Is there a month when the new models start appearing?
I know that with cars September is typically when the new model years appear
so I'm wondering if bikes have a similar time frame.
Specifically I'm interested in trek and specialized.

Specialized already has them in their on line catalog. I'd say the 2016 models are either in shops now or soon to be there.

Back in the day.... decades and decades ago. The hot manufacturing plants would often shut down in the hottest part of summer for a mandated "vacation". This is also when the lines would be "re-tooled" with the new designs and modifications. So the returning workers would then make the "new" models.

I think bicycle models.... are more like clothing fashions... and less like large scale manufacturing logistics. Model changes can reflect technology advances... but are more orientated towards increased (prolonged) sales.

+1, Hey, they are now taking order$ for the 2016 Corvette. Ye$, there i$ another motive for introducing model$ well before the current model year i$ over. Maybe profit$ have $omething to do with it, ju$t a gue$$.

Yeah. Things have changed dramatically since the old "auto-industry days" I referred to.

Manufacturing used to be (even though automated) very labor intensive. Car plants would often have thousands of workers and a car might require more than a man-year (2080 work-hours) to make. Those same shut-down/re-toolings practices spanned many of the manufacturing industries... and spawned the (August) vacation industry.

Although... much of how things are... are because of how things once were. These forums are filled with old-paradigm ideals that haven't been relevant since the days of the safety bicycles introduction.

2016 Madones are on Trek's website. Ditto with Felt's Z's...

When I purchased my '15 Z85 a few weeks ago they had my size in the bike shop. Good thing -- otherwise, they were already sold out in my size.

Euro Bike trade shoe is in August , The US bike trade show in Vegas is soon after that , then is when dealers see the next years stuff.

Sometimes the Pre Season orders influence the size of the orders with their contract factories ..

Going to the trade shows is expensive , hotel rooms and air fare and all that,

so sometimes the quantities made run out early in the season, due to the preseason , in the Booth orders

not being indicating potential demand from all the shops that cannot afford to Go To Vegas .

When I owned my shop run-of-the-mill models came out whenever the factory could no longer ship a complete size run. Cutting edge models came out at the Vegas bike show.

Thanks, by checking the various manufacturer websites it occurred to me that the bikes I was interested in, i.e. hybrids, weren't designated by year. that told me that there was no particular "new model year" introduction month as with cars. To further cement this notion is the rather prominent disclaimer that "specs can change without notice" I have put the 'car v. bike' comparison completely out of the picuture.

Some of the Specialized bikes have started to leak out. See link below.

Early Release 2016 Bikes

Does it really make any difference? Some little frill or new decal isnt going to make that much difference. After 130 years there is little new with DF bikes. Plus remember most frames are generic frames built in Asia and then tricked out with paint and decals for the separate so call manufactures.

It makes a difference if you don't like the color of a particular bike, and it changes to something you do like for the next year. And it matter if you want to get a deal on the previous years bike and save yourself some cash. Marketeers are going to play their games, so take advantage of it. So damn right it matters.

It might seem like they're all the same but, before you even get to the myriad components, if you look at just endurance class road bikes, for example, while you'd be correct to expect taller headtubes compared to racier breeds you still find that fore and aft angles are different, wheelbase and chain stay lengths are different, effective top tube lengths differ, BB drops aren't all the same, there's every kind of tube shape from simply round to big, swooping, highly tapered oval-tangular tubes; and, unlike the slope of a top tube, all of these details have an effect on the fit and feel of the bike. I thought I was living through the renaissance of road biking during the 70s and 80s but I think there is more happening now than ever at prices that anyone can afford.

Exactly. Best time to buy, IMO. But then again, I wear out of date clothing from places like T.J. Max and Marshall's.

They are available now....at least my LBS can order them. We just bought a 2016 Synapse for my Husband and they told us it should be in by Friday....so excited we can hardly wait!