SWorks Tarmac SL8 2x12 dura ace on 30mm PZero Race TLR’s
vs
Crux Pro 1x12 Force XPLR on 32mm Specialized Mondo endurance tires
Both set up tubeless, both running about 55psi.
I’ve had both bikes for 2 years, have thousands of miles on both, and typically ride solo on calm residential roads or multi-use paths that are majority fair-to-poor quality tarmac.
Looking at Strava, it is a toss-up which bike is quicker. Watts and HR are consistent. I’m COMPLETELY flummoxed as I would expect my Tarmac with the better aero and much faster/deeper wheels to be faster. If I go look at my segment history I have just as many PR’s on my Crux as I do my Tarmac.
One other thing worth mentioning is that perceived effort on my Tarmac is almost always higher, it’s like psychologically I want that bike to be faster so I push harder. Get back from my ride, look at Strava, and the average speed is basically the same as average speed on my Crux (when I’m not even pushing).
Only answers I can see are 1) my Tarmac bike fit is trash or 2) wider tires on Crux simply roll faster on the surfaces on which I’m riding.
Your position on the bike will make more difference aero wise than anything else.
Unless conditions are the same (wind and air density) you can’t really compare.
What you could do is to ensure identical fit between the two and then compare across a few segments ensuring identical power and environmental conditions.
Also like you said the slightly wider tires could just be quicker if the conditions are right and the road is sufficiently shit.
That does sound very strange. Why don’t you do a quick test with a loop close to you and test both bikes out one after the other? I have an arrow bike which is a polygon, and that is not a high-end bike by any means, and I am way faster on that than on my one year-old crux every single day of the week when I’m riding on the road.
I think you ought to do some benchmark testing to be sure and then start looking at your bike fit, and position on each. Because that does not make any sense at all.
Aero optimisations on tarmac likely only make a difference above 18-20 mph
Crux may be more comfortable, and comfort = power. Comfort also can be more aero, Crux has a higher stack vs Tarmac and this may influence how aero the body position is (as in less aero on tarmac if it’s uncomfortable low and you sit more up)
You could put 32 GP5000 on Tarmac and see if that makes a difference
I also have both and agree that tarmac feels like you’re working more - it’s stiff it’s low.
Lastly your freshness can differ, I have a PR on a road cat 4 climb on a Stigmata with a sus fork, just because it was on a good day in a very short ride.
Having said that it you do the same segment a few times and with same power and one bike is always faster - it’s either body position/aero and/or rolling resistance. (Assuming drivetrain works fine on both)
< / sarcasm >