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AGV K4 EVO Diapason Helmet
  • AGV K4 EVO Diapason Helmet - White/Black/Red
  • AGV K4 EVO Diapason Helmet - White/Black/Red
  • AGV K4 EVO Diapason Helmet - White/Black/Red
  • AGV K4 EVO Diapason Helmet - White/Black/Blue
  • AGV K4 EVO Diapason Helmet - White/Black/Blue

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9047 8072

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Video Reviews (3)

AGV K4 EVO Diapason Helmet Videos

Shape: Intermediate Oval

Weight: 3.36 lbs

What's this?

AGV K4 EVO Diapason Helmet

The AGV K4 EVO is the most balanced and versatile helmet in the AGV range. Performs great on sportbikes or scooters, and everything in between. Improvements in weight and comfort, the K4 EVO represents the ideal solution for those who want an attractive, safe, comfortable helmet with an excellent price/quality ratio. The design of the AGV K4 EVO reflects that of the K4, the model it replaces in the range. A design distinguished by the front air vents, the chin strap, the lateral lines and the spoiler, creating an immediate family feeling with other products in the recent AGV range.


  • Shell:  Fiberglass ACF (Advanced Composite Fiber)
  • Number of shells:  2 shell sizes
  • Ventilation System:  Front air intakes and rear extractors
  • Internal padding:  Removable and washable (excluding neckroll)
  • Internal Padding:  New 3D construction for richer and more stylish padding
  • Fabrics:  Dry-Comfort fabric with sanitizing treatment and new skin-friendly fabric, reduces skin irritation
  • Face Shield:  Clear, anti-scratch and anti-fog polycarbonate Street 8 visor
  • Shield Mechanism:  XQRS (Extra Quick Release System) for shield replacement without tools in seconds
  • Safety Certification:  ECE22.05 Certified

AGV Helmet Sizing

Size  Head (cm)
2XS  51-52
XS  53-54
SM  55-56
MD  57-58
LG  59-60
XL  61-62
2XL  63-64
3XL 65-66

Sizing information is provided by the manufacturer and does not guarantee a perfect fit.

How To Measure

H Head Wrap a cloth measuring tape around your head just above your eyebrows and ears. Pull the tape comfortably snug, read the length, repeat for good measure and use the largest measurement.
Product Style RevZilla Item # Manufacturer Product # Availability
White/Black/Red / LG 918219 0031O2C0-013-L Out of Stock
White/Black/Red / MD 918218 0031O2C0-013-M Out of Stock
White/Black/Red / SM 918217 0031O2C0-013-S Only 1 Left: Ships within 24 hours
White/Black/Red / XL 918220 0031O2C0-013-XL Out of Stock
White/Black/Red / XS 918216 0031O2C0-013-XS Out of Stock
White/Black/Red / 2XL 918221 0031O2C0-013-XXL Out of Stock
White/Black/Blue / LG 918225 0031O2C0-014-L Out of Stock
White/Black/Blue / MD 918224 0031O2C0-014-M Out of Stock
White/Black/Blue / SM 918223 0031O2C0-014-S Out of Stock
White/Black/Blue / XL 918226 0031O2C0-014-XL Out of Stock
White/Black/Blue / XS 918222 0031O2C0-014-XS Out of Stock
White/Black/Blue / 2XL 918227 0031O2C0-014-XXL Out of Stock


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If your order arrives and it is not right, we will we'll fix it, NO NONSENSE, we promise.

Doesn't fit or just not happy with it? You can return any new, unused and unaltered item within 30 business days of delivery receipt of your item. We will issue a full refund to your original payment method.

