Anything silicate-free and aluminum-safe is fine. You may want phosphate-free also. For the small amount of coolant used in a bike, I prefer pre-mixed coolant. It avoids needing to get distilled water and the hassle of mixing them. It works out to being a few bucks more over several years, but it's a lot simpler.
FYI, when I picked some up a couple months ago, neither the Prestone or Peak jugs mentioned being silicate/phosphate-free on them. I was expecting to be able to see it somewhere that was somewhat readily available, like the bottle or the product page on their website (checked from my phone while in the store).
Here's more info I copied from my post on the 500 board then...
Peak's Long Life (yellow) and Lifetime (amber) formulas are listed as being phosphate/silicate-free.
Long Life Pre-Mixed is a blue jug with a yellow cap.
Long Life Concentrated is a blue jug with a red cap.
Lifetime Pre-Mixed is a gold jug with a red cap.
Lifetime Concentrated is a gold jug with a blue cap.
Prestone's FAQ makes me wonder a bit...
That makes it sound like they don't feel being phosphate-free is a big deal, and leads me to believe their coolants aren't.
Their long-life coolants are labelled pretty plainly. Based on their product page, it looks like you have to go to their Prime line to get regular green coolant now.
Pre-Mixed is a yellow jug with a blue cap.
Concentrated is a yellow jug with a black cap.
