garagedog

I'm 5'10 and I can usually ride a 54 or 56. I'm looking at buying a 2020+ Roubaix. I prefer a quicker handling frame but not too twitchy. My current bike is a 2011 54cm Scott CR1 (73° head angle). I'm 53 now so I'm looking for more comfortable ride. I realize I'll probably have to sacrifice some nimbleness to get a smoother ride... thus the search for a Roubaix. Looking at geometrygeek.bike website, the 54 vs 56 numbers are a little puzzling to me (head angle, trail). What are your thoughts on how the handling compares between these two? -Appreciate it
-Bob

surak

Depends on how low you want to go. I'm 5'9" and chose the 2019 54cm Roubaix over the 56cm after testing riding both because I wanted a more aggressive fit and it definitely felt nimbler. I don't regret it, but taking the smaller size does have some compromises, like needing a longer stem, more weight distributed over the front, and more toe overlap. The 2019 geo is only slightly different from the 2020+ generation's.

Iride01 

Handling and anything most people call "twitchy" are usually something you can easily get use to and it'll no longer seem twitchy. Between a 54 and a 56 probably not much difference at all for handling. Between a 54 and a 60cm, then probably noticeable. The 60cm being the ride of a luxury sedan vs the ride of a sports car for the 54. Whether you can fit on a 60 is a different matter altogether. However I'm only 5' 11" and I use to ride a 64 cm (25") bike comfortably for many years.

Your 54 cm Roubaix will have a lower stack, but still not as low as my 56 cm Tarmac. Whether that will directly translate into a more aggressive position might depend on how you hold your arms, very bent elbows or almost straight.

Instead of wondering, you really ought to just try them out. Even if they don't have the exact bike you want to ride, a 54 cm Roubaix and 56cm Roubaix in any tier level available will be pretty much the same fit. Though maybe the S-Works version might be newer frame design, but I haven't seen if they've changed that on the Roubaix if they even make an S-works model anymore.

Bacciagalupe

Bike Insights makes it a lot easier to visualize the difference.
https://bikeinsights.com/compare?geo...b60200252de3eb,

Basically, the Roubaix 54 and 56 have the same wheelbase and BB height. 56 puts the saddle a little bit further back, and the head tube a little bit further forward. I.e. it puts the rider up slightly higher. The head tube angle is a little different to keep the wheelbase and, I assume, keep the handling consistent between sizes. Differences in trail are probably neutered by the required changes in stem size, etc. In other words: Since the bikes share the same design goals, I doubt you'd notice a huge difference in handling between sizes. If you do, that's probably much more your mind than anything about bike geometry.

I.e. you should focus on what fits you better, rather than how it handles.

I'd add that you don't really need a huge sacrifice in responsiveness in order to increase comfort. While endurance bike geometry is a bit more slack, it's not like you're switching to a touring bike; they're still racing bikes. The relevant buzzwords for most endurance bike designs are "laterally stiff and vertically compliant." Much of the comfort difference will be in tube construction, the amount of exposed seat post, and wider tire clearance. The Roubaix also adds its suspension stem ("Future Shock"), which doesn't change the handling.

scottfsmith

There is a Roubaix Facebook group and people posted their height and what frame they have. It is all over the map, I was surprised the degree of difference. I am 5'11" and am on a 58 myself, probably a bit larger than the average there. 5'10"-ers are almost evenly split between 54 and 56, with a couple bigger or smaller than that. If you join and search for frame size you will find hundreds of comments.

If you can't get a fit I would take the 54, for most people a bit small is better. I probably would have been better off on a 56, my previous bike was a 54 but in the shop they thought 58 looked best on the Roubaix (2020). My bike fitter thought either 56 or 58 would work for me; with a shorter stem the 58 is doing great now.

cyclezen

agree with @Bacciagalupe, position setup is gonna make the key difference.
maybe compare to what you currently are riding, the Scott Cr1 and the ROubaix in same sizing, using Bike Insights and/or Geometry geeks. And then compare to the 56 Roubaix.
If you compare on Bike Insights, you'll get a visual comparo - which can point out similarities and diff. in geometry.
The 2 big diffs which stand out are Stack and BB height. BB Height of the CR1 is on the high end, typical for real race bikes which might be used for circuits with lots of turns/corners - Crits. The High BB allows a bit more lean angle clearance before possible pedal strikes (if one needs to pedal through corners...) But Higher BB also moves the CoG/CoM higher, which feels a little less stable at speed.
Maybe consider how you're currently positioned on your CR1, and what you want to change and what to keep. Once you get your saddle positioned, then its Stack and Reach. Ultimately the Roubaix in 54 starts out at 20mm higher stack than the CR1, How much further you got then depends on the stem angle and length (and spacers...)
The ROubaix will 'feel' different on the road, compared to the Scott, but that will shake out after a ride or 2. Or maybe not... You'll only be able to know, once you get some time on whatever you choose.
If you are in analysis and decision paralysis, and 'stack seems to loom large on the decision - you could buy an adjustable stem (at least 1, maybe 2 cm longer than current stem) and just try different angles which will give an effective 'stack' to compare to your current setup. - There are reasons why the adjustable stem should be longer,,, for testing...
I have Roubaixs and Tarmacs, but what and why I have, size-wise shouldn't be a consideration for anyone else. Most everyone considerations might be quite different.
Ultimately, getting on a bike, even for a short ride around a block, helps... If you do get to ride a Roubaix, bring your Scott along and ride it on the same section - compare...
And if you're buying a complete bike, as opposed to frame and parts, then what is hung onto the bike may have as large an impact.

garagedog

Great input all! I appreciate it. I've been shopping and reading reviews for months. I am looking for a 54 for sure. In fact I will be checking out one this Saturday. I'm pumped!

