XC racing has traditionally been about efficiency, with skinny tyres and rockhard suspension. That’s quickly changing though, as courses around the world get technically harder: so step forward the RockShox SID SL, which has been redeveloped for unadulterated comfort.

The flagship whippet fork RockShox, SID SL now uses a bigger volume air spring for more comfort, a new chassis with less flex, and tyre clearance up to 2.4in: that’s chunky, for an XCO-winning squisher. 

The new SID SL also gets a blinging new red colour, and a reworked brace and lower leg design

Rubber up to 29×2.4in wide is nicely in keeping with the trend in modern XC racing that wider tyres can be faster. Although that doesn’t stop some riders running what can only be described as gravel tyres in some of the dusty tracks.

Inside the SID SL you’ll now find the DebonAir+ spring Guy Kesteven loved on the RockShox Pike Ultimate, one of the best mountain bike forks going. It’s got more space for air in the positive and negative, and we’ve found that really does make it more cosetting on impacts.

XC is no joke, the tracks are gnarly and RockShox has listened to riders when developing the new SID SL

RockShox has also added in more bushing overlap between the lowers and stanchions, which should make the whole package stiffer when you’re loading into corners or bouncing down steep terrain. Again that’s becoming more important than ever thanks to gnarlier XC tracks most of us wouldn’t dare ride on anything shorter than an enduro bike.

The new SID SL also gets the latest Charger Race Day 2 damper, which previously was an upgrade on the old fork.

Flight Attendant now has an Auto mode that’ll keep it in open mode

Finally, new Flight Attendant features include an Auto mode which can disable Pedal or Lock positions – although the firmware to disable the Pedal feature won’t be released until later this year.

The SID SL has always been about keeping weight down without compromising on performance for XC racers. It is called SID for a reason – it stands for Superlight Integrated Design. All that adds up to a fork with a claimed weight of 1,390g for the SID SL Ultimate 110mm, with prices starting at £739.

The rest of the details haven’t changed much though, there are still two travel options from 100-110mm, and the chassis is still 32mm. There are now five models to pick from though, SID SL Base, Select, Select+, Ultimate, and Flight Attendant.

Let’s check out the range details, including pricing and spec…

RockShox SID SL 2025

SID SL Ultimate Flight Attendant

The fork the pros are using this summer, the SID SL Flight Attendant uses the Charger Race Day 2 Flight Attendant damper, and DebonAir+ spring. Travel is from 100mm to 110mm, and it’s 29er only. 

Pricing: £1,339 ($1,499, €1,499, AU$2,320) 

SID SL Ultimate 3P and 2P

The Ultimate uses the same tech as the Ultimate Flight Attendant, the difference is you have to manually switch it between pedal, open or lock modes. There are two variants, 3P has all three damping modes while 2P is open or lock only. It’s adjustable via a handlebar switch or on the fork crown.

Pricing: £959 ($989, €1,079, AU$1,545)

SID SL SELECT+ 3P & 2P

The Select+ uses the same Charger Race Day 2 damper and DebonAir+ spring as the top models, but you can’t actually buy it, instead it’ll come stock on some bikes.

SID SL Select 

The Select uses a Charger damper but the same DebonAir+ spring as all the rest.

Pricing: £739 ($759, €819, AU$1,185)

SID SL 

Another OEM only fork, it uses the DebonAir+ spring, but something called a Rush RL damper… which I’ve never heard of before.

How good does the new RockShox Reba Gold look?!

The SID SL isn’t the only new fork from RockShox, the brand has also redone the Reba. It’s an XC fork too, uses an “air spring inspired by SID”, RockShox Isolator damper, and a 35mm chassis.

IT comes in more travel options though, from 100-130mm in 10mm increments, and you’ll only find the DebonAir spring on the left leg, rather than the posh new +. The Gold costs £485 ($549, €545, AU$860).