Why is 56s best hand against pocket Aces?

Was wondering why 56s has higher probability to beat AA than slightly higher suited connectors (e.g., 67s. 78s, or 89s). There is obviously a reason but intuitively, I'm not getting it. The way I'm thinking about it, 56s and 67s have smaller chances to make a straight than 78s and 89s because there are already two dead aces pre-flop (so less chance the board will be A 2 3 4 5 or A 2 3 4 6). 78s and 89s have all of their straight cards available (though would still lose on a straight on the very rare occasion that AA hits higher straight or better). Is 56s the best hand simply because the 5 takes away some straight possiblities from AA?

If you have 65s as opposed to 76s (for instance) then yes, the difference is that 65s wins on a board of

6-6-4-3-2

whereas 76s doesn't.

ok thx, thats what I thought.

76 would still win there.....trips vs 2 pair.

And as for the first statement:

You don't need A2345 to get a straight with 56, you just need 2345.....or 234 for that matter. 56 still has all its straight cards too.

Serves me right for posting before breakfast.

You're right of course, and I don't really know what the difference is made up of. The only difference between the hands that I can think of are how many straights they can make, and I'd have thought 76 to be better at that.

The only difference is that by holding a 5 the Aces can't make as many straights.

Have a look at this. About half way through they mention the 'U shaped function of suited connecters'

A New Guide to the Starting Hands in Texas Hold'em Poker

They claim that Smaller suited connectors are more powerfull than the mediium ones.

I would hazard a guess that the reason is that if a small suited connecter develops into a hand then the board is far less likely to help other players at the table and so players with high pairs and high cards are more likely to believe they have the best hand and thus not fold

I have a concern since this is in the beginner thread. My humble opinion is that playing small suited or unsuited connectors is more for advanced/indetermediate players not beginners. My reason being is that to play these type of hands you must have dicipline and good reads. They can win monster pots but also can cripple or bust a stack. The ablity to play these hands according to stack size ,positon and table image is vital. This is great infomation for the beginners but we must add this warning to it. Not knocking the great info in thread but adding the pitfalls to the beginner in falling in love with these hands.

Hmm. Can that be it?

If the aces would make more straights when I have 76s than when I have 65s, then that means I make more straights, and mine are bigger, so I'd win those. But maybe I'm thinking about it the wrong way.

The AA can't make a low straight without you having the bigger straight with 56 or 67 so that's a wash, but the AA can't make as many straights because it NEEDS a 5 to make the low straight and you hold one.

But for the AA to make a low straight, and we are holding 67, it would have to catch 2345 meaning my 67 would still be better than the AA.

Ok, I've actually had to open PokerStove to look at this. The only difference between 56s and 67s vs AA is tie equity. Both hands beat AA 22.87% of the time but 56s ties AA .19% of the time while 67s ties AA .16% of the time. This accounts for the equity edge of .03 going to 56s.

So ignore my entire argument. It's just the 56 gets a few more ties, not a few more wins.

*Numbers given assume we do not share our suit with one of the Aces.

Thanks for all the great answers