I was curious as to why the head angles were different between the 54 and 56 but I just watched a video that stated Specialized massaged the frames on every size to give them a similar ride.

bikeinsights.com and geometrygeek.bike are great sites!

oldbobcat

If you were comfortable on the 54 Scott, stick with 54 on the Roubaix. They both run larger than, say, a Trek. And the 56 comes with longer cranks.

Personally, I'd never trade a CR1 for a Roubaix. The CR1 hits the sweet spot for being comfortable, nimble, and stable all at the same time. It's the proverbial "bike that disappears under you."

garagedog

Well, I picked up a very nice 2020 54cm Roubaix (Ultegra Di2 with Roval 38c rims). It has 32mm Pirelli tires and 172.5 cranks like the 56+. Wow, this thing rides very nice and smooth.
It not quite as light as my CR1 though. The handling is obviously slower. How much of that is contributed to the 32mm tires? I'll probably put on a set of 28 once these wear out.
The di2 shifting is pretty cool. I wish I had a little more "stack". My flexibility isn't what it use to be. I probably should have looked harder at the 56 size. I'll be taking it on a pretty good ride this weekend and will probably find some more advantages and disadvantages.

I probably will not sell my CR1. That bike is sweet but the max tire width is 26. I looked at many road bikes including the Emonda and newer Scotts. No regular road bikes have enough "stack" for me.

rm -rf

I looked at Stack and Reach when shopping for my new bike 8 years ago. Sizes vary a lot!
I still have the bike, 8 years and more than 30,000 miles later. It's a really great fit.

It's easier than "effective top tube" and all the other lengths and degrees details.

Stack and Reach compares the distances from the drivetrain axle to the top of the frame at the head tube. Then there's a stem calculator to include differences in stem angle, spacer stacks, and stem distance.

Some bikes that would fit me were 54, some 56.
Most newer bikes have stack and reach in the dimensions.

To compare to an existing older bike: Measuring stack and reach with a tape measure, a floor and wall.

Stack and reach diagram and comments.

oldbobcat

Congrats on the Roubaix. Remember, you can always get a longer stem.

scottfsmith

Not a lot I don't think, unless your pressures are extra low. Note that things can "feel" slower with wider tires since it is a lot easier to handle, less jerky. I use 30s on my Roubaix myself, the Paris-Roubaix winner this year had 30s so they can't all that shabby. 80% of the race is pavement.

If you flip the stem you will get another 20mm or so. I have the stem flipped on my Roubaix and things feel a lot better for me that way.

garagedog

Here is a pic. Lovely bike!
I have the original stem and it came with a 90mm angled up already. I wish I had another 20mm to go higher. I'm ok right now (at the end of the riding season) but come spring, I'll want a little more height. Then over the summer I usually flip the stem over as I get more flexible throughout the season. I know, I know, I need to stretch more!
I rode a few days ago on a nasty road that use to chatter my teeth and jar my arms. On this new Roubaix, it was so much better. I had 38psi plus the future shock made this ride something to look forward to again.


2020 Roubaix, Ultegra di2, Roval 38c, 32mm Pirelli tires


I'm guessing that if I would have gone with a 56, I wouldn't have the lack of stack issue and I wouldn't have to slide my seat as far back. But I'd need a shorter stem for sure.

scottfsmith

Your bars are even with the seat so that is already pretty high by road bike standards. Maybe a 100 or 110mm flipped stem will feel better..

38 psi is super low for 32mm tires on road riding, 55psi is more a standard recommendation (e.g. with the SRAM or Silca calculators). I run 60-65psi on my 30mm tires.

Polaris OBark

You might want to get a proper bike fit.

If the saddle is so far back that it puts the center of the ball-and-socket joint of your hip further back than a line drawn through the seat post and bottom bracket center, you might actually benefit from centering/balancing the saddle and dropping (not raising) your bars.

I say this as someone who is as flexible as a 3 day old corpse.

Iride01 

Sliding the saddle all the way back is probably more about how you sit... likely very upright. And how your body wants to balance over the BB due to other aspects of how the bike fits you.

Though everyone likes the sexy aesthetics and racing looks of a road bike, you might actually like a proper cruiser style geometry bike with a slack seat tube angle. Though it's hard to find what I'd call a proper cruiser style bike any more. And they generally are less expensive builds on the heavy side compared to road bikes. But for 60 minutes of riding at a comfortable effort the weight really isn't an issue if they are appropriately geared.