Giro Source MTB Helmet Review – Everything you Need to Know

Giro has released an excellent, cost consious helmet named the ‘Source’ in 2021. It is an affordable top-tier helmet with all the features you expect from advanced modern helmets. In this review on the Giro Source, we will look at how it performs and what it brings to the Giro helmet range.

Giro Source MIPS

Designed to have all the features you need, with great ventilation and comfort, without bumping the price up with unnecessary features. Perfect for the all-mountain rider not wanting to make any sacrifices!

Check Latest Price On Amazon
We earn a commission if you click this link and make a purchase at no additional cost to you.
Rotational Impact Protection SystemMIPS
Intended UseAll-mountain
Adjustable VisorYes
Fitting SystemRoc Loc 5


It looks somewhat like the older Giro Chronicle and Montaro combined- with the best features of both! It has the extended rear coverage of the Chronicle and the two-color outer shell that wraps right around the base of the helmet, similar to the Montaro. The fully wrapped shell helps prevent wear and tear of the base of the helmet, extending the life of the lid.

The rear of the helmet extends low, and is fully wrapped to prevent damage.

Cost and Comparison

What is unbelievable about this helmet is that it is very reasonably priced. Found in the price range between Giro’s top two selling helmets, the Chronicle and the Montaro. This puts the Source in contention for the best value helmet on the market!

Helmets in the same price range as the Giro Source include the Fox Speedframe MIPS or the Bell 4Forty MIPS. All three helmets have MIPS rotational protection, have adjustable visors and fit retention systems.

Both the Fox Speedframe and the Bell 4Forty are lighter and slightly better ventilated. However, neither cover as much of the rear of the head as Source, and around the temples. Hence the Source has a bit better protection if you hit the ground.

Additionally, neither of these helmets compare in terms of comfort! The Giro Source is still one of the most comfortable helmets I have riden with. The Troy Lee Designs A3 helmet would be the only helmet in competition for the more comfortable helmet- which you pay a pretty penny more for!

Fit Review

The design of the helmet includes the Roc Loc 5 fitting system, which is a 360-degree retention system to ensure that the helmet stays securely on your head. It won’t move around or create pressure points on your head as it tightens all areas at the same time.

We found that the size was highly adjustable. With a size medium, we were able to get it to snugly fit riders who were normally a size small and other riders who were usually a size large.

Retention system of the Giro Source

The fitting system also allows you to adjust the ’tilt’ of the helmet (up and down your forehead effectively), so how the helmet sits on your head is entirely up to you!

Safety Review

Firstly, it has a MIPS liner (Multi-directional Impact Protection System), which reduces the rotational energy transferred to the rider in an angled crash. Slip plane technology (such as MIPS) is considered essential in today’s market, and personally, I would never ride without it!

The MIPS liner is integrated with the ventilation system, so nothing blocks the vents. If you move the helmet around on your head, you can feel the MIPS system in action- which is certainly reassuring!

And secondly, the extended rear coverage of the helmet means your head will be much more protected if you come off.

The shell is constructed of EPS (expanded polystrene) with a polycarbonate outer shell. These two aspects work in conjunction to reduce the impact felt by the rider’s head. The EPS foam acts as a crumple zone (similar to a car), increasing the duration of the crash in order to reduce the force of the impact. The outer shell is a hard plastic which allows the helmet to slide in a crash, as opposed to coming to an immediate holt. It also protects the EPS liner so the helmet lasts a long time.

For these reasons, the Source exceeds the current safety standards!

Giro Source Rear View
Giro Source on a backpacking adventure. It was super comfortable for 4 days straight and provided good ventilation despite our often slow-moving pace.

Ventilation Review

The ventilation of the Source is somewhat mid-range. While it is better than the Chronicle, the 16 vents don’t quite compare with the breezy Montaro. However, it does have internal channeling, which helps flow the air over the rider’s head to keep them cool.

Visor Review

The visor is adjustable, as you would expect for a top-tier helmet. The visor lifts up enough to store goggles beneath, too, which is very handy.

The side profile of the giro source with the visor up

Comfort Review

As with pretty much all the Giro Helmets, the Source is very very comfortable. The padding is soft to the touch, and quite thick.

The anti-microbial padding prevents the build-up of odors, so you won’t be riding around with a smelly helmet! Additionally, the padding is removable and washable if need be!

See our post on how to clean a helmet here.

Final Remarks on the Giro Source

The Giro Source is not anything super fancy like the pricey new Giro Manifest, but it is an exceptional helmet for an all-mountain rider. The extended rear coverage and MIPS liner give it good safety ratings while still being comfortable and well ventilated.

I can highly recommend as a good buy for anyone wanting an updated helmet for an excellent price!

Giro Source helmet in action

Similar Products

While the Source is a great helmet, it is good to compare with similar helmets.

We would recommend having a look at the Giro Merit review– a pretty similar helmet, but a little lighter and breathable.

Alterntively, check out out best helmets with MIPS or best low profile MTB Helmets.