Originally Posted by
bobbyl1966
My height is 5` 7". My trek 830 is 18" the GT i be looking to buy and no have deside yet is 20" wich size is good for me. i look online different mountain bikes size chart and comfuse me
18" Trek will fit you well.
I'd be looking at 15-18" bikes. 16.5" Trek 830 would be too small for you, though, since they have pretty short top tubes, but some brands have longer top tubes.