Tall Cool One

If I swap out my 105 rear cogs with Dura Ace rear cogs will I have any compatibility issues with my other 105 components?

operator

With the limited information you gave us, no.

Tall Cool One

Sorry for the limited info...

I am getting ready to order a Cannondale CAAD9 5 with compact crank. I am a clyde (6'7" 240 lbs) and it was recommended by an ultra-experienced fellow clyde that I upgrade the rear cogs from 105 to Dura Ace to prevent tooth breakage.

Is there any other info that would be helpful in answering my question?

Thank you for your advice.

Jed19

Bulls**t! You don't need Dura Ace cogs to prevent tooth breakage, whatever that means. I am 215Ibs, and I have been riding Ultegra "for ever" and no breakage or let-down whatsoever.

In my view and experience, the value proposition in the Ultegra group is "the sweet spot" of the whole Shimano line!

kycycler

Clydesdale or not a Dura Ace or 105 cassette will not make any difference. DA cassettes are lighter than 105. In my experience Clydesdale need to worry more about braking spokes that teeth on cassettes. As mater of fact in over 40years of cycling I cannot remember 1 instance of teeth braking on either a cassette or freewheel.
If you want to spend the extra $$$ for DA go for it. IMHO not worth the cost unless you are a racer and the weight difference is important.

DMF 

Yeah, I'm heavier than you and I'd be perfectly comfortable on 105. DA, if anything, is more fragile.

Len66

I agree with the others, it is very unlikely you will break the teeth on you cogs because you weigh 240 lbs. The 105s should work just fine. The Dura-ace is lighter and therfore more expensive. On road bikes, the more you pay the less you get.

Al1943

You definitely do not need Dura-Ace, in fact it would be a waste of money. You should be more concerned about the number of teeth on the largest cassette cog on the 105.

Al