There is no such thing as bike specific grease, it's all repackaged auto or machine grease. The advantages of synthetic is that it doesn't get way thick in really cold temps. I've been using Citgo Marine grease (the blue stuff) for years now. Get it at Autozone for about $3.50 per grease gun tube. Never had a problem with it, and I've never seen the oil separate out of it. If you've got money to burn, go ahead and buy the bike boutique grease -- while you're at it, buys some special boutique air for your tires as well.