With the Flight Attendant system, this fork is more efficient and advanced than ever before. The new Charger Race Day 2 Flight Attendant electronic damper features a three-position (3P) Compression adjuster— Open, Pedal, and Lock positions, all at your fingertips. SID Ultimate Flight Attendant adapts to everything from full-gas cross-country to sporty backcountry loops thanks to a new, higher-volume DebonAir+ spring that’s supple at the top of its travel with tons of tunability.

Key Features:

Remove suspension complexity to elevate your ride experience. Flight Attendant has an all new algorithm that uses a suite sensors to read rider and terrain inputs to anticipate the perfect suspension position. No other suspension system has this level of personalization to match your riding preferences, your terrain, your style, and your physical capabilities. Elevate your ride.
Adaptive Ride Dynamics enables the Flight Attendant system to learn from the rider to make smarter, more personalized decisions for greater efficiency and even more speed.
Charger Race Day 2 Flight Attendant electronic damper features an automatic three position Compression adjustment (Open/Pedal/ Lock positions) with independent adjustable Rebound.
AXS-enabled and cable free, Flight Attendant is an integrated part of the SRAM AXS ecosystem, meticulously crafted to disappear.
35mm chassis is the perfect blend of light weight and rigidity for the modern XC bike. Plus, we made it lighter…again.
Longer-travel 120mm option, in case you’re feeling extra.
Machined crown to shave weight without compromising strength and stiffness.
Covetable “Blue Crush” signature colorway and Ultimate High Gloss Black, featuring the new lustrous Pearl White Flight Attendant graphics package.
Maxima Plush Dynamic Suspension Lube reduces friction, lasts longer, and enhances suspension performance ride after ride.
DebonAir+ provides more small-bump sensitivity and tunable mid-stroke support.
Shared battery with all SRAM AXS-enabled components.
Flight Attendant System is waterproof to IPX7 rating.
Flight Attendant system only gets better with the more AXS components you pair into the system.
Short fender compatibility. (RockShox fender included)

Occasionally, without notice, manufacturers change product design and/or specifications.

Suspension Forks Sizing

A new suspension fork is one of the most noticeable and worthy upgrades you can make to your mountain bike. A higher quality fork will be able to deal with more difficult terrain, remaining composed on the trail and keeping your wheel in contact with the ground. This gives more grip, and therefore a more confidence inspiring ride.

Not all forks are made equal, there are some very important size and compatibility aspects to look at first.

Compatibility

Wheel size

There are a few different wheel sizes for mountain bikes. 26”, 27.5” (650b) and 29” are the most common.

There is also plus (+) and fat versions available. If you are not sure it should be written on the side of the tyre.

Whatever wheel size you have, the fork must be designed to suit.

Fork steerer

The fork steerer is attached to the fork crown, this comes up through the frame and headset to be clamped at the top by the stem.

Most modern bikes will have a tapered steerer, this is 1.5” inch wide at the fork and 1 1/8th inch at the stem. Some DH bikes and older mountain bikes will suit a straight 1 1/8th inch steerer.

It is easiest and best if the replacement fork has the same diameter steerer to fit into your frame and headset.

If you are unsure on the size, drop the forks out from the frame and you should be able to see straight away if the steerer is tapered or straight.

Axle size

If you are planning on using the same front wheel with your new fork, the fork’s dropouts must suit your wheel.

The width of the front hub has traditionally been 100mm, with either a 9 or 15mm axle. With a 9mm Quick Release (QR), a fork could be described as 9mm x100mm or QR to fit. A larger 15mm bolt through axle is more common on higher end bikes, a fork could be described as 15 x 100 to suit. This 15mm axle can be a quick release style and can be referred to as 15QR

Over the last few years, a wider 110mm spacing known as “Boost” has become the new standard, this is not available for 9mm QR axles and would be shown as 15mm x 110 or 15mm Boost.

20mm axles have been common on DH bikes for some time. Although DH wheels will be 110mm wide, they are not always “Boost”. There is a new DH Boost for front wheels and forks, this means the hub is still 110mm wide, but the disc rotor/mount sits 5mm out.

For more on MTB wheels see our full guide here

Travel

The amount of distance the fork can move vertically is referred to as travel (shown in mm). The frame manufacturer will have designed the bike around a certain amount of travel. The general rule is to stay with this. Increasing or decreasing the fork travel can result in the geometry being severely compromised, making the bike handle worse than intended and putting more stress on the headtube structure.

*Changing fork travel can void frame warranty from the manufacturer, please check with the manufacturer before any travel increase/decrease.

As fork travel increases so can flex, to combat this a triple clamp design is used for forks with over 180mm of travel. The hub plus the two crowns creates a triple clamp. The forks are for DH use.

A triple clamp DH fork, travel is measured from the lower crown to the top of the fork lower legs

Offset/Rake

The distance the axle is offset from the steering axis. This directly affects the “Trail”. Trail is the distance between the contact point of the tyre and where the steering axis hits the floor. The shorter the offset the longer the trail and vice versa. Wheelsize also affects trail. Larger wheels have a longer trail. With the popularity of 29er MTB’s, there is often an offset choice to be made.

The most common offset for a 29er fork is 51mm, however, fork manufacturers offer shorter offsets to increase trail.

Fitting

Once the correct fork has been chosen there are a few things you should know before fitting.

Crown race – Slid down over the steerer is the crown race, these are usually particular to the headset on your bike. They create a seat for the lower bearings of the headset to sit on, this should be removed from your forks and slid into place on the new fork steerer before installing the new forks.

Star Nut – Inside the steerer tube there is a star nut. This has a wedge design allowing it to be slid down into place but not slid back up. There is an internal thread that takes the top cap bolt allowing the forks to be held in place and allowing adjustment of the pressure on the bearings.

Steerer length – A new fork will have a long uncut steerer, this will more than likely need to be cut to match the length of your original forks, however, it can be cut longer or shorter if you wanted to have more adjustment for stem height.

Setting Sag

See our full guide to setting sag here

Rear shock buyers guide >

RockShox SID Ultimate Flight Attendant Race Day 3P Crown 29" Boost 120mm Electric Red DebonAir Forks