I was cleaning the bikes and I noticed cable rub on the seat tube of my road bike. It's the cable that goes to the rear brake. It doesn't move and is pretty tight to the tope tube and runs past the seat tube as it goes to the brake. I didn't think that cable rub occurred on static cables. Is this common?

Just got a new Mtn bike. There are several cables that run to the rear for the derailleur and the disc brake. they are really tight as it runs past the seat tube, but they don't move. just wondering if this will cause cable rub on the frame over time. My other bikes are polished silver color, so they aren't apparent. This is my first painted bike and I'd think it'd be pretty noticeable.

Anyway, once I start getting the bike dirty and well used, it probably won't make any difference to me, but right now it's still almost shiny showroom new.

THanks.

If you can't reroute, put a piece of clear shipping tape (like thick Scotch tape, cheap in the stationery department of any drug or grocery store) on the tube where it hits. It won't show from two feet away.
They also make bike-specific tape circles that do the same thing, but you pay bike prices. You can get eight miles of the tape for a few dollars.

That's what cable donuts are for. Harris cyclery will give you a few for free or sell you a bottle of 600 for $37.95 that I paid $3 for on eBay.

The donuts are for the top tube, not the seat tube as the OP has stated

LizardSkins makes clear patches for housing rub but as stated, thick packing tape will do the same

I've found these products that go by the name CLEAR BRA or INVISIBLE SHIELD. They go on car's front ends to prevent dings from road rubble when driving. Whatever name the retailers call them, they are all pretty much made by 3M as PAINT PROTECTION polyeurothane supplies. They are usually 8mil. Some are thicker and rated for outdoor use.

Thinking about creating some custom shapes using a CAD program and having them laser cut either from the retailer or from a laser cutter that we use for making architectural models.

8mil should be thick enough, I'd think. and if the cables rub thru, I can make loads of spares and can replace them easily enough.