Choose Your Bike's Handling: Agile, Neutral, Stable

Chainstay length (rear-center) is one of the simplest geometry numbers with outsized influence. Move the rear axle 5mm closer to or farther from the bottom bracket and you change wheelbase, weight distribution over the front and rear wheels, and the bike’s rotational inertia. The result: changes to how the bike steers, how easy it is to manual, and how planted it feels at speed.

Shorter chainstays = quicker, more playful handling — easier to pivot and manual but potentially twitchier on high-speed straights. Longer chainstays = more stable tracking and a steadier platform for high-speed descents and heavy riders or loaded bikepacking rigs. Atherton’s +/-5mm options are designed to subtly tune character without upsetting suspension curves or kinematics.

The new online configurator extends Atherton’s built-to-order ethos into a visual, click-to-build experience. Riders select frame size, suspension spec, drivetrain, cockpit parts, colours and now handling: Agile, Neutral or Stable.

Importantly, Atherton limits the chainstay options to sizes where the frame design allows the change without altering suspension behaviour. The adjustment is ~5mm shorter or longer from the standard chainstay. This keeps the brand’s intended kinematics intact while letting you pick the handling flavor that suits your riding and terrain.

Agile (~5mm shorter): best for riders who prioritize quick direction changes, tech trail agility, and easy manuals. If you ride tight singletrack, frequent rock gardens, or want a lively park/flow bike feel, Agile will make the bike feel snappier. Note: shorter stays can make the front end feel slightly lighter under extreme climb-outs.

Neutral (standard): Atherton’s baseline tuning — balanced for predictable handling across mixed terrain. It’s a good default for riders who do everything from local trail laps to longer singletrack days and aren’t looking for an extreme handling bias.

Stable (~5mm longer): leans toward high-speed composure and straight-line tracking. Useful for aggressive descenders, heavier riders, and bikepackers who carry weight over the rear triangle. The trade-offs are a touch less flickability and marginally slower-feeling acceleration out of tight corners.

How do you choose? Start by matching handling to terrain and style. Pick Agile if you ride tight, technical singletrack, jump or pump tracks, or if you prefer a nimble front-end. Choose Stable for fast, flowy trails, enduro stages, steep chutes, or when you often descend with big loads. Neutral is sensible if you want a do-it-all setup.

Also consider rider size and bike size. Smaller riders often benefit from shorter stays to keep the bike feeling lively; larger riders or those carrying kit may prefer longer stays for confidence at speed. If you’re between frame sizes, use Atherton’s sizing first and then tune handling — the configurator is designed to change character without compromising the size-specific fit you choose.

Customization of handling isn't new — manufacturers have offered flip chips, adjustable shock mounts, and angle sets for years — but the industry has typically treated these as suspension or geometry tweaks rather than a customer-facing handling option at order time.

Flip chips (found on many modern platforms) change head angle, bottom bracket height or leverage to shift geometry on the fly. Adjustable headsets or angle sets like the Cane Creek AngleSet let you alter headtube angle for steep vs slack setups. Some brands also use size-specific chainstays to tune handling across frame sizes. What’s interesting about Atherton’s configurator is that it packages a targeted chainstay choice as a spec-level decision at purchase: you’re choosing ride character (Agile/Neutral/Stable) in the same way you pick drivetrain or suspension.

Picking Agile, Neutral or Stable is only part of dialing the ride. Match cockpit, suspension and tyre choices to the handling you want. For an Agile setup consider a shorter stem (30–40mm on 29er trail bikes), a wider but low-rise bar to increase steering leverage, and supple tyres (e.g., Maxxis 2.4 EXO+) tuned to slightly lower pressures for flickability. For Stable setups use a slightly longer stem (40–50mm), a stiffer cockpit (Race Face Next R or One), and grippier tyres at higher pressure for predictable tracking.

Suspension: pair Atherton’s geometry choice with a progressive compression tune for descents (Fox Float X2 or RockShox Super Deluxe with medium-high compression for heavier riders) and a platform-appropriate spring curve. For drive train and cockpit, SRAM GX Eagle or Shimano XT group sets offer durable, serviceable options while Thomson or Race Face posts and stems keep the front end solid. If you want to adjust head angle later, consider adding a Cane Creek AngleSet to your build to gain another layer of fine-tuning.

How big a difference will a 5mm chainstay change really make?

A 5mm chainstay change is subtle but perceptible to many riders. Expect a smaller wheelbase, quicker steering and easier manuals with shorter stays, and improved straight-line stability, rear traction and composure with longer stays. Atherton designed the option so suspension kinematics remain unchanged — you get handling nuance without a reengineered linkage.

Can I change the chainstay length after I’ve ordered my Atherton?

Because Atherton’s +/-5mm options are built into the frame’s manufacturing spec, changing chainstay length after the fact would require a different frame or different dropouts if available. It’s intended to be selected at order time via the configurator. Check with Atherton customer service for retrofit options — some frames use modular dropouts, but that’s model-dependent.

Is one option better for 29" wheels vs mixed wheel setups?

General guidance: 29ers already track straighter and feel more stable, so riders often favor shorter chainstays (Agile) to maintain agility. If you run a mixed wheel setup or smaller wheels, you may lean toward Neutral or Stable to recover some high-speed composure. Always balance chainstay choice with head angle and reach for overall geometry harmony.

Do these changes affect climbing performance?

Yes, but modestly. Shorter stays can make the bike feel more lively on climbs and easier to lift the front wheel over obstacles; longer stays can offer more planted rear traction under power. Suspension platform and rider positioning have a larger impact on climbing than a 5mm chainstay change, so treat the option as a tweak rather than a climbing overhaul.

How does Atherton ensure suspension behavior isn’t compromised?

Atherton’s statement emphasizes that the +/-5mm change is implemented only where it won’t compromise suspension performance. That means the brand has validated the adjustment through design tolerances and testing so the leverage curve and kinematics remain within intended ranges.

Should I pair a Stable build with different tyre pressures or forks?

Stable bikes benefit from slightly higher tyre pressures to reinforce straight-line tracking, and forks with firm mid-stroke support for high-speed hits. For example, a Fox 36 or RockShox Pike with a volume spacer and medium compression tune works well. Tyre pressures are rider-specific, but aim for a balance that prevents squirm while keeping grip for braking and cornering.

Is this the next step after offering more frame sizes?

Possibly. The industry has moved from a few sizes to very granular sizing to match rider fit. Atherton’s approach treats handling as another customer choice at purchase, suggesting ride-character customization may be the next frontier. Expect other brands to offer more customer-facing handling choices as riders demand personalization beyond components.