Tractor Bearing

A tractor bearing can sit in a dozen places on one machine: the front wheel hubs, the gearbox, the PTO, the differential and final drive, the clutch and the engine. Most of these positions use standard bearing types. Tapered pairs carry the front hubs and the bevel pinion. Deep groove types from the 6000, 6200 and 6300 series carry the gearbox, PTO and differential shafts. FULI supplies deep groove ball bearings, metric and inch tapered roller bearings and spherical roller bearings for these positions, and pillow block and flange units for the implements a tractor pulls. Below we cover where each one sits, example numbers, front hubs, gearbox and PTO shafts, clutch release parts, reading maker part numbers, signs of wear, common causes of early wear and what to send with an inquiry.

Where the bearings sit on a tractor

The table is built from a published tractor application catalogue by the bearing maker NBC, which lists bearings by tractor model and position [1]. The numbers are examples from that list; the bearing in your tractor depends on the model, the axle and the gearbox version.

Position	Load	Usual bearing type	Examples listed in [1]	FULI product pages
Front wheel hub, inner and outer	Weight on the front axle, side load in turns, road shock	Tapered roller bearings, one pair per wheel	32207 with 30305; 30207 with 30205; LM48548/LM48510 with 1988/1922 or LM11949/LM11910	32207, 30305, 30205, LM48548, LM11949
Gearbox main drive, counter and lay shafts	Gear loads, oil bath	Deep groove ball bearings, some cylindrical roller bearings	6208N, 6210C3, 6206N; NUP208	6208, 6210, 6206
PTO shafts	Torque from the implement, shock at engagement	Deep groove ball bearings	6207, 6209, 6307, 6009NR	6207, 6209, 6307, 6009
Bevel pinion, front and rear	Radial and axial load, must hold gear mesh	Tapered roller bearings in an adjusted pair	32211, 32309, 3780/3720, HM903249/HM903210	32211, 32309, 3780
Differential, right and left	Heavy radial load, some axial	Deep groove or tapered roller bearings	6213C3, X32212, 30214	6213, 32212, 30214
Rear axle, reduction shaft and rear wheel	Heavy radial load, low speed	Deep groove ball bearings, tapered roller bearings	6211C3, 6212C3, 32211	6211, 6212
Hydraulic pump	Pump loads, oil	Deep groove ball bearings	6303C3, 6302RSSC3, 6006ZZ	6303, 6006
Clutch release	Axial load from the clutch spring	Special release bearings; some models list a deep groove ball bearing	306445C, 1346P0010, CT-1310, TX-41; 6011LLU and 6013LLU on some models	Send the part number, we confirm
Engine crankshaft	Heavy radial load	Cylindrical roller bearings	N314, NUP315, NUP313	Send the part number, we confirm

Three points stand out in the catalogue. The front wheel almost always runs on a tapered pair. The PTO and gearbox shafts are dominated by a handful of deep groove sizes: 6207 is the PTO shaft bearing that appears most often in the list, followed by 6209, then 6307 and 6009NR [1]. And many positions carry suffixes such as C3, N or NR that matter as much as the base number.

Bearing makers also build special ball bearings for single tractor positions. Timken’s catalogue lists special agricultural bearings for positions such as a clutch shaft, a tractor water pump and PTO drives, each with its own number and often with a special bore, ring width or seal [2]. When the number on the old bearing is not a standard series number, treat it as a special part and send the number.

FULI products for tractor positions

These are the types on our product pages that cover the standard positions:

• Deep groove ball bearings. The 6000 series, 6200 series and 6300 series, open, ZZ or 2RS, for gearbox, PTO, differential and hydraulic pump shafts.
• Tapered roller bearings. Metric 302, 303, 320, 322 and 323 series, and inch cone and cup sets such as LM48548, LM11949, LM501349 and 3780, for wheel hubs, bevel pinions and differentials.
• Thrust ball bearings. 51100 and 51200 series thrust bearings for positions where the load runs along the shaft only. Send the old number and we will confirm the size.
• Spherical roller bearings. The 22200 and 22300 series for heavy shafts. A few tractor positions list them, for example a 22212 on the bull pinion shaft of some models [1], but most are on the implements.
• Mounted units. Pillow block and flange units carry shafts on the rotary tillers, threshers and other implements the tractor drives through its PTO. The agricultural bearings page covers those machines.

