Motocross

Triumph TF 250-X

Motocross, 250cc 4T, 2026, US version

Partly verified

Illustration: a Triumph motocross bike, not this exact model.

Gearing

3 of 5 filled

Stock front sprocket: 13T; Manufacturer spec sheet (research), checked 2026-09-27 (source 1)
Stock rear sprocket: 48T; Manufacturer spec sheet (research), checked 2026-09-27 (source 1)
Chain pitch: Not yet verified
Stock chain links: Not yet verified
Stock final drive ratio: 3.69 : 1; Calculated from the stock sprockets (research-level inputs)

Wheels and tires

4 of 4 filled

Front rim: 21 x 1.6; Manufacturer spec sheet (research), checked 2026-09-27 (source 1)
Rear rim: 19 x 1.85; Manufacturer spec sheet (research), checked 2026-09-27 (source 1)
Front tire: 80/100-21; Manufacturer spec sheet (research), checked 2026-09-27 (source 1)
Rear tire: 100/90-19; Manufacturer spec sheet (research), checked 2026-09-27 (source 1)

Suspension

3 of 7 filled

Fork: KYB 48mm coil spring fork; Manufacturer spec sheet (research), checked 2026-09-27 (source 1)
Fork travel: 310 mm (12.2 in); Manufacturer spec sheet (research), checked 2026-09-27 (source 1)
Shock travel: 305 mm (12.0 in); Manufacturer spec sheet (research), checked 2026-09-27 (source 1)
Stock fork spring rate: Not yet verified
Stock shock spring rate: Not yet verified
Static sag, bike only: Not yet verified
Race sag, rider on: Not yet verified

Fluids and capacities

1 of 5 filled

Engine oil spec: Not yet verified
Engine oil capacity: Not yet verified
Coolant capacity: Not yet verified
Premix ratio: Not yet verified
Fuel capacity: 6.8 L (1.80 gal); Manufacturer spec sheet (research), checked 2026-09-27 (source 1)

Dimensions

3 of 3 filled

Seat height: 960 mm (37.8 in); Manufacturer spec sheet (research), checked 2026-09-27 (source 1)
Wheelbase: 1492 mm (58.7 in); Manufacturer spec sheet (research), checked 2026-09-27 (source 1)
Weight: 104 kg (229 lb); Manufacturer spec sheet (research), checked 2026-09-27 (source 1)

Solid marks are owner's-manual pages; hollow marks are manufacturer web or spec-sheet figures still waiting on a manual page. Last reviewed 2026-09-27. Rows marked not yet verified are blank on purpose.

What's missing

0 of 25 fields read off a manual page.

Not yet verified (12): chain pitch, chain links, fork spring rate, shock spring rate, static sag, race sag, engine oil spec, engine oil capacity, coolant capacity, tire pressure (off-road), chain slack, spark plug and gap.

From a spec sheet, awaiting a manual page (13): front sprocket, rear sprocket, front rim, rear rim, front tire, rear tire, fork, fork travel, shock travel, fuel capacity, seat height, wheelbase, weight.

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Buying parts

The stock sizes and specs this bike left the factory with, each with its source. Take them to any shop. Retailer links will appear here once a store approves MotoXSports.

Sprockets: Stock front sprocket 13T Manufacturer spec sheet (research)Stock rear sprocket 48T Manufacturer spec sheet (research)
Tires: Front tire 80/100-21 Manufacturer spec sheet (research)Rear tire 100/90-19 Manufacturer spec sheet (research)

7 part specs not yet verified; see data coverage.

Garage tool 01

Sprocket calculator

Put your current gearing in Setup A and the setup you are considering in Setup B. Everything updates as you type.

Start from a bike's stock gearing

Pick a bike to fill both setups with its stock sprockets.

Front sprockets 10–16 teeth, rear 34–60. Values outside that range are brought back to the nearest limit.

Setup A — what you run now

Front teeth

Rear teeth

Setup B — what you are thinking about

Front teeth

Rear teeth

Final drive ratio

— — : 1

—

Pull at the wheel—

Top speed—

Chain (est.)—

A —

B —

Taller · more speed Shorter · more pull

—

Ratios are exact. The chain figure is an estimate of roughly one link per two teeth of change — confirm against your manual before ordering.

Sources

1
Triumph 2026 TF 250-X specifications (triumphmotorcycles.com, US)Manufacturer web or spec sheet, research level. Covers stock front sprocket, stock rear sprocket, front rim, rear rim, front tire, rear tire, fork, fork travel, shock travel, fuel capacity, seat height, wheelbase, weight; checked 2026-09-27.

Always confirm against the manual for your exact year before ordering parts or setting up suspension. Torque specs are deliberately not published here. How we verify a value.

My settings

Date / track
Sprockets run
Race sag / free sag
Fork air pressure or spring
Fork clickers (compression / rebound)
Shock clickers (low / high / rebound)
Tire pressures (front / rear)
Notes

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