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

    <schemaVersion>X0305</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-05-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001287151</issuerCik>
        <issuerName>XERIUM TECHNOLOGIES INC</issuerName>
        <issuerTradingSymbol>XRM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000942826</rptOwnerCik>
            <rptOwnerName>CARL MARKS MANAGEMENT COMPANY, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>900 THIRD AVENUE, 33RD FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2012-05-16</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>97000</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.9120</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1914482</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock, par value $0.001 per share</value>
            </securityTitle>
            <transactionDate>
                <value>2012-05-17</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>32500</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.9583</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1946982</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnotes</value>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The purchase price of the shares of common stock, par value $0.001 per share (&quot;Common Stock&quot;), of Xerium Technologies, Inc. (the &quot;Company&quot;), reported in Column 4 of this report is a weighted-average price. The shares of Common Stock purchased on May 16, 2012, were purchased in multiple transactions at prices ranging from $3.81 to $4.02, inclusive. Carl Marks Management Company, LLC (the &quot;Reporting Person&quot;) undertakes to provide to the Company, any security holder of the Company, or the Staff of the Securities and Exchange Commission (&quot;SEC&quot;), upon request, full and complete information regarding the number of shares of Common Stock purchased at each separate price within the range set forth in this Footnote (1).</footnote>
        <footnote id="F2">The purchase price of the shares of Common Stock reported in Column 4 of this report is a weighted-average price. The shares of Common Stock purchased on May 17, 2012, were purchased in multiple transactions at prices ranging from $3.85 to $4.06, inclusive.  The Reporting Person undertakes to provide to the Company, any security holder of the Company, or the Staff of the SEC, upon request, full and complete information regarding the number of shares of Common Stock purchased at each separate price within the range set forth in this Footnote (2).</footnote>
        <footnote id="F3">The Reporting Person is a Delaware limited liability company and registered investment adviser and serves as the investment adviser to (i) Carl Marks Strategic Investments, L.P. (&quot;CMSI&quot;), a Delaware limited partnership and private investment partnership, and (ii) Carl Marks Strategic Opportunities Fund, L.P. (&quot;CMSO&quot;), a Delaware limited partnership and private investment partnership.  CMSI GP, LLC (&quot;CMSI GP&quot;), a Delaware limited liability company, is the general partner of CMSI, and Carl Marks GP, LLC (&quot;CMSO GP&quot;), a Delaware limited liability company, is the general partner of CMSO. Of the shares of Common Stock purchased on May 16, 2012, 26,316 shares were purchased by CMSI and 70,684 shares were purchased by CMSO. Of the shares of Common Stock purchased on May 17, 2012, 8,817 shares were purchased by CMSI and 23,683 shares were purchased by CMSO.  Following the transactions reported herein, CMSI holds 598,754 shares of Common Stock and CMSO holds 1,348,228 shares of Common Stock.</footnote>
        <footnote id="F4">Shares of the Company held by CMSI and CMSO may be deemed to be beneficially owned (i) indirectly by the Reporting Person, as the investment adviser to CMSI and CMSO; (ii) indirectly by CMSI GP, as the general partner of CMSI, and CMSO GP, as the general partner of CMSO, respectively; and (iii) indirectly, on a shared basis, by the three individual managing members of the Reporting Person, who share the power to direct the vote or disposition of such securities.  The Reporting Person and the three individual managing members of the Reporting Person have previously filed statements pursuant to Sections 13 and 16 of the Securities Exchange Act of 1934, as amended, with respect to the securities of the Company which they may be deemed to beneficially own. The Reporting Person's beneficial ownership of the Company's securities is limited to its indirect interest (if any) in the shares of Common Stock held by CMSI and CMSO, limited to its pecuniary interest in CMSI and CMSO (if any).</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ James Forbes Wilson, Managing Member</signatureName>
        <signatureDate>2012-05-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
