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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-08-14</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0000737210</issuerCik>
        <issuerName>LNB BANCORP INC</issuerName>
        <issuerTradingSymbol>LNBB</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001228812</rptOwnerCik>
            <rptOwnerName>CAMPANA ROBERT M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>LORAIN NATIONAL BANK</rptOwnerStreet1>
            <rptOwnerStreet2>457 BROADWAY</rptOwnerStreet2>
            <rptOwnerCity>LORAIN</rptOwnerCity>
            <rptOwnerState>OH</rptOwnerState>
            <rptOwnerZipCode>44052</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>LNB Bancorp, Inc. Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2015-08-14</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>28717</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Under the Agreement and Plan of Merger (&quot;Merger Agreement&quot;), dated December 15, 2014, between Northwest Bancshares, Inc. (&quot;Northwest&quot;) and LNB Bancorp, Inc. (&quot;LNB&quot;), the holder has the right to elect to receive consideration of either 1.461 shares of Northwest common stock or $18.70 in cash for each LNB common share, subject to proration to ensure that, in the aggregate, 50% of LNB's common shares will be converted into Northwest stock. No fractional shares of Northwest common stock will be issued, and the cash in lieu amount will be determined by multiplying such fractional share amount by $12.66. As of the date of this Form 4, the calculations related to the election and proration procedures set forth in the Merger Agreement have not been completed. Accordingly, it is not possible at this time to determine the form of merger consideration to be received by the Reporting Person.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/Robert M. Campana, by James Nicholson as attorney-in-fact, pursuant to Power of Attorney</signatureName>
        <signatureDate>2015-08-19</signatureDate>
    </ownerSignature>
</ownershipDocument>