Rings and rolling elements are GCr15 chrome steel. Clutch release bearings, cylindrical roller bearings and other special tractor parts are not on our product pages. Send the part number and we confirm what we can supply.

Front wheel hub bearings

Each front wheel of a two-wheel-drive tractor turns on two tapered roller bearings set facing each other in the hub. The inner bearing, next to the axle beam, is the larger one because it carries most of the load. The outer bearing, under the hub cap, is smaller. The pair takes the weight on the front axle and the side load when the tractor turns or works across a slope.

Application lists show both metric and inch pairs [1]:

• Metric pairs. A 32207 inner with a 30305 outer appears on several models; a 30207 inner with a 30205 outer on others.
• Inch pairs. An LM48548/LM48510 inner with a 1988/1922 or an LM11949/LM11910 outer appears on tractors built to inch drawings.

The same tractor model can use different hub bearings depending on whether the front axle is fixed or adjustable [1], and four-wheel-drive front axles use a different arrangement again. So the model name alone is not enough; read the numbers from the old bearings.

For inch tapered bearings, the cone (inner ring with rollers) and the cup (outer ring) each carry their own number, written together as LM48548/LM48510. Order them as a set, and give both numbers. When you assemble the hub, set the end play the tractor maker gives, pack the bearings with grease, because tapered bearings normally leave the factory with rust protection only, and fit a new hub seal. The tapered roller bearing page lists common metric and inch sizes, and how to choose wheel hub bearings covers hub bearings in more detail.

Gearbox, PTO and differential bearings

Gearboxes, PTO housings and differentials share one oil supply in many designs, and the parts inside run in that oil. That is why most of them are open deep groove ball bearings rather than sealed ones. The suffixes in the catalogue tell you what else the position needs:

• C3 means more internal clearance than normal. It suits bearings that are pressed onto the shaft and run warm, such as 6210C3 on a counter shaft or 6213C3 in a differential [1]. The internal clearance article explains when it matters.
• N means a snap ring groove in the outer ring, and NR means the groove with the snap ring fitted, as in 6208N or 6009NR [1]. The ring locates the bearing in the housing. A bearing without it will fit the bore but will not be held in place.
• Z, ZZ and RS variants appear where a bearing is lubricated separately or sits next to a dry space, for example 6006ZZ in a hydraulic pump [1].

The bevel pinion that drives the crown wheel runs on tapered roller bearings in an adjusted pair, because it must hold its position precisely for the gears to mesh. Numbers such as 32211, 32309 and the inch 3780/3720 appear in this position [1]. The setting is done with shims or a nut to the tractor maker’s figure; replace the bearings as a pair and set them again rather than reusing the old shim pack blindly. The gearbox bearing page covers deep groove and tapered bearings in gearboxes in more detail.

Clutch release bearings

The clutch release bearing, also called the throw-out bearing, sits on the clutch shaft and presses against the release levers or diaphragm spring when the driver pushes the clutch pedal. It carries an axial load and turns only while the clutch is held down. Many models with a live or independent PTO have a double clutch, with release arrangements for both.

Release bearings are usually special parts. Application lists show maker-specific numbers such as 306445C, 1346P0010, CT-1310 and TX-41, and on some models a sealed deep groove ball bearing such as 6011LLU for a single clutch or 6013LLU for a double clutch [1]. Even where the base number is a standard size, the release bearing may need a particular seal, grease or carrier, so a plain bearing with the same base number is not automatically a replacement.

If your tractor uses a clutch release bearing, send the number from the old bearing or from the parts catalogue, with the tractor model and whether it has a single or double clutch, and we confirm whether we can match it before quoting.

