D9R Caterpillar D9T Bulldozer Track Carrier Roller Forged 50Mn Steel Induction Hardened HRC 48-55 Undercarriage Part

The YT D9R track carrier roller is an undercarriage top roller built for Caterpillar D9R and D9T crawler bulldozers. It is mounted on the upper track frame where it carries the return side of the track chain between the drive sprocket and the front idler. A correctly functioning carrier roller keeps chain sag under control, reduces whipping when the machine travels fast, and protects the roller frame from hammering on rough ground.

This D9R carrier roller is produced from forged 50Mn or 40Mn2 alloy steel and induction hardened on the running surface to HRC 48-55. YT supplies it as a complete assembly with shaft, bushings and seals, ready to bolt into the existing carrier bracket. Every roller is measured against the original mounting geometry so that the flange profile, bore size and bracket spacing match the D9 track layout without modification.

Carrier Roller Structure

Key Features

• Forged body blank: closed-die forging of 50Mn or 40Mn2 rounds gives a dense grain structure that stands up to repeated impact loads.
• Induction hardened surface: the race and flange flanks are medium-frequency hardened to HRC 48-55 with a deep, uniform case.
• Tough tempered core: quenching and tempering before hardening keeps the roller core ductile so it absorbs shock instead of cracking.
• Sealed rotating group: precision bushings with dual-lip seals lock lubricant in and keep dust and water out of the bore.
• Accurate machining: CNC turning and cylindrical grinding control diameter, width and concentricity to tight tolerances.
• Rust protected: phosphating plus anti-rust oil protects the roller during storage and ocean shipment; black paint is optional.

Main Parameters

The models above are just for reference, we can't list all models here. We can supply more products as your requirements. Please feel free to send us your inquiry.

*Values are reference; OEM part number confirmation advised before ordering.

*Values are reference; OEM part number confirmation advised before ordering.

Production Process

1. Spectrometric analysis of each 50Mn / 40Mn2 heat verifies carbon and alloy content before the billet is released to the forge shop.
2. Closed-die forging shapes the roller body at controlled temperature so the grain flow follows the contour of the part.
3. Normalizing removes forging stress, then quenching and tempering establish a tough, uniform core hardness.
4. CNC turning machines the bore, race and flange faces to blueprint dimensions.
5. Medium-frequency induction hardening raises the working race temperature and quenches it to the specified case depth.
6. Cylindrical grinding finishes the race to low surface roughness for smooth chain contact.
7. Bushings, shaft and seal kits are pressed and assembled on a clean bench.
8. Hardness testing, magnetic particle inspection and dimensional gauging are performed on every completed roller.
9. Anti-rust oil is applied, then the roller is wrapped and packed for export.

XIAMEN YINTAI MACHINERY CO., LTD. is an ISO 9001:2015 certified manufacturer and exporter that has been making undercarriage parts under the YT brand since 2011. The factory runs its own closed-die forging line, a CNC machining workshop and complete heat treatment equipment, which means the D9R carrier roller is forged, hardened, machined and assembled on one site with full process control.

The company employs 50-100 people and records annual sales of USD 10-20 million, with 90-100% of output shipped to overseas markets. YT serves equipment distributors, rental fleets and mine maintenance teams in over forty countries, supports OEM/ODM programs, and welcomes SGS or other third-party inspection before shipment.

• Mining overburden duty: dozers stripping rock overburden get carrier rollers with deeper case hardness and sealed bushings to stretch the interval between rebuilds.
• Worn machine repair: a collapsed or loose D9 carrier roller can be replaced without removing the whole track group, cutting downtime to hours.
• OEM cost reduction: YT rollers are dimensionally interchangeable with factory parts at a lower unit price, protecting the maintenance budget of large fleets.
• Scheduled fleet renewal: multi-machine owners can buy full sets with staged deliveries to match their service calendar.
• Emergency breakdown: for machines down on site, popular D9 sizes are kept in stock and can be shipped quickly by air or express.

Caterpillar D9R and D9T bulldozers fitted with YT carrier rollers are used in open-pit mining, quarrying, landfill operations, pipeline spreading and heavy road construction. On the upper chain run, the roller shortens the unsupported span, keeps track tension even and lowers the shock transmitted to the undercarriage frame when the dozer travels over uneven terrain. The part also suits rebuild programs where the complete undercarriage, including track shoes, links, idlers and rollers, is renewed at the same time.

Frequently Asked Questions

Q1: How do I confirm this D9R carrier roller fits my machine?

Check the roller outer diameter, overall width, shaft bore and bracket spacing against your worn part. Send photos and measurements to YT and our team will cross-check the drawing before dispatch.

Q2: Is the roller an OEM part or an aftermarket part?

It is a YT aftermarket part engineered as an equivalent replacement. We do not use the OEM trademark, and fitment is verified by dimension rather than by brand name.

Q3: Why is a surface hardness of HRC 48-55 important?

The hardened race resists abrasive wear from the chain links while the tough core absorbs shock. This combination normally delivers a long service life in normal dozing duty.

Q4: What is the minimum order and can I get a sample first?

The minimum order is one piece. A single sample is welcome for fitment trials, and the sample cost is credited back once you place the first bulk order.

Q5: What delivery time and warranty do you offer?

Stock items ship in 5-7 days while production orders take 20-30 days. YT provides a 12-18 month warranty against defects in material and workmanship.

Each roller receives a final anti-rust treatment, is wrapped individually in protective film, and is packed on steel pallets or export-grade wooden pallets with steel strapping and moisture barriers suitable for sea freight. Finished rollers are 100% inspected for hardness, dimensions and seal condition, and inspection records are available upon request. YT offers a 12-18 month warranty against defects in material and workmanship and supports third-party quality audits such as SGS.

Why Choose Us?

• Through quench-tempering processes to ensure excellent mechanical properties, high strength and superior wear resistance to bending and breakage.
• Advanced Germany KUKA automatic machining center, horizontal and vertical CNC machining ensure the accuracy of assembly dimensions. This is to maximize the life span of each component and minimize production cost.
• MAKZAK Precison Finishing Machinery from Japan makes sure we have steady and good welding quality.
• We have complete production line and professional designers and working team. We can also produce any requested parts according to your blue print or samples.