I have the rear bumper on my 850 and I zip tied it to the grab bar and rear bumper. It sits on a bit of and angle and looks good on there. If you do use zip ties, make sure to put a couple extra ones in the rear box incase one breaks out on the trail.
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2009 850 XP
2002 500 HO
1994 300 2x4
1962 wife HO
Zip ties will work, but with that metal edge the plate and a lot of bouncing around could lead to a broken zip tie. Had my tail light zip tied for the longest time, and it did work. When it did finally cut the tie, it was out on the trail and I almost lost the tail light.
For 13 bucks, I think the plate mount Biz linked would be a good solution.
Mine has been there since new and never broke one zip tie......And that was 4 yrs. ago...
That is the plate I have on my XP. I had the ATV-GURU add some tabs to my rear brushguard for mounting.
If I didn't have a brushguard i would tap into the heat shielding.
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A four-wheeled adventure will soon bring you happiness.
2009 Polaris Sportsman XP 850 EPS Mossy Oak
26" Maxxis Bighorns on Black Polaris Wheels
2010 Camoplast Tatou 4s Tracks
Dual registered as both a Class 1 ATV (tires) and a Off-Road Vehicle (tracks)
The factory mounted mone and It seemed like a factory location but for the life of me I can't remember where it is mounted. Im at work right now but when I get home I will take a look and post a picture of where it's mounted.
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2009 POPO SP 500
X2 Alum rims
rear seat
Viper Winch (synthetic cable)
2 1/2 yr old co pilot
thats the same thing I did but my plate is plastic and it started to melt just below the heat shield. That is why I cut another piece of aluminun to put behind the plate.
Well done!
Time to hit the trails! 
