Socket Head Bolt / Allen Bolt for Royal Enfield (Order by Part No.) – 587605/B (Critical: verify size before buying)

The 587605/B is a genuine Royal Enfield fastener used across multiple assemblies in different models/years (examples seen in wheel/brake-related parts lists and dealer catalogues). The challenge: public sources conflict on the exact size/spec for this same part number—some list it as Socket Head Bolt M8×1.25×20, while others list it as Hex/Socket Button Head Screw M6×1×14.

So this listing is optimized for accurate ordering by part number + physical match. If your bike already has this bolt/screw installed, replace it with the same part number and confirm the thread diameter, pitch, and length before checkout. Also searched as Allen bolt, imbus bolt, socket head cap bolt, disc bolt, rear disc bolt, and hex socket button head screw.

Before you buy: match your old bolt by (1) part number 587605/B, (2) thread size (M6 vs M8), (3) pitch (if M8: 1.25), (4) length under head (14mm vs 20mm), or share a clear photo + measurements with us for confirmation.

Key Features 

• Genuine Royal Enfield part number: 587605/B

• Common naming: socket head / Allen / imbus fastener

• Critical spec conflict in public catalogues (M8×1.25×20 vs M6×1×14) → buyer must verify

• Ideal for replacements where the original is worn, rusted, rounded, or missing

• Helps prevent loosening when the correct grade + tightening method is used (application-dependent)

• Works best when installed with the correct Allen key/hex bit and proper torque procedure

• Reduces risk of wrong-order returns via measurement-first checkout flow

• Suitable for export orders where the customer needs exact hardware matching by part number

Compatibility Table 

Explicit exclusions (return-prevention):

• Not a “universal bolt” you should buy by guesswork. If your bike uses a similar-looking bolt but different pitch/length, it will not fit.

• If your existing bolt is M6, do not order assuming M8 (and vice versa).

Variants
No variants.

FAQs 

Q1 (Fitment): How do I confirm 587605/B is correct for my bike?
A: Confirm in this order: (1) your old bolt packaging/part number shows 587605/B, (2) measure thread diameter (M6 or M8) and length under head (14mm or 20mm), (3) match head type (socket/Allen). Public sources conflict on spec, so measurement is mandatory.

Q2 (Fitment): Is this for rear disc / wheel applications?
A: Many sellers label it for wheel/brake-related use (including rear disc wording), but because the spec differs across catalogues, you should treat it as part-number + dimension matched hardware, not “rear disc bolt for all bikes.”

Q3 (Comparison): Genuine OEM vs local hardware shop bolt—what’s the difference?
A: OEM bolts match the original head profile and tolerances for that assembly. Local bolts may differ in pitch, grade, head height, or thread engagement—common cause of stripping/loosening. If you’re replacing a critical fastener, OEM is the safer route, but only if you match the correct size.

Q4 (Installation): Any precautions while installing?
A: Clean the threads, start by hand to avoid cross-threading, use the correct Allen bit, and tighten as per your service manual torque for that exact joint. If thread-lock was used previously, remove residue before reinstalling.

Q5 (Symptoms): What issues does replacing this solve?
A: Rounded Allen head, rusted/chewed threads, missing fastener, abnormal play/noise from a mounted component, or recurring loosening due to damaged threads/head.

Q6 (Returns-prevention): What photo/measurements should I send to confirm before ordering?
A: Send (1) top view of bolt head, (2) side view with a ruler showing length under head, and (3) thread diameter reading (vernier preferred). If you can’t measure pitch, share a clear close-up of threads.