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AGV K4 EVO Diapason Helmet 4.4 5 61 61
Great Value for a good helmet I just barely got into riding so my review is just my opinion for this helmet. I bought it on the closeout deal and it was an amazing deal. I love the look and it is comfortable just a little pressure on the forehead or just needs to be broken in a little. It seems like it has good airflow, my head hasn't really sweated too much in it. Some of the cons to this in my opinion though is it is not as long as I needed my chin kind of pokes out the bottom. Also I don't really have anything to base it off of but the noise level seems loud in the helmet. Not excessively so but enough that I wear ear plugs. April 26, 2016
Best attribute is light weight but other than that nothing special First off I ordered a medium and it fit pretty tight so it runs small. I don't know if it was the smaller size that was the problem but the the helmet area under the face shield inside is really close to your mouth, I don't even know if you could fit a bluetooth mic there, and it being so close to your mouth it fogs the face shield easier and is just very annoying. I found this helmet to be very loud at speeds over 40mph as well. But if your looking for a super lightweight sleek looking helmet its very nice, it doesn't even feel like your wearing a helmet. I would definitely order one size larger. February 8, 2016
can't go wrong with matte black This helmet is the sexiest helmet for the price point November 9, 2015
I would buy it again! You can't beat this helmet for the price. It is very light, and has great airflow. The liner gets a little out of whack sometimes, but other than that I have had no issues with it. October 19, 2015
Perfect for my head shape - more round than oval First off, the Red Arrow graphic looks fab! As Anthony says--it'll be phenomenal even after 5 years. Secondly, but more importantly, this helmet perfectly fits my more round than oval head. I got this after trying many other helmets that gave me really bad pressure points on the sides of my head. Anyone having concerns about fit should talk to the supreme all-knowing Gear Geeks; they saved me at least a week of hassle! Thirdly, it's a good quality lightweight helmet for the price. But, the liner and comfort is just OokAy; perhaps in accordance with its price. Overall I am just glad that I didn't have to order a helmet from the asian market (where I previously lived) for my more round than oval head shape. October 7, 2015
My Last AGV I really wanted to love this helmet: great visibility, good airflow, BT ready and it does look nice but construction was a letdown. I found the following: 1. The padded liner is very cheaply made. The pad at the forehead will not stay in place allowing the sharp ridge of EPS to contact my forehead. (see picture) 2. Airflow is not as good as the Horizon. 3. Not related to quality but this helmet is more round then the Horizon. Ultimately I had to swallow my investment because I will not wear a helmet with liner defects. Even though I love AGV for its visibility and weight, this is my second and last AGV. Both suffered from liner issues and that is where my head lives. August 3, 2015
Decent helmet for the price Been wearing one of these for almost a year now - it's a good helmet but IMO it's quite loud, even with all vents closed, and there's some quality/durability issues that could be addressed. The good: - fits well - I typically wear a large helmet, I bought a large, no complaints. - Vents move enough air to keep from fogging if you're going more than 30 mph, even in actual fog. I commute 25 miles in the Portland area, 20 or so of which are on the highway through the valleys west of town, where it gets VERY foggy sometimes. Never had a problem with the visor fogging, just water condensing on the outside - Visor is easy to swap out - pads and liner are easy to remove for cleaning The bad: - Noisy. I don't have much experience with other motorcycle helmets but I always wear ear plugs in this thing regardless of what speed I'm going to go, and I'm not on a loud bike at all - it's the wind that bothers me. - Visor mounting system is fairly low quality. The visor mounting/ratcheting system is essentially two pieces - one piece that it actually rotates on, and one piece that clips in to a small channel that has grooves in it for the ratcheting action. This smaller piece that does the ratcheting has gotten worn from flipping the visor up and down enough that it doesn't stay in its groove anymore unless I move the visor very deliberately - no more whipping it up and down willy nilly or that piece won't stay in its channel and the visor won't seal until I push that part back into its channel. Easy to do while riding but it is annoying. - The plastic doohickey on the back that forms the point and houses the rear vents is VERY EASY to break. The helmet fell off my foot pegs once and landed directly on that - it cracked in two places. The little tabs that hold it onto the helmet also have worn down a lot (for no apparent reason, I never remove it) and at some point I'm assuming the whole thing will fall off, leaving me with an awkward looking helmet. I'd say it's a quality helmet but the visor ratcheting system and the rear vent cover leave a bit to be desired. For the money, however, it'll last you if you take care of it, and the visor can easily be fixed by replacing it. Not so sure about the rear vent cover. May 7, 2015
Dude. Sweet Light weight, decent airflow, very low profile helmet. Very quiet when your face is level. Agv's site says this is a sport touring helmet and the aerodynamics agrees. When you tuck the rear spoiler/vents work well. Errs slightly round in shape, but fits me very well now that it is broken in. May 4, 2015
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