Bicycle Mechanics - 105 to DA upg. Same cables?

I'm upgrading my 105 Shifters, FD, and RD to DA 9spd. The 105 stuff has very little time on it. Will I need to replace the std Shimano cables that are on the bike and already fitted or will I be able to use the ones that are already there?

You can use the old ones but if it was me, I'd replace them with new ones.

Why replace them? In most cases, the cable housings are Dura Ace anyway (at least they are on my Specialized Allez with 105). If they are in good shape and only have a few miles on them, why bother? Technically, they will work just fine- 105 or DA.

It's the perfect opportunity to look at them and see if they are OK or if they are kinked or frayed near the head (where they bend).

Also, sometimes, if you change shifters, some housing, a derailleur, etc. the place where the cable was attached to the derailleur has flattened the cable and it may get kinked in the housing if the positioning is different.

Anyway, when I do changes like that, I often re-use the cables. Sometimes I also cut the frayed end of the rear shifter cable and install it to the front (lesser used) and install a new cable to the rear derailleur.

Anyway, when I do changes like that, I often re-use the cables. Sometimes I also cut the frayed end of the rear shifter cable and install it to the front (lesser used) and install a new cable to the rear derailleur.

I often do that myself, whether they be brake or derailleur cables...

I typically replace. If they aren't that old, I use the back for the front. I don't like the "freying" I get when I clip the old cables. I also think it is easier to set them with the 3rd hand tool when they are long and un-cut.

Cables are $1.99... why not replace them while you have the derailleurs off and are going to need to readjust the derailleurs anyways?

If you use a good quality bicycle cable cutter (ie Park or Pedros) you shouldn't get any fraying at the cut either. Oh and a third hand is a tool used to adjust brakes on old roadbikes. The cable tensioner is good but its very easy to set the tension TOO high with it. To prevent fraying if you grip the cable with a needlenose pliers about 2" below the cut end and pull it taught you should be good to go.

If you do replace the cables its a good idea to spray some teflon based lubricant into the housing (aerosols are good for this because the pressure blows the crap out of the housing), before you put the new cables in.

Why would you want to spend big dollars on all of that DA stuff and then degrade the performance with a tired set of cables? Don't skimp on the housings either - replace them too. Get all of the shifting crispness that you paid for.

Notice he says the 105 has very little time on them. This being the case, I highly doubt the cables are "tired". Actually they probably are not far past the "stretch" stage. This would actually be a plus, not a minus. Shifting should be crisp and stay crisp. However, if the cables are damaged or are truly mucked up, then yes, replace them.

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If you use a good quality bicycle cable cutter (ie Park or Pedros) you shouldn't get any fraying at the cut either. Oh and a third hand is a tool used to adjust brakes on old roadbikes. The cable tensioner is good but its very easy to set the tension TOO high with it. To prevent fraying if you grip the cable with a needlenose pliers about 2" below the cut end and pull it taught you should be good to go.

If you do replace the cables its a good idea to spray some teflon based lubricant into the housing (aerosols are good for this because the pressure blows the crap out of the housing), before you put the new cables in.

Seely, thanks for clarifying what I meant.
I didn't mean "3rd hand tool", I meant cable tensioner. I like to pre-set my barrel adjusters a bit, use the tensioner, then back the adjusters off so they the cable isn't too tight. I wrongly think of any hand saving tool as a third hand tool. Glad I don't have to use my real third hand tool anymore.

He is also right that investing in a good cable cutter is very worth it (I need to).