Restore the factory Jet Black rear profile of your Thunderbird X with the genuine Royal Enfield 855036 – Rear Mudguard Assembly (BS4). This is the complete rear fender used on Thunderbird X 350/500 (BS4/ABS). Being OEM, the pressing, hole pattern, stay/bracket mounting points, tail-lamp/indicator bosses and wiring pass-through match stock exactly—so it bolts up cleanly to OE stays, accepts the original tail-lamp/indicator assemblies, and aligns perfectly with the seat and side-panels.

If your mudguard is cracked, bent after a tip-over, or corroded, avoid patchwork and color-mismatch: fit this factory-painted Jet Black unit for a precise color/finish match on TB X models. Pair with new mounting bolts, rubber washers, and grommets if your old hardware is tired; that prevents rattles and paint chafing. We verified identity and application across multiple trusted sources listing “REAR MUDGUARD ASSY TB X BLACK BS IV – 855036” for the Thunderbird X family. Only confirmed TB X BS4 models are listed below to reduce returns. 

Key Features

• Genuine OEM Royal Enfield Rear Mudguard Assembly – 855036 (TB X, Jet Black, BS4). 

• Correct OE pressing & hole spacing for tail-lamp/indicator mounts.

• Factory Jet Black paint/texture matches Thunderbird X panels. 

• Direct bolt-on to OE rear stays—no drilling or shimming.

• Restores alignment with seat/side-panels; eliminates vibration points.

• Ships in OE-labelled packaging with GST invoice (authenticity guaranteed).

Compatibility Table 

Exclusions: Thunderbird (non-X), Classic/Bullet/Electra UCE, J-Series (Classic Reborn/Bullet 350 J/Meteor), Himalayan/Scram, and 650 Twins. Order only for Thunderbird X BS4. If unsure, share your VIN for a fiche check. 

Variants / Related

• Other TB X rear mudguard colors (model/year-specific; confirm by VIN).

• Related fasteners: rear-stay bolts, rubber washers/grommets, tail-lamp & indicator assemblies (sold separately).

FAQs

Q1. Is 855036 painted Jet Black from factory?
Yes—listed as “TB X Black (BS IV)” for Thunderbird X. Finish matches OE panels. 

Q2. Will this fit a standard Thunderbird 350/500 (non-X)?
Not confirmed. The X uses different color/trim; order by VIN if your bike isn’t TB X BS4.

Q3. What comes in the box?
The mudguard shell with OE mounts. Tail-lamp, indicators, wiring, stays, bolts are separate.

Q4. Any install tips?
Support the rear subframe, route wiring carefully through the pass-through, use new rubber washers to prevent paint damage, and torque to spec.