So, my wife is threathening to buy a new bike
 

I'll believe it when I see it but, hey, I'm supporting her all the way.
She's maybe 5'1" and thinks she'd be more comfortable and secure on a MTB as opposed to a roadie.
She won't ride it all that much so I'd say whatever she feel better about is the way to go. I suppose a hybrid wouldn't really be out of the mix, either.

Is there any reason to just look at women's models or is the game pretty wide open?

My wife is 5'3 and 109 lbs , loves her Trek 7500 (hybrid).

Motobecane makes some very small road bikes for vertically challenged riders.

Now an MTB frame has to be smaller than a hybrid or Road frame on fit so choose carefully. If she decides it is not for her- then you can have that Mountain Bike I have always dreamed off. The Whyte 46

http://www.whytebikes.com/whyte-2007/index.html

Have her try a small Specialized Sequoia.

Get a tandem!!!!

What does woman want? You expect me to know? Even Freud was clueless.

I'd say help her shop, but dont' make assumptions for her.

But the question still being, is there any real reason for her not to consider a small -appropriately sized- men's bike? I'm not necessarily looking for recommendation (but they are gratefully accepted)

The smallest hybrids are pretty small. I think they are a little more comfortable and are an easier ride than a lot of lower-end mountain bikes.

An example would be something like this, which is available in frames as small as 13" and is a Women's Specific Design (WSD):
http://www2.trekbikes.com/bikes/bike...d=1323013&f=26

Of course a big factor is how she expects to use it.

I was riding up a decent sized hill one day when I came up on a woman struggling to get up the hill on a mountain bike with huge tires. Her husband was waiting at the top of the hill on his roadie, either encouraging her or making fun of her, depending on your perspective. I told her she should make him get her a bike like his and then she could smoke him on the hills. He said he tried but that is what she wanted. A lot of yelling back and forth was going on as I rode off LMAO.
On your other point, women's only bikes usually have longer seat tubes and shorter top tubes, because women usually have longer legs than men. The only other real differences are colors and the saddle, which most people change out anyway. Get her whatever fits best, whether it is a women's bike or not.

Look at it this way, they make bikes designed for a woman for a reason. Not only are they shorter(yes I know there are tall women too, I dated a girl that was three inches taller than me, but that's a whole 'nother story), but their bodies are proportioned differently than men. So she might find that mens bikes just don't fit 'right'. Which means she wont ride it.

I'm trying to get my wife interested in some casual biking. One bike I'm trying to get her interested in is the Giant Suede. These are comfortable, not too heavy or large-framed, are nice for neighborhoods ride & rail trails, and the crank-forward position enables the rider to put their feet on the ground from a sitting position. You can do a longer ride on them too, as long as speed isn't desired.

I'm looking at a 7-speed, to make shifting less complicated. She would likely never shift the front crank anyway.

So I think it would be nigh perfect for her.

http://www.giant-bicycles.com/en-US/...yle/729/28445/

There are Electra Townie models very similar to this, although they have more of a heavier, cruiser-like frame. Likewise for the Trek Pure.

If I bought her a road bike, it would guarantee that the bike would never be ridden.

Georgena Terry makes some fantastic road bikes that truly fit a woman in the 5'0 range. My ex is 5'2" and her Terry generated a lot of pure bike lust in me. The only downside we found to the Terry was it was a bit too much of a jump to go from the old Panasonic mixte frame 40 pounder to the Terry, and she had a few spectactular spills because the Terry was so light and lively in comparison.

I know 2 women with Trek Navigatiors, they are very happy.

How about a folding bicycle? The seat post and stem post are adjustable to the specific height of the rider. She can either fit on the 16" or 20" folder.

I'm 5'3" and find that most men's bikes have a reach too long for me to be comfortable on the bike. The one exception is my 1800C which is a man's model but we put a shorter stem on it. The other bikes are WSD and I love them. Many things on the WSD bikes make them more comfortable for smaller hands, shorter reach, etc.

Most of the major companies are putting out women's specific bikes. Mostly they are built for those under 5'6" & include smaller frames (not only accomodate height, but also shorter torsos and arms) and for the well thought ones, smaller levers for smaller hands.

