icyclist 

"I'm a novice and I'm trying to understand something that puzzles me."

OP, I don't you you ever got around to telling us what puzzles you.

"What are the visceral or technological or emotional reasons that someone would upgrade to a Tarmac"

Have you not answered your own question with this:

"I am very impressed with the "plush" Specialized Roubaix."

A Roubaix can be set up to ride more comfortably than a Tarmac, and has mini-shock absorbers. A Tarmac can be set up to be more aero than a Roubaix and lacks the shock absorbers. In shape riders of all ages would enjoy having either. There is nothing more to know.

NomadVW 

My 2005 Roubaix: Lincoln Town Car. Plush, smooth, but a boat. Frame hanging in my bike stable on a hook, hoping to be rebuilt one day.
My 2007 Felt F55 (RIP) (carbon stays/forks, alu frame): Dodge Daytona
My 2010 Blue RC8 (all carbon): Right in between - stiffer than the Roubaix, but softer than the Felt. Agile, and even a bit twitchy.

umd

Except, as some have said, how the differences in geometry contribute to the handling...

icyclist 

Picky, picky, picky!

OK, of course you're right. However, I still think the main difference is that, as the OP said, the Roubaix is considered to be more "plush" than the Tarmac, and that is a far greater difference than how the two bikes handle, especially since the OP was asking about differences as they apply to non-racers.

On both bikes, stems can be flipped, and spacers rearranged, which offer a greater difference in feel on the same bike than will differences in geometries between the two that effect (minor) differences in handling.

umd

Everything that PaulRivers was saying about how it felt descending is because of the geometry differences. I'm not talking about how high the bars can go, but the chainstay/wheelbase length and the steering trail, mostly. The stability vs. twichiness difference is not a minor difference in handling; the Tarmac may be too twitchy for some when they are tired at the end of a long ride.

icyclist 

"I'm not talking about how high the bars can go, but the chainstay/wheelbase length and the steering trail, mostly."

I know you are.

"The stability vs. twichiness difference is not a minor difference in handling; the Tarmac may be too twitchy for some when they are tired at the end of a long ride."

I think we're discussing the same thing, in different words. After all, someone on a bike that's too twitchy for them will be more comfortable on a bike that isn't too twitchy, so I think we're in perfect agreement.

NomadVW 

The fork rake on my roubaix was 49mm.... crazy big rake (also next to impossible to replace) . I have two forks in boxes at 43mm rake that I am going to play with when I get a chance.

(edited - was, cause the original forks developed cracks along the top)

hobkirk

OP here

icyclist - No I didn't answer my own question. The essence was why someone would ditch a Roubaix for a Tarmac unless they raced? It seems to me that all the logic pointed to the Roubaix being a better choice for virtually all riding except racing, but I know people do switch so I was curious. I also like ultra-high technology - F1 racing cars, competition skis, and (yes), racing bikes. If I could see my way to afford a Roubaix, would I regret it? I'm retired - I don't spend much money.

The link from Pacific Slim was to a comparison reviewer who concluded the Tarmac was unquestionably faster down steep descents.

"...a really great comparison between the Tarmac and Roubaix. The conclusion: https://redkiteprayer.com/?p=1408"

FWIW, as a novice I have found three downhill situations scary. I like speed! But...

1. I found it thoroughly frightening when I hit some really bad pavement on a 40+ downhill. [I think the Roubaix might work well in this situation.]
2. My old bike went into a very bad wobble at around 35 on a group ride where there were other riders around me [I now know to shift to rear of seat, grip top tube with knees, loosen grip on bars[.
3. And I have found several situations on group rides where I don't trust the other riders enough to pass them. I'm a Clyde - my weight really helps on descents! It seems that a lot of riders just don't expect to be passed when they're going so fast, or maybe it reflects a general lack of consideration. When I do pass I will accelerate (50/11 gears) if appropriate to decrease the length of the passing zone. [And some of this is just my inexperience.]

umd

Think of it this way... why would someone want a fast-handling sports car unless they took it to a track?

WHOOOSSHHH...

