Lucky, or has someone tried to have a go ?

[Louise]

Got to work this morning. .
Noticed some residents family looking at my bike, so I go over for a friendly chat. He pointed out my number plate was missing.
Then noticed it wedged very low into the Hugger/swing arm.
Thought the whole bracket had just come loose.
Plate destroyed.
Got a friend to come with a new bracket just now - Noticed the top part still bolted to the undertray, But was cleanly snapped from the ajoining part which holds the plate.
Ive not seen this happen before
Its like someone has physically bent the plate back n forth to weaken it...
The numberplate holder is less then two weeks old from Motrax & I cant see how, in anyway it would snap so cleanly off like it did.....
Has someone had a go :/ (considering theres a 2010 Honda next to mine)
Opinions. . . .
Bit mortified, it could of spat me off

[Dischord]

You been doing 12 o clocks?
____________________
2012 KTM EXC 250

Check out my vids - https://www.youtube.com/user/KTMSparky/videos

[Louise]

I wish

[Robby]

The reason is in your post.

Motrax.

[Louise]

Robb - Thanks for the input...
Im just a bit miffed - Had Motrax for years on the 636 without fail.
Just found this one a bit wrong and was asking if anyone has had the same problem

[sickpup]

Was the METAL bracket by any chance bolted to a PLASTIC part on the bike?

[G]

[st3v3]

Motrax are a semi-decent brand,

The fact it's plastic makes no difference, pretty much all bike makers use plastic for such parts. If they failed often, by simple wear and tear then people wouldn't buy them and they'd become too unprofitable to make.

Before you all go "nooo, they're not, they're shoite!!1"

How many people here have aftermarket indy's, usually from Motrax? Cheapo Tax disk holders, usually by Motrax? Oh, and bar ends....
____________________
Roger wrote: Women don't get damp for clingy puppies. Get some better happy pills, hit the gym & buy a medallion the size of a dinner plate. Job done

[G]

[Frost]

Numberplates are very un-aerodynamic and catch a lot of wind. It doesn't have to be a hard enough push to snap it clean off, it only needs to flex it a little. Much like working a paperclip back and forth, eventually the metal fatigues and it snaps with very little effort.

[sickpup]

[Jefr0]

Had this happen to me, wouldn't buy again, poor metal.....was the numberplate close to the tyre (inc suspension travel) and it's hit the tyre and broke off instead?
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Rides: Honda XR 125 ('03) Honda CBR 600F ('91), Ducati 916 Biposto ('95)

[Louise]

[stinkwheel]

I wouldn't have expected a bit of aluminium plate that big with a numberplate attached to hold on for very long.

This isn't accurate because the plate is protected from the wind to a fair extent, but it would be accurate if that bracket was attaching it to the front of the bike. Should give you an idea of the forces involved.

Number plate is 0.041 square metres.

Say you're doing 70mph (31.3m/s).

Drag coeffiecient of squared flat plate = 1.17

Mass density of air = 1.225 kg/cubic metre

https://upload.wikimedia.org/math/9/9/a/99a6015b6a230860c9b1517b238e5de9.png

So F = 28.8N

So at 70mph, you have a force of 3kg (give or take) of air pressure on your numberplate acting to bend that bracket.

Now do 100mph, you'll notice velocity is squared in that equation.
F=58.7. Nearly 6kg.

It snapped because it was not strong enough to take the forces acting on it. You could probably make one like that but it would need to be a very high grade alumimium like dural.
____________________
“Rule one: Always stick around for one more drink. That's when things happen. That's when you find out everything you want to know.”
I did the 2010 Round Britain Rally on my 350 Bullet. 89 landmarks, 3 months, 9,500 miles.

[Frost]

Also it assumes that the plate is mounted vertical, which it won't be exactly. Also i think the plastic mountings and even the plate itself flexes due to the force tilting it further and reducing the force on it. Combined with the lower pressure behind the bike i'd expect those number to be in the real world about half what you've calculated. It's still a lot more force than people expect! Like i said the constant flexing over a few weeks can easily crack something like that progressively.

[G]

Considering there's not only the bike, but the rider's legs there too, I'd have thought it'd be pretty hard to model and more be a case of 'turbulence' than direct wind.

[SoND]

The bracket has work hardened (aluminiumium) because of vibrations, wind etc then suddenly let go. The break is clean indicating it had hardened, the forces don't need to be big at all for this to happen.

Cheap crap is cheap crap. Generally this is true, there is a chance that the particular batch of material they used wasn't up to standard and got processed with no questions asked but then again there's a chance the correct grade of material was never specified.

I would definitely bring this up with the manufacturer as it's obviously not fit for purpose and many other people could be facing the same problem.
____________________
Go back to bed - You have no rights - "Streetfighters ~ Mainstream motorcycling's crackwhore sister."

[Skudd]

Louise has had her rear end done in.
____________________
Famous last words of Humpty Dumpty. " Stop pushing me "
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[G]

[colin1]

[dgo1212]

This might sound stupid but is there any chance you may have backed the bike into something before going to work, ie clipped wall whilst wheeling out of garage etc?

If the plate came off whilst travelling forward wouldn't it have flew off behind you and not into the swingarm/hugger? Doesn't look like it's been trapped in there for very long.

[jimspeed]

can you not fit an old door hinge there now plate would flip up at speed then and maybe cut down on drag too.
wonder if someone has tried to break it off to use the plate on a dodgy motor tho .
____________________
Hyosung cruise 125(passed test on, sold) Kawasaki el 252 (better than expected but sold on) Kawasaki GPZ500S first "big"bike.(sold) ZZR600 E5..Z750 2007,ER5, currently on a 2008 Enfield bullet electra x and loving it..
,"Alpha-9: Is there any correlation between dyno rod and dyno kits?"

[sickpup]

[Blau Zedong]

Just buy a standard number plate mount instead of tacky Motrax shit that looks worse than stock.

Kthxbai.
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18:54:48 Rob Fzs: jews don't give away stuff for free

18:54:59 Rob Fzs: unless its their clothes/ hair/ golden teeth

[stinkwheel]