Posted on November 09 2017
The 2018 line of Fox rear shocks now mostly come standard with the EVOL air can. The EVOL air can is basically an air can that has a larger body width at the negative air section of the shock's air volume, allowing for a greater volume of negative air.
Negative air is what gives us the sensitivity, and traction that our suspension systems are designed to give. Thus, the greater the volume of negative air, the more sensitivity and suppleness felt from the rear end.
So in basic terms, the EVOL air can gives us a larger volume of negative air.
Prior to 2018, the EVOL air can had an additional sleeve which made up the negative air chamber's additional size (see here) , but for 2018 - The air can has been modified along with a revised bearing assembly (seal head). This has allowed for a re-position of the main damper side air seal resulting in a cleaner looking, larger volume negative air chamber that changes in size according to the shock's length/size, keeping the air spring rate consistent.
Another big change for the EVOL sleeve in 2018, is that it is compatible down to smaller sizes where it previously wasn't offered. 165 x 38 (6.5 x 1.5) and 184 x 45 (7.25 x 1.75) and many other metric sizes now have the ability to use the EVOL air can.
On the downside, the 2018 EVOL cannot be simply purchased and screwed on like the previous model when upgrading pre 2018 model shocks. It does require partnering with the appropriate 2018 bearing assembly (damper seal head), which means it needs to come in for a rebuild at the same time. But, let the upgrade encourage you to stick to those service intervals, and you'll get the air can at a discounted rate when purchased/upgraded at the time of a service. Contact us for more info.
If you have a 2018 shock without the EVOL as standard, it is quiet likely that no new internal parts are needed if you want to upgrade the air can to EVOL - 2018 shock's only.
