Kubota Compact Tractor Torque Specs

OEM wheel-bolt and loader/backhoe torque specifications for Kubota's BX, B, and L compact tractor lines, cited page-by-page to Kubota's own operator's manuals — including the re-torque intervals Kubota builds into its service schedule. Always verify against your machine-specific manual; some figures below carry a market or serial-number caveat that matters.

Quick-reference torque specs

Front Wheel Bolt — BX1880 / BX2380 / BX2680 149-179 N·m (110-132 lb-ft) (15.2-18.3 kgf·m. Re-check after 200 m (200 yards) of driving AND after 1 day (8 hours), then every 50 hours per the Service Intervals table.) Source: KUBOTA Corporation, Operator's Manual BX1880/BX2380/BX2680 (Code No. K2874-7131-1, © 2017, USA) p.67: "Front 149 N⋅m to 179 N⋅m (15.2 kgf⋅m to 18.3 kgf⋅m) [110 lbf⋅ft to 132 lbf⋅ft]". Rear Wheel Bolt — BX1880 / BX2380 / BX2680 109-130 N·m (80-96 lb-ft) (11.1-13.3 kgf·m. Same re-check interval as the front wheel bolt above.) Source: KUBOTA Corporation, Operator's Manual BX1880/BX2380/BX2680 (K2874-7131-1, © 2017, USA) p.67: "Rear 109 N⋅m to 130 N⋅m (11.1 kgf⋅m to 13.3 kgf⋅m) [80 lbf⋅ft to 96 lbf⋅ft]". Front Loader Main Frame Bolts/Nuts, M14 — BX1880/BX2380/BX2680 and BX23S (with LA340) 147 N·m (108 lb-ft) (15.0 kgf·m. Identical value in both manuals. On the BX23S, re-tighten all loader main-frame mounting bolts/nuts once after the loader's first 20-30 hours of operation, then check at every 50-hour service.) Source: KUBOTA Corporation, Operator's Manual BX1880/BX2380/BX2680 (K2874-7131-1) p.26: "Main frames | M14 bolts or nuts | Required Torque 147 N⋅m (15.0 kgf⋅m) [108 lbf⋅ft]"; BX23S/LA340/BT603 manual (K2992-7121-8) p.145, identical wording; loader re-torque interval p.145: "After 20 hours to 30 hours of initial loader operation, re-tighten all mounting bolts and nuts to the required torque value". Front Wheel Bolt — BX23S (with LA340 loader / BT603 backhoe) 149-179 N·m (110-132 lb-ft) (Identical figure to the BX1880/BX2380/BX2680 manual, confirmed in the BX23S's own combined loader+backhoe manual.) Source: KUBOTA Corporation, Operator's Manual BX23S/LA340/BT603 (Doc No. K2992-7121-8, 2021 US edition) p.129: "Front wheel bolt Tightening torque 149 N⋅m to 179 N⋅m (15.2 kgf⋅m to 18.3 kgf⋅m) [110 lbf⋅ft to 132 lbf⋅ft]". Rear Wheel Bolt — BX23S (with LA340 loader / BT603 backhoe) 109-130 N·m (80-96 lb-ft) (Identical figure to the BX1880/BX2380/BX2680 manual.) Source: KUBOTA Corporation, Operator's Manual BX23S/LA340/BT603 (K2992-7121-8) p.129: "Rear wheel bolt Tightening torque 109 N⋅m to 130 N⋅m (11.1 kgf⋅m to 13.3 kgf⋅m) [80 lbf⋅ft to 96 lbf⋅ft]". Backhoe Sub Frame Bolts/Nuts — BX23S (with BT603) 147 N·m (108 lb-ft) (15.0 kgf·m. Checked under "Service of the Backhoe Every 50 Hours" — same figure as the loader main-frame bolts.) Source: KUBOTA Corporation, Operator's Manual BX23S/LA340/BT603 (K2992-7121-8) p.150: "If the bolts and nuts of the sub frame are loose, tighten them as follows. Tightening torque 147 N⋅m (15.0 kgf⋅m) [108 lbf⋅ft]". Front Wheel Bolt — B2601 79-92 N·m (58.3-67.9 lb-ft) (8.1-9.4 kgf·m. MARKET NOTE: this manual's cover is explicitly labeled "English (Australia)" and "Printed in Japan" — no US-specific print of the B2301/B2601 operator's manual could be located. Treat this figure as the Australia-market edition, not confirmed for US-spec