Timken GR217 GR220 GR231 GR255 Mounted Bearing Grease

Timken greases for mounted ball and roller bearings

Timken GR-series greases are the lubricants Timken suggests for its mounted bearing product line, from pillow blocks and split plummer blocks to solid block and Type E units. The range covers premium all-purpose, polyurea ball bearing, food-safe, multi-use lithium and high-performance roller bearing grades, each in cartridges, tubs, pails, kegs or drums depending on the grade.

Timken lists the suggested grease by bearing type. GR255 or GR217 are suggested for SNT split plummer blocks, SAF split pillow blocks and split cylindrical units, GR255 for solid block spherical roller units, GR217 for Type E tapered roller units, GR220 for Fafnir mounted ball bearings, GR231 food-safe grease for Survivor Series PT, NT and PS units, and GR237 for UC-series units available outside the United States.

Technical specifications

Summary of the grease table in the Timken mounted bearing lubrication brochure (Order No. 10955). Temperature range is in degrees Celsius:

Choosing the right grade

GR217 suits moderate loads and speeds, higher-than-average temperatures and shock loading, with protection against rust, corrosion and wear. GR220 is a polyurea grease for lightly loaded ball bearings in pillow blocks, idler pulleys, electric motors, fans and pumps at up to 10,000 rpm; it has no extreme-pressure additives and is inhibited against rust and oxidation. GR255 targets extreme loads, high wear and shock loading in metals, mining, aggregate, power generation, cement and heavy industry, and meets NLGI GC-LB.

GR231 is for food and beverage and pharmaceutical ball bearing applications with incidental food contact. GR237 is a general industrial lithium EP2 grease for pins, bushings, track rollers and water pumps. Pack sizes vary by grade, for example 400 g cartridges are listed as GR217C, GR220C, GR231C, GR237C and GR255C.

Confirm grease compatibility before changing grades. The brochure notes that GR217 and GR255 are both acceptable for many standard applications and common uses, and that non-standard applications should be referred to a Timken sales engineer. Relubrication interval and quantity depend on speed, temperature, load and contamination, and are given in the bearing catalogs.

Applications for Timken mounted bearing greases

Mounted bearings are used throughout heavy and light industry: conveyor head and tail pulleys, screw conveyors, crushers and screens in quarries, kiln and mill auxiliaries in cement plants, air-handling equipment, pumps, and process machinery in food and beverage plants. The grease table above links each Timken grease to the mounted bearing types for which Timken suggests it, which gives maintenance teams a simple starting point when setting up a lubrication schedule for a mixed population of pillow blocks and flanged units.

Using the grade suggested for each housing type also helps keep the number of greases on site under control. Fewer grades mean fewer chances of putting the wrong lubricant into the wrong bearing, a common cause of early failures.

Matching grease to duty

Start from the bearing type, then check the operating conditions. Heavily loaded roller bearings with shock loading, such as those in mining, aggregate and cement equipment, point towards the high-performance grade with EP/AW properties. Lightly loaded ball bearings in pillow blocks and motors suit the polyurea ball bearing grease. General plant equipment with moderate loads and higher-than-average temperatures is covered by the premium all-purpose grade, and food and pharmaceutical lines with incidental food contact need the food-safe grade. Compare the temperature range of each grade with the actual bearing operating temperature, not the room temperature.

Changing grades and relubrication practice

Grease compatibility should be confirmed before switching from one product to another, since mixing incompatible thickeners can soften or harden the grease in the housing. When changing, purge the old grease as far as practical and monitor the bearing more frequently for a period afterwards. Relubrication intervals and quantities should follow the bearing catalogs, adjusted for speed, temperature, load and contamination. Clean grease fittings before applying grease, use clean tools and containers, and label grease guns by grade so that products are not mixed by accident.

Good records make lubrication easier to manage. List each bearing position with its housing type, the suggested grade from the Timken table, the interval and the quantity, and update the list when equipment or operating conditions change. Watch for signs such as rising bearing temperature, unusual noise or grease leaking from the housing, which can indicate over-greasing, under-greasing or the wrong grade for the duty. Sharing the same records with contractors and shift teams keeps practice consistent when different people carry out the lubrication rounds over the year.

Site conditions in Oman and the GCC

High ambient temperatures, direct sun on outdoor conveyors and heat from nearby process equipment all raise bearing temperatures in the Gulf, which shortens grease life and makes the temperature range of the chosen grade especially important. Dust and sand in quarries, cement plants and desert installations are a major source of contamination, so relubrication in these conditions often needs to be more frequent to keep dirt out of the bearing. Coastal humidity and salt air add corrosion risk, which the rust-inhibiting grades listed above help address. Store grease containers closed, out of direct sun and in a clean area.

Documents and quotation

The attached Timken brochure lists the suggested grease by mounted bearing type, benefits, pack sizes and interchange references. Grease choice should always be confirmed against the bearing manufacturer and operating conditions. Bearings are listed under Electric Motors, Pumps and Turbines. To request a quotation from Seven Star LLC, an independent supplier in Muscat, send the grease code, pack size and quantity.