Cracking and breaking my number plates

Hi all hope you are all well
I am sick of buying number plates for my bike i have spent over £100 thats about $ 130.00 over the years replacing broken or cracked plates the culprit is vibtartion I have rubber mounted them i have put them on perspex 6mm thick and they still break. I have bought metal pressed number plates and mounted them on perspex also and they end up cracking around the mount holes also ....
have any of you had this issue and how did you resolve it
All the best
Funky

Are you talking about your license plate? I mount mine to an aluminum backing plate with 4 bolts and a layer of sheet rubber in between. I've never had one crack around the bolt holes nor have I ever lost one. I also use rubber backed washers on the plate side of the bolts .....

Hi 5Twins hope your well.... yes i am talking about my license plate I have used rubber penny washers 3mm thick either side of the mounting holes ... So rear mount bracket then a rubber washer then the Perspex with the license plate mounted on that and drilled 7mm holes
I thought i would upgrade to Ally back plate to and made this (last pic) for my new pressed Ally plate which should come in tomorrows post .
I am going to fit a rubber damper on the end of the mud guard or fender to stop the license plate touching or the Ally back plate hope that solves the issue .
All the best
Funky

I will use four bolts as you have also

You want a complete rubber sheet under the plate, not just washers at the bolts. Maybe you could cut one from an old inner tube? I also use nylock nuts on the bolts. That way they don't have to be super tight, just tight enough to compress the rubber a little.

Ok thanks for the tip I have some inner tube and i think i torqued the bolts to tight anyway will see how i get on ....
Thanks again 5T
All the best Funky

The rubber/metal washers I use came from the #12 sheet metal screws we used at work all the time. The hole through them is just slightly larger than 6mm so they fit on a 6mm screw/bolt perfectly. The metal washer part is domed slightly. You tighten the fastener down enough just to flatten that "dome" out of the metal washer and so that the rubber part underneath bulges out around the edge slightly .....



In the above pic you can also see how I made up rubber mounts for my regulator by putting 2 of the washers on the bolt back to back.

I just use an expired plate behind the plate, a bead of silcone around the perimeter and in an X between the two, bolts through all 4 holes, have over 10,000 miles on one done this way, no cracks. I have to make my plates last 'cause they are "lifetime" vintage plates.

My first plate lasted 50ish miles. Now I have a 1/8" aluminum plate behind it with bolts at all 4 corners and no cracks after a few hundred miles.

Hi funky,
you should know that while British vehicles are plated for life, North American plates change every time
the vehicle gets a new owner and in some jurisdictions, every year, so they don't tend to be as sturdy as Brit ones.
Me too with hard-bolting the first plate onto my XS650 and only finding two ragged triangles 50 miles later.
OK, the Saskatchewan and Manitoban plates are quite small when compared to the modern British bikes
giant dive brake but my fix should work on those too.
Check the way the vanity plate in my avatar is mounted.
A stiff rubber sheet (part of a truck mudflap I found in the street) bolted to the bike's plate hanger.
The plate isn't bolted to the bike at all but to rubber sheet an inch or so below the bike attachment bolts.
The rubber sheet has swapped bikes, Provinces and plates over 20+ years and it's never lost a plate.

Agreed Fred, I was going to suggest a semi truck mud flap. They can be sourced very cheap, sometime free at a truck repai shop or truck stop