RockShox Lower Leg - BoXXer Ult GLB

$415.00

In Stock

OEM RockShox replacement lower leg for BoXXer Ult GLB forks (2019+). Gloss-black, 29/20x110 Boost fit with foil decals — factory fit and finish for downhill and enduro rigs.

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Product Details

Overview & Technology

Direct OEM replacement for the RockShox BoXXer Ult GLB (2019+ C1/C2) fork lowers. These lowers are finished in gloss black and are engineered to match the stiffness, geometry, and serviceability of the factory component. The part ships with foil decals for an authentic factory look and SRAM Model ID FS-SPP-A0 for exact identification. The lowers are precision cast and machined for consistent tolerances, optimized internal oil flow and mounting points, and a durable scratch-resistant finish. That construction keeps unsprung weight low while delivering the rigidity needed for high-speed hits, drops, and aggressive trail laps — critically important for downhill and gravity riding where reliability and predictable steering matter.

Key Features & Construction

Purpose-built materials: These lower legs use a high-strength magnesium/aluminum alloy casting designed for the BoXXer's heavy-duty duty cycle — you get a very favorable stiffness-to-weight ratio and better impact resistance than generic replacements. Critical bore and seal surfaces are machined after casting for factory-level tolerances. Practical benefits: improved axle-to-crown stiffness, accurate brake caliper mounting, and sealed cartridge interfaces that simplify service. The lowers accept a 20x110 Boost thru-axle and are sized for 29" wheel setups (29/20x110 Boost). Foil decals are included so you can restore your fork's OEM appearance after service or crash replacement.

Fit, Compatibility & What’s Included

This lower leg is compatible with RockShox BoXXer Ult GLB forks from model year 2019 onward with C1 and C2 damper variants. It is designed for 29" wheel setups and a 20x110 Boost axle spacing. SRAM Model ID: FS-SPP-A0 and Manufacturer Part #: 11.4018.091.009 ensure you can match the exact factory replacement. Included in the box: one lower leg (gloss black) and factory foil decals. It does not include the crown, steerer, axle, damper cartridge, seals, or hardware — those should be re-used from the original fork or ordered separately. Check serial and model markings on your fork before ordering to confirm compatibility.

Who This Part Is For

Designed for enduro and downhill riders running RockShox BoXXer Ult GLB forks who need an OEM-quality lower after crash damage, wear, or cosmetic replacement. If you want factory fit, geometry, and serviceability — including accurate brake caliper and axle alignment — this is the direct replacement part. Mechanically-minded riders and shops who perform fork rebuilds will appreciate the precision machining and correct mounting bosses that minimize fitment headaches and keep service times low. It's also a great piece for riders restoring a fork to stock appearance with the included foil decals.

Key Features

✓ OEM RockShox lower leg for BoXXer Ult GLB (2019+ C1/C2)
✓ Gloss black factory finish with included foil decals for authentic look
✓ Designed for 29" wheel setups and 20x110 Boost thru-axle standard
✓ Precision cast and machined alloy construction for stiffness and low weight
✓ SRAM Model ID FS-SPP-A0 and part # 11.4018.091.009 ensure exact fit
✓ Direct brake caliper and axle mounting bosses for hassle-free installation
✓ Ships light and compact — easy to store or carry as a service spare

Product Identifiers

Vendor Item #	11.4018.091.009
UPC	710845835391

Frequently Asked Questions

Will this lower leg fit my BoXXer from 2018?

This lower leg is specified for BoXXer Ult GLB forks from 2019 and newer (C1/C2). If your 2018 fork uses a different generation or non-GLB spec, physical mounting points and axle standards may differ. Check your fork's model year and SRAM model ID on the lowers to confirm compatibility before ordering.

Does the package include seals, axle, or damper internals?

No — the listing includes the lower leg and foil decals only. Seals, axle, damper cartridges, crown, and steerer are not included and must be reused from your original fork or purchased separately. This is a direct lower leg replacement for service or crash repair.

Can I install these lowers myself?

Experienced home mechanics with the right tools can swap lower legs, but the job requires fork disassembly, correct torque settings, and fresh lubricants and seals. If you're not comfortable with damper removal or reassembly, we recommend professional installation at a trusted suspension shop to ensure safety and warranty compliance.

Are these lowers the same material as factory BoXXer Ult lowers?

Yes — these are OEM-spec RockShox lowers produced with cast and machined alloy construction to match factory stiffness and durability. The finish and mounting geometry are made to factory tolerances to ensure correct performance and serviceability.

How do I verify the correct part number on my fork?

Inspect the stamped or printed identifiers on your existing lowers; the RockShox part number and SRAM model ID should be visible. Match Manufacturer Part #: 11.4018.091.009 and SRAM Model ID: FS-SPP-A0 to be certain. If in doubt, send a photo of your current lowers to our support team for confirmation.

Buying Guide

When buying replacement fork lowers, prioritize exact OEM fit and matching part numbers — mismatched lowers can change axle-to-crown length, brake alignment, and wheel positioning. Check model year, SRAM/RockShox IDs, and axle/wheel size before purchase. Buying OEM lowers ensures correct mounting bosses, seal bore dimensions, and cosmetic finish. Also consider whether you need additional service parts: swapping lowers generally requires new seals, foam rings, and sometimes a service kit for the damper and air spring. If your lowers were damaged in a crash, inspect the crown, steerer, and damper for hidden damage and replace components as needed to maintain safety and suspension performance.

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