I'd suggest:

http://i25.photobucket.com/albums/c6..._main_pink.jpg

She deserves the best, no?

No reason not to consider anything. She should try, with the help of a good salesperson, a variety of different bikes so she can figure out what works for her. Theory is fine, but she'll be riding the bike in the real world.

Its going to be her bike so see what the shop can suggest. The womens specific frames are sized for those of us that do not fit a conventional bike but she will know when she sits on the bike she wants. Just make certain it is not quite as good as yours. Does she want a Mountain bike or a Hybrid? Or does she solely want to ride on the road? That is the first thing to decide- or rather your wife to decide.

Thanks all. Lots of good stuff here, as always.
We've had some talks about this and she definitely is looking more to a MTB or Hybrid as stated OP
The roadie life is not for her. She is not -and never has been- very comfortable on a bike (growing up in Manhattan and all) and especially not since I splatted her ~30 years ago. She's like an elephant in that regard ;) In any event, she intends to be a very light, recreational rider, staying mainly on the flats and at low speed. She is looking to me for advice and guidance, hence this request. Next, I guess, is to to get her out to the shops and le tthe chips start falling.

As you know, hybrids can vary a lot, from very relaxed and heavy (like the Trek Navigator mentioned above) to being close to a road bike. Lots and lots of choices in between.

I think the most common "trap" for the novice rider to fall into is to buy too comfortable and then quickly outgrow it. Although even that "trap" may be a good path to follow, because all of that comfort got them onto a bike often enough to get into condition & want to move on.

So one decision you'll have to make is: A) Go for the most comfortable bike in hopes that it will be ridden more and then be willing to upgrade, or B) Push the comfort level a bit to buy a bike that one can grow/ride themselves into with some effort. The weakness of option B) is that they might not enjoy riding it enough to accomplish the goal.

Another one that I like is the Specialized Crossroads Elite. Not as heavy as their Expedition line. Semi-relaxed seat tube - kinda like a mild crank forward. Easy gearing, puncture-resistant medium-width tires, good Deore rd.
http://www.specialized.com/bc/SBCBkM...16&language=US

But if she's an aggressive person, who's going to try to keep up with you, then it might be a bit sedate.

Howse about a beautiful new Specialized Ruby in a nice blue to match your Reno?

That's an excellent question!

Bikes for short women are almost a specialty area. Simply downsizing a larger bike doesn't work. The issue is top tube length and toe clearance. As you progressively shorten the top tube, at some point your toe starts to contact the front wheel. Bicycle designers have a variety of ways of addressing this issue. Some change the bike's geometry by steepening the seat tube or slackening the head tube. Using smaller wheels is a possibility. Some retain the longer top tube from larger bikes or even ignore the issue.
When you're picking out a bike for a short woman it's kind of nice to figure out what the designer did and decide if that's a solution that you think you can live with long term.

One of the other posters mentioned Georgena Terry bikes. Terry has made a specialty of desiging bikes for small women.They are an unusual manufacturer in that, in the past at least, they would ship a test ride bike to virtually any LBS and, if the customer chose not to buy it, take it back and pay the return shipping cost. Try getting a deal like that from Trek or Specialized. I asked a Terry sales rep if that was an expensive program. He said, at that time at least, it was pretty much a non-issue because they got so few returns. I tend to believe him because I have never had a serious customer test ride a Terry bike and not buy it. The women who own Terry bikes seem to universally love them. I suspect it's because the people who try them have never before been on a bike that really fits.

Trek pilot 1.2 woman specific. My wife loves hers. Has the dual brake contraption so a person who is used to flat bars, need never go into the drops. But as the person gets more comfortable riding the road bike, they naturally begin gravitating to the drops. Its an evolutionary thing.

I bought this for Mrs G for her last birthday.

http://trekwsd.co.uk/home.php?sec=ov...angeID=&ID=340

Light, comfortable (she tells me) and she's noticably faster than on her last (fairly comparable) Specialized Crossroads. She likes the more upright riding position, which doesn't slow her down at all , and the light weight- she's pretty nippy on it.
(We're boxing it up in a couple of weeks time, to fly to the start of our London to Copenhagen trip. Can't wait!)