I tried them in very hot and humid conditions and was surprised to find they work straight away.
I thought they wouldn’t be effective until highway speeds, but you can feel the air rushing up your arms as soon as you start moving.
To check the temperature difference, I tried them on one wrist at a time and found the difference quite remarkable. Ventz claims they offer 25% reduction in temperature and that the air flows right around your jacket. That would depend on your jacket’s construction.
I tried them with a few of different jackets – leather and fabric – and on one, the air only flowed up to my elbow as the sleeves are fairly snug. Another jacket with wide sleeves allowed the air to flow right up to my armpits and around to my back.
The Ventz are shaped so they become slightly narrower at the back which accelerates the air flow much like when you pinch the end of the hose to make the water spurt faster and further.
You could just loosen the cuffs of your jacket for the same effect but there are two problems with that: While riding, your sleeves will flap around annoyingly and ride up your arms, leaving your wrists exposed to sunburn; and in a crash, your sleeve could pull up and expose your arm to abrasion injuries.
Ventz allows you to have airflow without having loose sleeves.
They are quick and easy to fit. Just loosen off your cuff, slide the Ventz into place, then fasten the cuff. It will only work with cuffs that are adjustable, otherwise, it might be a bit uncomfortable.
I didn’t find them at all uncomfortable and forgot about them after a while. They also didn’t interfere with hand movement on the controls.
The company’s website photos and packaging images show the Ventz being used on the back of the arms. I also used them on the other side to direct air on to my wrists and this actually seemed to work better. Maybe it’s because there are more veins on your wrists than the back of your forearms.
Different handlebars and hand guards may also interfere with the effectiveness of the Ventz, but I tried them on a couple of bikes and they worked ok.
Obviously, you can’t wear them with gauntlet gloves, but they are effective with short gloves which is what you would be wearing in summer, anyway.
The vent has a plastic grille to prevent small stones and insects going up your sleeve. The outside shell is durable, shatterproof plastic and the rest is a pliable rubber. I don’t think they would cause any problems in the event of a crash, but I didn’t crash test them to find out.
Anything that allows you to ride a little cooler means you ride calmer and therefore safer.