Hey GT,
Welcome to the forum. I'm just a little north of you in the Downey area. I too ride the SG river bed but headed south. Another shop you may want to try is Downey Cyclery. I know what you're thinking (they're actually in Los Al) so they're pretty close to you. They recently moved from their old Downey location to Los Alamitos. When they were in Downey they didn't have a HUGH selection of parts but they could get it for you. The best thing about this shop was/is their mechanic. Top-notch and very reasonable. I sometimes wondered how they stayed in business. I was sad to see them move but at least they didn't fold up shop. Since my Litespeed is still like new condition I haven't been to the shop but once I need some mechanical work I'll be making the 15 mile drive. Tom's the owner and Paul was the grease monkey BTW.
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Litespeed, lasts a lifetime.
Specialized Tarmac, lasts a lifetime, or until it breaks.