I almost exclusively use the tachometer to tell me how fast I'm going.
One of the previous threads had mentioned Dri-Slide, so I looked in to it and ordered some - it's pretty cool stuff. I also carefully calculated the driven gear ratio for my tires and rear and ordered a nice Scott Drake 19 tooth driven gear from Summit. Well, when I pulled it apart there was a 19 tooth gear already in there. I then pulled the transmission cable end up through the engine bay, so it was higher than the speedometer, and then put paper towels around it. This Dri-Slide stuff stains everything, permanently, and you need rubber gloves to use it -- if you get it on your fingers, it's next to impossible to wash it off. It comes with a small syringe-like squirter that you slip in to the cable, squirt the liquid in, and then the liquid evaporates off and leaves the dry lubricant. I did that a couple of times, turning the cable by hand after squirting it in so it would work its way down (which is really up) the cable.
You can see in the pics how I did it, then I put the extra driven gear in my reversible drill, put my remote camera on the speedometer, and the display right there in front of me. The fastest my drill will go is about 40 miles an hour, but the needle is almost rock-solid at all speeds up to that, which was never the case before.
This is about a ten minute job, with about 20 minutes of preparation to avoid making a big mess. But it does indeed eliminate the needle bounce.
Lubricating the Smiths Speedometer Cable To Stop Needle Bounce
Threaded Mode
