The tariff classification of two (2) models of timing chain tensioning assemblies from South Korea

N361650May 28, 2026CLA-2-84:OT:RR:NC:N2:201
CATEGORY: Classification
TARIFF NO.: 8409.91.5085
Jae Young SonHyundai Motor Company231, Yangjae-dong, Seocho-guSeoul, 06797South KoreaRE: The tariff classification of two (2) models of timing chain tensioning assemblies from South KoreaDear Mr. Son:In your letter dated
May 19, 2026
, you requested a tariff classification ruling.The first item has been identified as a timing chain tensioner assembly, Part number 24410-2S001, which isused in the Hyundai THETA-III Engine.The second item has been identified as a timing chain tensioner assembly, Part number 24410-2S300, whichis used in the Hyundai THETA-III Engine.The subject item is a component of a timing chain system that links the crankshaft and the camshaft, therebyprecisely synchronizing piston movement with the operation of the intake and exhaust valves. It is a part of aspark-ignition internal combustion piston engine designed to maintain optimal tension in the timing chain.The timing chain system consists of a driver side and a non-driven side, each exhibiting differentcharacteristics depending on the chain’s tensile load and the operating characteristics of the tensioner.Driver side: the side that directly transmits motive power from the crankshaft to the camshaft. It isalways under tension during engine operation and bears the largest tensile load on the chain.Non-driven side: the return side to the crankshaft after power transmission. It is more prone to slackthan the driver side and requires a separate tensioning mechanism.The subject item is installed on the non-driven side and functions to maintain proper tension of the timingchain and prevent slack, thereby enabling accurate synchronization between the crankshaft and the camshaft.This ensures that the motion of the pistons is precisely synchronized with the opening and closing of theintake and exhaust valves.
The cam mechanism inside the subject item maintains the position of the plunger and limits its reversemovement(retraction). After the plunger advances under the combined action of spring force and hydraulicpressure, any reverse force caused by changes in chain tension or external loads is limited by the cam profile,thereby preventing plunger retraction. Furthermore, as the plunger advances, the cam mechanism engagesprogressively, thereby continuously maintaining the required chain tension and positional stability.During engine operation, the chain tension fluctuates continuously with changes in engine speed (RPM),causing the plunger to undergo repeated minute advance and retraction movements. In this process, thesubject item performs a damping function by increasing the hydraulic pressure in its internal oil chamberwhen the plunger retracts, thereby absorbing shock prior to cam engagement. By maintaining the timingchain at its optimal tension, the subject item minimizes friction and impact on the sprocket andaccommodates chain wear and elongation, thereby improving the durability and service life of both the chainand the sprocket.In your request you suggest classification of the timing chain tensioning assemblies in 8409.91.5085,Harmonized Tariff Schedule of the United States (HTSUS), which provides for “Parts suitable for use solelyor principally with the engines….” We agree.The applicable subheading for the timing chain tensioning assemblies, Part number 24410-2S001 and24410-2S300, will be 8409.91.5085, HTSUS, which provides for “Parts suitable for use solely or principallywith the engines of heading 8407 or 8408: Other: Suitable for use solely or principally with spark-ignitioninternal combustion piston engines (including rotary engines): Other: Other: Other.” The general rate of dutywill be 2.5% ad valorem.The duties cited above are current as of this ruling’s issuance. Duty rates are provided for your convenience and are subject to change. The text of the most recent HTSUS and the accompanying duty rates are providedat https://hts.usitc.gov/.This ruling does not address the applicability of any additional duties, taxes, fees, exactions and/or othercharges, which may apply to the goods discussed herein. This includes, but is not limited to, tariffs and otherduties as provided for in Subchapter III to Chapter 99, HTSUS.Thus, for example, in addition to the classification stated above, the merchandise covered by this ruling may also need to be reported with eitherthe Chapter 99 provision under which an additional tariff applies or one of the Chapter 99 provisionscovering exceptions to such tariffs.For further information to assist with the importation process, please refer to the frequently updated CargoSystems Messaging Service (CSMS) messages at https://www.cbp.gov/trade/automated/cargo-systems-messaging-service and the Trade Remedies page at https://www.cbp.gov/trade/programs-administration/trade-remedies.The holding set forth above applies only to the specific factual situation and merchandise description asidentified in the ruling request. This position is clearly set forth in Title 19, Code of Federal Regulations(CFR), Section 177.9(b)(1). This section states that a ruling letter is issued on the assumption that all of theinformation furnished in the ruling letter, whether directly, by reference, or by implication, is accurate andcomplete in every material respect. In the event that the facts are modified in any way, or if the goods do notconform to these facts at time of importation, you should bring this to the attention of U.S. Customs andBorder Protection (CBP) and submit a request for a new ruling in accordance with 19 CFR 177.2. Additionally, we note that the material facts described in the foregoing ruling may be subject to periodicverification by CBP.This ruling is being issued under the provisions of Part 177 of the Customs and Border ProtectionRegulations (19 C.F.R. 177).
A copy of the ruling or the control number indicated above should be provided with the entry documentsfiled at the time this merchandise is imported. If you have any questions regarding the ruling, please contactNational Import Specialist Matthew Sullivan at [email protected].
Sincerely,
(for)James P. ForkanDirectorNational Commodity Specialist Division