The Troy Lee D3 is a full-face downhill mountain bike helmet constructed of a fiberglass composite shell over a protective polystyrene liner. This stylish lid is one of the most well designed, protective, and comfortable helmets on the market, and took the highest overall score in our test.
Luke Lydiard rides Mammoth Mountain's Velocity downhill trail in the Troy Lee D3.
Photo: Jeff Fox
The plushly padded D3 is one of the most comfortable helmets we tried. Our testers scored it as the second most comfortable helmet, just behind the Bell Transfer-9. Both helmets are well-cushioned with high quality interior padding to guard against pressure points between the head and the polystyrene foam. The Transfer-9 slightly outscored the D3 because it uses slightly denser cheek padding and our testers prefer the feel of the Transfer's velvety lining over the D3's meshy lining. We also found that the Transfer has a more neutral fit than the D3, meaning that it will fit both round and oval shaped heads.
Obviously fit is a component of comfort in a helmet. Our heads are not your head. We feel that this helmet has all the components for being a very comfortable helmet, however it did not fit all of our testers perfectly. We came to the conclusion that it has a rounder shape rather than an oval shape. Our oval-headed testers upsized the helmet in order to get an appropriate front to back fit, which resulted in a slightly baggy side-to-side fit. If you have a very round head, this is the helmet for you. If you are average to oval-headed then you may want to try this helmet on before you buy. See our Buying Advice article for more discussion on fitting a full-face helmet. The good news is that the D3 is available in five sizes, so getting a dialed fit is a lot more likely than in a helmet which is available in just three sizes.
The D3 is so comfortable it is quickly forgotten about and allows you to concentrate on technical lines.
Photo: Jeff Fox
The D3's visor scored the highest in our test and is nearly perfect in our opinion. It is both long and wide enough to shield the eyes from any angle of sun, mud, or rain. It also completes this helmet's very moto look, so don't even think of rolling Rogatkin style with out it.
The visor is attached with titanium screws, which Troy Lee claims saves weight. These screws are very nicely finished, as well as durable, though we doubt that the weight savings is very significant relative to the total weight of the helmet. In addition to the screws at either side, the visor is also secured by a plastic thumbscrew which passes through a slider beneath the center of the visor. We found that this method of securing the visor is easier to manipulate on the fly than visors attached and secured with just two screws. Troy Lee also includes a second color-matched visor so you will have a back-up if you damage the original in a minor crash. If you find yourself needing another visor, you can buy one on the Troy Lee website for $40 while you contemplate why you crash so much.
The D3's visor is locked in place by a plastic thumbscrew that passes through a slider beneath the center of the helmet.
Photo: Luke Lydiard
The D3 is the second heaviest helmet in our test at 42.56 ounces. Besides the price, we see this as its biggest detractor, and it was the only area that it scored lower than average. However, consider two things which influenced this score: first, our test helmet was an XL rather than Large or Medium; second, we consider the this to be one of the more protective helmets in our test. If the weight is really an issue for you, consider spending $75 more and getting the lighter Troy Le D3 Carbon, which lightens up by using carbon instead of fiberglass for the shell.
The average weight of the six full-shells we tested was 39.1 ounces. The lightest helmet in our test is the Bell Sanction which weighed in at just 34 ounces on our digital scale. The Sanction is in no way comparable to the D3 in terms of protection, and Bell recommends it only for groms and light-duty riding. If low weight is high on your priority list, check out either the Giro Cipher or the Fox Rampage which weigh a few ounces less than the D3 but still meet the ASTM-F1952 standard for downhill mountain bike helmets. (Which the Sanction does not.) Another option would be spending $75 more on the D3 Carbon, which shares all of the attributes of the composite version but shaves a few ounces with a carbon shell.
This helmet scored similarly to the majority of the others we tested in overall ventilation. This is actually impressive considering this substantial helmet fits more securely than most. Protective and secure is not usually synonymous with being well-ventilated, but the this helmet is able to stay cool with a remarkably well-designed ventilation system. For starters, it has by far the largest number of vents of the helmets we evaluated, with 20.
Troy Lee labels 14 of these vents as intake ports and the remaining 6 as exhaust ports. At the front of the helmet the airflow starts with intake vents that are molded into the vinyl gasket that lines the face opening. These intake vents are linked to deep air channels molded into the polystyrene. Between the head and the polystyrene foam is inner padding that has sections of mesh to allow for heat transfer from the head to the air flowing through the helmet. All of this adds up to perceptible airflow through the helmet, which isn't something we can say for many of the lids we tested.