machines.) Source: KUBOTA Corporation, Operator's Manual B2301/B2601 (Code No. 6C545-6311-1, © 2015, English/Australia edition) p.40: "(1) 79 to 92 N-m (8.1 to 9.4 kgf-m, 58.3 to 67.9 ft-lbs) [Front Wheels]". Rear Wheel Bolt — B2601 145-150 N·m (107.0-110.6 lb-ft) (14.8-15.3 kgf·m. Same Australia-market caveat as the front wheel bolt above. Re-check after driving 200 m (200 yards) and 10 shuttle movements of 5 m, then per the periodic service interval.) Source: KUBOTA Corporation, Operator's Manual B2301/B2601 (6C545-6311-1, © 2015, English/Australia edition) p.40: "(1) 145 to 150 N-m (14.8 to 15.3 kgf-m, 107.0 to 110.6 ft-lbs) [Rear Wheels]". Front Wheel Nut — B2650 / B3350 / B3350SU 77-90 N·m (57-67 lb-ft) (7.9-9.2 kgf·m. Callout (1) in the manual's wheel-bolt-torque diagram — the small wheel next to the hood/grille, confirmed by cross-referencing the same base illustration reused (with different callouts) in the sibling B2301/B2601 manual's separately-headed "Front Wheels"/"Rear Wheels" pages. Only a single Nut value is printed for the front wheel — no separate front bolt figure, unlike the rear.) Source: KUBOTA Corporation, Operator's Manual B2650/B3350/B3350SU (Doc No. 6C410-6311-9, English/USA) p.72: "(1) Nut: 77 to 90 N-m (7.9 to 9.2 kgf-m, 57 to 67 ft-lbs.)". Rear Wheel Bolt — B2650 / B3350 / B3350SU 196-225 N·m (145-166 lb-ft) (20-23 kgf·m. Callout (2) — the large wheel next to the ROPS/fender mount. Rear tread width can NOT be adjusted on this model (per the manual's own "Rear Wheels" heading). Callout (2) prints both a Bolt figure and a Nut figure for the rear wheel; the manual doesn't say which joint each applies to — torque each to its figure.) Source: KUBOTA Corporation, Operator's Manual B2650/B3350/B3350SU (Doc No. 6C410-6311-9, English/USA) p.72: "(2) Bolt: 196 to 225 N-m (20 to 23 kgf-m, 145 to 166 ft-lbs.)". Rear Wheel Nut — B2650 / B3350 / B3350SU 167-191 N·m (123-141 lb-ft) (17-19.5 kgf·m. Printed directly under the rear wheel Bolt torque as a second value for the same wheel assembly — both apply.) Source: KUBOTA Corporation, Operator's Manual B2650/B3350/B3350SU (6C410-6311-9) p.72: "Nut: 167 to 191 N-m (17 to 19.5 kgf-m, 123 to 141 ft-lbs.)". Front Wheel Bolt — L2501 137 N·m (100 lb-ft) (14 kgf·m. Printed as a single value, not a range. Identical figure repeated verbatim at the periodic "Service Every 50 Hours" section.) Source: KUBOTA Corporation, Operator's Manual L2501 (Doc No. TC550-1971-8, English/USA, ROPS) p.67: "Bolt (1) Tightening torque 137 N⋅m (14 kgf⋅m) [100 ft⋅lbs]". Rear Wheel Bolt — L2501 215 N·m (160 lb-ft) (22 kgf·m. Single value, from the ballast/rear-wheel refitting section.) Source: KUBOTA Corporation, Operator's Manual L2501 (TC550-1971-8) p.69: "Bolt (1) Tightening torque 215 N⋅m (22 kgf⋅m) [160 ft⋅lbs]". Front Wheel Bolt — L3301 / L3901 137 N·m (100 lb-ft) (14 kgf·m. Identical value and wording to the L2501 manual.) Source: KUBOTA Corporation, Operator's Manual L3301/L3901 (Doc No. TC620-1973-9, English/USA) p.83: "Bolt (1) Tightening torque 137 N⋅m (14 kgf⋅m) [100 ft⋅lbs]". Rear Wheel Bolt — L3301 / L3901 215 N·m (160 lb-ft) (22 kgf·m. Identical value to the L2501 manual.) Source: KUBOTA Corporation, Operator's Manual L3301/L3901 (TC620-1973-9) p.85: "Bolt (1) Tightening torque 215 N⋅m (22 kgf⋅m) [160 ft⋅lbs]". Always confirm against your machine’s service manual.

