Rear Fender Vibration = Vanishing License Plate

[kenalmond]

When I lost the first one, I thought that since all the hardware was missing, that it was license plate/inspection sticker theft. Next, one day I noticed the license plate light unit missing. I replaced it. Then, I lost a second license plate. Now, I thought it was caused by the inspection sticker frame projecting down below the plate mount. To stop the flapping, I would remove the inspection sticker plate. When I lost the third plate, I drilled a hole in the center bottom of the plate to prevent the license plate flapping and cracking along the upper bolt line. So, now on my fourth plate and second plate light fixture, I heard a strange clicking noise from the rear at speed. I checked the plate, no cracks, my third, center bolt has stopped the plate vibration. But, when I looked higher, I saw a two (2) inch crack on both sides of the support frame for the rear fender. It obviously has been in the process of cracking for a long time. I have 27,000 miles on the machine. I bet the cracking started a long time ago as evidenced by the rust in the cracks. When I discussed this with the dealer, he said he had heard of many lost license plates. I wonder why they never mentioned it? When I talked to Can Am, they said it is not covered by the extended warranty, but in the interests of good will, they would replace the bracket.

So, check your rear fender support bracket early and often.

Any ideas on mitigating this problem?

[Paladin]

strange.. I will have to look at mine but only have bout 5000 miles

[SpyderL]

To get that much Vibration, I would consider the possibility that your rear tire isnt balanced properly.

Can you see wheel balanceing weights stuck to the inside of the rim?

[kenalmond]

I have checked that. Plus, it has been with three separate tires. No, the vibration is very high frequency. If you think about it, the rear fender is a cantilevered appliance. When I was losing license plates, because the lower edge was not secured and the plate extends beyond the tapered plate mounting area, it would flap in the wind like a reed. This high frequency back-and-forth fatigued the thin metal of the plate along the attachment line of the upper bolts. It is almost inevitable with the shape of the plate mounting area and with only attachments at the top. Like I said, not using the inspection sticker extension and by adding a center bolt in the bottom, I have stopped plate loss. Now it is just an issue with the fender support frame. As I look into this further, it seems that this is not unique to my cycle. I am hearing from many people about similar issues. One rider out of Florida has told me that in 100k+ miles (since 08) he has lost 7 plates and replaced the fender support three times.

[sassapnts]

Does it make a difference what type of Spyder you have, or are both RTs and RSs losing plates?

[kenalmond]

I do not know about the RT, but in your Avatar photo, I see exactly the situation that resulted in multiple lost plates.