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While doing off-roading in a group, you are prone to a lot of accidents and mishaps. If you are riding behind a motorcycle, there is a possibility that his/her rear tyre might throw a few pebbles or even water at the rider behind that motorcycle (or at you). This motorcycle has a number of contact areas where these can hit:
For the rider, he has a couple of safety gears on him like a helmet, riding gloves, jacket, riding pants, shoes, so the rider's case is sorted. But then what about the poor bike that is already in motion, the speed of the object flying towards it and the speed of the bike, the force of that object gets added and the point of impact will take a heavy or mild damage (depends on both their speeds). Now, if the speed is above 40 Kmph, there is a high possibility that the object (say a pebble), would hit the upper portion of the motorcycle (keeping the projectile angle in mind) which are the headlight and the windshield. The windshield is made up of hard plastic and the probability of it breaking into two pieces is very less, say the probability could be 1:10. Whereas the headlight is made up of glass (the front part), if this breaks, there a lot of other damages that could follow. The broken pieces can puncture your tyres as well as the rider behind you. Also, the bulb itself can be damaged if it has a greater impact. To avoid such mishaps, it is advisable that a headlight grill be installed as a safety and preventive measure. Mind you, this does not zero the probability of the object hitting the headlight, but it reduces the probability drastically.
What are the demerits of installing a headlight grill? Well, for obvious reasons the visibility of the bike's headlight or the range reduces because the grill is obstructing the projection of the light. But, does that even matter? For a person who does off-roading, it is done usually at day time rather than at night as it can be very dangerous. So, during day time you really don't require the "extra" light from your headlight to see the track. I would also like to mention that use and trust your eyes when you are offroading. If you are gung-ho about lights, it would be better if you could install separate auxiliary lights for your motorcycle as the ones that come in stock on the Royal Enfield Himalayan which is not very powerful. The second demerit that I observed was that it is possible that the light could reflect back from the grill and you could see the reflected light on the bottom of your windshield. This can bother you (it did to me) and you can ignore it eventually (yup, i did) or you can look for other manufacturers that make such grills.
The merits are, one, they protect your headlights on roads or on the off-roading tracks. Secondly, the bike looks good aesthetically, specially, if you have an adventure touring/ off-roading motorcycle, this is something that you should get it installed on your motorcycle.
The one that I have installed on my Royal Enfield Himalayan is the Barrel Exhaust headlight grill which I had ordered through Amazon. The following are the links of Royal Enfield Himalayan compatible headlight grill that I had found on Amazon (India) while I was looking for one for myself:
Also, there are a few offline places as well from where you can directly speak to the respective store and place an order, again I came across these while I was hunting for the headlight grill:
If you ask my opinion on this, whether you should invest your money on a headlight grill? I would say, Yes! I don't usually ride at night and whatever off-roading that I have done till now have been during the day time. Though, I do plan on installing auxiliary lights as I have come across a lot of people who do early morning rides to have recommended this, but then that's for the future. This year, 2020, I doubt if I will be able to go for any rides considering the cases that have been rising, there is hope though that this too shall pass, that's how life has been till now.