Is the BB-UN300 compatible with Shimano Deore cranks?

Not directly — Deore cranks since 2008 use Hollowtech II outboard bearings, not square taper. BB-UN300 is for older square taper Shimano cranks (Tourney, Altus FC-M series, etc.).

Which size is right for a standard MTB frame?

The 68mm x 113mm is the most common MTB fitment for standard triple cranksets. For doubles, 68mm x 107mm is typical. Always verify against your crankset specification.

Does this come with installation tools?

No — the BB-UN300 requires a Shimano TL-UN74-S splined BB tool. Most bike shops carry this; it is also available online for under 300 rupees.

Shimano

Shimano BB UN300 Square Tyre Bottom Bracket

Name: Shimano BB UN300 Square Tyre Bottom Bracket
Brand: Shimano
SKU: EBBUN300B07X
Price: 990.00 INR
Availability: InStock
Author: InstaSport Editorial

₹990.00

Description

SHIMANO - Square Type Bottom Bracket - MTB - Standard Structure DESCRIPTION Square Type Bottom Bracket SHIMANO quality/performance cartridge bearing square bottom bracket Better chainline stability with chain line stabilizer 3 structures available Standard, E-type, chaincase options Adapter Material