Im 5'9" What frame size for mountain and road?

You really have to try each bike on for size to get a good fit as bikes and the riders are all a little different. A ballpark size for you would be 17" MTB or a 54cm road frame. I'm 5-8 and ride a 16.5 MTB and 52cm road bike.

Sizes are not measured in any standard way. A 56 cm road bike might fit you from one brand but not fit from another, just like shoes. There is more to proper bike fit than just your height. You should go to a bike shop where properly qualified people can help you select the size that is right for you. That, and the ongoing service and support, is what makes buying from your local shop worth the few extra dollars compared to other sources. If the bike needs adjusting, will an online vendor help you? Probably not.

HTH

Go to your local bike shop and get fit. Frame size does not depend on your height but your arm and leg length. You may be 5'9" but what is your leg lenght (inseam on your pants) that is more important. That is where the measurment for you frame is taken. Im 5'11" and ride a 55cm (got long middle and 33" inseam) so your best bet to get a bike that fits is to go get measured at a shop.

I'm 5'9, with a 54cm tri-bike and 17" MTB. There is some variation among manufacturers in tube ratios and how they measure size.

Its always best to give it a test ride.

I'm the same height and I'm around a 56cm road frame size.

I suggest you try and see for yourself, though. Go to a bike shop and try out some bikes to see what size you like. It'll be worth it.

I am 5'9" and i have a 19 inch which is a little to big. Get and 18" and you will still have a little room to grow.