I don't understand the obsession bike riders & supply houses have with short sleeves and pants. Seems veterans are proud of their road scars. I ride >2000 miles a year now, and wear long sleeves and pants, thick ones, in dark blue usually. I don't get too hot, even at 102 deg F in the sun. I do drink water.A bright green or orange Tee or vest is over top.
I haven't skinned my knees since I was seven riding a 20" bike. I go over the handlebars about once a year when the wheel turns sideways on obstacles, hitting usually my chin & chest. I usually alight on my arms, but have for 30 years worn cotton or cotton/poly long sleeves workshirts, which are a lot cheaper than those knox items linked to above.
https://www.automotiveworkwear.com/mm5/graphics/00000001/SP14_small.jpg Scrapes are minimal in that heavy cloth. The all cotton workshirt costs more but is cooler in summer, wicking the sweat effectively. I wear long sleeves in all weather on the bike. Dickies makes cotton/poly workshirts available in discount stores; red cap has that and a full cotton one (for welding) which has to be mail ordered. See automotiveworkwear.com or equivalent sites.
Dickies long pants also keep my legs from getting roadburn; red kap makes an equivalent cotton/poly workpant that doesn't fit my round *** and thick thighs as well.
As far as chin protection, I broke it in November on the pavement and am ****ed that nobody online would show me a ventilated bike helmet with chin guard in September. Niagara, competitive, modernbike, nothing, jenson I got javascript error. Jenson actually has them, but you can't see it with my browser unless you know the secret word: "downhill mountain bike racing helmet". I bought the Fox Rampage Comp,
http://www.jensonusa.com/globalasse...91g06-yellow~black.jpg?w=250&h=300&quality=85 It is in fact very well ventilated although heavy at 2.2 lb. The stupid wind catching visor does unscrew if you're not racing downhill through the forest with a risk of being stabbed in the face by a branch or planting it onto a rock. I ride on pavement 99.9999% of the time. Do this mod at your own risk.