I've had some problems with an erratic speedo needle that start to present after a few straight hours on the bike and gradually gets worse as the ride gets long. Starts off fine but after about 2 - 3 hours of riding the needle starts to wobble and gradually worsens. On the way home last night, it wound off the clock past 160 all the while still flailing about. If my C5 could actually do that speed, i'd be very happy but I was being overtaken by other traffic so I suggest it was a little misleading.I've deduced it to be the speedo drive box on the front wheel not due to certainty but merely process of elimination as everything else is in order, lubed and checked sufficiently. I pulled it off and spun it by hand - very stiff, grinding a little. Didn't feel "right" and didn't spin very freely. Can i pull it apart and pack it full of high temp wheel bearing grease? It seems permanently pressed together but I could be wrong so I thought i'd check.Failing that id prefer not to replace it with another flimsy plastic piece of junk - the replacements for older bullets look similar and are made of alloy.....are they compatible? What is the ratio on a metric C5 speedo drive?