General Cycling Discussion - Make a cruiser bike?

I want to make a lazy bike for my girl.
I was wondering 2 things.
Would i want to use a single speed/fixie on the bike? The idea is that it is lazy to ride would you still want single speed? I always find my single speed to be more tiring than my multi speed

How do you size a cruiser frame? Like that frames with big handlebars.
Shes 5'10" what should i look for to make this the right size? I imagine having the wrong size makes hurting knees.

3-speed gear box gets my vote. You might even find one in the trash. She would probably want a female frame. Try craigslist.

Good luck! It sounds like you should get a tandem and she can be lazy and you can ride her around!

a lot of cheap cruisers are single speed with a coaster brake.

i would either go for a 3 speed hub or try and find a nicer cruiser with 5-7 speeds.

If it's pretty flat, a single speed will work fine. If you have some serious hills, you either need big muscles or gears.

Most older department-store-type cruiser frames are a 1-size-fits-all frame. Women's frames are usually a little smaller than men's. You adjust seat height and fiddle with handlebars and deal with whatever you get. At 5'-10", she might be better off on a men's cruiser just because they're a little bigger frame. (Women's frames were intended to let a woman ride in a skirt, which not too many women do, anyway.) If you're buying a new higher-end cruiser, I think they do come in different sizes.

For whatever reason, women's cruisers are more abundant and go for less money than men's, so it should be easier to find a used one than with men.

Single speed but not fixed, and just gear it low; she's not looking to go fast, and people who don't like riding really don't like shifting.

Single speed but not fixed, and just gear it low; she's not looking to go fast, and people who don't like riding really don't like shifting.

disagree. when I have my singlespeed around non-cyclists they're like "wait...you have no gears?!?, i wouldn't ever ride that."

I would go with a 3-speed myself.

I've had a couple of days to think about your question and I think I'm going to discourage you. The whole key to a cruiser bike is the "look".

Everything on a bike works together. When you change one part it affects other things. If you were to install a cruiser handlebar on a mountain bike frame, for example, it would probably change the riding position. Then you're going to have to make some other changes in the seatpost and stem to adjust for that. Even aside from all of the single speed, IGH, derailleur discussions, it's going to be hard to put together a bike that has the right "look" on the first try.

Bottom line, it's the kind of project that I might attempt for myself, but I wouldn't try to assemble such a bike for somebody else.