Fleet operators servicing Isuzu NPR and NQR trucks need a rear brake drum that matches OE dimensions without trial fitting. The 8970812191 brake drum is a rear axle component for these medium-duty trucks, covering both 4HF1 and 4HG1 engine variants. It replaces Isuzu part numbers 8-97081-219-2, 8970812190, 8970812192, and BD630.
Why the 8970812191 Brake Drum Fits NPR and NQR Models
Isuzu NPR and NQR trucks share the same rear axle hub design across 4HF1 and 4HG1 engine options. The 8970812191 brake drum has a 6-hole bolt pattern, 320 mm inner diameter, and 100 mm lining width to match this hub. Six mounting holes distinguish this drum from the 5-hole variants used on other Isuzu platforms like the NPR66.
A common source of confusion: the front axle on NPR and NQR uses part number 8970812182 (8-97081218-2). The front and rear drums look similar from the outside but differ in minor dimensional details. Aftermarket suppliers sometimes list them interchangeably, so always confirm the fitting position before ordering. [internal link: Isuzu brake drum collection]
Key Specifications at a Glance
| Parameter | Value |
|---|---|
| OE Number | 8970812191 / 8-97081-219-2 / 8970812190 / 8970812192 / BD630 |
| Part Description | Drum; brk, rr (Rear Brake Drum) |
| Vehicle Application | Isuzu NPR, NQR |
| Engine Model | 4HF1, 4HG1 |
| Axle Position | Rear |
| Material | HT250 Grey Cast Iron (G3000 / GG25) |
| Inner Diameter | 320 mm |
| Lining Width | 100 mm |
| Bolt Holes | 6 |
| Weight | 21 kg |
| Warranty | 1 Year / 50,000 km |
| MOQ | 20 Pieces |
| Packing | Pallet |
| Port | Qingdao |
How HT250 Cast Iron Performs Under Load
The 8970812191 brake drum uses HT250 grade grey cast iron. HT250 holds a hardness range of 180 to 220 BHN, which balances surface wear resistance against crack resistance. The graphite structure in grey cast iron provides natural vibration damping, which reduces brake noise during operation. The G3000 and GG25 designations listed in the product standard refer to equivalent cast iron grades in Japanese and German specifications.
The graphite flakes in grey cast iron absorb vibration, so the drum runs quieter than alternative materials. HT250 also resists thermal fatigue under repeated braking cycles. The product listing groups HT250 with G3000 and GG25, which are cast iron grades from Japanese and German standards. [external link: ISO/TS16949 standard overview]
What to Check Before Installing a Replacement Drum
- Confirm the OE number stamped on your original drum. The 8970812191 is a rear axle part; the front axle counterpart is 8970812182.
- Count the bolt holes. This drum has 6 holes. If your hub has a different hole count, you need a different part.
- Measure the inner friction diameter. It should read 320 mm on a drum micrometer before the drum reaches its wear limit.
- Check the lining width. This drum pairs with 100 mm brake linings. Narrower or wider linings will not seat properly.
- Replace drums in axle pairs. A new drum on one side and a worn drum on the other creates uneven braking force and can pull the truck during stops.
Frequently Asked Questions
What is the difference between 8970812191 and 8970812182?
Does this drum fit both 4HF1 and 4HG1 engines?
What does the BD630 cross-reference number mean?
Can brake drums be resurfaced (machined)?
What is the maximum wear diameter for this drum?
Get Pricing from Xingtai Yiwo
Xingtai Yiwo Auto Parts Co., Ltd. has produced brake drums for over 15 years from our facility in Longyao County. Our annual output reaches 10,000 tons, supplying fleet operators and parts distributors across multiple export markets. Every drum ships with a 1-year / 50,000 km warranty.
Need a quote on the 8970812191 brake drum? Send us your target quantity and destination port. Sample orders are available for evaluation before bulk commitment. [internal link: contact Xingtai Yiwo]
