The new Troy Lee Designs full face helmets have arrived for 2024 and as usual, they do not disappoint.

If you've been using a TLD lid for a while, you'll know that the D4 Helmet is their blue ribbon offering.

Used by everyone from World Champion BMX racers, to the wildest Freeride MTBers (like our mate Remy Morton), the Troy Lee D4 offers up the highest level of protection and features of just about any full face helmet on the market.

Amongst the regular Carbon ($1099.99 AUD) and Composite ($789.99 AUD) D4 full face line up, Troy Lee have added a new D4 style for 2024 - a version called the Troy Lee Designs D4 Polyacrylite which cuts the price almost in half ($589.99 AUD).

With the range making its way into Backbone, we thought we'd see what the benefits - and potential setbacks - are of their latest full face helmet release, comparing all three options, to see if the extra spend is worth it..

Troy Lee D4 helmets 2024 review comparison

The Troy Lee Designs D4 helmet 2024 looks good

The 2024 Troy Lee D4 helmets all feature the same shell design, making the three different price tiers almost impossible to tell apart.

The Troy Lee D4 Carbon helmet does have a carbon look to the shell, which gives it a more lustrous appearance through the gloss paint.

For 2024, most of the TLD D4s have a retro/throwback vibe to the early 2000s designs - retro is rad and these helmets have a timeless feel that would go well with any kit.

As well as some fancy 'Block' design colour options, the Polyacrylite version also comes in the three, more standard, 'Stealth' and 'Shadow' colours - Stealth Black, Shadow Blue and Shadow Olive.

Troy Lee Designs D4 Polyacrylite helmet colours
The three standard colours in the D4 Polyacrylite helmet.

TLD D4 Helmet features

Features at a glance:

  • Attention to detail
  • Wide field of vision
  • Custom sizing with multiple pads for each helmet
  • Sleek/less bulky

Attention To Detail

What makes the D4 helmet so impressive is the attention to detail.

Regardless of what material you choose, TLD has spared no expense with ensuring the fit and protection of the D4 is second to none.

Utilizing Mips-C2 as a safety feature across all three options (Carbon, Composite, Polyacrylite) means there is no compromise regardless of budget.

Mips allows for your helmet to do a better job protecting you against concussion, by reducing the rotational movement during a crash.

To do that, the Mips technology sits between you and the helmet shell, allowing the shell to move slightly, while still being snug on your head. It can be a different feel at first, but easy to get used to and actually provides a more comfortable riding experience, as the helmet is less rigid feeling while riding.. Think of it like a shock absorber.

I feel like you'd know this already, but the TLD D4 helmet in all versions complies with AUS/NZ safety standards.

Add to that, is the easily removable cheek pads, which can be swapped for different sizes (more on that later).

The internal soft padding is anti-microbial across all the D4s, which is nice, considering helmets can get pretty sweaty.

The sweat/heat is also dealt with by using a whopping 28 ventilation points, including large cheek vents.

All D4 helmets come with a plush helmet bag and extra visor screws too, which is a cool touch.

Troy Lee Designs D4 helmet Shadow Olive
tld d4 helmet bag
The Troy Lee Designs D4 Full Face helmets come with a helmet bag for storage.

Wide Field of Vision

Compared to other helmets I've worn in the past, the D4 gives a wider field of view - I didn't notice any loss of vision in my peripherals. While my last stint in BMX racing was in 2018 (4th in Masters at the ACT State Titles if you must know, haha), I can fully appreciate the ability to see riders out of the corner of your eye, which the D4 full face allows with ease compared to my old Bell helmet.

Troy Lee D4 Helmet Sizing

The TLD D4 helmets come in three different shell sizes; XS/S, M/L and XL/2XL.

Within those three shell sizes, each helmet comes with a variety of soft padding to go between the two sizes.

  • XS/S size: 54 - 57cm
  • M/L size: 57 - 59cm
  • XL/2XL size: 60 - 63cm

In the photos I am wearing the D4 helmet in the Medium/Large size. My head measures at 58cm and I replaced just the cheek pads to the large which made the helmet fit perfectly.

This is cool, because you can mix and match the different soft padding to get that custom, perfect fit.

The Troy Lee D4 Helmet looks sleek

I have always been a fan of the Troy lee full face shape, simply because it is less bulky and looks less robotic, compared to other helmets.

With more expensive helmets from other brands (like the Bell Full-9), more features seems to equate to more overall size.

Not the case with the D4.

Troy Lee D4 Polyacrylite helmet Ruckus vest

D4 Polyacrylite vs. Carbon helmet - Pros and Cons

TLD D4 Polyacrylite Helmet Pros:

  • $500 (AUD) cheaper than the TLD D4 Carbon helmet
  • Same features and tech
  • Same shape as Carbon and Composite models

TLD D4 Polyacrylite Helmet Cons:

  • 230 grams heavier than carbon version
  • 120 grams heavier than composite version
  • Does not feature 'Iconic +' Self-cleaning Anti-microbial soft padding (used in Carbon and Composite models)
tld d4 helmet weight
The weight difference from (L - R) Carbon, Composite and Polyacrylite D4 Helmets. All M/L size.. on our old scales is was 755 grams for carbon, 860 grams for composite and 980 grams for Polyacrylite.


The Troy Lee Designs D4 helmet is an absolute ripper of a full face helmet.

If money wasn't a concern, the D4 Carbon helmet sits atop of the throne, for the fact that it is 200+ grams lighter.

This might be a real benefit to smaller riders.

The TLD D4 Composite full face helmet cuts the price down quite considerably, weighing right in between the Carbon and Polyacrylite versions.

However, it can't be overstated, that you are getting the same level of comfort and protection with the new Polyacrylite D4 - for almost half the price.

Cheaper doesn't equate to less safe in this instance and I'm really impressed that Troy Lee Designs stepped up with the Polyacrylite D4 helmet option that doesn't compromise, but is much more friendly for those on a budget.

- Tyson Jones-Peni
Backbone BMX

March 23, 2024 — Tyson Jones-Peni