The D3 has air intake vents molded into the gasket above the brow area. The vents lead to front to back air channels molded into the polystyrene liner.
Photo: Luke Lydiard
The D3 along with the Bell Transfer-9 took the highest protection score in our test. Yes, they are also the two heaviest helmets in our test, but we feel that a few extra ounces are worth it for added protection. We are talking about helmets here. Simply put, these two lids are what we would want to be wearing if we knew we were about to take a serious digger.
The D3 is certified by more standards than any other helmet we tested. It meets the CPSC 1203 and CE EN 1078, the minimum standards for bike helmets. It is also certified to the more stringent ASTM-F1952, which we feel is the certification downhill riders should look for in a helmet. In addition to these three, it also meets a variety of other standards including CE EN 1077 for skiing and snowboarding, which is something to consider if you are looking for one helmet for a variety of sports.
We felt the Troy Lee D3 and Leatt DBX combination provided for as much safety as we could get for our heads and necks. Luckily we didn't get to test this theory.
Photo: McKenzie Long
The inner polystyrene is laced with strips of very dense closed-cell foam that is supposed to help absorb small impacts. Large impacts are absorbed by the usual destruction of the polystyrene foam. Troy Lee Designs doesn't label the D3 as a multi-impact helmet, but we like the idea that minor impacts are absorbed by something other than destruction of the polystyrene. We understand that nobody is going to replace a $375 helmet after a minor impact for fear of comprised safety. As always, if you take a whomper on the head, consider that you got your money's worth and replace your helmet.
The cheek pads are backed with large areas of velcro that attach them to the inside of the helmet. This makes them easy to both remove and re-install. These pads have red fabric tabs which protrude from the bottom of each pad to instruct emergency rescuers how to quickly remove them from the helmet before removing the helmet from an injured person's head. This may allow a trained rescuer to remove the helmet with less movement of the head and neck, which could minimize secondary injuries to the spine. We see this as an added safety feature that we hope nobody has to use.
The D3's cheek pads attach to the helmet with large areas of velcro which make removing and reinstalling them easy. They are labeled with red tabs to instruct rescuers how to quickly remove the pads to better facilitate careful helmet removal which protects the neck from further injury.
Photo: Luke Lydiard
This deluxe helmet comes with several notable extras. As we mentioned before, it comes with an extra color-matched visor that we think is very useful since visors sometimes don't survive minor crashes that leave the rest of the helmet in tact. Ours also came with a zippered bag that is large enough to hold extra gear like goggles, gloves, or extra lenses.
All of the other helmets in our test came with a storage sack that we don't think many riders would even bother putting a helmet in on a regular basis. This bag is much more substantial and likely to be put to use rather than just tossed in the corner of your gear room.
Troy Lee includes a color matched visor and a sweet helmet bag with the D3.
Photo: Luke Lydiard
It is no surprise that the D3 shares the same high quality that we have come to expect from gear bearing the TLD logo. From the paint to the titanium buckle, it has a very quality feel and we had no failures in either material or workmanship with our test helmet. Along with the Bell Transfer-9, the D3 received the highest score in our day-to-day durability evaluation. Did we mention the "D" rings and helmet attachment screws are made from titanium so that they don't corrode? Everything about this helmet is quality down to the included storage bag.
This lid excels at downhill mountain biking, winning Rampage, winning Joyride, and really just winning.
Luke Lydiard rides one of Mammoth Mountain's many paver berms in the Troy Lee D3.
Photo: Jeff Fox
This is the most expensive helmet in our test by far. It is nearly twice as expensive as the next most expensive options, the Bell Transfer-9 and Giro Cipher, which cost $200 each. Retailing for $375, the D3's price tag is more on par with carbon-shelled helmets that typically cost over $400. The carbon version actually retails for just $75 more than the composite-shelled helmet we tested. We are guessing that most riders who have $375 to drop on a D3 could spare 20% more dinero for the carbon shell. If you're going to drop the cash, consider going all out and getting the slightly lighter carbon version.
The D3's vents are covered by thick metal mesh to protect from sticks and other pointy objects.
Photo: Luke Lydiard
This is our favorite fiberglass/composite downhill helmet. The sizing can be a little funky if you have an oval head so try it on before you buy. If you can swing the price we don't think you will be disappointed. You may be able to swoop a deal on this awesome helmet using our price finder tool.
Troy Lee D3 Carbon
- Few ounces lighter than this model
- A worthy upgrade if already spending $375 - If you want the best, get the best.