RockShox SID Ultimate Fork Review


Words & Photos by Nic Hall

The RockShox SID (Superlight Integrated Design) first came on the scene back in 1998, with 28mm stanchions and 100mm of air sprung travel. It was ultra-light, at 1,250 grams but didn’t offer much in the way of damping or rebound adjustment. Then again not much did back then. It was one of the first “real” forks that I rode and set my early expectations for what an air fork could do. Over the years we have seen the RockShox SID name on every kind of fork from dual crown affairs to a carbon fiber crown dream fork. We had not spent much time on any recent SID forks and were excited to put time on the latest version as it packs a lot more punch.

Early this Spring, we got word that SRAM had a full redesign coming for the SID. We received three bikes with SID forks in the last couple months and have been busy running the SID through the wringer on those bikes quite aggressively ever since.

RockShox SID Ultimate Fork Review

RockShox offers two new SID forks for slightly different applications: The SID SL is their 100mm pinner XC race fork offering with 32mm stanchions, weighing in at just 1,326 grams. The SID Ultimate is the 120mm model for the gram counter who still likes to yank up when they see the bonus hits off the side of the trail.

We’ve been on both forks but will be focusing this review on the burlier 35mm-chassised SID Ultimate. This 1,535gram fork’s crown is machined from a single piece of aluminum and it appears to have been taken down to the very limit. The 120mm of travel is controlled by the Charger Race Day damper, which is amazingly small and light, weighing in at about 90 grams. That’s nearly 100 grams lighter than the last SID damper! The downside, nothing’s free afterall, is that the new damper offers minimal adjustments. Riders get a lockout lever or TwistLoc remote to stiffen the fork up, and a low-speed rebound adjuster at the bottom of the fork leg.

A more affordable version of the SID, the Select, uses the Charger RL damper and weighs a bit more, at 1,670 grams.

RockShox SID Ultimate Fork Review

RockShox uses Maxima Racing Oil’s Plush Fluid in the light and small Race Day damper. Maxima claims their fluid offers greater consistency and feel compared to other suspension oil on the market, which is important since there’s not much of it. Overall compression tune is lightened a bit to offer a more compliant and softer feel from the fork since most XC bikes already have firmer spring rates and less travel. Something we noted right off the bat.

RockShox is only building the SID with a 44mm offset for 29-inch wheels secured with a bolt-on Maxle. Bottomless tokens can be added to the DebonAir spring which increases the progressiveness of the curve and resists bottom out. To top it all off, RockShox worked with SKF seals to develop their lowest friction wiper seal to date. For you gravity hounds, 220mm is the max rotor size and a 2.6in tire compatibility width hint to the departure from traditional XC thinking.

RockShox SID Ultimate Fork Review

As we said earlier, we’ve been lucky enough to have three different bikes show up with SID forks in the last several months. Each bike had color matched decals on the fork which is a nice OEM touch we did not have to go searching for later. While these were short travel bikes, we took them on all our normal test tracks around the PNW and were quite impressed with their capabilities.

The first impression we took away from the SID was how rigid it is both laterally and fore-aft. We did not expect a 1,500g XC fork to be able to hold a line the way the SID does. While it is no replacement for 140mm of travel, it isn’t a lack of stiffness that will hold you back. Gone are the days of noodley forks that twist and bend at the mention of rock gardens, jumps or heavy braking into catch ruts.

If you had to have one option for travel on a cross country trail bike, 120mm is not a bad place to start. Especially when that travel is controlled by the new Race Day Damper. With two tokens installed, we were putting the SID down all but the rockiest of gardens and gapping our favorite jumps without issue. While we were impressed with the damper and control, there is a limit to what 120mm can do. To put it simply, the fork is bad ass and will allow you to charge 100-120mm terrain more aggressively, and it’ll even let you charge harder than your old 120 or even 130mm fork could handle, but if you need more travel, there’s no replacement for squish. When we took our XC bikes on aggressive trail bike trails, we found the limit, as expected. That limit was surprisingly different than we expected based on our experiences on earlier XC forks.

We had no major issues with either of our forks during testing and found they rode very consistent once set up. We tried Rockshox’s TrailHead app, which recommends initial setup and tuning and it had us pretty happy right out of the box.

The Wolf’s Last Word

If you are looking for a dedicated cross country mountain bike fork, the Rockshox SID ultimate offers huge amounts of control and stiffness in a lightweight package. From blasting up singletrack to jumps and rocks on the way down, the SID achieves a new level for the lineage of the fork. Throw a few tokens in and see what 120mm can do.

Price: $899-$969;
Weight: 1,532g;

We Dig

Performance to weight ratio
Color options

We Don’t

Can get overwhelmed if taken outside of its intended use


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