Step One: Frequently Asked Questions
1 - Is the 177 lighter than the 168? YES.
2 - Is the 168 more aero than the 177? YES.
3 - Does the 177 have more flex than the 168? Probably, since it’s lighter…
4 - Is the 168 more stiff than the 177? Probably, since it’s heavier…
5 - Does this mean the 177 is a “flexy” frame overall? NO.
6 - Is the 168 one the stiffest frames you’ve tested? NO.
7 - Are both frames stable at high speeds? Road stability is not exclusive to the frame.
Bottom Line: The differences between the two frame are marginal at best. Especially for a $500 frame. There are more important aspects to your overall bike build to consider. 168 does in fact support 32c tires. The 177 (at least mine) does not. Maybe 30c max. This alone might be a deal breaker for the 177. The 177 uses is a standard seatpost which will be wildly easier to find on the open market for replacements.
Step Two: Geometry
VB 177 Geometry (Size 56/L)
Stack: 556
Reach: 395
VB 168 Geometry (Size 56/L)
Stack: 556
Reach: 398
VB 177 Geometry (Size 54/M)
Stack: 536
Reach: 392
VB 168 Geometry (Size 54/M)
Stack: 535
Reach: 388
Bottom Line: You should probably seek a professional bike fit if you’re uncertain. Geometry is similar for both frames, plus/minus a couple of millimeters in reach. I personally am not a fan of zero-degree setback seatposts. Neither frames are intended to fit all body types. I’m also not a fan of integrated handlebars either, since they limit adjustability later.
Step Three: Aerodynamics
Your wheel choice is one of the most critical areas where aerodynamics can be either saved or loss. The 177 paired with deep sectioned aero wheels will be faster on the flats than the 168 with shallow wheels. And the aerodynamic design of the 168 will inherently trump the lightweight of the 177 on the flats when paired with identical wheels.
Bottom Line: DO NOT SKIMP on your wheelset.
Step Four: Total System Weight
There is not enough emphasis put on total system weight (bike + rider + gear). Nothing wrong with having weight weenie tendencies, but 50-200 gram weight savings isn’t going to make the difference for anything below a World Pro Tour Race. See example below:
Bike: 7900g
Rider: 74000g
2 Water Bottles: 1400g
Helmet/Gear/Ect: 1000g
Total System Weight: 84300 grams (84.3kg)
Bottom Line: Striving to save even 100-200 grams (regardless of cost) is literally only like 0.25 percent of the total weight. 0.25 PERCENT. One-fourth of one percent. Also when it comes to wheels and frames...you WILL eventually be penalized on stiffness once the weight dips to a certain threshold.
Step Five: Road Stability
Your stem length and wheel choice play a pivotal role in stability at higher speeds. These aspects should be considered before asking the question of stability in general. Yes both frames are stable...but I run a 130mm stem paired with aero wheels at a depth (60-65mm) that is suitable for my weight (74kg).
Final thoughts - For the pursuit of speed (and even climbing) your wheel choice, position on the bike, tire/innertube/tubeless choice, and drivetrain efficiency all matter significantly more than simply comparing weight. The 177 is probably the better choice if bike fit is a concern, you absolutely need a climbing bike, and you don’t need clearance for wider tires. Some people may also prefer the "look" of the 177 which is totally understandable. For everyone else…168 is mostly likely the more reasonable choice. And this actually makes sense, since the Tarmac SL7 is supposed to be the one bike to rule them all.
Okay this guide took way longer than I anticipated. Time to suit up my party clothes, get some drinks in me, and hit the clubs. Have a great weekend.