Reading tractor part numbers

Tractor makers such as Mahindra, Sonalika, TAFE, Escorts, Eicher, Swaraj and John Deere list bearings in their parts catalogues under their own part numbers. The bearing itself carries a bearing number such as 6207 or 32211. Application lists like the NBC catalogue show both side by side, for example a front wheel inner bearing listed with the tractor maker’s part number and the bearing number LM48548/LM48510 [1].

When you buy replacement bearings, the bearing number is the reliable reference. If you only have the tractor part number, send it with the tractor model, the year and the position, and we check it against the bearing number before quoting. Our bearing cross reference pages list brand numbers for common series, and the bearing number decoder explains prefixes and suffixes.

Lawn and garden tractors

These are a different case. Mower deck spindles usually run on sealed deep groove types from the 6200 series, such as the 6203-2RS, 17 mm bore, 40 mm OD and 12 mm wide, or the 6205-2RS. Numbers vary by maker, so read the one on the old part before you order.

Signs of failure, maintenance and repair

Most worn parts give warning before an unexpected stop:

• Noise. A growl that rises with speed, or a click once per turn.
• Play. A knock when you rock the raised wheel top to bottom.
• Heat. One side much hotter than the other after work.
• Grease and oil. Grease thrown out past the seal, milky grease, or metal in the gear oil.

Regular inspection before each season is the most cost-effective way to maintain the machine. Check end play, renew the grease, change the gear oil on schedule, and fit a new seal whenever the axle end is opened. Good lubrication does more than anything else to extend service life. When you repair one side, replace both parts of the pair and the seal together, and do it between jobs to avoid downtime at peak work. The lubrication basics article covers grease choice and quantities, and this comparison explains which type suits which load.

Why tractor bearings fail early

1. Water and mud in the front hubs. A worn hub seal lets water in when the tractor works in wet fields or is washed. The grease turns to a milky paste and the rollers start to pit.
2. Wrong end play. Tapered bearings set too tight run hot; set too loose they hammer under road shock and when the front axle hits bumps.
3. Extra front load. Front loaders and front weights add heavy loads to the front hub bearings and the axle. Bearings chosen for the bare tractor wear faster when a loader is fitted.
4. Dirty or low gear oil. Gearbox, PTO and differential bearings depend on the oil. Metal particles from worn gears and water from condensation shorten their life.
5. Riding the clutch. A driver who rests a foot on the pedal keeps the release bearing turning under load and wears it out early.
6. A missing suffix. A 6009 ordered without the NR, or a 6210 without the C3, may fit the shaft but not the position.

How to write a tractor bearing inquiry

An inquiry with these items can usually be priced in one round:

1. The bearing number with every prefix and suffix, for example 6207, 6009NR, 6210C3, 32211 or LM48548/LM48510. For inch tapered bearings, give both the cone and the cup number.
2. If you only have the tractor maker’s part number, send it with the tractor model, the year and the position.
3. The quantity for each number.
4. The position on the tractor: front wheel inner or outer, PTO shaft, bevel pinion, differential, clutch release.
5. For clutch release bearings, whether the tractor has a single or double clutch, and a photo of the old part with its carrier.
6. Any marking requirement. Rings can carry your authorized brand, the factory brand, or no brand.

Send your list to sales@fuli-bearings.com or through the contact page. We check each number against the standard designations, mark any item we cannot match as an exception rather than substituting it, and send the quote. The quotation request template has a copy-ready format, and how to avoid ordering the wrong bearing lists the usual mistakes. An inspection report can cover dimensions, radial clearance, rotation noise, vibration, appearance, material certificate and batch traceability.

Backed by 20+ years of bearing export experience in Linqing, Shandong. FULI ships to 50+ countries & regions.

NBC, Timken, Mahindra, Sonalika, TAFE, Escorts, Eicher, Swaraj and John Deere are trademarks of their respective owners. FULI is not affiliated with, authorized by or endorsed by any of them. Their names and published technical material are cited here as general reference only, to help identify bearing numbers.

Sources

1. https://www.nbcbearings.com/nbc-tractors.pdf
2. https://www.timken.com/wp-content/uploads/2018/04/Timken-Ball-Bearing-Catalog_10734.pdf