Sequence-required & verify-against-manual fasteners

These structural or safety-critical fasteners require the machine-specific tightening sequence or a service-manual value rather than a single number: Wheel Bolt Re-Torque Interval — BX-series — See interval note (Re-check timing on both BX1880/BX2380/BX2680 and BX23S: after driving the tractor 200 m (200 yards), after 1 day (8 hours), and thereafter every 50 hours per the periodic Service Intervals table (also listed there as "Wheel bolt torque - Check - every 50 Hr").) Source: KUBOTA Corporation, Operator's Manuals BX1880/BX2380/BX2680 (K2874-7131-1) p.67 and BX23S/LA340/BT603 (K2992-7121-8) p.95: "Timing to recheck the bolts: After driving the tractor 200 m (200 yards), after 1 day (8 hours), and thereafter every 50 hours". Front Loader Main Frame Bolts — B2601 — See service manual (No front-loader section or main-frame torque table exists anywhere in this 173-page B2301/B2601 operator's manual — Kubota publishes the LA-series loader for this tractor with its own separate loader manual, not covered by this pass.) Source: KUBOTA Corporation, Operator's Manual B2301/B2601 (6C545-6311-1) — no loader/main-frame torque table present. Wheel Bolt Re-Torque Interval — B and L series — See interval note (B2601, B2650/B3350/B3350SU, L2501, and L3301/L3901 all use the same wording: recheck after driving the tractor 200 m (200 yards) AND 10 shuttle movements of 5 m (5 yards), then per the periodic Service Intervals table (every 50 hours). No separate front-loader torque table exists in any of these four manuals.) Source: KUBOTA Corporation, Operator's Manuals B2301/B2601 (6C545-6311-1) p.40, B2650/B3350/B3350SU (6C410-6311-9) p.55, L2501 (TC550-1971-8) p.67, L3301/L3901 (TC620-1973-9) p.83 — each: "When re-fitting or adjusting a wheel, tighten the bolts to the following torques then recheck after driving the tractor 200 m (200 yards) and 10 times of shuttle movement by 5 m (5 yards), and thereafter according to service interval.". Wheel Bolt Torque — L4701 / LX2610 / LX2610SU / LX3310 — See service manual (Manual not publicly available — not covered. No free, legitimately downloadable OEM operator's manual for these three models was found on kubotausa.com, media.kubota.io, or Garton Tractor's manual libraries; they exist only as paid print/PDF copies from third-party resellers. Do not carry over the L2501/L3301/L3901 figures above — these are different axle/tire configurations and Kubota does not guarantee a shared spec across this size class.) Source: Search of kubotausa.com/support/manuals, media.kubota.io, and Garton Tractor's current (19) and prior-generation (40) manual listings — L4701 and LX2610/LX2610SU/LX3310 absent from all three; third-party listings (Messicks, kubotaprints.com) confirm the doc codes (TC630-5971-1; 6C830-63119/6C830-63152) exist but were not accessed.

Model coverage

BX1880 / BX2380 / BX2680 (2017 US-market operator's manual (Code No. K2874-7131-1)), Sub-Compact Tractor; BX23S (with LA340 loader / BT603 backhoe) (2021 US edition (Doc No. K2992-7121-8)), Sub-Compact Tractor, Loader & Backhoe; B2601 (2015, Code No. 6C545-6311-1 — Australia-edition manual (see note)), Compact Tractor; B2650 / B3350 / B3350SU (US edition (Doc No. 6C410-6311-9)), Compact Tractor; L2501 (US edition (Doc No. TC550-1971-8)), Compact Utility Tractor; L3301 / L3901 (US edition (Doc No. TC620-1973-9)), Compact Utility Tractor.

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