<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2020-11-30</periodOfReport>

    <dateOfOriginalSubmission>2020-12-02</dateOfOriginalSubmission>

    <issuer>
        <issuerCik>0001324948</issuerCik>
        <issuerName>RBC Bearings INC</issuerName>
        <issuerTradingSymbol>ROLL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001256535</rptOwnerCik>
            <rptOwnerName>HARTNETT MICHAEL J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>102 WILLENBROCK ROAD</rptOwnerStreet1>
            <rptOwnerStreet2>ONE TRIBOLOGY CENTER</rptOwnerStreet2>
            <rptOwnerCity>OXFORD</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06478</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>true</isDirector>
            <isOfficer>true</isOfficer>
            <isTenPercentOwner>false</isTenPercentOwner>
            <isOther>false</isOther>
            <officerTitle>President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-11-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>38744</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>168.8299</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>348859</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2020-12-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>false</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>21337</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>168.2411</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>327522</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Sold pursuant to a 10b5-1 plan.</footnote>
        <footnote id="F2">Includes 79,143 shares of restricted stock, which vest according to the following schedule; 17,347 shares vest on 6/7/2021; 34,693 shares 1/2 of which vest on 6/3/2021 and 1/2 vest on 6/3/2022; and 27,103 shares 1/3 of which vest on 6/2/2021, 1/3 vest on 6/2/2022 and 1/3 vest on 6/2/2023.</footnote>
    </footnotes>

    <remarks>Column 5 of Table I is amended to reflect the sale of 9,882 shares on November 27, 2020 and reported on December 3, 2020 following the filing of this amendment.</remarks>

    <ownerSignature>
        <signatureName>/s/John J. Feeney/attorney in fact</signatureName>
        <signatureDate>2020-12-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