A Tarmac is not an UPGRADE. Just the opposite, IMHO...

umd

wut

Matt2.8NJ

I have a 105 equipped Roubaix, bought it long before I got into racing based on the bike shop recommendation. It's ~20lbs in race trim with my Powertap.

I also have a 14.9 lb super-stiff race bike.

I race both extensively, and I'm damn sure that it doesn't make a difference in my racing.

I end up doing thousands of training miles on the Roubaix because it's so damn comfortable.

My thought is that the Roubaix-style bike is more than enough for 95%+ of riders out there, simply because putting in huge mileage is really pleasant.

Ride both for a while and see if you agree.

WHOOOSSHHH...

Tarmac is an UPGRADE ??? Not to me, and I imagine a lot of other people...That's W U T...

umd

I can understand that some people may not prefer it. It is neither an upgrade nor a downgrade, it's just different.

Allegheny Jet

I have both a 07 Roubaix Expert and a Tarmac Pro. I began racing three years ago using the Roubaix which worked fine. Last fall I got the Tarmac and instantly discovered the big difference betwen the two bikes. As mentioned, it is only important if you are racing. In crits I always struggled with turning and thought everyone's bike turned like mine. The first race on the Tarmac was a "WTF moment". The Tarmac turns to where you are thinking the bike should be and the Roubaix fights you all the way. I have used the same wheelsets, Williams 50cm CF tubulars and Mavic Krisium Elete's on both bikes. I don't notice any difference on longer rides as for comfort or road buzz. I recently rode a 102 mile charity ride with over 5,000' of climbing and took the Tarmac.

umd

qft

BarracksSi

Posing.

umd

You can post in a Rolls just as much as in a Ferrari.

BarracksSi

Just depends on what kind of tail you want to attract.

umd

mtalinm

priceless

Jesse143

Question to go with this thread... I have a 2009 Allez. I am looking to step to the Carbon world and have been looking at either the 2011 Tarmac or Roubaix. I don't race although I might do one only to check it out. I am more into group rides and long solo and charity rides. When I am solo though I seek out every hill in my way. I love climbing 100x more than descending. I love feeling the burn and getting a good workout.

Is the Roubaix as good to climb on as the Tarmac? I stand about 40 - 50% of the climbs. Climbing is what I like to do and I would like the best bike for that purpose. Does anyone have any comments to the similarities or differences when climbing?

purdyd

I guess I will wade in here ....

I had a chance to ride a roubaix and tarmac today, not top of the line frames. It only took me a block to notice the roubaix really likes to go straight and the tarmac likes to turn. And while I didn't get a chance to go down some steep windy roads at speed, I know I would prefer the tarmac in descending technical roads.

Climbing wasn't quite as straight forward as while the tarmac might be a better climber, since the roubaix is so steady, it can require less attention, particularly when going slow.

I don't know if the difference in head tube height makes that much difference at least to me

The roubaix had a plush ride but the tarmac was not harsh.

So I suppose if I were looking to ride farther, like double centuries, I would go for the roubaix but if I wanted to ride faster centuries, I would get the tarmac. Funny that is how Specialized markets them?

Not sure if you would go wrong buying either bike.

BarracksSi

How about this --

Think of the other bike(s) you already have. Would you want this one to be similar or different?

I'm looking at my bikes now and I'm thinking that since I already have a more upright "comfort" bike (which I still want to convert to drop bars), my poseur... I mean, "fast road bike" can be more aggressive, contrasting with the other street bike and making itself more worthwhile.

I'd rather have drastically different bikes than some that overlap too much. However.... if I've got a bike and just want something else that does some things just a bit better, I'd sell the first one as soon as I picked the new one. If I had an entry-level road bike and were now choosing between the Roubaix and Tarmac, I'd think about what I don't like about the cheap bike, then think about where I like riding the most.

To use the car analogy, instead of Rolls & Ferrari, I'd say that the Roubaix is to the Tarmac as the Nissan Z is to the GT-R.

umd

Yeah I didn't mean to imply that they were analagous to the bikes, just trying to think of very contrasting high end cars for poseuring