In late 2016 I decided to add a chin guard to my Bell Super 3 to make it a Super3R. At the time I thought I would only wear it when things got hairy on my commute. Like riding at night. I didn't want to look like a geek. I immediately discovered the ventilation on the Super3 was amazing vs. my previous Bell Urban. I ride in up to 110 fahrenheit (in the shade) weather, with the days commonly registering over 100 here. The visor allowed me to clamp my mirror boom onto it so my mirror provided an in-frame, rock-solid rear view even riding downhill at high speeds. I soon decided it was too much trouble to disconnect and reconnect the chin bar. Screw what other people think lets leave it on all the time.
Winter rolled around and in December of 2017 I was t-boned by an inattentive motorist. Went over the car (thankfully I was not hit squarely and my leg was free of the impact, so I could fly forward) and landed on my head some 20 feet down the road (impact was approximately 15-20 mph). As my body rolled over with just my head in contact with the ground as I slid along, I felt MIPS do its job and my head rotated with my body while my helmet's attitude' stayed the same. After that, I came down on my back (wearing a backpack protected my spine and also contributed to spraining/stretching ... everything in my shoulders, spine and pelvis ... when I hammered down). From there I flopped around before coming to a stop. My vision in one eye was strangely blurry. This is why:
I was wearing those at the time, so as I rolled/flopped/skidded to a stop, my face did some skidding along the ground and got so close to it that happened to my eyeglass lens, but not so much it scored the eyeglass frame. So that right there is my anecdotal proof that the chin bar did a great job.
My face was untouched by the tarmac. Helmet was smashed pretty good though.
I recovered, mostly. Immediately bought another Super3R. It lasted me until January of 2021 when I decided that advancing tech had gotten to a point where I wanted an upgrade. The Bell Super DH had upgraded the MIPS sliding membrane with an entire rotating inner styro shell. This helmet is meant to get bashed on hard and I did not really see any difference in how it was laid out except - thanks to that inner shell versus just thin plastic - it was a physically bigger helmet in its diameter which gave it a specific kind of look. And its heavier than the 3R by a fair bit. Not noticeable wearing it, but you feel it holding the thing.
Still, its a safer helmet and has plenty of ventilation on super hot days. In Sep of 2021, needing a helmet that stays at my home (separated from my work residence by a couple hours), I bought a Super Air on a big discount (goofy color) and added the Air R chinbar to it. This is sort of the gen2 of the inner-liner style of MIPS and its a clear improvement. Gone is the Gazoo sized diameter and that inner liner is much thinner. It feels as light as my 3R. Absolutely the best helmet on my shelf.
These are not motorcycle helmets. Motorcycle helmets are like sticking your head in an oven. Especially if its hot where you live and you pedal for exercise.
I tape over my forward facing and chin bar air vents in the winter with blue painter's tape, A watch cap under the helmet like an Under Armour (thin) cap for the winter. Worst case a full USGI tanker nomex balaclava.